U.S. patent application number 13/379599 was filed with the patent office on 2012-07-05 for polymerizable ambipolar hosts for phosphorescent guest emitters.
This patent application is currently assigned to Georgia Tech Research Corporation. Invention is credited to Stephen Barlow, Gaelle Deshayes, Sung-Jin Kim, Bernard Kippelen, Julie Leroy, Seth R. Marder, Yadong Zhang, Carlos Zuniga.
Application Number | 20120172556 13/379599 |
Document ID | / |
Family ID | 42470758 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120172556 |
Kind Code |
A1 |
Zhang; Yadong ; et
al. |
July 5, 2012 |
POLYMERIZABLE AMBIPOLAR HOSTS FOR PHOSPHORESCENT GUEST EMITTERS
Abstract
The inventions describe disclosed and described herein relate to
polymerizable ambipolar monomers, useful for making polymer or
copolymer host materials for guest phosphorescent metal complexes,
which together can form emission layers of organic light emitting
diodes (OLEDs). Methods of making the ambipolar monomers are also
described. Formula (I) wherein at least one of the R.sup.1, R.sup.2
and R.sup.3 groups is an optionally substituted carbazole group.
##STR00001##
Inventors: |
Zhang; Yadong; (Alpharetta,
GA) ; Zuniga; Carlos; (Atlanta, GA) ;
Deshayes; Gaelle; (Atlanta, GA) ; Leroy; Julie;
(Atlanta, GA) ; Barlow; Stephen; (Atlanta, GA)
; Marder; Seth R.; (Atlanta, GA) ; Kim;
Sung-Jin; (Atlanta, GA) ; Kippelen; Bernard;
(Decatur, GA) |
Assignee: |
Georgia Tech Research
Corporation
|
Family ID: |
42470758 |
Appl. No.: |
13/379599 |
Filed: |
June 21, 2010 |
PCT Filed: |
June 21, 2010 |
PCT NO: |
PCT/EP10/58730 |
371 Date: |
March 19, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61220116 |
Jun 24, 2009 |
|
|
|
Current U.S.
Class: |
526/259 ;
548/145 |
Current CPC
Class: |
C08F 12/22 20130101;
C08F 12/32 20130101; C08F 12/26 20130101; C08F 12/14 20130101; H01L
51/0072 20130101; C08G 2261/149 20130101; C08G 61/08 20130101; C08G
2261/418 20130101; C09D 125/18 20130101; H01L 51/0043 20130101;
H05B 33/20 20130101; H01L 51/007 20130101; H01L 51/004 20130101;
C08F 232/08 20130101; H01L 51/5016 20130101; C08F 120/36 20130101;
C07D 413/10 20130101; C08F 220/36 20130101; C07D 413/14 20130101;
C08F 212/14 20130101; C08F 220/36 20130101; C08F 212/32 20130101;
C08F 220/36 20130101; C08F 212/26 20200201; C08F 220/36
20130101 |
Class at
Publication: |
526/259 ;
548/145 |
International
Class: |
C08F 226/12 20060101
C08F226/12; C07D 271/10 20060101 C07D271/10 |
Goverment Interests
STATEMENT OF GOVERNMENT LICENSE RIGHTS
[0002] The inventors received partial funding support through the
STC Program of the National Science Foundation under Agreement
Number DMR-020967 and the Office of Naval Research through a MURI
program, Contract Award Number 68A-1060806. The Federal Government
may retain certain license rights in this invention.
Claims
1. A monomer comprising a polymerizable group linked to a
2-phenyl-5-phenyl-1,3,4-oxadiazole group having one or more
carbazole groups bound thereto, the monomer having the formula:
##STR00096## wherein a) L is a C.sub.1-C.sub.20 organic group
linking the polymerizable group to the 2-phenyl ring of the
oxadiazole group; b) at least one of the R.sup.1, R.sup.2 and
R.sup.3 groups is an optionally substituted carbazole group, and
the remaining R.sup.1, R.sup.2 or R.sup.3 groups are independently
selected from hydrogen, fluoride, a C.sub.1-C.sub.6 alkyl, cyano,
perfluoroalkyl, alkoxide, or perfluoroalkoxide groups, and a second
optionally substituted carbazole group; wherein the optionally
substituted carbazole groups have the structure ##STR00097##
wherein R.sup.5 and R.sup.6 are independently selected from
hydrogen, fluoride, and a C.sub.1-C.sub.6 organic group selected
from alkyls, cyano, perfluoroalkyls, alkoxides, and
perfluoroalkoxides; c) R.sup.4 is selected from hydrogen, fluoride,
and a C.sub.1-C.sub.6 alkyl, perfluoroalkyl, alkoxide, or
perfluoroalkoxide group.
2. The monomer of claim 1 wherein the polymerizable group comprises
a styrene, acrylate, methacylate, or norbornyl group.
3. The monomer of claim 1 having the structure ##STR00098##
4. The monomer of claim 1 wherein R.sup.4 is hydrogen.
5. The monomer of claim 1 having the structure ##STR00099##
6. The monomer of claim 1 having the structure ##STR00100##
7. The monomer of claim 1 having the structure ##STR00101##
8. The monomer of claim 1 wherein one of the R.sup.1, R.sup.2 and
R.sup.3 groups comprises an optionally substituted carbazole group,
and the remaining R.sup.1, R.sup.2 or R.sup.3 groups are
hydrogen.
9. The monomer of claim 1 wherein one of the R.sup.1 and R.sup.2
groups has the structure ##STR00102## and the remaining R.sup.1,
R.sup.2 or R.sup.3 groups are hydrogen.
10. The monomer of claim 1 wherein both the R.sup.1 and R.sup.3
groups have the structure ##STR00103## and R.sup.2 is hydrogen.
11. The monomer of claim 1 wherein one of the R.sup.1, R.sup.2 and
R.sup.3 groups is an optionally substituted carbazole group having
the structure ##STR00104## and the remaining R.sup.1, R.sup.2 or
R.sup.3 groups are hydrogen.
12. The monomer of claim 1 wherein L is an alkylene or alkyleneoxy
group.
13. The monomer of claim 1 wherein L has ##STR00105## wherein n is
an integer from 1 to 20.
14. The monomer of claim 1 wherein L has the structure
##STR00106##
15. The monomer of claim 1 having the structure ##STR00107##
##STR00108## ##STR00109##
16. The monomers of claim 1 having the structure ##STR00110##
wherein one of the R.sup.1, R.sup.2 and R.sup.3 groups is an
optionally substituted carbazole group having the structure
##STR00111## and the remaining R.sup.1, R.sup.2 or R.sup.3 groups
are hydrogen.
17. A copolymer prepared by mixing at least one monomer of claim 1,
with one or more additional olefinic monomers, and polymerizing the
mixed monomers.
18. The copolymer of claim 17 wherein the one or more additional
olefinic monomers are optionally substituted styrene, acrylate,
methacrylate, or norbornene monomers.
19. The copolymer of claim 17 wherein the one or more additional
olefinic monomers comprise one or more styrene, acrylate,
methacrylate, or norbornene monomers linked to a phosphorescent
metal complex.
20. The copolymer of claim 17 that comprises at least one
polymerized subunit having the structure ##STR00112##
Description
RELATED APPLICATIONS
[0001] This application claims the priority of U.S. Provisional
Application No. 61,220,116 filed 24 Jun. 2009. The entire
disclosure of the predecessor application is hereby incorporated
herein by reference in its entirety.
TECHNICAL FIELD OF THE INVENTION
[0003] The inventions disclosed and described herein relate to
polymeric ambipolar host materials that can transport all of
electrons, holes, and/or excitons to guest phosphorescent materials
so as to form the emission layers of organic light emitting diodes
(OLEDs). Methods of making the ambipolar polymers or copolymers
from novel monomeric ambipolar materials, and ambipolar small
molecules are also described, as are unexpectedly efficient OLED
devices containing the ambipolar host materials.
BACKGROUND OF THE INVENTION
[0004] Considerable research has been directed toward the synthesis
of organic light-emitting diodes (OLEDs), in view their potential
applications in full-color flat panel displays and solid state
lighting. Such OLEDs often contain a light emissive layer
comprising a luminescent material as a guest, dispersed and/or
dissolved in a mixture of host/carrier materials capable of
transporting holes, electrons, and/or excitons into contact with
the luminescent guest. The luminescent guest is excited by the
electrons, holes, and/or excitons, and then emits light. The light
emissive layer is typically disposed between an anode and cathode.
Single layer OLED devices are known, but typically exhibit very low
quantum efficiencies, for a variety of reasons. Efficiency has been
dramatically improved in some cases by employing additional layers
of materials in the OLED devices, such as an additional layer
comprising a material whose properties are optimized for
transporting holes into contact with the emission layer, and/or an
additional electron transport layer comprising a material whose
properties are optimized for carrying electrons into contact with
the emission layer. Upon application of voltage/current across the
OLED devices, holes and electrons are transported through the
intermediate layers and into the emissive layer, where they combine
to form excitons and/or stimulate the formation of excited states
of the luminescent guest material.
[0005] The luminescent guest materials can either be fluorescent
materials that emit from a singlet excited state, or phosphorescent
materials that emit light from a triplet excited state. While
phosphorescent triplet emitters can potentially produce
significantly enhanced quantum efficiencies as compared with
singlet fluorescent emitters, the use of materials that emit from
triplet states imposes additional requirements on the other
materials of the OLED devices. In phosphorescent OLEDs, in order to
reduce the excited state quenching often associated with relatively
long exciton lifetimes and triplet-triplet annihilations, etc., the
triplet guest emitters of the emission layers are typically
inserted as guests into host materials. All the materials should be
selected to optimize efficient injection of charges from the
electrodes, in the form of holes, electrons, and the formation of
singlet and triplet excitons, that are transferred as efficiently
as possible by the host materials to the luminescent guest
material.
[0006] In order to maximize energy transfer from the host materials
to the guest phosphors, the energies of both the singlet and
triplet states of the hole and/or electron carrying materials in
the host should be higher than the energies of the corresponding
singlet and triplet states of the guest phosphors. See FIG. 1.
Furthermore, the conjugation length of the host materials should be
limited, in order to provide a triplet energy level higher than
that of the guest phosphors. Such triplet energy requirements
become particularly challenging when designing host molecules that
also provide the large charge (hole and/or electron) transport
mobilities that are desired.
[0007] Thus, development of effective host materials for
transporting holes, electrons, and excitons is as important as
developing guest phosphors for the production of efficient
OLEDs.
[0008] High-performance phosphorescent OLEDs with good short term
luminescence and efficiency have been reported, but most such prior
art devices have been fabricated by expensive multilayer vacuum
thermal evaporation of small molecule electron or hole transport
materials, to provide multi-layer OLED devices, as shown in FIG. 2.
For example, host materials comprising carbazoles have been
utilized as hole transporter and/or electron blocking materials in
OLED applications. Examples of known small molecule carbazole-based
hole-carrying materials are shown below. Polymeric carbazoles such
as PVK are also known for use in the hole carrying layers of OLED
devices.
##STR00002##
[0009] Similarly, small-molecule 2,5-diaryl oxadiazoles such as
those shown below (PBD and OXD-7) are known as suitable electron
carrying materials for use in making electron carrying layers for
OLED devices. Polymeric oxadiazole based electron transporting
polymers have also been reported, such as for example PCT
Application Serial No. PCT/EP/2008 068119 filed 19 Dec. 2008,
claiming the priority of U.S. Provisional Application 61/015,777
filed 21 Dec. 2007, both of which are hereby incorporated herein by
reference for their disclosures relating to monomeric oxadiazoles
useful for preparing the disclosed polymers.
##STR00003##
[0010] Furthermore, the use of "ambipolar" mixtures of hole
carrying and electron carrying materials to form a mixed host
material for phosphorescent guests in the emissions layers of
multi-layer OLEDs are known. Nevertheless, devices based on
mixtures of hole carrying and electron carrying materials in their
emission layers, whether based on mixtures of small molecules
and/or polymers tend to undergo phase separations, undesirable
partial crystallizations, and/or otherwise degrade upon extended
OLED device heating, decreasing OLED device efficiency and/or
lifetimes over time.
[0011] Accordingly, there remains a need in the art for improved
"ambipolar" host materials that can efficiently transport holes,
electrons, and/or excitons into contact with phosphorescent guests
in emission layers, without undergoing phase separations,
crystallization, or thermal or chemical degradation. Furthermore,
if a single "ambipolar" amorphous and polymeric host material could
be used to transport holes, electrons, and/or excitons into contact
with phosphorescent guests, it is possible that one or more of the
electron carrying or hole carrying layers of the multi-layer OLED
devices could be omitted, simplifying device design and
manufacture, and lowering fabrication costs, especially if high
cost vacuum deposition techniques could be replaced with lower cost
solution processing techniques.
[0012] It is to that end that the various embodiments of the
ambipolar polymers, copolymers, and materials and methods for their
preparation described below are directed.
SUMMARY OF THE INVENTION
[0013] The various inventions and/or their embodiments disclosed
herein relate to and include "ambipolar" polymers, "ambipolar"
copolymers, and ambipolar small molecules having both hole carrying
and electron carrying groups bound thereto, and the use of such
ambipolar polymers, copolymers, and/or small molecules as host
materials for carrying holes, electrons, and/or excitons into
contact with guest light emitters, for use in the emissive layers
of electronic devices such as organic light emitting diodes.
[0014] Some embodiments of the inventions described and/or claimed
herein relate to "ambipolar" homopolymers or copolymers that have
at least one hole carrying group and at least one electron carrying
group bound to the same subunit of the homopolymer or copolymer
backbone. A related but different class of ambipolar copolymers
have the hole carrying groups and the electron carrying groups
bound to different subunits of the polymer or copolymer backbone.
Many of these classes of ambipolar homopolymers and copolymers are
readily soluble in common organic solvents, and therefore can be
readily processed in solution (via processes like spin coating or
printing) to make layers in organic electronic devices, such as,
when co-deposited with phosphorescent metal complexes, emissive
layers of OLED devices.
[0015] Many different types of polymer and/or copolymer backbones
derived from polymerizable monomers can be employed to make the
homopolymers and copolymers described herein, including for example
polymerized styrenes, acrylates, methacylates, and the like,
epoxides, hydroxyacids for forming polyesters, aminoacids for
forming polyamides, isocyanides for forming polyisocyanates, and
the like, as well as ring opening metathesis polymerization, ROMP,
polymerized cyclic olefins such as polynorbornenyl polymer
backbones.
[0016] Furthermore, some embodiments of the inventions described
and/or claimed herein relate to "ambipolar" "small molecules" that
have at least one hole carrying group and at least one electron
carrying group, which can either be solution processed or vacuum
sublimed to form organic electronic devices.
[0017] Examples of suitable hole carrying groups bound and/or
linked to the ambipolar monomers, polymers, copolymers, and/or
small molecules include but are not limited to variously
substituted carbazole groups having the basic carbazole ring
structure shown below:
##STR00004##
[0018] Examples of suitable electron carrying groups bound and/or
linked to the ambipolar small molecules, monomers, polymers and/or
copolymer include but are not limited to variously substituted
2,5-diaryl-1,3,4-oxadizole groups (often referred to below as
"oxadiazole" groups). Further details regarding suitable carbazole
and oxadiazole groups are provided below.
##STR00005##
[0019] In many embodiments, the inventions relates to monomers,
polymers or copolymers wherein at least one of the polymer or
copolymer subunits is linked to at least one carbazole group and
also at least one oxadiazole group. See the drawing below.
##STR00006##
[0020] To provide non-limiting examples, some embodiments of the
inventions relate to ambipolar polymers or copolymers having at
least one, or more, polymerized styrene (i.e. class (I)), acrylate
or methacrylate (class (II)), or norbornene (class (III)) subunits
in their polymer backbones, wherein at least some of the polymer or
copolymer subunits is linked to at least one carbazole group and
also at least one oxadiazole group.
[0021] In additional embodiments, ambipolar norbornenyl copolymers
of a different class (IV) contain hole carrying groups such as
carbazoles and electron carrying groups such as for example
oxadiazole groups linked to different norbornenyl subunits within
the polymer or copolymer backbone. Ambipolar norbornenyl copolymers
of class (IV) can also comprise optional additional subunits
derived from a wide variety of additional polymerizable monomers.
In such embodiments, the ambipolar copolymers described herein can
comprise [0022] a. at least one first norbornenyl subunit linked to
at least one optionally substituted carbazole group; and [0023] b.
at least one second norbornenyl subunit linked to an optionally
substituted 2-phenyl-5-phenyl-1,3,4-oxadiazole group; and [0024] c.
optionally one or more additional polymer subunits.
[0025] For example, in some embodiments, ambipolar copolymers of
class (IVa) shown immediately below are norbornenyl copolymers that
have at least some subunits having each of the structures shown
below:
##STR00007##
wherein [0026] a. L.sup.1 and L.sup.2 are independently selected
C.sub.1-C.sub.20 organic linking groups, [0027] b. R.sup.c
comprises at least one carbazole group, and [0028] c. R.sup.ox
comprises at least one 2-phenyl-5-phenyl-1,3,4-oxadiazole
group.
[0029] As disclosed above, the copolymers of inventions, including
copolymers of classes (I), (II), (III), and (IV), can also comprise
one or more additional copolymer subunits as desired. In some such
embodiments, the additional copolymer subunits can comprise
linkages to crosslinkable groups, or luminescent groups, such as
suitable organic phosphors or phosphorescent metal complexes.
[0030] The ambipolar polymers and copolymers of the inventions can
be prepared by any of a variety of polymerization methods as would
be obvious to one of ordinary skill in the art in view of the
disclosures herein. For example, norbornenyl copolymers wherein
some subunits are linked to carbazole groups and other subunits are
linked to oxadiazole subunits can be prepared by a process
comprising the steps of [0031] a. mixing [0032] i. at least one
first norbornene monomer comprising a norbornene group linked to a
carbazole group; and [0033] ii. at least one second norbornene
monomer comprising a norbornene group linked to an optionally
substituted 2-phenyl-5-phenyl-1,3,4-oxadiazole group; and [0034]
iii. optionally one or more additional optionally substituted
norbornene monomers; and [0035] b. polymerizing the mixture of
norbornene monomers in the presence of a ROMP catalyst, to produce
the copolymer.
[0036] In other embodiments, ambipolar copolymers comprising
subunits that each are linked to both a carbazole subunit and an
oxadiazole subunit can be prepared by polymerization (in some case
radical in others living) or copolymerization of suitable monomer
compounds, such as substituted styrene monomers (Ia), substituted
acrylate or methacrylate monomers (IIa) or substituted norbornene
monomers (IIIa)
[0037] Other embodiments of the inventions disclosed herein relate
to methods for preparing compounds (Ia), (IIa), or (IIIa), as well
as certain novel intermediates used for their synthesis.
