U.S. patent application number 13/053776 was filed with the patent office on 2011-07-14 for aromatic monomer- and conjugated polymer-metal complexes.
This patent application is currently assigned to SUMITOMO CHEMICAL COMPANY, LIMITED. Invention is credited to James J. O'Brien, Wanglin YU.
Application Number | 20110172426 13/053776 |
Document ID | / |
Family ID | 34193124 |
Filed Date | 2011-07-14 |
United States Patent
Application |
20110172426 |
Kind Code |
A1 |
YU; Wanglin ; et
al. |
July 14, 2011 |
AROMATIC MONOMER- AND CONJUGATED POLYMER-METAL COMPLEXES
Abstract
A halogenated aromatic monomer-metal complex useful for
preparing a polymer for electronic devices such as a light-emitting
diode (LED) device is described. The aromatic monomer-metal complex
is designed to include a linking group that disrupts conjugation,
thereby advantageously reducing or preventing electron
delocalization between the aromatic monomer fragment and the metal
complex fragment. Disruption of conjugation is often desirable to
preserve the phosphorescent emission properties of the metal
complex in a polymer formed from the aromatic monomer-metal
complex. The resultant conjugated electroluminescent polymer has
precisely controlled metal complexation and electronic properties
that are substantially or completely independent of those of the
polymer backbone.
Inventors: |
YU; Wanglin; (Midland,
MI) ; O'Brien; James J.; (Midland, MI) |
Assignee: |
SUMITOMO CHEMICAL COMPANY,
LIMITED
Tokyo
JP
|
Family ID: |
34193124 |
Appl. No.: |
13/053776 |
Filed: |
March 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12718238 |
Mar 5, 2010 |
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13053776 |
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|
10893182 |
Jul 16, 2004 |
7705528 |
|
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12718238 |
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60492434 |
Aug 4, 2003 |
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Current U.S.
Class: |
546/4 |
Current CPC
Class: |
C09K 2211/1425 20130101;
C09K 2211/185 20130101; H01L 51/0035 20130101; Y10S 428/917
20130101; C09K 11/06 20130101; H05B 33/14 20130101; C07F 15/004
20130101; C07F 15/008 20130101; C07F 15/0026 20130101; H01L 51/0085
20130101 |
Class at
Publication: |
546/4 |
International
Class: |
C07F 15/00 20060101
C07F015/00 |
Claims
1. A halogenated aromatic monomer-metal complex compound comprising
a halogenated aromatic monomer fragment and a metal complex
fragment and represented by the following formula (I): ##STR00010##
where L is a bidentate ligand; M is Ir, Rh, or Os; Ar' and Ar'' are
aromatic moieties which may be the same or different with the
proviso that at least one of Ar' and Ar'' is heteroaromatic; and
wherein R.sub.a and R.sub.b are each independently a monovalent
substitutent or H, with the proviso that at least one of R.sub.a
and R.sub.b contains a halogenated aromatic monomer fragment and a
linking group that disrupts conjugation between the halogenated
aromatic monomer fragment and the metal complex fragment; wherein
the halogenated aromatic monomer-metal complex compound is not a
compound of formula (I) in which Ar' represents a benzene moiety,
Ar'' represents a pyridine moiety, and R.sub.a represents a phenoxy
group which may be substituted by halogen.
2. The compound of claim 1 wherein Ar' and Ar'' are each
independently selected from the group consisting of benzene,
pyridine, thiophene, and fluorene moieties; L is selected from the
group consisting of diamines, imines, diimines, heterocyclics
containing two nitrogen atoms, diphosphines, .beta.-diketonates,
3-ketonates, salicyliminates, dialcoholates, and dithiolates; and
R.sub.a is -G-Ar--X, where G is selected from the group consisting
of O, methylene, or oxymethylene, Ar is a benzene, napthalene, or
anthracene moiety, and X is a halogen, provided that the compound
is not a compound in which Ar' represents a benzene moiety, Ar''
represents a pyridine moiety, G is O, Ar is benzene, and X is a
halogen.