[0038] Further detailed description of preferred embodiments of the
various ambipolar polymers and copolymers and methods and materials
for their preparation broadly outlined above will be provided in
the Detailed Description section below.
BRIEF DESCRIPTION OF THE FIGURES
[0039] FIG. 1 shows a schematic diagram of the energetics of the
HOMOs and LUMOs and their corresponding singlet and triplet excited
states for both host and guest materials used the emission layers
of OLED devices, and how they can be matched to produce good energy
transfer to the phosphorescent guests, or mismatched so as to
provide pathways for energy dissipation.
[0040] FIG. 2 shows a common physical configuration of multi-layer
OLED devices.
[0041] FIG. 3 discloses a generic scheme for the synthesis of
certain "linear" isomers of ambipolar compounds comprising both one
carbazole and one oxadiazole group, which can serve as synthetic
precursors of ambipolar monomers, as further described elsewhere
herein and specifically exemplified in Example 1.
[0042] FIG. 4 discloses a generic scheme for the synthesis of
certain "non-linear" isomers of ambipolar compounds comprising both
one carbazole and one oxadiazole group, which can serve as
synthetic precursors of ambipolar monomers, as further described
elsewhere herein and specifically exemplified in Example 1.
[0043] FIG. 5 discloses a generic scheme for the synthesis of
ambipolar compounds comprising both two carbazole and one
oxadiazole groups, which can serve as synthetic precursors of
ambipolar monomers, as further described elsewhere herein and
specifically exemplified in Example 1.
[0044] FIG. 6 schematically discloses a synthetic scheme for
linking polymerizable norbornenyl, styrenyl, or methacrylyl groups
to the ambipolar precursor compound from FIG. 3, to form compounds
within generic formulas (Ia), (IIa), and (IIIa).
[0045] FIG. 7 schematically discloses a synthetic scheme for
linking polymerizable norbornenyl, styrenyl, or methacrylyl groups
to the ambipolar precursor compound from FIG. 4, to form compounds
within generic formulas (Ia), (IIa), and (IIIa).
[0046] FIG. 8 schematically discloses a synthetic scheme for
linking polymerizable norbornenyl, styrenyl, or methacrylyl groups
to the ambipolar precursor compound from FIG. 5, to form compounds
within generic formulas (Ia), (IIa), and (IIIa).
[0047] FIG. 9a schematically illustrates the preparation of three
ambipolar homopolymers of class (I) by free radical polymerizations
of styrene linked ambipolar monomers of classes (Ia). FIG. 9b
schematically illustrates the preparation of three ambipolar
homopolymers of class (II) by free radical polymerizations of three
different methacrylate linked monomers of classes (IIa).
[0048] FIG. 10 schematically illustrates the preparation of three
ambipolar homopolymers of class (III) as carried out by ROMP
initiated polymerizations of norbornenyl based monomers of classes
(IIIa). See Example 3.
[0049] FIG. 11a illustrates a ROMP copolymerization reaction
described in Example 4 that produced a copolymer of class (IV).
FIG. 11b shows the .sup.1H NMR spectrum of the ambipolar copolymer
of class (IV) prepared by the copolymerization reaction of FIG.
11a. See Example 4.
[0050] FIG. 12 shows the luminescence and external quantum
efficiency versus voltage performance of OLED devices having
emissive layers comprising three ambipolar polymers of class (II)
as a host material and a phosphorescent Iridium complex as a guest.
See Example 5.
[0051] FIG. 13 compares the luminescence and external quantum
efficiency versus voltage performance of OLED devices having
emissive layers comprising an ambipolar polymer of class (II) as a
host material with OLED devices with two alternative host materials
comprising mixtures of hole and electron carrying materials. See
Example 5.
[0052] FIG. 14 shows compares the luminescence and external quantum
efficiency versus voltage performance of OLED devices having
emissive layers comprising one of the ambipolar polymers of class
(II) described herein as a host material with OLED devices
employing two alternative host materials that also comprise added
hole or electron carrying materials. See Example 5.
[0053] FIG. 15a shows the electroluminescence spectrum of an OLED
device comprising an ambipolar copolymer of class (IV) as described
in Example 4. FIG. 15b shows a CIE diagram of the emission from the
OLED device of FIG. 15a that shows that the light emitted from the
OLED is almost white. See Example 6.
[0054] FIG. 16a shows the luminescence and external quantum
efficiency versus voltage performance of OLED devices having
emissive layers comprising an ambipolar copolymer of class (IV) as
a host material and a phosphorescent platinum complex as a guest.
See Example 6.
[0055] FIG. 17a shows the current density versus voltage
characteristics of an OLED device comprising an emissive layer
comprising
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
as a hole and electron carrying host and Ir(ppy)3 as an emissive
guest, as described in Example 7. FIG. 17b shows the luminescence
and external quantum efficiency versus voltage performance of the
OLED device
[0056] FIG. 18a shows the current density versus voltage
characteristics of an OLED device comprising an emissive layer
comprising
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
as a hole and electron carrying host and FIrpic as an emissive
guest, and PVK as a hole-transmission layer, as described in
Example 7a. FIG. 18b shows the luminescence and external quantum
efficiency versus voltage performance of the OLED device.
[0057] FIG. 19a shows the current density versus voltage
characteristics of an OLED device comprising an emissive layer
comprising
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
and 6% FIrpic as an emissive guest, and TCZ as a hole-transmission
layer, as described in Example 7a. FIG. 19b shows the luminescence
and external quantum efficiency versus voltage performance of the
OLED device.
[0058] FIG. 20 shows a generic synthetic scheme for making a series
of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(substituted-phenyl)-1,3,4-oxadiazoles
as reported in Example 7a.
[0059] FIG. 21a shows the current density versus voltage
characteristics of an OLED device comprising an emissive layer
comprising
24346-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)phenyl)-5-(3-methoxyphen-
yl)-1,3,4-oxadiazole, and 6% FIrpic as an emissive guest, and PVK
as a hole-transmission layer, as described in Example 8. FIG. 21b
shows the luminescence and external quantum efficiency versus
voltage performance of the OLED device.
DETAILED DESCRIPTION OF THE INVENTION
[0060] The various inventions and/or their embodiments disclosed
herein relate to and include "ambipolar" polymers and copolymers
that are bound and/or linked to both hole carrying and electron
carrying groups. Those ambipolar polymers and/or copolymers are
useful as host materials for luminescent guests, and are capable of
carrying holes, electrons, and excitons into contact with the
guests. The combined host/guest combinations comprising the
polymers and/or copolymers described herein are useful as materials
for making the emissive layers of electronic devices such as
organic light emitting diodes (OLEDs).
Ambipolar Small Molecules, Polymerizable Monomers, and/or Polymers
or Copolymers
[0061] Some embodiments of the inventions described and/or claimed
herein relate to "ambipolar" small molecules, polymerizable
monomers, and polymers and/or copolymers that have polymer
subunits, each of which have at least one hole carrying group and
at least one electron transporting group bound and/or bonded into
or linked thereto.
[0062] At least one and sometimes more hole carrying groups are
chemically and/or covalently bound into the ambipolar small
molecules, polymerizable monomers, and/or linked to the subunits of
the polymer and copolymer chains. Examples of suitable
hole-carrying groups bound and/or linked to the polymer subunits
include but are not limited to variously substituted carbazole
groups having the basic ring structure shown below:
##STR00008##
[0063] Examples of suitable electron transporting groups also bound
into the ambipolar small molecules and polymerizable monomers,
and/or linked to the polymer and/or copolymer backgrounds include
but are not limited to variously substituted
2,5-diaryl-1,3,4-oxadizole groups (shown below and typically
referred to herein as "oxadiazole" groups).
##STR00009##
[0064] In many embodiments, the ambipolar small molecules,
polymerizable monomers, and/or polymers and/or copolymers of the
invention comprise at least one optionally substituted carbazole
group and at least one optionally substituted
2,5-diaryl-1,3,4-oxadizole group.
[0065] Accordingly, in many embodiments, the inventions described
and/or claimed herein relate to ambipolar small molecules,
polymerizable monomers, and the polymers and copolymers derived
therefrom, that comprise an electron transporting 1,5-diaryl
1,3,4-oxadizole group that is bonded to a carbazole group and also
linked to an aryl or heteroaryl "Ar" group, a polymerizable group,
or a polymer or copolymer derived therefrom, as shown below:
##STR00010##
wherein Ar is an optionally substituted aryl or heteroaryl group, n
is an integer representing the number of polymer subunits, L is a
linking group connecting the monomeric polymerizable group or
polymer subunit(s) to the 2-phenyl ring of the oxadiazole group,
and at least one of the R.sup.1, R.sup.2 and R.sup.3 groups is an
optionally substituted carbazole group having the structure
##STR00011##
wherein the various embodiments of the remaining R.sup.1, R.sup.2,
R.sup.3, and optional R.sup.4, R.sup.5, and R.sup.6 groups are
described below.
[0066] Such ambipolar small molecules, monomers and the polymers or
copolymers derived therefrom can be unexpectedly effective as hole
and/or electron transport compounds and/or exciton forming and
transporting compounds and can be used to make highly efficient and
stable OLED devices. Moreover, the ambipolar small molecules,
monomers and/or polymers or copolymers derived therefrom can have
unexpectedly superior physical properties, such as high solubility
and processability, and/or high resistance to crystallization
and/or thermal degradation during OLED operation.
Ambipolar Small Molecules
[0067] In some embodiments, the inventions described and/or claimed
herein include certain ambipolar "small molecules", for example a
compound comprising an optionally substituted aryl or hetereoaryl
group bonded to a 1,3,4-oxadiazole group having one or more
carbazole groups bound thereto, the compound having the
formula:
##STR00012##
[0068] wherein [0069] a. Ar is a C.sub.1-C.sub.30 aryl or
heteroaryl group optionally comprising one to five substitutent
groups; [0070] b. at least one of the R.sup.1, R.sup.2 and R.sup.3
groups is an optionally substituted carbazole group, and the
remaining R.sup.1, R.sup.2 or R.sup.3 groups are independently
selected from hydrogen, fluoride, cyano, or an alkyl,
perfluoroalkyl, alkoxide, and perfluoroalkoxide groups, and
optionally one or more additional optionally substituted carbazole
groups; [0071] wherein the optionally substituted carbazole groups
can have the
[0071] ##STR00013## [0072] wherein R.sup.5 and R.sup.6 can be
independently selected from hydrogen, fluoride, cyano, and an
organic group selected from alkyls, perfluoroalkyls, alkoxides, and
perfluoroalkoxides.
[0073] The ambipolar small molecules shown above comprise an Ar
group that can be an aryl or heteroaryl group optionally
substituted with one to five substitutent groups. Any suitable
optionally aryl or heteroaryl group can be employed, such as for
example optionally substituted phenyl, biphenyl, napthyl,
fluorenyl, anthracenyl, pyridyl, bipyridyl, thiophenyl, furanyl, or
pyrollyl groups In many embodiments, the optionally substituted
aryl or heteroaryl group can be a C.sub.1-C.sub.30,
C.sub.2-C.sub.20, or C.sub.5-C.sub.20 group, including the optional
substitutents. The optional substituents can be independently
selected from non-polymerizable groups such as hydrogen, hydroxyl,
fluoride, cyano, or C.sub.1-C.sub.20 alkyl, perfluoroalkyl,
alkoxide, or perfluoroalkoxide groups.
[0074] Some embodiments of the inventions relate to ambipolar small
molecules having the structure
##STR00014##
wherein R.sup.7-R.sup.11 are independently selected from hydrogen,
fluoride cyano, and a C.sub.1-C.sub.20 alkyl, perfluoroalkyl,
alkoxide, or perfluoroalkoxide group.
[0075] In many embodiments of the ambipolar small molecules
described above (as well as polymerizable monomers, polymers, and
copolymers), at least one of the R.sup.1, R.sup.2 and R.sup.3
groups is an optionally substituted carbazole group, and the
remaining R.sup.1, R.sup.2 or R.sup.3 groups are independently
selected from hydrogen, fluoride, cyano, or a C.sub.1-C.sub.20
alkyl, perfluoroalkyl, alkoxide, or perfluoroalkoxide groups, and
optionally one or more additional optionally substituted carbazole
groups.
[0076] Both the first optionally substituted carbazole group, as
well as any additional optionally substituted carbazole groups
bound to the first carbazole group, can have the structure
##STR00015##
wherein R.sup.5 and R.sup.6 are independently selected from
hydrogen, fluoride, cyano, and a C.sub.1-C.sub.6 organic group
selected from alkyls, perfluoroalkyls, alkoxides, and
perfluoroalkoxides. In some embodiments, one of the R.sup.1,
R.sup.2 and R.sup.3 groups comprises an optionally substituted
carbazole group, and the remaining R.sup.1, R.sup.2 or R.sup.3
groups are hydrogen. In other related embodiments, one of the
R.sup.1 and R.sup.2 groups
##STR00016##
and the remaining R.sup.1, R.sup.2 or R.sup.3 groups are
hydrogen.
[0077] Examples of such "monocarbazole" compounds include compounds
having the structure
##STR00017##
wherein R.sup.5, R.sup.6, and R.sup.12 are independently selected
from hydrogen, fluoride, hydroxide, cyano, and a C.sub.1-C.sub.6
organic group selected from alkyls, perfluoroalkyls, alkoxides, and
perfluoroalkoxides. Examples of species compounds having these
structures whose synthesis is described in the examples include
##STR00018##
[0078] In other embodiments, both the R.sup.1 and R.sup.3 groups
have the structure
##STR00019##
and R.sup.2 is hydrogen. Examples of such compounds include
compounds having the structure
##STR00020##
wherein R.sup.5, R.sup.5', R.sup.5, R.sup.6', and R.sup.12 are
independently selected from hydrogen, fluoride, cyano, and a
C.sub.1-C.sub.6 organic group selected from alkyls,
perfluoroalkyls, alkoxides, and perfluoroalkoxides. An example of a
species compound whose synthesis is described in the examples
include
##STR00021##
[0079] This small molecule compound has been used to form very high
efficiency emissive layers in several OLEDs, see Example 7 and
FIGS. 17-19.
[0080] In yet additional related embodiments, one of the R.sup.1,
R.sup.2 and R.sup.3 groups is first optionally substituted
carbazole group having "additional" optionally substituted
carbazole group bound thereto, such as for example the
"tricarbazole groups having the structure
##STR00022##
and the remaining R.sup.1, R.sup.2 or R.sup.3 groups are hydrogen.
Examples of such compounds include compounds having the
structures
##STR00023##
wherein R.sup.5, R.sup.5', R.sup.5, R.sup.6', and R.sup.12 are
independently selected from hydrogen, fluoride, cyano, and a
C.sub.1-C.sub.6 organic group selected from alkyls,
perfluoroalkyls, alkoxides, and perfluoroalkoxides.
[0081] In many embodiments of the optionally substituted carbazole
groups, R.sup.5, R.sup.5', R.sup.6, and R.sup.6' are hydrogen or
t-butyl.
[0082] Many of the ambipolar small molecules described above are
either sublimable under high vacuum or readily soluble in common
organic solvents, and therefore can be readily processed to form
compositions useful in organic electronic devices, especially when
mixed and/or co-deposited with phosphors, to form the emission
layers of organic light emitting diodes.
[0083] Furthermore, many of the ambipolar small molecules described
above, especially those with hydroxyl or methoxy substituent groups
on their Ar rings, can be used as synthetic precursors of ambipolar
monomers, polymers, or copolymers described below. It should be
understood that any of the disclosures above with respect to the
oxadiazole groups, carbazole groups, or their R.sup.1-R.sup.11
substituents are intended to also apply with respect to the
teachings below regarding ambipolar monomers, polymers, or
copolymers.
Ambipolar Polymers of Classes (I), (II), and (III)
[0084] Many embodiments of the inventions described and/or claimed
herein relate to "ambipolar" polymerizable monomers, and polymers
and/or copolymers linked to ambipolar groups comprising both
oxadiazole and carbazole groups.
[0085] Many types of polymer and/or copolymer subunits can be bound
to ambipolar groups having structures equivalent to those of the
ambipolar small molecules described above. For example, polymer
backbones comprising subunits derived from styrenes, acrylate
esters, methacrylate esters, norbornenes, and the like can be
employed, so long as the polymerized chains are resistant to both
oxidation by holes, and reduction by electrons present during the
operation of electronic devices such as OLEDs. To provide
illustrative and non-limiting examples, the "ambipolar polymers
and/or copolymers typically have at least one subunit having the
structure shown below:
##STR00024##
wherein Ar is an optionally substituted aryl or heteroaryl group, n
is a positive integer representing the number of polymer subunits,
L is a linking group connecting the monomeric polymerizable group
or polymer subunit(s) to the 2-phenyl ring of the oxadiazole group,
and at least one of the R.sup.1, R.sup.2 and R.sup.3 groups is an
optionally substituted carbazole group having the structure
##STR00025##
wherein the various embodiments of the remaining R.sup.1, R.sup.2,
R.sup.3, and optional R.sup.4, R.sup.5, and R.sup.6 groups are
described below.
[0086] Such polymers and copolymers can comprise at least one
polymerized styrenyl, acryl or methacryl, or norbornenyl subunit
having the formulas (I), (II), or (III) illustrated below:
##STR00026##
wherein n is an integer representing the number of polymer
subunits, L is a linking group connecting the styrenyl, acryl or
methacryl, or norbornenyl subunit(s) to the 2-phenyl ring of the
oxadiazole group, and at least one of the R.sup.1, R.sup.2 and
R.sup.3 groups is an optionally substituted carbazole group having
the structure
##STR00027##
wherein the identities of the remaining R.sup.1, R.sup.2, R.sup.3,
and optional R.sup.4, R.sup.5, and R.sup.6 groups are described
above and below, and R.sup.7 is hydrogen (acrylate groups) or
methyl (methacrylate) groups.
[0087] For example, styrenyl compounds of formula (I) having only
one carbazole group can have one of the isomeric structures shown
below:
##STR00028##
[0088] The remaining R.sup.1, R.sup.2 or R.sup.3 groups of the
compounds of formulas (I) (II), or (III) can be independently
selected from hydrogen and various other substituents as further
described above and below, including an additional and optionally
substituted carbazole group. If an additional optionally
substituted carbazole group is present, such a polymeric styrenyl
derivative could have subunits having the exemplary structures such
as those shown below:
##STR00029##
[0089] Analogous polyacrylate, polymethacrylate, and/or
polynorbornenyl polymers can have at least one subunit having the
structures:
##STR00030##
[0090] The polymers or copolymers having one or more subunits
having formulas (I), (II), or (III) can have a widely varying
number of total subunits, as defined by the index n, which can be
any integer between 1 and 1000. In some embodiments, n is an
integer between 5 and 500, or between about 20 and 5000. Copolymers
having one or more subunits having formulas (I), (II), or (III) can
be either random or block copolymers, and the drawings herein
and/or "n" indices should not be interpreted as indicating whether
the copolymers are random or block unless clearly indicted to the
contrary.
[0091] The "L" groups of polymer subunits of formulas (I), (II), or
(III) link the subunits of the polymer or copolymer backbone to the
2-phenyl rings of the oxadiazole groups. L can be any chemical
group that covalently and stably links the polymer or copolymer
backbone to the 2-phenyl rings of the oxadiazole groups, such as
inorganic atoms or groups such an oxygen or sulfur atom, a sulfate,
sulfone, or sulfoxy group, etc, but in many embodiments L is
C.sub.1-C.sub.20 organic group, or preferably a C.sub.1-C.sub.4 or
C.sub.1-C.sub.10 organic group which may optionally comprise
heteroatoms such as halogens (especially fluoride), O, N, or S.
Preferably the L linking group is effectively resistant to
oxidation by holes or reduction by electrons under the operating
conditions of OLED devices. Examples of L groups are alkylene or
alkyleneoxy groups, such as for example wherein L has the
structure:
##STR00031##
wherein x is an integer from 1 to 20, or from 1 to 12, or from 1 to
4. In some embodiments, L is a methyleneoxy group having the
structure:
##STR00032##
[0092] Further examples of L groups include alkylene ester groups
as those illustrated below:
##STR00033##
wherein x is an integer from 1 to 20, or from 1 to 12, or from 1 to
4.
[0093] The identities of the optional R.sup.1, R.sup.2, R.sup.3,
R.sup.4, R.sup.5, and/or R.sup.6 substituent groups for the
compounds of formulas (I) and (II) can vary widely, and can include
inorganic substituent groups such as hydrogen or halogen
(especially fluorine), or C.sub.1-C.sub.20 organic groups,
C.sub.1-C.sub.12 organic groups, or C.sub.1-C.sub.6 organic groups.
Examples of preferred organic groups include alkyl, cyano,
perfluoroalkyl, alkoxide, or perfluoroalkoxide groups
[0094] The various embodiments of the R.sup.1, R.sup.2, R.sup.3,
R.sup.4, R.sup.5, R.sup.6, and/or R.sup.7 groups of the polymers
and copolymers can be the same as any of the variety of embodiments
of those substituents described above in connection with the
ambipolar small molecules. The identities of the R.sup.1, R.sup.2,
R.sup.3, R.sup.4, R.sup.5, and R.sup.6, substituent groups can also
be rationally varied so as to "tune" the physical and electronic
properties of the polymers and/or copolymers to help optimize the
efficient transfer of holes, electrons, and/or holes to a
luminescent host in the emission layer of an OLED device, and/or
provide for improved physical properties and/or lost cost solution
processing, and/or application of the polymers during OLED
construction, and/or minimize undesirable crystallization, phase
separation, and/or thermal decomposition during device
operation.
[0095] The R.sup.7 substituent of the backbones of the polymers
and/or copolymers of formula (II) can be any of the substituents
disclosed above, but in many embodiments are either hydrogen
(polymers or copolymers derived from acrylate esters) or CH.sub.3
(polymers or copolymers derived from methacrylate esters).
[0096] In some embodiments, the invention relates to styrene-based
polymers or copolymers having at least one subunit having the
structure
##STR00034##
[0097] In other embodiments, the invention relates to polyacrylate
or polymethacrylate-based polymers or copolymers having at least
one subunit having the structure
##STR00035##
[0098] In other embodiments, the invention relates to
polynorbornenyl polymers or copolymers having at least one subunit
having the structure
##STR00036##
Ambipolar Copolymers of Class (IV)
[0099] In additional embodiments of the inventions described
herein, ambipolar copolymers of a different class (IV) contain hole
carrying groups such as carbazoles and electron carrying groups
such as oxadiazole groups linked to different copolymer subunits
within the copolymer chains. Copolymers of class (IV) can also
contain additional and optional polymerized subunits derived from a
wide variety of additional polymerizable monomers, including
various optionally substituted vinyl, styrenyl, acryl, methacryl,
and/or norbornenyl monomers that can be linked to luminescent
groups, such as luminescent metal complexes. In such embodiments,
the ambipolar Copolymers of class (IV) described herein can
comprise [0100] a. at least one first norbornenyl subunit linked to
at least one optionally substituted carbazole group; and [0101] b.
at least one second norbornenyl subunit linked to an optionally
substituted 2-phenyl-5-phenyl-1,3,4-oxadiazole group; and [0102] c.
optionally one or more additional polymer subunits.
[0103] For example, in some embodiments, ambipolar norbornenyl
copolymers of class IVa shown immediately below have at least some
subunits having each of the structures shown below:
##STR00037##
[0104] wherein [0105] a. L.sup.1 and L.sup.2 are independently
selected C.sub.1-C.sub.20 organic linking groups, [0106] b. R.sup.c
comprises at least one optionally substituted carbazole group, and
[0107] c. R.sup.ox comprises at least one optionally substituted
2-phenyl-5-phenyl-1,3,4-oxadiazole group.
[0108] Possible structures for the L.sup.1 and L.sup.2 groups, and
possible substituents optionally substituted carbazole groups and
optionally substituted 2-phenyl-5-phenyl-1,3,4-oxadiazole groups
can be the same as described above for the similar substituent
groups of compound classes (I), (II), and (III). Some examples of
the synthesis of suitable carbazole or oxadiazole monomers for
making the copolymers of class (IVa) are provided below, and
additional examples were disclosed in PCT Application Serial Nos.
PCT/EP/2008 068119 filed 19 Dec. 2008 claiming the priority of U.S.
Provisional Application Ser. No. 61/015,777 filed 21 Dec. 2007, and
PCT Application Serial No. PCT/EP/2008 068124 filed 19 Dec. 2008
claiming the priority of U.S. Provisional Application Ser. No.
61/015,641 filed 20 Dec. 2007, both of which are hereby
incorporated by reference.
[0109] For example, the R.sup.c carbazole groups can have exemplary
structures such as those shown below:
##STR00038## [0110] wherein R.sup.1 is selected from hydrogen,
fluoride, and a C.sub.1-C.sub.6 organic group selected from alkyls,
cyano, perfluoroalkyls, alkoxides, and perfluoroalkoxides.
[0111] Similarly, the R.sup.ox carbazole groups can have exemplary
structures such as those shown below:
##STR00039## [0112] wherein Y is an aryl group, including a phenyl
group, and each optional R.sup.a or R.sup.b group is independently
selected from hydrogen, fluoride, or one or more C.sub.1-20 alkyl,
cyano, perfluoroalkyl, alkoxy, or perfluoroalkoxy groups, and each
x is an independently selected integer 0, 1, 2, 3 or 4.
[0113] Specific examples of such ambipolar copolymers can include
at least some subunits having the structures shown below
##STR00040## [0114] wherein x is an integer from 1 to 20.
[0115] As disclosed above, copolymers of class IV can also comprise
one or more additional polymer subunits as desired. In some such
embodiments, the additional monomers can comprise linkages to
luminescent groups, such as suitable organic phosphors or
phosphorescent metal complexes. A disclosure of suitable
norbornenes linked to phosphorescent Iridium complexes can be found
in PCT publication WO 2009/026235 published Feb. 26, 2009, which is
incorporated herein by reference for its disclosures of such
norbornene-linked phosphorescent Iridium and similar metal
complexes.
Polymerizable Ambipolar Monomers
[0116] In some aspects, the inventions described herein relate to
ambipolar monomers that comprise a polymerizable group linked to
both hole carrying and electron carrying groups. For example, in
some embodiments, the inventions relate to a monomer comprising a
polymerizable group linked to a 2-phenyl-5-phenyl-1,3,4-oxadiazole
group having one or more carbazole groups bound thereto, the
monomer having the formula:
##STR00041##
[0117] wherein [0118] a. L is a C.sub.1-C.sub.20 organic group
linking the polymerizable group to the 2-phenyl ring of the
oxadiazole group; [0119] b. at least one of the R.sup.1, R.sup.2
and R.sup.3 groups is an optionally substituted carbazole group,
and the remaining R.sup.1, R.sup.2 or R.sup.3 groups are
independently selected from hydrogen, fluoride, a C.sub.1-C.sub.6
alkyl, cyano, perfluoroalkyl, alkoxide, or perfluoroalkoxide
groups, and optionally one or more additional optionally
substituted carbazole groups; wherein the optionally substituted
carbazole groups have the structure
[0119] ##STR00042## [0120] wherein R.sup.5 and R.sup.6 are
independently selected from hydrogen, fluoride, and a
C.sub.1-C.sub.6 organic group selected from alkyls, cyano,
perfluoroalkyls, alkoxides, and perfluoroalkoxides; [0121] c.
R.sup.4 is selected from hydrogen, fluoride, and a C.sub.1-C.sub.6
alkyl, perfluoroalkyl, alkoxide, or perfluoroalkoxide group.
[0122] Such monomers and the homopolymers and copolymers derived
from them are useful as host materials for the manufacture of
emission layers of OLED devices, and are capable of transporting
holes, electrons, and/or excitons into contact with guest
luminescent materials, so as to excite and/or induce luminescence
from such guest luminescent materials.
[0123] Thus, in some embodiments, the inventions disclosed herein
include substituted styrene monomers (Ia), substituted acrylate or
methacrylate monomers (IIa), or the substituted norbornene monomers
(IIIa) whose structures are shown below:
##STR00043##
wherein one or two of the R.sup.1, R.sup.2 and R.sup.3 groups is an
optionally substituted carbazole group having the structure
##STR00044##
and wherein the index n and the L, R.sup.1, R.sup.2, R.sup.3,
R.sup.4, R.sup.5, R.sup.6, and/or R.sup.7 groups of one or all of
compounds of formula (Ia), (IIa), or (IIIa) can have any of the
meanings described above in connection with the corresponding
ambipolar small molecules described above, or polymer, or copolymer
subunits (I), (II), or (III).
[0124] Specific examples of polymerizable ambipolar monomeric
styrene compounds of formula (Ia) include compounds having the
structures:
##STR00045## ##STR00046##
wherein x is an integer between 1 and 20, or 1 and 10.
[0125] Specific examples of related polymerizable ambipolar
monomeric acrylate or methacrylate compounds of formula (IIa)
include compounds having the structures:
##STR00047## ##STR00048##
[0126] wherein R.sup.7 can be hydrogen or CH.sub.3.
[0127] Specific examples of polymerizable ambipolar monomeric
norbornene compounds of formula (IIa) include compounds having the
structures:
##STR00049## ##STR00050##
[0128] Generic schemes for the synthesis of the
carbazole/oxadiazole precursors of the phenolic ambipolar monomers
above are diagramed in FIGS. 3-8 attached herewith, and specific
examples of such syntheses are provided below. Such "ambipolar"
precursor compounds are novel, and if the phenolic group is
appropriately modified to increase its resistance to oxidation or
reduction (by the attachment of appropriate "protecting groups"
such as alkyls, aryls, acyls, etc, the resulting intermediate
compound can be transformed to be useful as small molecule host
materials for the production of OLEDs. Such materials can have the
unexpected property of providing a single host material that is
capable of transporting holes, electrons, and/or excitons into
contact with other guest materials, such as luminescent guest
materials.
[0129] Furthermore, the phenolic carbazole/oxadiazole precursor
compounds disclosed in FIGS. 3-5 can be chemically linked to
various polymerizable monomeric groups such as styrenes, acrylates,
methacrylates, and norbornenes, as is disclosed in FIGS. 6-8, and
specifically exemplified below.
[0130] Homopolymerization of Monomers (Ia), (IIa), and (IIIa)
[0131] Homopolymerization of nine examples of monomers (Ia), (IIa),
and (IIIa) were carried out as disclosed in FIGS. 9-11 and
exemplified in Example 3. Six homopolymers were prepared by free
radical polymerization based on styrene (FIG. 9a) and methacrylate
(FIG. 9b) polymerizable ambipolar monomers using AIBN as thermal
free radical initiator. Initiator concentrations used for
methacrylate is 1.5% (mol ratio) and for styrene is 2.5% in mol
ratio. For methacrylate polymerization, high yields (over 90%)
could be obtained after 3 day polymerization at 60.degree. C. For
styrene polymerization, low yield (46%) was obtained after 3 day
polymerization at 60.degree. C. However, polymers were obtained in
good yield (over 80%) after 7 day polymerization. All the resulting
polymers were purified by multiple dissolution/precipitation.
CH.sub.2Cl.sub.2/ethanol was used for polymethacrylate and
polynorbornene purification and CH.sub.2Cl.sub.2/acetone was used
for polystyrene purification. All polymers were characterized by
.sup.1H-NMR, EA and GPC.
[0132] Three homopolymers were prepared by ROMP polymerization of
three monomers of formula (IIIa) using Grubbs catalyst 1.sup.st
generation as a catalyst in 1% mol ratio. (See Example 4 and FIG.
10)
[0133] It is well known in the art that cyclic olefins, including
norbornenes, can be polymerized via ring-opening metathesis
polymerization (ROMP), a living polymerization method resulting in
polymers with controlled molecular weights, low polydispersities,
and which also allows for the easy formation of either random or
block co-polymers. See, for example, Furstner, A. Angew. Chem.,
Int. Ed. 2000, 39, 3013; T. M. Trnka, T. M.; Grubbs, R. H. Acc.
Chem. Res. 2001, 34, 18; Olefin Metathesis and Metathesis
Polymerization, 2nd Ed.; Ivin, J., Mol, I. C., Eds.; Academic: New
York, 1996; and Handbook of Metathesis, Vol. 3--Application in
Polymer Synthesis; Grubbs, R. H., Ed.; Wiley-VCH: Weinheim, 2003,
each of which is respectively incorporated herein by reference for
their teachings regarding methods and catalysts for ROMP
polymerizations. Catalysts (also termed initiators) commonly used
by those skilled in the art include Grubb's ruthenium catalysts
(below).
##STR00051##
[0134] Ruthenium-based ROMP initiators are highly functional-group
tolerant, allowing for the polymerization of norbornene monomers
linked to fluorescent and phosphorescent metal complexes. ROMP
polymerizations can also be carried out with molybdenum or tungsten
catalysts such as those described by Schrock (Olefin Metathesis and
Metathesis Polymerization, 2nd Ed.; Ivin, J., Mol, I. C., Eds.;
Academic: New York which is respectively incorporated herein by
reference for its teachings regarding molybdenum or tungsten
catalysts for ROMP polymerizations).
[0135] Copolymerizations of Carbazole and Oxadiazole Monomers to
Yield Ambipolar Copolymers of Formula (IV)
[0136] Accordingly, in some embodiments the inventions relate to a
process for preparing norbornenyl copolymers of class (IV)
comprising the steps of [0137] a. mixing [0138] i. at least one
first norbornene monomer comprising a norbornene group linked to a
carbazole group; and [0139] ii. at least one second norbornene
monomer comprising a norbornene group linked to an optionally
substituted 2-phenyl-5-phenyl-1,3,4-oxadiazole group; and [0140]
iii. optionally one or more additional optionally substituted
norbornene monomers; and [0141] b. polymerizing the mixture of
norbornene monomers in the presence of a ROMP catalyst, to produce
the copolymer.
[0142] A norbornenyl monomer linked to a trimeric carbazole group
was copolymerized with the norbornenyl monomer linked to an
oxadiazole monomer via ring opening metathesis as described in
Example 4 below, to form a copolymer of class (IV). The copolymer
was synthesized using a 1:1 molar ratio of the monomers. No steps
were taken to control the polymer morphology therefore the
copolymer was likely random although no information about the
reactivity ratios of the monomers was available that would have
lead to an expectation of the formation of a copolymer with a
morphology other than random. The copolymer was purified by
multiple re-precipitations using methanol to obtain. 0.261 g (53.4%
isolated yield)) of a light cream colored powder. The .sup.1H NMR
of the soluble powder in CDCl.sub.3 (See FIG. 11) is consistent
with the formation of a copolymer of the starting monomers. The
copolymer was also successfully characterized by gel permeation
chromatography and elemental analysis.
[0143] It should also be noted that such copolymerizations can also
be carried out the presence of other norbornenyl co-monomers linked
to other functional groups, such as cinnamate groups that can used
to induce photocrosslinking of the polymers, or phosphorescent
"guest" groups such as 3d row transition metal complexes.
[0144] Organic Electronic Devices Comprising the Ambipolar Polymers
and Copolymers
[0145] Some aspects of the present inventions relate to novel
organic electronic devices, including light emitting diodes and
OLED devices that comprise the various ambipolar compounds,
homopolymers, copolymers described above. As further described
below, the various ambipolar compounds, homopolymers, copolymers
are readily soluble in common organic solvents and can be mixed
with compounds that can serve as guest phosphorescent emitters, and
the mixture solution processed and/or spin coated onto appropriate
substrates to form the emission layer of an OLED device.
[0146] In some embodiments, light emitting diodes and/or OLED
devices comprise an anode layer, a hole transporting layer, an
emission layer, an electron transporting layer, and a cathode
layer. Such devices are illustrated in the diagram below:
##STR00052##
[0147] Accordingly, in many embodiments of the OLED devices
disclosed herein, the OLEDs comprise the following layers: [0148]
a. an anode layer, [0149] b. a hole transporting layer, [0150] c.
an emissive layer, [0151] d. an electron transporting layer, and
[0152] e. a cathode layer.
[0153] In many embodiments of the OLED devices disclosed herein,
the emissive layer comprises at least some of the compound.
[0154] Indium tin oxide (ITO) is an example of a suitable material
for the anode layers, and is often applied by vacuum deposition in
a layer over an inert and transparent substrate such as glass.
[0155] Many materials are potentially useful as hole transporting
layers, including monomeric or polymeric carbazole compounds such
as polyvinyl carbazole (PVK). Poly-TPD-F (structure shown below,
see Zhang, et al., Synthesis 2002, 1201 and Domercq, et al., Chem.
Mater. 2003, 15, 1491, both of which are incorporated herein by
reference in their entirety) is especially useful because it is
photo cross-linkable and can be used to produce photo-patterned
hole transporting layers.
##STR00053##
[0156] Many materials are suitable as electron transporting and/or
hole blocking materials, such as bathocuproine
(BCP=2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, BCP, or
structure shown below) which can be readily applied to the devices
via vacuum/thermal deposition techniques.
##STR00054##
[0157] Many materials can be suitable as cathode layers, one
example being a combination of lithium fluoride (LiF) as an
electron injecting material coated with a vacuum deposited layer of
Aluminum.
[0158] As already previously noted above, the ambipolar polymers or
copolymers of the current inventions can transport both holes and
electrons, and therefore function as an efficient host for
phosphorescent guests, such as well known Iridium complexes such as
Ir(ppy) (ppy=2-phenylpyridine) and Platinum complexes exemplified
below.