3. The compound of claim 2 wherein Ar' is a benzene moiety and Ar''
is a pyridine moiety; L is selected from the group consisting of
.beta.-diketonates, pyridine-2-carboxylates, salicyliminates,
derivatives of 8-hydroquinoline, derivatives of
quinoline-2-carboxylic acid; and Ar is a benzene moiety; and X is
Br.
4. The compound of claim 3 wherein L is a .beta.-diketonate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. application Ser.
No. 12/718,238 filed Mar. 5, 2010, which is a Divisional of U.S.
application Ser. No. 10/893,182 filed Jul. 16, 2004, which claims
the benefit of U.S. Provisional Application No. 60/492,434 filed
Aug. 4, 2003. The entire disclosures of the prior applications are
hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an aromatic monomer-metal
complex, an aromatic polymer-metal complex, which can be prepared
from the monomer-metal complex, and an organic electronic device
that contains a film of the polymer-metal complex.
[0003] Organic electronic devices are found in a variety of
electronic equipment. In such devices, an organic active layer is
sandwiched between two electrical contact layers; the active layer
emits light upon application of a voltage bias across the contact
layers.
[0004] Polymers containing pendant metal-complex groups constitute
a class of polymers suitable for light emitting applications,
particularly in active matrix driven polymeric LED displays. These
polymers can be prepared, for example, by first polymerizing a
monomer containing a ligand capable of complexing with a metal,
then contacting the polymer with an organometallic complexing
compound to insert the metal center into the polymer bound ligand.
For example, in Macromolecules, Vol. 35, No. 19, 2002, Pei et al.
describes a conjugated polymer with pendant bipyridyl groups
directly coordinating with various Eu.sup.+3
.alpha.,.beta.-diketones.
[0005] Similarly, in WO 02/31896, pp 17-18, Periyasamy et al.
describes lanthanide metal-complexed polymers prepared by either a
one- or two-step synthetic route. In the one-step route, an
ML.sub.n emitter is reacted with a polymer having metal-reactive
functionality (X) to form a polymer with pendant --X-ML.sub.n-1
groups. In the two-step route, a polymer with pendant hydroxyethyl
functionality is first condensed with a bipyridyl compound
containing carboxylic acid functionality to form a polymer
containing bipyridyl ester functionality (X-L'), which is then
reacted with ML.sub.n to form a polymer with pendant
X-L'-ML.sub.n-1 functionality.
[0006] One of the problems with these metal complexed
electroluminescent polymers is the incomplete reaction of pendant
ligands with the metal complexing reagent. This inefficient
coupling results in unpredictability of the properties of the final
polymer due to the difficulty in controlling the degree of
metal-ligand complexation. Accordingly, it would be advantageous to
prepare a luminescent polymer with precisely controlled metal
complexation.
SUMMARY OF THE INVENTION
[0007] The present invention addresses a need by providing in one
aspect a halogenated aromatic monomer-metal complex compound
comprising a halogenated aromatic monomer fragment and a metal
complex fragment and represented by the following structure:
##STR00001##
where L is a bidentate ligand; M is Ir, Rh, or Os; Ar' and Ar'' are
aromatic moieties which may be the same or different with the
proviso that at least one of Ar' and Ar'' is heteroaromatic; and
wherein R.sub.a and R.sub.b are each independently a monovalent
substitutent or H, with the proviso that at least one of R.sub.a
and R.sub.b contains a halogenated aromatic monomer fragment and a
linking group that disrupts conjugation between the halogenated
aromatic monomer fragment and the metal complex fragment.
[0008] In a second aspect, the present invention is an
electroluminescent polymer having a backbone comprising a)
structural units of an aromatic monomer-metal complex having an
aromatic fragment and a metal complex fragment, which structural
units are represented by the following formula:
##STR00002##
where L is a bidentate ligand; M is Ir, Rh, or Os; Ar' and Ar'' are
aromatic moieties which may be the same or different with the
proviso that at least one of Ar' and Ar'' is heteroaromatic; and
wherein R'.sub.a and R'.sub.b are substitutents or H, with the
proviso that at least one of R'.sub.a and R'.sub.b contains an
aromatic group that is part of the polymer backbone and a linking
group that disrupts conjugation between the aromatic group and the
metal complex fragment; and b) structural units of at least one
aromatic comonomer, which polymer is characterized by being
conjugated along a polymer backbone created by structural units of
the aromatic monomer-metal complex and structural units of the at
least one aromatic comonomer.
[0009] In a third aspect, the present invention is an electronic
device comprising a thin film of a luminescent polymer sandwiched
between an anode and a cathode, which luminescent polymer has a
backbone with a) structural units of an aromatic monomer-metal
complex, which structural units are represented by the following
formula:
##STR00003##
where L is a bidentate ligand; M is Ir, Rh, or Os; Ar' and Ar'' are
aromatic moieties which may be the same or different with the
proviso that at least one of Ar' and Ar'' is heteroaromatic; and
wherein R'.sub.a and R'.sub.b are substitutents or H, with the
proviso that at least one of R'.sub.a and R'.sub.b contains an
aromatic group that is part of the polymer backbone and a linking
group that disrupts conjugation between the aromatic group and the
metal complex fragment; and b) structural units of at least one
aromatic comonomer, which polymer is characterized by being
conjugated along a polymer backbone created by structural units of
the aromatic monomer-metal complex and structural units of the at
least one aromatic comonomer.
[0010] The present invention addresses a need in the art by
providing a simple way of preparing a conjugated electroactive
polymer with precisely controlled metal complexation. Moreover, the
metal complex groups have electronic and/or luminescent properties
that are minimally affected by the conjugated polymer backbone.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The first aspect of the present invention is a composition
comprising a halogenated aromatic monomer-metal complex having a
halogenated aromatic monomer fragment and a metal complex fragment
and represented by the following formula:
##STR00004##
where L is a bidentate ligand; M is Ir, Rh, or Os; Ar' and Ar'' are
aromatic moieties which may be the same or different with the
proviso that at least one of Ar' and Ar'' is heteroaromatic; and
wherein R.sub.a and R.sub.b are each independently a monovalent
substitutent or H, with the proviso that at least one of R.sub.a
and R.sub.b contains a halogenated aromatic monomer fragment and a
linking group that disrupts conjugation between the aromatic
monomer fragment and the metal complex fragment.
[0012] The halogenated aromatic monomer-metal complex of the
present invention can be thought of as comprising a metal complex
fragment and one or more halogenated aromatic monomer fragments as
illustrated:
##STR00005##
R.sub.a is X.sub.mAr-G- and R.sub.b is X.sub.nAr-G-; each Ar is
independently an aromatic group; each G is independently a divalent
linking group that disrupts conjugation between Ar and Ar'--Ar'',
preferably alkylene, O, S, carbonyl, SiR.sub.2, where R is a
substituent, or oxyalkylene, more preferably methylene,
oxymethylene, or O; each X is independently a halogen group,
preferably, each X is chloro or bromo; the sum of m+n is a positive
integer, preferably 1 or 2; more preferably 1; and the sum of o+p
is a positive integer, preferably 1 or 2, more preferably 1. When o
(or p) is 0, R.sub.a (or R.sub.b) can be any substituent including
H. Thus, it is most preferred that each Ar'--Ar'' ligand contain
one monohalogenated aromatic substituent separated from Ar'--Ar''
by conjugation disrupting group.