[0159] It is also worth noting that the ambipolar polymers or
copolymers of the current inventions can transport both holes and
electrons, and therefore can also potentially be used as a
substitute for the hole transporting material in the hole
transporting layer, or the electron transporting material of the
electron transporting layer. When the emission layer of the device
comprises the ambipolar polymers or copolymers of the current
inventions, it is also possible to simply omit the hole or electron
transporting layers.
[0160] Electroluminescent Properties of the OLED Devices
[0161] A number of exemplary OLED devices comprising the ambipolar
polymers or copolymers of the current inventions as guests for
Platinum and Iridium complexes as phosphorescent guests are
described in the Examples below, which describe the particular
photoluminescence properties measured for those exemplary devices.
See Examples 5 and 6, and FIGS. 12-16. In most examples, same
device structure was fabricated from different host polymers (as
shown in FIG. 5).
EXAMPLES
[0162] The various inventions described above are further
illustrated by the following specific examples, which are not
intended to be construed in any way as imposing limitations upon
the scope of the invention disclosures or claims attached herewith.
On the contrary, it is to be clearly understood that resort may be
had to various other embodiments, modifications, and equivalents
thereof which, after reading the description herein, may suggest
themselves to one of ordinary skill in the art without departing
from the spirit of the present invention or the scope of the
appended claims.
[0163] General--All experiments with air- and moisture-sensitive
intermediates and compounds were carried out under an inert
atmosphere using standard Schlenk techniques. NMR spectra were
recorded on either a 400 MHz Varian Mercury spectrometer or a 400
MHz Bruker AMX 400 and referenced to residual proton solvent.
UV-vis absorption spectra were recorded on a Varian Cary 5E
UV-vis-NIR spectrophotometer, while solution and thin-film PL
spectra were recorded on a Fluorolog III ISA spectrofluorometer.
Lifetime measurements were taken using a PTI model C-72
fluorescence laser spectrophotometer with a PTI GL-3300 nitrogen
laser. Cyclic voltammograms were obtained on a computer controlled
BAS 100B electrochemical analyzer, and measurements were carried
out under a nitrogen flow in deoxygenated DMF solutions of
tetra-n-butylammonium hexafluorophosphate (0.1 M). Glassy carbon
was used as the working electrode, a Pt wire as the counter
electrode, and an Ag wire anodized with AgCl as the
pseudo-reference electrode. Potentials were referenced to the
ferrocenium/ferrocene (FeCp.sub.2.sup.+/0)) couple by using
ferrocene as an internal standard. Gel-permeation chromatography
(GPC) analyses were carried out using a Waters 1525 binary pump
coupled to a Waters 2414 refractive index detector with methylene
chloride as an eluent on American Polymer Standards 10 .mu.m
particle size, linear mixed bed packing columns. The flow rate used
for all measurements was 1 ml/min, and the GPCs were calibrated
using poly(styrene) standards. Differential scanning calorimetry
(DSC) data were collected using a Seiko model DSC 220C. Thermal
gravimetric analysis (TGA) data were collected using a Seiko model
TG/DTA 320. Inductively coupled plasma-mass spectrometry (ICP-MS)
for platinum and ruthenium was provided by Bodycote Testing Group.
.sup.1H-NMR and .sup.13C-NMR spectra (300 MHz .sup.1H NMR, 75 MHz
.sup.13C NMR) were obtained using a Varian Mercury Vx 300
spectrometer. All spectra are referenced to residual proton
solvent. Abbreviations used include singlet (s), doublet (d),
doublet of doublets (dd), triplet (t), triplet of doublets (td) and
unresolved multiplet (m). Mass spectral analyses were provided by
the Georgia Tech Mass Spectrometry Facility. The onset of thermal
degradation for the polymers was measured by thermal gravimetric
analysis (TGA) using a Shimadzu TGA-50. UV/vis absorption
measurements were taken on a Shimadzu UV-2401 PC recording
spectrophotometer. Emission measurements were acquired using a
Shimadzu RF-5301 PC spectrofluorophotometer. Lifetime measurements
were taken using a PTI model C-72 fluorescence laser
spectrophotometer with a PTI GL-3300 nitrogen laser. Elemental
analyses for C, H, and N were performed using Perkin Elmer Series
II CHNS/O Analyzer 2400. Elemental analyses for iridium were
provided by Galbraith Laboratories.
[0164] Unless otherwise noted, cited reagents and solvents were
purchased from well-known commercial sources (such as Sigma-Aldrich
of Milwaukee Wis. or Acros Organics of Geel Belgium, and were used
as received without further purification.
Example 1
Synthesis of Precursors of Ambipolar Monomers (See FIGS. 3-5)
Synthesis of 4-Iodobenzohydrazide
##STR00055##
[0166] To Methyl 4-iodobenzoate (30.0 g, 114 mmol) in ethanol
(180.0 ml) was added hydrazine hydrate (30.0 g, 599 mmol). The
reaction mixture was reflux for 22.5 hours. Heating was stopped and
then water (300.0 ml) was added. After cooling down to room
temperature, white solid was appeared. The white product solid was
collected by filtration. The product was washed with water and
dried under vacuum. Final white pure product was obtained in 26.0 g
(86.7%). .sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.): 9.84 (s, 1H,
NH), 7.82 (d, J=8.4 Hz, 2H), 7.59 (d, J=8.4 Hz, 2H), 4.50 (s, 2H,
NH.sub.2).
Synthesis of N'-(4-iodobenzoyl)-3-methoxy benzohydrazide
##STR00056##
[0168] To a solution of 4-Iodobenzohydrazide (5.0 g, 19.1 mmol) in
dry THF (80.0 ml) was slowly added 3-methoxybenzoyl chloride (3.5
g, 20.5 mmol) at 0.degree. C. under nitrogen. During addition of
3-methoxybenzoyl chloride the white solid was appeared. After
addition of 3-methoxybenzoyl chloride, the reaction was warmed up
to room temperature. The reaction mixture was stirred for 18 hours
at room temperature and then pyridine (5.0 ml) was added and
stirred for additional 2 h. Water (300.0 ml) was added to reaction
mixture. The white solid was obtained and collected by filtration.
After dried under vacuum, product was obtained as white powder in
7.2 g (94.7%). .sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.): 10.60
(s, 1H, NH), 10.52 (s, 1H, NH), 7.91 (d, J=8.0 Hz, 2H), 7.68 (d,
J=8.0 Hz, 2H), 7.50 (d, J=8.0 Hz, 1H), 7.45 (d, J=2.4 Hz, 1H), 7.41
(d, J=8.0 Hz, 1H), 7.15 (dd, J.sub.1=8.0 Hz, J.sub.2=2.4 Hz, 1H),
3.81 (s, 3H, OCH.sub.3).
Synthesis of
2-(4-Iodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00057##
[0170] N'-(4-iodobenzoyl)-3-methoxybenzohydrazide (7.0 g, 17.67
mmol) was suspended in POCl.sub.3 (40.0 ml) and heating was
started. The reaction was kept at 100.degree. C. During heating
white solid of starting materials dissolved into a clear solution
and the reaction was monitor by thin layer chromatography. After 1
h, the reaction mixture was brought to room temperature and was
carefully dropped into ice-water (500.0 ml). White solid
precipitated out was collected by filtration and washed with water.
After dry, the crude product was purified by silica gel column
chromatography eluting with dichloromethane and ethyl acetate in
25:1 ratio. After evaporating solvent the white solid was
recrystallized from acetone/water and finally dried under vacuum.
Pure product was obtained as white solid in 5.8 g (86.8%) yield.
.sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 7.86 (d, J=8.4 Hz, 2H),
7.83 (d, J=8.4 Hz, 2H), 7.67 (dt, J.sub.1=8.0 Hz, J.sub.2=1.2 Hz,
1H), 7.63 (m, 1H), 7.42 (t, J=8 Hz, 1H), 7.07 (m, 1H), 3.88 (s, 3H,
OCH.sub.3). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 164.66,
164.00, 159.92, 138.32, 130.23, 128.21, 124.73, 123.26, 119.29,
118.26, 111.56, 98.60, 55.52.
Synthesis of
2-(4-Carbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00058##
[0172] To a solution of
2-(4-iodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (3.0 g, 7.93
mmol), carbazole (1.5 g, 8.97 mmol), Cu (2.0 g, 31.47 mmol) in DMF
(20.0 ml) was added potassium carbonate (4.0 g, 28.94 mmol) under
nitrogen and stirring. Heating was started. The reaction was
carried out at 150.degree. C. for 4 h. After cooling, the reaction
mixture was filtrated. The solid residues were carefully washed
with THF. THF was evaporated from the combined filtration solution.
Water (200.0 ml) was added, the yellow solid product was obtained
by filtration. The crude product was purified by silica gel column
chromatography using dichloromethane/ethyl acetate (9.5:0.5) as
eluent. After evaporating solvent, the white solid was
recrystallized from acetone/water and finally dried under vacuum.
Pure product was obtained as white solid in 3.2 g (96.7%) yield.
.sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 8.38 (m, 2H), 8.16 (d,
J=8.0 Hz, 2 Hz), 7.81-7.72 (m, 4H), 7.52-7.43 (m, 5H), 7.33 (m,
2H), 7.12 (m, 1H). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.):
164.72, 164.02, 159.99, 140.90, 140.21, 130.28, 128.58, 127.21,
126.21, 124.88, 123.76, 122.40, 120.57, 120.48, 119.33, 118.29,
111.61, 109.68, 94.23, 55.55. [M].sup.+ calcd for
C.sub.27H.sub.19N.sub.3O.sub.2, 417.2, found 417.1.
Synthesis of
3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol
##STR00059##
[0174] To a solution of
2-(4-carbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (1.0
g, 2.40 mmol) in dichloromethane (10.0 ml) was dropwise added
BBr.sub.3 (10.0 ml, 1 M in dichloromethane) at -78.degree. C.
(dry-ice/acetone) under nitrogen. After addition of BBr.sub.3
solution, the reaction was taken to room temperature and kept at
room temperature for 5 h. The reaction mixture was poured into
ice-water (50.0 ml). Dichloromethane was evaporated under reduced
pressure. The white solid was collected by filtration. After drying
under vacuum, product as white solid was obtained in 0.97 g (100%)
yield. .sup.1H NMR (400 MHz, acetone-d.sub.6, .delta.): 8.91 (s,
1H, OH), 8.48 (m, 2H), 8.24 (dt, J.sub.1=8.0 Hz, J.sub.2=1.2 Hz,
2H), 7.91 (m, 2H), 7.71 (t, J=1.2 Hz, 1H), 7.69 (t, J=1.6 Hz, 1H),
7.56 (d, J=0.8 Hz, 1H), 7.54 (t, J=0.8 Hz, 1H), 7.46 (m, 3H), 7.32
(m, 2H), 7.12 (m, 1H), 3.93 (s, 3H, OCH.sub.3). .sup.13C NMR (100
MHz, acetone-d.sub.6, .delta.): 165.43, 164.72, 158.87, 141.48,
141.12, 131.44, 129.41, 128.23, 127.17, 126.04, 124.56, 123.65,
121.43, 121.26, 119.88, 118.89, 114.18, 110.62. MS-EI (m/z):
[M].sup.+ calcd for C.sub.26H.sub.17N.sub.3O.sub.2, 403.1, found
403.1.
Synthesis of Methyl 3-iodobenzoate
##STR00060##
[0176] To a solution of 3-iodobenzoic acid (50.0 g, 0.202 mol) in
methanol (300.0 ml) was added H.sub.2SO.sub.4 (1.0 ml). The
reaction mixture was heated to reflux. After reflux 24 h, heating
was stopped. The reaction mixture was cooled to room temperature.
Water (400.0 ml) was added, the product was extracted with ethyl
acetate (2.times.300.0 ml). The organic layer was washed with 20%
of NaHCO.sub.3 water solution and followed with water. After
removal of ethyl acetate, the crude product was purified by
recrystallization from ethanol/water. Final white pure product was
obtained in 51.0 g (96.5%) after dry under vacuum. .sup.1H NMR (400
MHz, CDCl.sub.3, .delta.): 8.35 (t, J=1.6 Hz, 1H), 7.97 (dt,
J.sub.1=8.4 Hz, J.sub.2=1.6 Hz, 1H), 7.85 (dt, J1=8.4 Hz, J2=1.6
Hz, 1H), 7.14 (t, J=8.4 Hz, 1H), 3.89 (s, 3H, OCH.sub.3). .sup.13C
NMR (100 MHz, CDCl.sub.3, .delta.): 165.56, 141.70, 138.42, 131.93,
130.03, 128.70, 93.76, 52.38.
Synthesis of 3-Iodobenzohydrazide
##STR00061##
[0178] To Methyl 3-iodobenzoate (25.0 g, 95.41 mmol) in ethanol
(120.0 ml) was added hydrazine hydrate (50.0 ml). The reaction
mixture was reflux for 18 hours. Heating was stopped and then water
(300.0 ml) was added. After cooling down to room temperature, white
solid was appeared. The white product solid was collected by
filtration. The product was washed with water and dried under
vacuum. Final white pure product was obtained in 23.0 g (92.0%).
.sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.): 9.85 (s, br, 1H, NH),
8.14 (t, J=1.6 Hz, 1H), 7.85 (m, 1 H), 7.82 (m, 1H), 7.25 (t, J=8.0
Hz, 1H), 4.50 (s, 2H, NH.sub.2). .sup.13C NMR (100 MHz, CDCl.sub.3)
.delta.: 168.54, 155.38, 129.54, 126.72, 125.57, 34.90, 31.07.
Synthesis of 3-Iodo-N'-(3-methoxybenzoyl)benzohydrazide
##STR00062##
[0180] To a solution of 3-iodobenzohydrazide (10.0 g, 38.16 mmol)
in dry THF/DMF (100.0 ml:10.0 ml) was slowly added 3-methoxybenzoyl
chloride (7.0 g, 42.03 mmol) at 0.degree. C. under nitrogen. During
addition of 3-methoxybenzoyl chloride, white solid was appeared.
After addition of 3-methoxybenzoyl chloride, the reaction was
allowed to warm up to room temperature. The reaction mixture was
stirred for 19 hours at room temperature and then pyridine (20.0
ml) was added and stirred for additional 45 min. Water (300.0 ml)
was added to reaction mixture. The white solid was obtained and
collected by filtration and washed with water. After dried under
vacuum, product was obtained as white powder in 12.4 g (82.0%).
.sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.): 10.62 (s, 1H, NH),
10.56 (s, 1H, NH), 8.25 (t, J=1.6 Hz, 1H), 7.96 (d, J=8.0 Hz, 1H),
7.91 (d, J=8.0 Hz, 1H), 7.49 (d, J=8.0 Hz, 1H), 7.45 (d, J=2.4 Hz,
1H), 7.41 (d, J=8.0 Hz, 1H), 7.34 (t, J=8.0 Hz, 1H), (dd,
J.sub.1=8.0 Hz, J.sub.2=2.4 Hz, 1H), 3.81 (s, 3H, OCH.sub.3).
Synthesis of
2-(3-Iodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00063##
[0182] 3-Iodo-N'-(3-methoxybenzoyl)benzohydrazide (11.0 g, 27.77
mmol) was suspended in POCl.sub.3 (60.0 ml) and heating was
started. During heating white solid of starting materials dissolved
into a clear solution. The reaction was kept at 100.degree. C. and
the reaction was monitor by thin layer chromatography. After 2 h,
the reaction mixture was brought to room temperature and was
carefully dropped into ice-water (1000.0 ml). White solid
precipitated out was collected by filtration and washed with water.
After dried, the crude product was purified by silica gel column
chromatography eluting with dichloromethane and ethyl acetate in
9.5:0.5 ratio. After evaporating solvent the white solid was
recrystallized from acetone/water and finally dried under vacuum.
Pure product was obtained as white solid in 6.4 g (61.0%) yield.
.sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 8.47 (t, J=1.6 Hz, 2
H), 8.12 (dt, J.sub.1=8.0 Hz, J.sub.2=1.6 Hz, 1H), 7.88 (m, 1H),
7.70 (dt, J.sub.1=8.0 Hz, J.sub.2=1.6 Hz, 1H), 7.67 (m, 1H), 7.45
(t, J=8.0 Hz, 1H), 7.28 (t, J=8.0 Hz, 1H), 7.10 (m, 1H), 3.92 (s,
3H, OCH.sub.3). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.):
164.79, 163.07, 159.94, 140.58, 135.46, 130.68, 130.26, 126.03,
125.68, 124.69, 119.36, 118.36, 111.59, 94.39, 55.56.
Synthesis of
2-(3-Carbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00064##
[0184] To a solution of
2-(3-iodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (3.0 g, 7.93
mmol), carbazole (1.5 g, 8.97 mmol), Cu (2.0 g, 31.47 mmol) in DMF
(20.0 ml) was added potassium carbonate (4.0 g, 28.94 mmol) under
nitrogen and stirring. Heating was started. The reaction was
carried out at 150.degree. C. for 5 h. After cooling, the reaction
mixture was filtrated. The solid residues were carefully washed
with THF. THF was evaporated from the combined filtration solution.
Water (150.0 ml) was added, the brown solid product was obtained by
filtration. The crude product was purified by silica gel column
chromatography using dichloromethane/ethyl acetate (9.5:0.5) as
eluent. After evaporating solvent, the white solid was
recrystallized from acetone/methanol and finally dried under
vacuum. Pure product was obtained as white solid in 3.15 g (95.4%)
yield. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 8.34 (m, 1H),
8.27 (m, 1 Hz), 8.18 (m, 2H), 7.78 (m, 2H), 7.71-7.65 (m, 2H),
7.46-7.41 (m, 5H), 7.36-7.31 (m, 2H), 7.09 (m, 1H), 3.89 (s, 3H,
OCH.sub.3). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 164.85,
163.84, 159.96, 140.60, 138.70, 130.85, 130.32, 130.25, 126.19,
125.84, 125.40, 124.72, 123.55, 120.45, 120.37, 119.39, 118.44,
111.52, 109.55, 55.55. [M].sup.+ calcd for
C.sub.39H.sub.26N.sub.4O.sub.2, 417.2, found 417.1.
Synthesis of
3-(5-(3-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol
##STR00065##
[0186] To a solution of
2-(3-carbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (3.0
g, 7.2 mmol) in dichloromethane (20.0 ml) was dropwise added
BBr.sub.3 (30.0 ml, 1 M in dichloromethane) at -78.degree. C.