[0013] The ligand Ar'--Ar'' is attached at least one substituent
that is a polymerizable aromatic monomer separated from the ligand
by a divalent linking group. Examples of suitable substituted
Ar'--Ar'' ligands include, but are not restricted to
2-phenylpyridines, 2-benzylpyridines, 2-(2-thienyl)pyridines,
2-(2-furanyl)pyridines, 2,2'-dipyridines,
2-benzo[b]thien-2-yl-pyridines, 2-phenylbenzothiazoles,
2-(1-naphthalenyl)benzothiazoles, 2-(1-anthracenyl)benzothiazoles,
2-phenylbenzoxazoles, 2-(1-naphthalenyl)benzoxazoles,
2-(1-anthracenyebenzoxazoles, 2-(2-naphthalenyl)benzothiazoles,
2-(2-anthracenyl)benzothiazoles, 2-(2-naphthalenyl)benzoxazoles,
2-(2-anthracenyl)benzoxazoles, 2-(2-thienyl)benzothiazoles,
2-(2-furanyl)benzothiazoles, 2-(2-thienyl)benzoxazoles,
2-(2-furanyl)benzoxazoles, benzo[h]quinolines, 2-phenylquinolines,
2-(2-naphthalenyl)quinolines, 2-(2-anthracenyl)quinolines,
2-(1-naphthalenyl)quinolines, 2-(1-anthracenyl)quinolines,
2-phenylmethylpyridines, 2-phenoxypyridines, 2-phenylthiopyridines,
phenyl-2-pyridinylmethanones, 2-ethenylpyridines,
2-benzenemethanimines, 2-(pyrrol-2-yl)pyridines,
2-(imidazol-2-yl)-pyridines, 2-phenyl-1H-imidazoles, and
2-phenylindoles.
[0014] As used herein, "aromatic compounds" includes both aromatic
and heteroaromatic compounds unless otherwise stated. Similarly,
the term "aryl" is used herein to include both aryl and heteroaryl
groups or compounds unless otherwise stated.
[0015] The divalent linking group G contains a linking group or
atom that disrupts conjugation, thereby inhibiting electron
delocalization between the aromatic monomer fragment and the metal
complex fragment. This disruption of conjugation between the
fragments results in a similar disruption between the complex and
the conjugated polymer backbone formed from the aromatic monomer
fragment. Disruption of conjugation is often desirable to preserve
the light emission properties of the metal complex in a polymer
formed from the aromatic monomer-metal complex. Such properties
could be disadvantageously perturbed if electrons are delocalized
between the conjugated polymer backbone and the complex.
[0016] The linking group is preferably a substituted or
unsubstituted non-conjugated linear, branched, or
cyclohydrocarbylene group or a divalent heteroatom or combinations.
thereof. Examples of linking groups include, alone or in
combination, alkylene or cycloalkyl groups such as methylene,
ethylene, propylene, isopropylene, butylene, isobutylene,
t-butylene, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl
groups; and heteroatoms such as oxygen and sulfur atoms and
R--Si--R, carbonyl, and amine groups, except for triaryl amines.
Preferred linking groups include an oxygen atom and methylene and
oxymethylene groups. As used herein, "oxymethylene" refers to
--OCH.sub.2-- or --CH.sub.2O--groups.
General Procedure for Preparation of a Bis(Monohalogenated
Aromatic) Monomer-Metal Complex
[0017] A halogenated aromatic monomer-metal complex containing a
bis(monohalogenated aromatic) fragment attached to a metal complex
through a linking group can be prepared by a 4-step process, as
shown:
##STR00006##
[0018] G is as previously defined and is preferably O, methylene,
or oxymethylene; Ar, Ar', and Ar'' are each independently aromatic
moieties with the proviso that at least one of Ar' and Ar'' is
heteroaromatic. Preferably, Ar is a non-heteroaromatic moiety
including a benzene, a naphthalene, or an anthracene moiety, more
preferably a benzene moiety. Preferably, Ar' and Ar'' are each
independently selected from the group consisting of benzene,
pyridine, thiophene, and fluorene moieties that are complexed with
the metal so as to form a 5-membered ring. More preferably one of
Ar' and Ar'' is a benzene moiety and the other of a Ar' and Ar'' is
pyridine moiety.