(dry-ice/acetone) under nitrogen. After addition of BBr.sub.3
solution, the reaction was taken to room temperature and kept at
room temperature for 6 h. The reaction mixture was poured into
ice-water (100.0 ml). Dichloromethane was evaporated under reduced
pressure. The white solid was collected by filtration. After drying
under vacuum, product as white solid was obtained in 2.9 g (100%)
yield. .sup.1H NMR (400 MHz, acetone-d.sub.6, .delta.): 8.89 (s,
br, 1H, OH), 8.41 (m, 1H), 8.34 (m, 1H), 8.26 (m, 2H), 7.92 (m,
2H), 7.66 (m, 2H), 7.53-7.41 (m, 5H), 7.33 (m, 2H), 7.10 (m, 1H).
MS-EI (m/z): [M].sup.+ calcd for C.sub.26H.sub.17N.sub.3O.sub.2,
403.1, found 403.1.
Synthesis of 3,5-Diiodobenzohydrazide
##STR00066##
[0188] To Methyl 3,5-diiodobenzoate (5.0 g, 12.89 mmol) in ethanol
(70.0 ml) was added hydrazine hydrate (20.0 ml) under stirring.
During heating, white solid was appeared. The reaction was kept
50.degree. C. for 1 h. Heating was stopped and then water (100.0
ml) was added. After cooling down to room temperature, the white
product solid was collected by filtration. The product was washed
with water and dried under vacuum. Final white product was obtained
in 4.6 g (92.0%). .sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.):
9.92 (s, 1H, NH), 8.22 (t, J=1.6 Hz, 1H), 8.12 (d, J=1.6 Hz, 2H),
4.53 (s, 2H, NH.sub.2).
3,5-diiodo-N'-(3-methoxybenzoyl)benzohydrazide
##STR00067##
[0190] To a solution of 3,5-Diiodobenzohydrazide (4.5 g, 11.60
mmol) in dry THF/DMF (100.0 ml:24.0 ml) was slowly added
3-methoxybenzoyl chloride (2.2 g, 12.90 mmol) at 0.degree. C. under
nitrogen. After addition of 3-methoxybenzoyl chloride, the reaction
was warmed up to room temperature. The reaction mixture was stirred
for 19 hours at room temperature and then pyridine (5.0 ml) was
added and stirred for additional 1 h. Water (300.0 ml) was added to
reaction mixture. The white solid was obtained and collected by
filtration. After dried under vacuum, product was obtained as white
powder in 5.05 g (83.3%). .sup.1H NMR (400 MHz, DMSO-d.sub.6,
.delta.): 10.72 (s, 1H, NH), 10.62 (s, br, 1H, NH), 8.33 (t, J=1.6
Hz, 1H), 8.23 (d, J=1.6 Hz, 2H), 7.50-7.41 (m, 3H), 7.15 (m, 1H),
3.81 (s, 3H, OCH.sub.3).
Synthesis of
2-(3,5-Diiodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00068##
[0192] 3,5-Diiodo-N'-(3-methoxybenzoyl)benzohydrazide (5.0 g, 9.58
mmol) was suspended in POCl.sub.3 (50.0 ml) and heating was
started. During heating white solid of starting materials dissolved
into a clear solution (130.degree. C.). The reaction was kept at
100.degree. C. and the reaction was monitor by thin layer
chromatography. After 5 h, the reaction mixture was brought to room
temperature and was carefully dropped into ice-water (1000.0 ml).
White solid precipitated out was collected by filtration and washed
with water. After dried, the crude product was purified by silica
gel column chromatography eluting with dichloromethane and ethyl
acetate in 9.5:0.5 ratio. After evaporating solvent the white solid
was recrystallized from acetone/water and finally dried under
vacuum. Pure product was obtained as white solid in 3.4 g (70.8%)
yield. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 8.43 (dd,
J.sub.1=1.6 Hz, J.sub.2=0.8 Hz, 2H), 8.23 (t, J=1.6 Hz, 1H), 7.71
(d, J=8.0 Hz, 1H), 7.66 (m, 1H), 7.46 (t, J=8.0 Hz, 1H), 7.12 (dd,
J.sub.1=8.0 Hz, J.sub.2=2.4 Hz, 1H), 3.92 (s, 3H, OCH.sub.3).
.sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 165.06, 161.67,
159.98, 148.05, 134.63, 130.31, 126.95, 124.44, 119.44, 118.56,
111.66, 94.98, 55.59.
Synthesis of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
##STR00069##
[0194] To a solution of
2-(3,5-diiodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (1.0 g,
1.98 mmol), carbazole (1.0 g, 5.98 mmol), Cu (4.0 g, 62.95 mmol) in
DMF (20.0 ml) was added potassium carbonate (6.0 g, 43.41 mmol)
under nitrogen and stirring. Heating was started. The reaction was
carried out at 150.degree. C. for 5 h. After cooling, the reaction
mixture was filtrated. The solid residues were carefully washed
with THF. THF was evaporated from the combined filtration solution.
Water (150.0 ml) was added, the brown solid product was obtained by
filtration. The crude product was purified by silica gel column
chromatography using toluene/ethyl acetate (9.7:0.3) as eluent.
After evaporating solvent, the white solid was recrystallized from
THF/methanol and finally dried under vacuum. Pure product was
obtained as white solid in 0.99 g (86.1%) yield. .sup.1H NMR (400
MHz, CDCl.sub.3, .delta.): 8.47 (d, J=2.4 Hz, 2H), 8.16 (d, J=8.0
Hz, 4 Hz), 8.01 (t, J=1.6 Hz, 1H), 7.69-7.64 (m, 2H), 7.58 (d,
J=8.0 Hz, 4H), 7.45 (m, 4H), 7.41 (t, J=8.0 Hz, 1H), 7.34 (m, 4H),
7.08 (m, 1H), 3.87 (s, 3H, OCH.sub.3). .sup.13C NMR (100 MHz,
CDCl.sub.3, .delta.): 164.72, 164.02, 159.99, 140.90, 140.21,
130.28, 128.58, 127.21, 126.21, 124.88, 123.76, 122.40, 120.57,
120.48, 119.33, 118.29, 111.61, 109.68, 94.23, 55.55. [M].sup.+
calcd for C.sub.39H.sub.26N.sub.4O.sub.2, 582.2, found 582.2. Anal.
Calcd for C.sub.39H.sub.26N.sub.4O.sub.2: C, 80.39; H, 4.50; N,
9.62. Found: C, 80.32; H, 4.41; N, 9.60.
Synthesis of
3-(5-(3,5-dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol
##STR00070##
[0196] To a solution of
2-(3,5-dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
(0.95 g, 1.63 mmol) in dichloromethane (20.0 ml) was dropwise added
BBr.sub.3 (7.0 ml, 1 M in dichloromethane) at -78.degree. C.
(dry-ice/acetone) under nitrogen. After addition of BBr.sub.3
solution, the reaction was taken to room temperature and kept at
room temperature for 5.5 h. The reaction mixture was poured into
ice-water (70.0 ml). Dichloromethane was evaporated under reduced
pressure. The white solid was collected by filtration. After drying
under vacuum, product as white solid was obtained in 0.92 g (98.9%)
yield. .sup.1H NMR (400 MHz, DMSO-d.sub.6, .delta.): 10.01 (s, br,
1H, OH), 8.46 (d, J=1.6 Hz, 2H), 8.28 (d, J=8.0 Hz, 4H), 8.17 (t,
J=1.6 Hz, 1H), 7.66 (d, J=8.0 Hz, 4H), 7.59 (d, J=8.0 Hz, 1H), 7.50
(m, 5H), 7.34 (m, 5H), 7.00 (dd, J.sub.1=8.4 Hz, J.sub.2=2.4 Hz,
1H). MS-EI (m/z): [M].sup.+ calcd for
C.sub.38H.sub.24N.sub.4O.sub.2, 568.2, found 568.2.
Example 2
Synthesis of Ambipolar Monomers (See FIGS. 6-8)
Synthesis of
2-(4-carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
mixed with
2-(4-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
##STR00071##
[0198] To a solution of
3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (1.0 g,
2.48 mmol) and
1-(chloromethyl)-4-vinylbenzene/1-(chloromethyl)-3-vinylbenzene
(1:1) (0.4 g, 2.62 mmol) in DMF (20.0 ml) was added K.sub.2CO.sub.3
(4.0 g, 28.94 mmol) at room temperature under stirring. The
reaction was carried out at room temperature for 23 h. Water (100.0
ml) was added. Brown solid product was obtained by filtration. The
crude product was purified by silica gel column chromatography
using dichloromethane as eluent. After removal of solvent, white
solid product was recrystallized from THF/methanol/water. White
pure solid product was obtained by filtration. After vacuum dry,
the product as white solid in 1.16 g (89.9%) was obtained. .sup.1H
NMR (400 MHz, CDCl.sub.3, .delta.): 8.36 (d, J=8.4 Hz, 2 H), 8.14
(d, J=8.0 Hz, 2H), 7.80-7.75 (m, 4H), 7.52-7.30 (m, 11H), 7.19 (m,
1 H), 6.78-6.69 (m, 1H, C.dbd.C--H), 5.81-5.74 (m, 1H, C.dbd.C--H),
5.30-5.25 (m, 1H, C.dbd.C--H), 5.16 (s, 1H, 0.5.times.OCH.sub.2),
5.15 (s, 1H, 0.5.times.OCH.sub.2). .sup.13C NMR (100 MHz,
CDCl.sub.3, .delta.): 164.76, 163.97, 159.54, 140.86, 140.20,
136.94, 132.34, 130.22, 128.55, 127.18, 126.20, 124.79, 123.75,
122.40, 120.55, 120.45, 119.10, 118.66, 112.26, 109.67, 68.31,
49.53, 45.37, 42.48, 38.65, 34.67, 32.38, 29.18, 28.37, 26.24.
[M].sup.+ calcd for C.sub.35H.sub.25N.sub.3O.sub.2, 519.2, found
519.2. Anal. Calcd for C.sub.35H.sub.25N.sub.3O.sub.2: C, 80.90; H,
4.85; N, 8.09. Found: C, 80.61; H, 4.87; N, 8.05.
Synthesis of
2-(3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate
##STR00072##
[0200] To a solution of
3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (1.0 g,
2.48 mmol) and 2-bromoethyl methacrylate (0.5 g, 2.59 mmol) in DMF
(20.0 ml) was added K.sub.2CO.sub.3 (4.0 g, 28.94 mmol) at room
temperature under stirring. The reaction was carried out at room
temperature for 23.5 h. Water (100.0 ml) was added. Brown solid
product was obtained by filtration. The crude product was purified
by silica gel column chromatography using dichloromethane/ethyl
acetate (9.7:0.3) as eluent. After removal of solvent, white
glass-like solid product was dissolved in acetone. The acetone
solution was slowly dropped into methanol (60.0 ml) under stirring.
After addition of acetone solution, water (30.0 ml) was added into
this solution. White solid product was obtained and collected by
filtration. After vacuum dry, the product as white solid in 0.98 g
(76.6%) was obtained. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.):
8.37 (d, J=8.0 Hz, 2H), 8.14 (dd, J.sub.1=8.0 Hz, J.sub.2=0.8 Hz, 2
Hz), 7.78-7.72 (m, 4H), 7.50-7.41 (m, 5H), 7.31 (m, 2H), 7.12 (dd,
J.sub.1=8.0 Hz, J.sub.2=2.4 Hz, 1H), 6.16 (d, J=0.4 Hz, 1H,
C.dbd.C--H), 5.59 (t, J=0.8 Hz, 1H, C.dbd.C--H), 4.55 (t, J=4.8 Hz,
2H, OCH.sub.2), 4.33 (t, J=4.8 Hz, 2H, OCH.sub.2), 1.96 (s, 3H,
CH.sub.3). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 167.28,
164.57, 164.06, 140.94, 140.22, 135.89, 130.40, 128.59, 127.21,
126.21, 124.97, 123.78, 122.34, 120.58, 120.47, 119.79, 118.74,
112.47, 109.87, 66.22, 62.86, 18.30. [M].sup.+ calcd for
C.sub.32H.sub.25N.sub.3O.sub.4, 515.2, found 515.2. Anal. Calcd for
C.sub.32H.sub.25N.sub.3O.sub.4: C, 74.55; H, 4.89; N, 8.15. Found:
C, 74.29; H, 4.79; N, 8.13.
Synthesis of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-yl)penty-
loxy)phenyl)-1,3,4-oxadiazole
##STR00073##
[0202] To a solution of
3-(5-(3,5-dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (0.90
g, 2.23 mmol) and 5-(bromomethyl)bicycle[2,2,1]hept-2-ene (0.74 g,
3.04 mmol) in DMF (10.0 ml) was added K.sub.2CO.sub.3 (5.0 g, 36.18
mmol) at room temperature under stirring. The reaction was carried
out at room temperature for 24 h. Water (150.0 ml) was added. Brown
semi-solid product was obtained by filtration. The crude product
was purified by silica gel column chromatography using
toluene/ethyl acetate (9.5:0.5) as eluent. After removal of
solvents, glass-like solid was obtained. Acetone (3.0 ml) was added
into this glass-like solid, at beginning solid was disappeared.
However, after several min, white solid was appeared. The methanol
(90%) in water was added into acetone solution under stirring.
White solid product was obtained by filtration. After vacuum dry,
the product as white solid in 0.99 g (78.6%) was obtained. .sup.1H
NMR (400 MHz, CDCl.sub.3, .delta.): 8.48 (d, J=1.6 Hz, 2H), 8.17
(d, J=8.0 Hz, 4 Hz), 8.02 (t, J=1.6 Hz, 1H), 7.68-7.58 (m, 6H),
7.50-7.33 (m, 9H), 7.07 (dd, J.sub.1=8.0 Hz, J.sub.2=2.0 Hz, 1H),
6.09 (q, J=2.8 Hz, 0.7H, endo), 6.08 (q, J=2.8 Hz, 0.3H, exo), 6.00
(q, J=2.8 Hz, 0.3H, exo), 5.90 (q, J=2.8 Hz, 0.7H, endo), 4.00 (t,
J=6.4 Hz, 2H, OCH.sub.2), 2.74 (s, br, 1.7H), 2.49 (s, br, 0.3H),
1.96 (m, 1H), 1.81 (m, 2.5H), 1.46-1.03 (m, 7.5H), 0.47 (m, 1H).
.sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 165.24, 163.26,
159.58, 140.47, 140.31, 136.91, 132.33, 130.23, 128.02, 127.42,
126.42, 124.44, 123.81, 123.72, 120.79, 120.59, 119.25, 118.96,
112.29, 109.52, 68.34, 49.52, 45.37, 42.48, 38.64, 34.63, 32.37,
29.13, 28.34, 26.20. [M].sup.+ calcd for
C.sub.50H.sub.42N.sub.4O.sub.2, 730.3, found 730.4. Anal. Calcd for
C.sub.50H.sub.42N.sub.4O.sub.2: C, 82.16; H, 5.79; N, 7.67. Found:
C, 82.31; H, 5.77; N, 7.68.
Synthesis of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadia-
zole mixed with
2-(3,5-dicarbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadia-
zole (1:1)
##STR00074##
[0204] To a solution of
3-(5-(3,5-dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (0.7
g, 1.23 mmol) and
1-(chloromethyl)-4-vinylbenzene/1-(chloromethyl)-3-vinylbenzene
(1:1) (0.2 g, 1.31 mmol) in DMF (20.0 ml) was added K.sub.2CO.sub.3
(2.0 g, 14.47 mmol) at room temperature under stirring. The
reaction was carried out at room temperature for 21 h. Water (100.0
ml) was added. Brown solid product was obtained by filtration and
washed with methanol. The crude product was purified by silica gel
column chromatography using dichloromethane/hexanes (7:3) as
eluent. After removal of solvent, white glass-like solid product
was dissolved in dichloromethane. The solution was added into
methanol (100.0 ml) under stirring. White solid product was
obtained and collected by filtration. After vacuum dry, the product
as white solid in 0.74 g (88.1%) was obtained. .sup.1H NMR (400
MHz, CDCl.sub.3, .delta.): 8.46 (d, J=2.0 Hz, 2H), 8.17 (dd,
J.sub.1=8.0 Hz, J.sub.2=0.8 Hz, 4H), 8.01 (t, J=2.0 Hz, 1H),
7.73-7.69 (m, 2H), 7.58 (d, J=8.0 Hz, 4H), 7.49-7.28 (m, 13H), 7.16
(m, 1H), 6.71-6.62 (m, 1H, C.dbd.C--H), 5.75-5.68 (m, 1H,
C.dbd.C--H), 5.24-5.20 (m, 1H, C.dbd.C--H), 5.11 (s, 1H,
0.5.times.OCH.sub.2), 5.10 (s, 1H, 0.5.times.OCH.sub.2). .sup.13C
NMR (100 MHz, CDCl.sub.3, .delta.): 165.10, 163.28, 159.09, 140.49,
140.31, 137.97, 136.54, 136.42, 136.28, 135.74, 130.38, 128.82,
127.70, 127.38, 126.88, 126.43, 125.98, 125.32, 124.56, 123.83,
123.72, 120.81, 120.60, 119.79, 119.31, 114.38, 114.22, 112.73,
109.52, 70.19, 70.02. [M].sup.+ calcd for
C.sub.47H.sub.32N.sub.4O.sub.2, 684.3, found 684.2. Anal. Calcd for
C.sub.47H.sub.32N.sub.4O.sub.2: C, 82.44; H, 4.71; N, 8.18. Found:
C, 82.18; H, 4.71; N, 8.20.
Synthesis of
2-(3-(5-(3,5-Dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate
##STR00075##
[0206] To a solution of
3-(5-(3,5-dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (0.7
g, 1.23 mmol) and 2-bromoethyl methacrylate (0.25 g, 1.30 mmol) in
DMF (20.0 ml) was added K.sub.2CO.sub.3 (2.0 g, 14.47 mmol) at room
temperature under stirring. The reaction was carried out at room
temperature for 21 h. Water (100.0 ml) was added. Brown solid
product was obtained by filtration and washed with methanol. The
crude product was purified by silica gel column chromatography
using dichloromethane/ethyl acetate (9.5:0.5) as eluent. After
removal of solvent, white glass-like solid product was dissolved in
THF (10.0 ml). Methanol (120.0 ml) was added into THF solution.
White solid product was obtained and collected by filtration. After
vacuum dry, the product as white solid in 0.7 g (83.3%) was
obtained. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.): 8.47 (d,
J=1.6 Hz, 2 H), 8.16 (d, J=8.0 Hz, 4 Hz), 8.01 (d, J=1.6 Hz, 1H),
7.71 (dt, J.sub.1=8.0 Hz, J.sub.2=1.6 Hz, 1H), 7.67 (m, 1H), 7.57
(d, J=8.4 Hz, 4H), 7.49-7.40 (m, 5H), 7.34 (m, 4 H), 7.10 (m, 1H),
6.11 (t, J=1.2 Hz, 1H), 5.55 (m, 1H), 4.49 (t, J=4.4 Hz, 2H,
OCH.sub.2), 4.29 (t, J=4.4 Hz, 2H, OCH.sub.2), 1.92 (t, J=1.2 Hz,
3H, CH.sub.3). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.): 167.24,
165.05, 163.35, 159.01, 140.51, 140.32, 135.85, 130.43, 128.12,
127.36, 126.43, 126.16, 124.60, 123.84, 123.77, 120.82, 120.61,
119.95, 119.09, 112.50, 109.52, 66.24, 62.81, 18.26. [M].sup.+
calcd for C.sub.44H.sub.32N.sub.4O.sub.4, 680.2.2, found 680.2.
Anal. Calcd for C.sub.44H.sub.32N.sub.4O.sub.4: C, 77.63; H, 4.74;
N, 8.23. Found: C, 77.49; H, 4.69; N, 8.21.
Synthesis of
2-(3-Carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
mixed with
2-(3-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
(1:1)
##STR00076##
[0208] To a solution of
3-(5-(3-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (1.0 g,
2.48 mmol) and
1-(chloromethyl)-4-vinylbenzene/1-(chloromethyl)-3-vinylbenzene
(1:1) (0.5 g, 3.28 mmol) in DMF (20.0 ml) was added K.sub.2CO.sub.3
(4.0 g, 28.94 mmol) at room temperature under stirring. The
reaction was carried out at room temperature for 17 h. Water (100.0
ml) was added. Brown solid product was obtained by filtration. The
crude product was purified by silica gel column chromatography
using dichloromethane/ethyl acetate (9.5:0.5) as eluent. After
removal of solvent, white glass-like solid product was obtained.
White solid product was obtained and collected from water by
filtration. After vacuum dry, the product as white solid in 1.17 g
(95.1%) was obtained. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.):
8.32 (m, 1H), 8.25 (m, 1H), 8.16 (dd, J1=8.0 Hz, J2=1.2 Hz, 2H),
7.80-7.69 (m, 4H), 7.47-7.25 (m, 11H), 7.12 (m, 1H), 6.73-6.64 (m,
1H, C.dbd.C--H), 5.77-5.70 (m, 1H, C.dbd.C--H), 5.23-5.22 (m, 1H,
C.dbd.C--H), 5.12 (s, 1H, 0.5.times.OCH.sub.2), 5.11 (s, 1H,
0.5.times.OCH.sub.2). .sup.13C NMR (100 MHz, CDCl.sub.3, .delta.):
164.79, 163.85, 159.07, 140.61, 138.72, 137.97, 137.50, 136.58,
136.45, 136.30, 135.78, 130.85, 130.34, 128.83, 127.74, 126.92,
126.46, 126.20, 125.99, 125.83, 125.41, 125.35, 124.75, 123.56,
120.45, 120.38, 119.70, 119.66, 119.06, 114.40, 114.22, 112.69,
109.55, 70.17, 70.01. [M].sup.+ calcd for
C.sub.35H.sub.25N.sub.3O.sub.2, 519.2, found 519.2. Anal. Calcd for
C.sub.35H.sub.25N.sub.3O.sub.2: C, 80.90; H, 4.85; N, 8.09. Found:
C, 80.69; H, 4.82; N, 8.02.
Synthesis of
2-(3-(5-(3-Carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate
##STR00077##
[0210] To a solution of
3-(5-(3-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (0.80 g,
1.98 mmol) and 2-bromoethyl methacrylate (0.40 g, 2.07 mmol) in DMF
(15.0 ml) was added K.sub.2CO.sub.3 (4.0 g, 28.94 mmol) at room
temperature under stirring. The reaction was carried out at room
temperature for 21 h. Water (100.0 ml) was added. Brown solid
product was obtained by filtration. The crude product was purified
by silica gel column chromatography using dichloromethane/ethyl
acetate (9.5:0.5) as eluent. After removal of solvent, Methanol
(120.0 ml) was added into this glass-like solid. After removal of
methanol, White solid product was obtained and collected from water
by filtration. After vacuum dry, the product as white solid in 0.78
g (76.4%) was obtained. .sup.1H NMR (400 MHz, CDCl.sub.3, .delta.):
8.34 (m, 1H), 8.26 (m, 1H), 8.15 (dd, J.sub.1=8.0 Hz, J.sub.2=0.8
Hz, 2H), 7.78-7.66 (m, 4H), 7.42 (m, 5H), 7.31 (m, 2H), 7.10 (m,
1H), 6.12 (t, J=1.2 Hz, 1H), 5.56 (m, 1H), 4.51 (m, 2H, OCH.sub.2),
4.27 (m, 2H, OCH.sub.2), 1.93 (t, J=1.2 Hz, 3H, CH.sub.3). .sup.13C
NMR (100 MHz, CDCl.sub.3, .delta.): 167.25, 164.71, 163.88, 158.97,
140.61, 138.73, 135.86, 130.86, 130.37, 126.19, 125.85, 125.78,
125.43, 124.80, 123.56, 120.45, 120.37, 119.85, 118.88, 112.42,
109.54, 66.21, 62.84, 18.27. [M].sup.+ calcd for
C.sub.32H.sub.25N.sub.3O.sub.4, 515.2, found 515.2. Anal. Calcd for
C.sub.32H.sub.25N.sub.3O.sub.4: C, 74.55; H, 4.89; N, 8.15. Found:
C, 74.26; H, 4.83; N, 8.03.
Synthesis of
2-(3-carbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-ylmethoxy)ph-
enyl)-1,3,4-oxadiazole
##STR00078##
[0212] To a solution of
3-(5-(3-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenol (1.0 g,
2.48 mmol) and bicycle[2,2,1]hept-5-en-2-ylmethyl
4-methylbenzenesulfonate (0.8 g, 2.93 mmol) in DMF (20.0 ml) was
added Cs.sub.2CO.sub.3 (1.6 g, 4.91 mmol) at room temperature under
stirring. The reaction was heated to 100.degree. C. and carried out
at this temperature for 3 h. Heating was stopped, the reaction
mixture was cooled down to room temperature. Water (120.0 ml) was
added. Brown solid product was obtained by filtration. The crude
product was purified by silica gel column chromatography using
toluene/ethyl acetate (9.5:0.5) as eluent. After removal of
solvents, glass-like solid was obtained. Glass-like solid was
dissolved in acetone and the acetone solution was added into
methanol/water (100.0 ml) (75:25) under stirring White solid was
obtained and collected by filtration. After vacuum dry, the product
as white solid in 1.07 g (84.9%) was obtained. .sup.1H NMR (400
MHz, CDCl.sub.3, .delta.): 8.34 (t, J=1.2 Hz, 1H), 8.27 (m, 1 Hz),
8.17 (d, J=8.0 Hz, 2H), 7.81-7.76 (m, 2H), 7.70-7.61 (m, 2H),
7.46-7.31 (m, 7H), 7.07 (m, 1H), 6.19-5.95 (m, 2H, C.dbd.C--H),
4.10 (dd, J.sub.1=8.8 Hz, J.sub.2=6.0 Hz, 0.6H,
0.3.times.OCH.sub.2), 3.92 (t, J=8.8 Hz, 0.4H,
0.2.times.OCH.sub.2), 3.78 (dd, J.sub.1=8.8 Hz, J.sub.2=6.0 Hz,
0.4H, 0.2.times.OCH.sub.2), 3.62 (t, J=8.8 Hz, 0.6H,
0.3.times.OCH.sub.2), 3.05 (s, br, 0.4H), 2.86 (m, br, 1.6H), 2.57
(m, 1H), 1.92 (m, 1H), 1.50-1.24 (m, 3H), 0.65 (m, 1H). .sup.13C
NMR (100 MHz, CDCl.sub.3, .delta.): 164.91, 163.81, 163.83, 159.55,
140.62, 138.71, 137.65, 136.88, 136.36, 132.26, 130.83, 130.31,
130.28, 130.21, 130.16, 126.19, 125.85, 125.42, 124.68, 124.63,
123.56, 120.45, 120.37, 119.23, 119.13, 118.84, 118.81, 112.28,
112.23, 109.55, 72.55, 71.75, 49.41, 45.04, 43.86, 43.68, 42.21,
41.58, 38.52, 38.30, 29.60, 28.98. [M].sup.+ calcd for
C.sub.34H.sub.27N.sub.3O.sub.2, 509.2, found 509.2. Anal. Calcd for
C.sub.34H.sub.27N.sub.3O.sub.2: C, 80.13; H, 5.35; N, 8.25. Found:
C, 80.00; H, 5.33; N, 8.19.
Example 3
Synthesis of Ambipolar Homopolymers (See FIGS. 9-10)
Synthesis of
Poly(2-(3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate)("Ambi-Polymer 1")
##STR00079##
[0214] A Schlenk flask was charged with
2-(3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate (0.5 g, 0.97 mmol), AIBN (2.5 mg, 0.015 mmol) and dry
THF (4.0 ml). Polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 72 h. After cooling to room temperature, the
polymer was precipitated with ethanol. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with ethanol again. This
dissolution/precipitation procedure was repeated three more times.
The collected polymer was dried under vacuum. After vacuum dry, the
polymer as white solid in 0.47 g (92.2%) was obtained. .sup.1H-NMR
(400 MHz, CDCl.sub.3, .delta.): 8.01 (s, br), 7.94 (s, br), 7.43
(m, br), 7.23 (m, br), 7.13 (m, br), 6.89 (m, br), 4.12 (m, br),
1.97 (s, br), 1.00 (m, br). GPC(CHCl.sub.3): M.sub.w=150000,
M.sub.n=21000, PDI=7.1. Anal. Calcd for
C.sub.32H.sub.25N.sub.3O.sub.4: C, 74.55; H, 4.89; N, 8.15. Found:
C, 73.64; H, 4.80; N, 7.94.
Synthesis of
Poly(2-(3-(5-(3-Carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate) ("Ambi-Polymer 2")
##STR00080##
[0216] A Schlenk flask was charged with
2-(3-(5-(3-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate (0.5 g, 0.97 mmol), AIBN (2.5 mg, 0.015 mmol) and dry
THF (6.0 ml). The polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 73 h. After cooling to room temperature, the
polymer was precipitated with ethanol. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with ethanol again. This
dissolution/precipitation procedure was repeated three more times.
The collected polymer was dried under vacuum. After vacuum dry, the
polymer as white solid in 0.46 g (92.0%) was obtained. .sup.1H-NMR
(400 MHz, CDCl.sub.3, .delta.): 8.06 (s, br), 7.93 (m, br), 7.44
(s, br), 7.22 (m, br), 7.10 (s, br), 6.81 (m, br), 4.04 (m, br),
1.82 (s, br), 1.00 (m, br). GPC(CHCl.sub.3): M.sub.w=103000,
M.sub.n=15000, PDI=6.9. Anal. Calcd for
C.sub.32H.sub.25N.sub.3O.sub.4: C, 74.55; H, 4.89; N, 8.15. Found:
C, 73.95; H, 4.72; N, 8.02.
Synthesis of
Poly(2-(3-(5-(3,5-Dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)eth-
yl methacrylate) ("Ambi-Polymer 3")
##STR00081##
[0218] A Schlenk flask was charged with
2-(3-(5-(3,5-dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate (0.5 g, 0.73 mmol), AIBN (2.0 mg, 0.012 mmol) and dry
THF (5.0 ml). The polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 72 h. After cooling to room temperature, the
polymer was precipitated with ethanol. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with ethanol again. This
dissolution/precipitation procedure was repeated three more times.
The collected polymer was dried under vacuum. After vacuum dry, the
polymer as white solid in 0.46 g (92.0%) was obtained. .sup.1H-NMR
(400 MHz, CDCl.sub.3, .delta.): 8.10 (s, br), 7.82 (s, br), 7.62
(s, br), 7.31 (m, br), 7.23 (m, br), 7.17 (s, br), 7.04 (s, br),
6.78 (m, br), 3.90 (m, br), 1.73 (m, br), 0.81 (m, br).
GPC(CHCl.sub.3): M.sub.w=140000, M.sub.n=19000, PDI=7.4. Anal.
Calcd for C.sub.44H.sub.32N.sub.4O.sub.4: C, 77.63; H, 4.74; N,
8.23. Found: C, 77.12; H, 4.63; N, 8.16.
Synthesis of
Poly(2-(4-carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadi-
azole-2-(4-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadi-
azole (1:1))
##STR00082##
[0220] Schlenk flask was charged with
2-(4-carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
mixed with
2-(4-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
(1:1) (0.5 g, 0.96 mmol), AIBN (3.95 mg, 0.024 mmol) and dry THF
(12.0 ml). The polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 72 h. After cooling to room temperature, the
polymer was precipitated with ethanol. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with acetone again. This
dissolution/precipitation (dichloromethane/acetone) procedure was
repeated three more times. The collected polymer was dried under
vacuum. After vacuum dry, the polymer as white solid in 0.23 g
(46.0%) was obtained. .sup.1H-NMR (400 MHz, CDCl.sub.3, .delta.):
8.00 (m, br), 7.45 (s, br), 7.28 (m, br), 7.15 (s, br), 6.85 (s,
br), 4.81 (m, br), 2.05-1.00 (m, br). GPC (CHCl.sub.3):
M.sub.w=73000, M.sub.n=28000, PDI=2.6. Anal. Calcd for
C.sub.35H.sub.25N.sub.3O.sub.2: C, 80.90; H, 4.85; N, 8.09. Found:
C, 80.30; H, 4.73; N, 8.10.
Synthesis of
Poly(2-(3-Carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadi-
azole-2-(3-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadi-
azole (1:1))
##STR00083##
[0222] A Schlenk flask was charged with
2-(3-Carbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
mixed with
2-(3-carbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadiazole
(1:1) (0.5 g, 0.96 mmol), AIBN (3.95 mg, 0.024 mmol) and dry THF
(7.0 ml). The polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 7 days. After cooling to room temperature, the
polymer was precipitated with acetone. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with acetone again. This
dissolution/precipitation procedure was repeated three more times.
The collected polymer was dried under vacuum. After vacuum dry, the
polymer as white solid in 0.44 g (88.0%) was obtained. .sup.1H-NMR
(400 MHz, CDCl.sub.3, .delta.): 8.09 (s, br), 7.96 (s, br), 7.46
(m, br), 7.25 (m, br), 7.14 (s, br), 7.03 (m, br), 6.81 (m, br),
6.42 (m, br), 4.71 (m, br), 2.00-1.00 (m, br). GPC (CHCl.sub.3):
M.sub.w=81000, M.sub.n=21000, PDI=4.0. Anal. Calcd for
C.sub.35H.sub.25N.sub.3O.sub.2: C, 80.90; H, 4.85; N, 8.09. Found:
C, 80.66; H, 4.76; N, 8.06.
Synthesis of
Poly(2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-o-
xadiazole-2-(3,5-dicarbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3-
,4-oxadiazole (1:1))
##STR00084##
[0224] A Schlenk flask was charged with
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(4-vinylbenzyloxy)phenyl)-1,3,4-oxadia-
zole mixed with
2-(3,5-dicarbazol-9-ylphenyl)-5-(3-(3-vinylbenzyloxy)phenyl)-1,3,4-oxadia-
zole (1:1) (0.5 g, 0.73 mmol), AIBN (3.0 mg, 0.018 mmol) and dry
THF (7.0 ml). The polymerization mixture was purged with nitrogen
(removal of oxygen), securely sealed under nitrogen, and heated to
60.degree. C. The polymerization was carried out at 60.degree. C.
with stirring for 7 days. After cooling to room temperature, the
polymer was precipitated with acetone. The white polymer
precipitate was collected by filtration, dissolved in
dichloromethane, and precipitated with acetone again. This
dissolution/precipitation procedure was repeated three more times.
The collected polymer was dried under vacuum. After vacuum dry, the
polymer as white solid in 0.42 g (84.0%) was obtained. .sup.1H-NMR
(400 MHz, CDCl.sub.3, .delta.): 8.10 (s, br), 7.86 (s, br), 7.67
(s, br), 7.35 (s, br), 7.21 (m, br), 7.08-6.60 (m, br), 6.30 (m,
br), 4.62 (m, br), 2.00-1.00 (m, br). GPC (CHCl.sub.3):
M.sub.w=68000, M.sub.n=17000, PDI=4.0. Anal. Calcd for
C.sub.47H.sub.32N.sub.4O.sub.2: C, 82.44; H, 4.71; N, 8.19. Found:
C, 82.29; H, 4.63; N, 8.19.
Synthesis of
Poly(2-(4-carbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-yl)pent-
yloxy)phenyl)-1,3,4-oxadiazole)
##STR00085##
[0226] To a solution of
2-(4-carbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-yl)pentyloxy-
)phenyl)-1,3,4-oxadiazole (0.5 g, 0.883 mmol) in dichloromethane
(8.0 ml) was added Grubbs catalyst 1.sup.st generation (7.2 mg,
0.0088 mmol) in dichloromethane (1.0 ml) at room temperature under
stirring in glove-box. The polymerization was carried out at room
temperature for 22 h. The polymerization mixture was taken out from
glove-box. Ethylvinyl ether (2.0 ml) was added under stirring.
After stirring 60 min, the polymer was precipitated with ethanol
(100.0 ml). The off-white polymer precipitate was collected by
filtration, dissolved in dichloromethane, and precipitated with
ethanol again. This dissolution/precipitation procedure was
repeated two more times. The final collected polymer was dried
under vacuum. After vacuum dry, the polymer as off-white solid in
0.41 g (82.0%) was obtained. .sup.1H-NMR (400 MHz, CDCl.sub.3,
.delta.): 8.28 (s, br), 8.08 (m, br), 7.68 (m, br), 7.38 (m, br),
7.28 (m, br), 7.02 (m, br), 5.26 (m, br), 3.96 (m, br), 2.87 (m,
br), 2.72 (m, br), 2.51 (m, br), 2.37 (m, br), 1.85 (m, br), 1.75
(m, br), 1.41 (m, br), 1.26 m, br), 1.12 (m, br). GPC(CHCl.sub.3):
M.sub.w=150000, M.sub.n=52000, PDI=2.9. Anal. Calcd for
C.sub.38H.sub.35N.sub.3O.sub.2: C, 80.68; H, 6.24; N, 7.43. Found:
C, 79.87; H, 6.16; N, 7.30.
Synthesis of
Poly(2-(3-carbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-ylmetho-
xy)phenyl)-1,3,4-oxadiazole)
##STR00086##
[0228] To a solution of
2-(3-carbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-ylmethoxy)ph-
enyl)-1,3,4-oxadiazole (0.5 g, 0.981 mmol) in dichloromethane (9.0
ml) was added Grubbs catalyst 1.sup.st generation (8.05 mg, 0.0098
mmol) in dichloromethane (1.0 ml) at room temperature under
stirring in glove-box. The polymerization was carried out at room
temperature for 22 h. The polymerization mixture was taken out from
glove-box. Ethylvinyl ether (2.0 ml) was added under stirring.
After stirring 30 min, the polymer was precipitated with ethanol.
The off-white polymer precipitate was collected by filtration,
dissolved in dichloromethane, and precipitated with ethanol again.
This dissolution/precipitation procedure was repeated two more
times. The final collected polymer was dried under vacuum. After
vacuum dry, the polymer as off-white solid in 0.38 g (76.0%) was
obtained. .sup.1H-NMR (400 MHz, CDCl.sub.3, .delta.): 8.26 (s, br),
8.08 (s, br), 7.66 (s, br), 7.57 (m, br), 7.36 (s, br), 7.26 (s,
br), 6.96 (m, br), 5.34 (m, br), 3.74 (m, br), 2.65 (m, br), 2.42
(m, br), 1.90 (m, br), 1.20 (m, br). GPC(CHCl.sub.3):
M.sub.w=190000, M.sub.n=73000, PDI=2.6. Anal. Calcd for
C.sub.34H.sub.27N.sub.3O.sub.2: C, 80.13; H, 5.34; N, 8.11. Found:
C, 79.55; H, 5.22; N, 8.11.
Synthesis of
Poly(2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-yl)-
pentyloxy)phenyl)-1,3,4-oxadiazole)
##STR00087##
[0230] To a solution of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-(5-(bicycle[2,2,1]hept-5-en-2-yl)penty-
loxy)phenyl)-1,3,4-oxadiazole (0.5 g, 0.684 mmol) in
dichloromethane (6.0 ml) was added Grubbs catalyst 1.sup.st
generation (5.6 mg, 0.0068 mmol) in dichloromethane (1.0 ml) at
room temperature under stirring in glove-box. The polymerization
was carried out at room temperature for 22 h. The polymerization
mixture was taken out from glove-box. Ethylvinyl ether (2.0 ml) was
added under stirring. After stirring 30 min, the polymer was
precipitated with ethanol. The off-white polymer precipitate was
collected by filtration, dissolved in dichloromethane, and
precipitated with ethanol again. This dissolution/precipitation
procedure was repeated two more times. The final collected polymer
was dried under vacuum. After vacuum dry, the polymer as off-white
solid in 0.38 g (76.0%) was obtained. .sup.1H-NMR (400 MHz,
CDCl.sub.3, .delta.): 8.39 (s, br), 8.07 (s, br), 7.91 (s, br),
7.53 (d, br), 7.39 (s, br), 7.25 (s, br), 6.94 (m, br), 5.21 (m,
br), 3.87 (m, br), 2.85 (m, br), 2.69 (m, br), 2.47 (m, br), 2.32
(m, br), 1.80 (m, br), 1.66 (m, br), 1.25 (m, br), 1.06 (m, br).
GPC(CHCl.sub.3): M.sub.w=160000, M.sub.n=61000, PDI=2.6. Anal.
Calcd for C.sub.50H.sub.42N.sub.4O.sub.2: C, 82.16; H, 5.79; N,
7.67. Found: C, 81.17; H, 5.74; N, 7.58.
Example 4
Synthesis of Ambipolar Copolymers of Type (IV)
Synthesis of
Poly[11-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)undecyl
bicyclo[2.2.1]hept-5-ene-2-carboxylate]
##STR00088##
[0232] Step 1: 11-(3,6-Diiodo-9H-carbazol-9-yl)undecan-1-ol: To a
solution of 3,6-diiodocarbazole (10.0 g, 23.87 mmol) and
11-bromo-1-undecanol (7.0 g, 27.87 mmol) in DMF (100.0 ml) was
added K.sub.2CO.sub.3 (32.0 g, 231.33 mmol). The reaction was
carried out at room temperature for 24 h. Water (300 ml) was added.
The precipitate was filtered. The crude product was purified by
silica gel column using Hexane/ethyl acetate (7:3) as solvent. 12.4
g (87.9%) of pure product as white solid was obtained. .sup.1H-NMR
(CDCl.sub.3, TMS, 500 MHZ): .delta.=8.32 (d, 2H.sub.arom, J=1.5
Hz), 7.71 (dd, 2H.sub.arom, J.sub.1=1.5 Hz, J.sub.2=8.5 Hz), 7.16
(dd, 2 H.sub.arom, J1=1.5 Hz, J2=8.5 Hz), 4.21 (t, 2H, NCH.sub.2),
3.64 (m, 2H, OCH.sub.2), 3.41 (t, 1H, OH), 1.81 (m, 4H,
2.times.CH.sub.2), 1.54 (m, 4H, 2.times.CH.sub.2), 1.30 (m, 10H,
5.times.CH.sub.2) ppm.
[0233] Step 2:
11-(6-(9H-Carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)undecan-1-ol: To a
solution of 11-(3,6-Diiodo-9H-carbazol-9-yl)undecan-1-ol (8.0 g,
13.6 mmol), carbazole (6.8 g, 40.7 mmol) in DMSO (50.0 ml) were
added Cu (10.0 g, 157.38 mmol) and Na.sub.2CO.sub.3 (30.0 g, 283.05
mmol). The reaction was stirred at 180.degree. C. for 12 h.
Insoluble inorganic salts were removed by filtration and washed
with THF. After removal of THF, water (250.0 ml) was added. The
precipitate was collected by filtration and purified by silica gel
column using toluene/ethyl acetate (7:3) as solvent. 8.1 g (91.0%)
of product was obtained as white solid. .sup.1H (300 MHz,
CDCl.sub.3): .delta.8.13-8.24 (m, 5H), 7.63-7.71 (m, 4H), 7.22-7.43
(m, 13H), 4.49 (t, J=6.98 Hz, 2H), 3.62 (t, J=6.34 Hz, 2H), 2.05
(p, J=7.28 Hz, 2H), 1.23-1.77 (m, 18H), 1.18 (s, 1H).
.sup.13C{.sup.1H} (75 MHz, CDCl.sub.3): .delta.42.09, 140.42,
129.54, 126.19, 126.08, 123.62, 123.35, 123.33, 120.51, 120.07,
119.85, 110.34, 109.97, 63.31, 43.94, 33.02, 29.82, 29.79, 29.71,
29.66, 29.43, 27.66, 25.98. ELMS (m/z): M.sup.+ calcd for
C.sub.47H.sub.45N.sub.3O, 667.36; found 667.4. Elemental Analysis
Calculated for C.sub.47H.sub.45N.sub.3O: C, 84.52; H, 6.79; N,
6.29. Found: C, 84.37; H, 6.74; N, 6.29.
[0234] Step 3:
11-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)undecyl
bicyclo[2.2.1]hept-5-ene-2-carboxylate: The purified product of
prepared in step 2, (0.501 g, 0.75 mmol), 5-norbornene-2-carboxylic
acid (0.235 g, 1.70 mmol) and 10 mL of dry THF were combined in a
round bottom flask (with stirring) and cooled in an ice bath for 20
minutes. DCC (0.17 g, 0.82 mmol) and DMAP (0.02 g, 0.16 mmol) were
weighed (on weighing paper) and added to the reaction flask. The
flask was subsequently removed from the ice bath and allowed to
warm to room temperature. The reaction proceeded overnight for 18
hours. The TLC showed the presence of starting material the next
day, therefore more DCC (0.10 g, 0.48 mmol) was added to the
reaction flask. After about 4 hours, TLC still showed the presence
of the starting material. Additional 5-norbornene-2-carboxylic acid
(0.02 g, 0.14 mmol) and DCC (0.04 g, 0.19 mmol) was added to the
flask and the reaction was allowed to proceed overnight for 18
hours. TLC still showed the presence of starting material the next
day so the reaction was stopped. The reaction mixture was filtered
to remove the insoluble DCC by-product and the filtrate was
rotovapped to give white precipitate. The precipitate was
recrystallized (2 times) from acetone with methanol but the
starting material impurity remained (as observed by TLC). Column
chromatography (silica gel, hexanes:ethyl acetate=8:2) was used to
purify the product followed by recrystallization from acetone with
methanol and vacuum drying overnight. Solvent contamination (as
observed by .sup.1H NMR) required additional recrystallization from
dichloromethane with methanol. The purified product was collected
by vacuum filtration and dried overnight at 60.degree. C. in a
vacuum oven (for 16 hours) to give a white powder (0.42 g, 71.2%).
.sup.1H (300 MHz, CDCl.sub.3): .delta.22-1.69 (m, 18H), 1.83-1.96
(m, 1H), 2.05 (p, J=7.4 Hz, 2H), 2.17-2.25 (m, 1H), 2.86-2.98 (m,
1H), 3.03 (s, 1H), 3.19 (s, 1H), 5.88-5.94 (m, 1H), 6.07-6.22 (m,
1H), 7.16-7.50 (m, 13H), 7.66 (m, 4H), 8.13-8.24 (m, 5H). .sup.13C
{.sup.1H} (75 MHz, CDCl.sub.3): .delta. 175.11, 142.10, 138.29,
137.99, 132.59, 129.53, 126.20, 126.08, 126.06, 123.35, 123.33,
120.54, 120.52, 119.85, 110.34, 109.94, 64.55, 49.86, 45.96, 43.60,
42.77, 29.80, 29.76, 29.74, 29.48, 29.46, 29.44, 29.40, 28.91,
27.69, 26.19. EI-MS (m/z): M.sup.+ calcd for
C.sub.55H.sub.53N.sub.3O.sub.2, 787.41; found 787.4. Elemental
analysis calculated. for C.sub.55H.sub.53N.sub.3O.sub.2: C, 83.83;
H, 6.78; N, 5.33. Found: C, 83.70; H, 6.72; N, 5.28.
[0235] Synthesis of di-Oxadiazole Monomer
243-(Bicyclo[2,2,1]hept-5en-2-ylmethoxy)phenyl)-5-(3-(5-(4-tert-butylphen-
yl)-1,3,4-oxadiazol-2-yl)phenyl)-1,3,4-oxadiazole: The following
synthesis and similar syntheses of similar monomers comprising
oxadiazole groups linked to norbornenyl groups has been previously
reported in PCT Application Serial No. PCT/EP/2008 068119 filed 19
Dec. 2008, the disclosures of which are hereby incorporated herein
by reference.
##STR00089##
[0236] Step 1:
3-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)-N'-(3-methyoxybenzoyl)ben-
zohydrazine: To a solution of
3-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)benzohydrazine (1.5
g, 4.46 mmol) in dry tetrahydrofuran (50.0 ml) and DMF (5.0 ml),
was slowly added 3-methoxybenzoyl chloride (0.8 g, 4.69 mmol) at
room temperature under nitrogen. During addition of
3-methoxybenzoyl chloride, white solids appeared. The reaction
mixture was stirred at room temperature for 21 hours and then
pyridine (10.0 ml) was added and stirred for another hour. Then,
water (300.0 ml) was added into the reaction mixture. The white
solid was collected by filtration and dried overnight under vacuum
and provided 1.9 g (90.4%) yield. .sup.1H NMR (400 MHz,
DMSO-d.sub.6) .delta.: 10.83 (s, br, 1H, NH), 10.64 (s, br, NH),
8.66 (s, 1H), 8.34 (d, 1H, J=7.6 Hz), 8.17 (d, 1H, J=7.6 Hz), 8.07
(d, 2H, J=8.0 Hz), 7.80 (t, 1H, J=7.6 Hz), 7.65 (d, 2H, J=8.0 Hz),
7.54-7.43 (m, 3H), 7.17 (d, 1H, J=8.0 Hz), 3.83 (s, 3H, OCH.sub.3),
1.33 (s, 9H, 3.times.CH.sub.3) ppm.
[0237] Step 2:
2-(4-tert-Butylphenyl)-5-(3-(5-(3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)phe-
nyl)-1,3,4-oxadiazole:
3-(5-(4-tert-Butylphenyl)-1,3,4-oxadiazol-2-yl)-N'-(3-methyoxy-benzoyl)be-
nzohydrazine (1.75 g, 3.72 mmol) was added in POCl.sub.3 (15.0 ml).
The reaction was heated to 90.degree. C. and kept at this
temperature for 4 hours. After cooling down to room temperature,
the reaction mixture was slowly dropped into ice-water (300.0 ml).
The white solid formed was collected by vacuum filtration. The
crude product was dried and purified by a silica gel column using
dichloromethane/ethyl acetate, ratio (9:1), as the eluent. After
the removal of the solvents, a pure white solid product was
obtained in 1.18 g (70.2%) yield. .sup.1H NMR (400 MHz, CDCl.sub.3)
.delta.: 8.86 (t, 1H, J=1.6 Hz), 8.34 (dt, 2H, J.sub.1=7.6 Hz,
J.sub.2=1.6 Hz), 8.11 (d, 2H, J=8.4 Hz), 7.73 (m, 3H), 7.57 (d, 2H,
J=8.4 Hz), 7.47 (t, 1H, J=7.6 Hz), 7.32 (dd, 1H, J.sub.j=7.6 Hz,
J.sub.2=1.6 Hz), 3.93 (s, 3H, OCH.sub.3), 1.39 (s, 9H,
3.times.CH.sub.3) ppm. .sup.13C NMR (100 MHz, CDCl.sub.3) .delta.:
165.11, 164.94, 163.62, 163.34, 159.95, 155.64, 130.26, 129.97,
129.74, 126.89, 126.10, 125.10, 124.92, 124.90, 124.65, 120.70,
119.42, 118.42, 111.60, 55.56, 35.10, 31.08 ppm. MS-EI (m/z):
[M].sup.+ calcd for C.sub.28H.sub.24N.sub.4O.sub.4 452.2, found
452.2.
[0238] Step 3:
3-(5-(3-(5-(4-tert-Butylphenyl)-1,3,4-oxadiazol-2-yl)phenyl)-1,3,4-oxadia-
zol-2-yl)phenol (YZ-I-269): To a solution of
2-(4-tert-butylphenyl)-5-(3-(5-(3-methoxyphenyl)-1,3,4-oxadiazol-2-yl)phe-
nyl)-1,3,4-oxadiazole (1.0 g, 2.21 mmol) in dichloromethane (30.0
ml), was dropwise added BBr.sub.3 (16.0 ml, 1 M in dichloromethane)
at -78.degree. C. (dry-ice/acetone) under nitrogen. After the
addition of the BBr.sub.3 solution, the reaction was taken to room
temperature and kept at room temperature for 7 hours. The reaction
mixture was poured into ice-water (150.0 ml). Dichloromethane was
evaporated under reduced pressure. The white solid was collected by
filtration. After drying under vacuum, a white solid product was
obtained in 0.98 g (100%) yield. .delta.: 10.02 (s, 1H), 8.68 (s,
1H), 8.31 (m, 2H), 8.07 (d, 2H, J=8.4 Hz), 7.86 (t, 1H, J=8.0 Hz),
7.63 (d, 2H, J=8.4 Hz), 7.58 (d, 1H, J=7.6 Hz), 7.53 (s, 1H), 7.42
(t, 1H, J=7.6 Hz), 7.03 (dd, 1H, J.sub.1=7.6 Hz, J.sub.2=1.6 Hz),
1.32 (s, 9H, 3.times.CH.sub.3) ppm.
[0239] Step 4:
2-(3-(Bicyclo[2,2,1]hept-5en-2-ylmethoxy)phenyl)-5-(3-(5-(4-tert-butylphe-
nyl)-1,3,4-oxadiazol-2-yl)phenyl)-1,3,4-oxadiazole: To a solution
of
3-(5-(3-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)phenyl)-1,3,4-oxadia-
zol-2-yl)phenol (0.92 g, 2.10 mmol) and
bicyclo[2,2,1]hept-5-en-2-ylmethyl 4-methylbenzenesulfonate (1.6 g,
5.75 mmol) in DMF (45.0 ml), was added Cs.sub.2CO.sub.3 (4.5 g,
13.81 mmol) at room temperature under nitrogen. The reaction was
carried out at 100.degree. C. for 2 hours. After cooling down to
room temperature, water (100.0 ml) was added into the reaction
mixture. A brown solid precipitate was collected by filtration and
washed with methanol and then dried under vacuum. The crude product
was purified by a silica gel column using dichloromethane/ethyl
acetate, ratio (9.3:0.7), as the eluent. After removal of the
solvents, a pure white solid product was obtained in 0.97 g (85.1%)
yield by recrystallization from dichloromethane/methanol. .sup.1H
NMR (400 MHz, CDCl.sub.3) .delta.: 8.86 (m, 1H), 8.34 (dd, 2H,
J.sub.1=8.0 Hz, J.sub.2=1.6 Hz), 8.11 (d, 2H, J=8.4 Hz), 7.73 (m,
2H), 7.67 (m, 1 H), 7.58 (d, 2H, J=8.4 Hz), 7.45 (m, 1H), 7.12 (m,
1H), 6.22-5.99 (m, 2H, C.dbd.C--H, endo and exo), 4.17-3.64 (m, 2H,
OCH.sub.2, endo and exo), 3.09 (s, br), 2.91 (m, br), 2.61 (m, br),
1.95 (m), 1.52 (m), 1.39 (s, 9H, 3.times.CH.sub.3), 1.40-1.23 (m),
0.68 (m) ppm. .sup.13C NMR (100 MHz, CDCl.sub.3) .delta.: 165.14,
163.65, 163.38, 159.57, 155.67, 137.68, 136.90, 136.38, 132.29,
130.26, 129.99, 129.77, 129.71, 126.92, 126.13, 125.13, 124.98,
124.94, 124.61, 120.73, 119.31, 119.22, 118.90, 112.29, 72.57,
71.78, 49.42, 45.06, 43.87, 43.69, 42.23, 41.60, 38.54, 38.32,
35.12, 31.10, 29.62, 28.99 ppm. MS (m/z): [M+1].sup.+ calcd for
C.sub.34H.sub.32N.sub.4O.sub.3 545.3, found 545.2. Anal. Calcd for
C.sub.34H.sub.32N.sub.4O.sub.3: C, 74.98; H, 5.92; N, 10.29. Found:
C, 74.77; H, 6.02; N, 10.27.
[0240] Copolymerization of Norbornenyl Tricarbazole and Norbornenyl
Dioxadiazole Monomers to Form Class (IV) Copolymer--
##STR00090##
[0241]
2-(3-(Bicyclo[2,2,1]hept-5en-2-ylmethoxy)phenyl)-5-(3-(5-(4-tert-bu-
tylphenyl)-1,3,4-oxadiazol-2-yl)phenyl)-1,3,4-oxadiazole monomer
(0.201 g, 0.37 mmol) and
11-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)undecyl
bicyclo[2.2.1]hept-5-ene-2-carboxylate monomer (0.288 g, 0.37 mmol)
were weighed into a bottle. Grubbs' first generation catalyst
(0.0076 g, 9.2.times.10.sup.-3 mmol) was weighed out into separate
vial. The bottle and vial were placed into a glovebox. 6.0 mL of
dry CH.sub.2Cl.sub.2 was added to the bottle containing the
monomers. 1.0 mL of dry CH.sub.2Cl.sub.2 was added to vial
containing Grubbs' first generation catalyst and solution was
quickly added to monomer solution. An additional 1.0 mL of
CH.sub.2Cl.sub.2 was added to catalyst vial (for washing) and
solution was transferred into the monomer bottle. The
polymerization was allowed to proceed overnight for 20 hours. The
reaction mixture was concentrated (under vacuum) and quenched (out
of glovebox) with 3.0 mL of ethyl vinyl ether and then transferred
(dropwise) into 40.0 mL of methanol to precipitate polymer. The
polymer was then vacuum filtered and re-dissolved with minimal
(<3.0 mL) CH.sub.2Cl.sub.2. The solution was then added
(dropwise) to 30.0 mL of methanol to precipitate polymer. Process
of isolating, dissolving, and vacuum filtering polymer repeated
three more repetitions in order to purify polymer. Final product
was dried under vacuum to give a white/off-white powder (0.261 g,
53.4%). .sup.1H (300 MHz, CDCl.sub.3): .delta.8.66-8.83 (br, 1H),
7.94-8.29 (br, 6H), 7.44-7.74 (br, 6H), 6.91-7.44 (br, 13H),
5.08-5.47 (br, 2H), 4.24-4.51 (br, 2H), 3.67-4.08 (br, 4H),
1.82-3.23 (br, 7H), 1.00-1.82 (br, 27H). Elemental anal. calcd.,
79.41; H, 6.35; N, 7.81. Found: C, 78.74; H, 6.43; N, 7.24. Gel
Permeation Chromatography (THF): M, =261,000; M.sub.n=68,000;
PDI=3.813.
Example 5
OLED Devices Comprising Homopolymers of Ambipolar Monomers
[0242] Multi-layer OLED devices were prepared as generally
described below, using solutions of the ambiopolar homopolymers
described herein and a known monomeric phosphorescent Iridium
complex to form the emission layer of the OLED devices, as further
described below.
[0243] In examples employing ambipolar homopolyers of class (I),
(II), or (III), 35 nm thick hole injection and hole transporting
layer of Poly-TPD-F was typically formed by spin coating on a
pre-cleaned ITO substrate, then, this hole transporting layer was
photo-crosslinked. On the top of crosslinked hole transporting
layer, a 40 nm thick emission layer of one of the ambipolar
polymers described herein was doped with 10 wt % Ir(ppy).sub.3 and
coated by spin coating. Then, the emitting layer was capped with a
40 nm thick layer of BCP used as hole blocking and electron
transporting layer by thermally evaporated. Finally, 2.5 nm of LiF
as an electron-injection layer and a 200 nm-thick aluminum cathode
were vacuum deposited on the top of BCP.
[0244] For the hole-transport layer, 10 mg of Poly-TPD-F was
dissolved in 1.0 ml of distilled and degassed toluene. For the
emissive layer, three individual solutions of the ambipolar
methacrylate homopolymers
Poly(2-(3-(5-(4-carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate), i.e. "Ambi-Polymer 1";
Poly(2-(3-(5-(3-Carbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)ethyl
methacrylate), i.e. "Ambi-Polymer 2"; and
Poly(2-(3-(5-(3,5-Dicarbazol-9-ylphenyl)-1,3,4-oxadiazol-2-yl)phenoxy)eth-
yl methacrylate),), i.e. "Ambi-Polymer 3"; were prepared by
dissolving 9.4 mg of the polymers and 0.6 mg of fac
tris(2-phenylpyridinato-N,C2') iridium [Ir(ppy).sub.3] in 1.0 ml of
distilled and degassed chlorobenzene. All solutions were made under
inert atmosphere and were stirred overnight.
[0245] 35 nm thick films of the hole-transport material were spin
coated (60 s at 1500 rpm, acceleration 10,000) onto air plasma
treated indium tin oxide (ITO) coated glass substrates with a sheet
resistance of 20.OMEGA./.quadrature. (Colorado Concept Coatings,
L.L.C.). Films were photo-crosslinked with a standard broad-band UV
light with a 0.7 mW/cm.sup.2 power density for 1.0 minute.
Subsequently, a 40 nm-thick film of ambipolar polymer doped 6.0%
(ratio in weight) of green phosphorescent compound (Ir(ppy).sub.3)
was spin coated from its solution on top of the crosslinked
hole-transport layer (60 s at 1000 rpm, acceleration 10,000). For
the hole-blocking layer, bathocuproine
(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, BCP) was first
purified using gradient zone sublimation, and a film of 40 nm was
then thermally evaporated at a rate of 0.4 .ANG./s and at a
pressure below 1.times.10.sup.-7 Torr on top of the emissive
layer.
[0246] Finally, 2.5 nm of lithium fluoride (LiF) as an
electron-injection layer and a 200 nm-thick aluminum cathode were
vacuum deposited at a pressure below 1.times.10.sup.-6 Ton and at
rates of 0.1 .ANG./s and 2 .ANG./s, respectively. A shadow mask was
used for the evaporation of the metal to form five devices with an
area of 0.1 cm.sup.2 per substrate. At no point during fabrication
were the devices were exposed to atmospheric conditions. The
testing was done right after the deposition of the metal cathode in
inert atmosphere without exposing the devices to air.
[0247] Comparison of Ambipolar Homopolymers As Hosts: FIG. 12 shows
the luminance vs. applied voltage and external quantum efficiency
vs. applied voltage characteristics for three ambipolar polymers,
Ambi-Polymer 1, Ambi-Polymer 2, and Ambi-Polymer 3. Devices with
Ambi-Polymer 1 and Ambi-Polymer 1 show low turn-on voltage
.about.4.5 V, and device with Ambi-Polymer 2 has turn-on voltage
.about.5.5 V. The external quantum efficiency obtained in the
devices were .about.10% for Ambi-Polymer 3 at 100 cd/m.sup.2,
.about.9% for Ambi-Polymer 2 at 100 cd/m.sup.2 and .about.7% for
Ambi-Polymer 1 at 100 cd/m.sup.2. The luminance of the all devices
can achieved over several thousand cd/m.sup.2. Based on turn-on
voltage, luminance and external quantum efficiency data,
Ambi-Polymer 3 arguably gave the best performance among these three
host polymers.
[0248] Comparison of OLED Devices Comprising Ambi-Polymer 3 with
Known Mixed Hole Carrying and Electron Carrying Hosts: Our previous
best OLED devices employed emissive layer host materials comprising
the PVK polycarbazole hole carrier, doped with 30% or more of PBD
or OXD-7 as small molecule electron carriers, as well as small
molecule 3d row transition metal complexes as phosphorescent
guests.
[0249] FIG. 13 compares the results of the OLED device comprising
the results of a comparison of the results obtained using the
Ambi-Polymer 3 with devices employing a mixture of PVK:PBD, or a
mixture of PVK:MMEther, where MMEther is polyoxadiazole having the
structure shown below:
##STR00091##
[0250] The OLED device employing Ambi-Polymer 3 gave results
comparable to the two devices based on mixed host materials, but is
likely to be much more stable under heating and/or long-term
use.
[0251] Effect of Addition of Additional Hole or Electron Carriers
on OLED Devices Comprising Ambi-Polymer 2: FIG. 14 shows that
addition of additional hole carrier materials (PVK) or electron
carrier materials (PBD) decreased the performance of OLED devices
comprising Ambi-Polymer 2.
Example 6
OLED Device Comprising an Ambipolar Copolymer of Class (IV)
[0252] An OLED device was fabricated using an ambipolar copolymer
host of class (IV) having the structure shown below, to form the
emission layer.
##STR00092##
[0253] The general experimental details for the device fabrication
were described earlier above. For the emissive layer, a 50 nm layer
was spin coated from a solution of chlorobenzene (10 mg/ml) using
the ambipolar host copolymer indicated above and the previously
known F--Pt emitter complex (structure shown below) in a weight
ratio of 9:1.
##STR00093##
[0254] The Electroluminescence spectrum of the OLED device
utilizing the ambipolar polymer is shown in FIG. 15a. The EL
spectrum of the OLED showed the emissions across the entire visible
spectrum, which gave CIE coordinates in the near-white region and a
high CRI of 90. The CIE coordinates for the WOLED device are shown
in FIG. 15b, as indicated by the arrow on the color coordinate
diagram. It can be seen that the observed CIE coordinate of (0.38,
0.36) is close to a white color coordinate (0.33, 0.33). It is also
worth noting here that this level of white emission was achieved
using less FPt dopant, 10% (by weight percent), than earlier
devices employing only hole transport homopolymers requiring around
18% doping levels for near white emission.
[0255] The current density-voltage (J-V) characteristics for the
WOLEDs with the ambipolar host are shown in FIG. 16a. The luminance
and EQE curves for the respective devices are shown in FIG. 16b.
With respect to efficiency, the WOLED device showed an EQE of
0.3.+-.0.1% (1.+-.1 cd/A)
Example 7
OLED Device Comprising an Ambipolar Small Molecule Hole and
Electron Carrier
[0256] An OLED device was fabricated using the small molecule
ambipolar compound
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazo-
le, whose synthesis is detailed in Example 1, and the known
phosphorescent Iridium complex Ir(ppy).sub.3 (to form the emission
layer).
[0257] For the hole-transport layer, 10 mg of PVK were dissolved in
1 ml of distilled and degassed toluene. 35 nm thick films of the
hole-transport material were spin coated (60 s@1500 rpm,
acceleration 10,000) onto air plasma treated indium tin oxide (ITO)
coated glass substrates with a sheet resistance of 20.OMEGA./square
(Colorado Concept Coatings, L.L.C.). For the emitting layer, a
concentration of 6% Ir(ppy).sub.3 was coevaporated into a
20-nm-thick film of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole.
For the hole-blocking and electron transport layer, BCP was vacuum
deposited at a pressure below 1.times.10.sup.-6 Torr and at rates
of 0.4 .ANG./s, respectively. Finally, 2.5 nm of lithium fluoride
(LiF) as an electron-injection layer and a 200 nm-thick aluminum
cathode were vacuum deposited at a pressure below 1.times.10.sup.-6
Torr and at rates of 0.1 .ANG./s and 2 .ANG./s, respectively. A
shadow mask was used for the evaporation of the metal to form five
devices with an area of 0.1 cm.sup.2 per substrate. The testing was
done right after the deposition of the metal cathode in inert
atmosphere without exposing the devices to air.
[0258] The current-voltage characteristic of the above referenced
device is shown in FIG. 17a. The light output and external quantum
efficiency as a function of voltage are shown in FIG. 17b. The
device referenced above exhibits an external quantum efficiency of
12.4% and 10.1% at a light output level of 100 cd/m.sup.2 and 1,000
cd/m.sup.2, respectively.
[0259] Additional otherwise similar OLED devices, instead utilizing
a 6% dispersion of the well known blue-green emitter iridium
(III)bis[(4,6-di-fluorophenyl)-pyridinato-N,C2']picolinate
(FIrpic), coevaporated into
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole,
to supply the emitting layer, together with either PVK or TCZ as
hole transport layers were also constructed (five devices each) and
tested as already described. The current-voltage characteristic of
the PVK devices are shown in FIG. 18a, and the light output and
external quantum efficiency as a function of voltage are shown in
FIG. 18b. The current-voltage characteristic of the PVK devices are
shown in FIG. 19a, and the light output and external quantum
efficiency as a function of voltage are shown in FIG. 19b
Example 7a
Synthesis and Characterization of a Series of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(substituted-phenyl)-1,3,4-oxadiazoles
[0260] In order to serve as a suitable host material for various
emitter complexes with a variety of emission wavelengths, the
energies of the lowest triplet states LUMO orbitals of the
oxadiazolecarbazoles ("ODZCBZs") disclosed herein, as already
exemplified by
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
as described in Example 7 above, should be rationally tuneable, so
as to properly match with the energies of the various emitter
complexes. Accordingly, Applicants synthesized a series of seven
variously substituted analogs of
2-(3,5-Dicarbazol-9-ylphenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole
(i.e. "ODZCBZ-x" compounds, where x is 1-7), as shown in the
drawing below, FIG. 20, and in Table 1, shown below.
TABLE-US-00001 TABLE 1 The Reduction Potentials of "ODZCBZ-x"
Ambipolar Small Molecules ##STR00094## No. R.sub.7 R.sub.8 R.sub.9
R.sub.10 R.sub.11 E .sub.1/2.sup.0/-1 ODZCBZ-1 --F --F --F --F --F
-2.05 V ODZCBZ-2 --H --H --F --H --H -2.38 V ODZCBZ-3 --H --H --H
--H --H --2.37 V ODZCBZ-4 --H --H --CF.sub.3 --H --H -1.50 V
ODZCBZ-5 --H --H --CH.sub.3 --H --H --2.41 V ODZCBZ-6 --H --H --H
--H --CF.sub.3 -2.25 V ODZCBZ-7 --H --H --H --CF.sub.3 --H -2.29 V
"ODZCBZ-x", where x is 1-7
[0261] Cyclic voltammetry (CV) measurements for each of the
ODZCBZ-x compounds was done in THF with 0.1 M of
(n-Bu).sub.4NPF.sub.6, with Pt wire counter electrode; Ag/AgCl
reference electrode; and 50 mV/s scanning rate, using Ferrocene as
an internal standard. The ODZCBZ-x compounds showed reversible
reductions at between about -1.5 and -2.5 volts vs ferrocene, at
the experimental potentials indicated in Table 1. The presence of
strong electron withdrawing substituents (F, CF.sub.3) at the para
"R.sup.9" position seemed to noticeably lower the reduction
potentials.
Example 8
Synthesis and Characterization of
2-(3-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)phenyl)-5-(3-methoxyph-
enyl)-1,3,4-oxadiazole
##STR00095##
[0263] 2-(3-iodophenyl)-5-(3-methoxyphenyl)-1,3,4-oxadiazole (1.023
g, 2.82 mmol, see Example 1 for preparation) and Triscarbazole
(1.386 g, 2.79 mmol, see Xing et al, Sensors and Actuatord, B 114
(2006) 28-31 for preparation) were added to DMF (25 mL) under
N.sub.2. Then Cu (1.790 g, 28.17 mmol) and K.sub.2CO.sub.3 (3.870
g, 28.00 mmol) were added and the reaction mixture heated to
160.degree. C. for 24 hours. The reaction mixture was cooled to
room temperature and then poured into THF (150 mL), stirring for 1
h. After filtering off all solids, the filtrate was concentrated by
rotary evaporation. Water (100 mL) was then added in to the
concentrated filtrate and the crude product precipitated and was
collected by filtration. The crude product was then dried and
purified by silica gel chromatography (toluene, then toluene:ethyl
acetate=9:1). After the chromatography solvents were removed, the
product was redissolved and reprecipitated in acetone to give a
white solid (0.870 g, 42%),
2-(3-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)phenyl)-5-(3-met-
hoxyphenyl)-1,3,4-oxadiazole.
[0264] .sup.1H NMR (400 MHz, CDCl.sub.3): .delta. (ppm): 8.52 (t,
J=1.6 Hz, br, 1H), 8.35 (dt, J.sub.1=7.2 Hz, J.sub.2=1.6 Hz, br,
1H), 8.29 (d, J=2.0 Hz, 2H), 8.15 (d, J=7.6 Hz, 4H), 7.94 (dt,
J.sub.1=8.0 Hz, J.sub.2=1.6 Hz, br, 1H), 7.91 (q, J=7.6 Hz, 1H),
7.73 (d, J=8.0 Hz, br, 1H), 7.67 (t, J=8.8 Hz, br, 4H), 7.64 (dd,
J.sub.1=8.8 Hz, J.sub.2=2.0 Hz, 1H), 7.45 (t, J=8.0 Hz, 1H), 7.40
(d, J=7.6 Hz, 8H), 7.27 (septet, J=4.0 Hz, 4H), 7.11 (dd,
J.sub.1=8.0 Hz, J.sub.2=2.4 Hz, 1H), 3.90 (s, 3H). .sup.13C NMR
(100 MHz, CDCl.sub.3): .delta. (ppm): 165.03, 163.70, 160.02,
141.68, 140.44, 138.21, 131.26, 130.82, 130.40, 130.34, 126.52,
126.27, 125.92, 125.59, 124.70, 124.21, 123.17, 120.31, 119.86,
119.75, 119.42, 118.37, 111.83, 111.15, 109.65, 99.96. Anal. Calcd.
for C.sub.51H.sub.33N.sub.5O.sub.2: C, 81.91; H, 4.45; N, 9.36.
Found: C, 81.61; H, 4.25; N, 9.30. ESI-Accurate Mass (m/z):
[M.sup.+] calcd. for C.sub.51H.sub.33N.sub.5O.sub.2: 747.26,
748.27, found: 748.2759. UV-Vis (CH.sub.2Cl.sub.2, r.t.): 342 nm,
293 nm, 238 nm (c=1.39.times.10.sup.5 mol.sup.-1Lcm.sup.-1), DSC:
T.sub.g=154.degree. C. TGA: 5% Mass lost at 467.degree. C.CV (vs.
Ferrocene): E.sub.1/2.sup.0/-1=-2.5 V (THF, r.t.),
E.sub.1/2.sup.0/+1=0.53 V (CH.sub.2Cl.sub.2, r.t.),
E.sub.1/2.sup.+1/+2=0.77 V (CH.sub.2Cl.sub.2, r.t.)
[0265] OLED devices comprising emissive layers comprising 6%
Ir(ppy)co-deposited with the
2-(3-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)phenyl)-5-(3-methoxyph-
enyl)-1,3,4-oxadiazole were made via the same procedures already
described to make OLED devices having the configuration ITO/PVK (40
nm)/[6%
Ir(ppy)/3-2-(3-(6-(9H-carbazol-9-yl)-9H-3,9'-bicarbazol-9-yl)phenyl)-5-(3-
-methoxyphenyl)-1,3,4-oxadiazole (20 nm)/BCP (40 nm)/LiF/Al.
[0266] The current-voltage characteristic of the above referenced
devices are shown in FIG. 20a The light output and external quantum
efficiency as a function of voltage are shown in FIG. 20b. The
device referenced above exhibits an external quantum efficiency of
10.5% and 9.5% at a light output level of 100 cd/m.sup.2 and 1,000
cd/m.sup.2, respectively.
CONCLUSIONS
[0267] The above specification, examples and data provide exemplary
description of the manufacture and use of the various compositions
and devices of the inventions, and methods for their manufacture
and use. In view of those disclosures, one of ordinary skill in the
art will be able to envision many additional embodiments or
sub-embodiments of the inventions disclosed and claimed herein to
be obvious, and that they can be made without departing from the
spirit and scope of the inventions disclosed herein. The claims
hereinafter appended define some of those embodiments.
* * * * *