[0019] X is halo, X' and X'' are each independently halogen,
boronate, --ZnCl, --ZnBr, --MgCl, MgBr,
or--Sn(C.sub.1-10-alkyl).sub.3, with the proviso that one of X' and
X'' is halogen and the other of X' and X'' is boronate, --ZnCl,
--ZnBr, --MgCl, MgBr, or--Sn(C.sub.1-10-alkyl).sub.3; X''' is
halogen, hydroxy, or alkoxy, preferably chloro, bromo, methoxy, or
ethoxy, more preferably chloro or bromo. Where X''' is halogen, the
addition of the hydroxide or alkoxide base is not necessary; where
X''' is hydroxy or alkoxy, the addition of a hydroxide or alkoxide
base is preferred.
[0020] L is a bidentate ligand which can be the same as or
different from Ar'--Ar''. Other examples of L include a diamine,
including ethylene diamine, N,N,N',N'-tetramethyl ethylene diamine,
propylene diamine, N,N,N',N'-tetramethyl propylene diamine, cis-
and trans-diaminocyclohexane, and cis- and
trans-N,N,N',N'-tetramethyl diaminocyclohexane; an imine, including
2[(1-phenylimino)ethyl]pyridine,
2[(1-(2-methylphenylimino)ethyl]pyridine,
2[(1-(2,6-isopropylphenylimino)ethyl]pyridine,
2[(1-(methylimino)ethyl]pyridine, 2[(1-(ethylimino)methyl]pyridine,
2[(1-(ethylimino)ethyl]pyridine,
2[(1-(isopropylimino)ethyl]pyridine, and
2[(1-(t-butylimino)ethyl]pyridine; a dimine, including
1,2-bis(methylimino)ethane, 1,2-bis(ethylimino)ethane,
1,2-bis(isopropylimino)ethane, 1,2-bis(t-butylimino)ethane,
2,3-bis(methylimino)butane, 2,3-bis(ethylimino)butane,
2,3-bis(isopropylimino)butane, 2,3-bis(t-butylimino)butane,
1,2-bis(phenyl)mino)ethane, 1,2-bis(2-methylphenylimino)ethane,
1,2-bis(2,6-diisopropylphenylimino)ethane,
1,2-bis(2,6-di-t-butylphenylimino)ethane,
2,3-bis(phenyl)mino)butane, 2,3-bis(2-methylphenylimino)butane,
2,3-bis(2,6-diisopropylphenylimino)butane, and
2,3-bis(2,6-di-t-butylphenylimino)butane; a heterocyclic compound
containing two nitrogen atoms, including 2,2'-bypyridine, and
o-phenanthroline; a diphosphine, including
bis-(diphenylphosphino)methane, bis-(diphenylphosphino)ethane,
bis-(diphenylphosphino)propane, bis-(dimethylphosphino)methane,
bis-(dimethylphosphino)ethane, bis-(dimethylphosphino)propane,
bis-(diethylphosphino)methane, bis-(diethylphosphino)ethane,
bis-(diethylphosphino)propane, bis-(di-t-butylphosphino)methane,
bis-(di-t-butylphosphino)ethane, and
bis-(di-t-butylphosphino)propane; a 1,3-diketonate
(.beta.-diketonate) prepared from a 1,3-diketone (.beta.-diketone),
including acetyl acetone, benzoyl acetone, 1,5-diphenylacetyl
acetone, dibenzoyl methane, and bis(1,1,1-trifluoroacetyl)methane;
a 3-ketonate prepared from a 3-keto ester, including acetoacetic
acid ethyl ester; a carboxylate prepared from an aminocarboxylic
acid, including pyridine-2-carboxylate, 8-hydroquinolinate,
quinoline-2-carboxylate, glycine, dimethyl glycine, alanine, and
dimethylaminoalanine; a salicyliminates prepared from a
salicylimine, including methyl salicylimine, ethyl salicylimine,
and phenyl salicylimine; a dialcoholate prepared from a dialcohol,
including ethylene glycol and 1,3-propylene glycol; a dithiolate
prepared from a dithiol, including 1,2-ethylene dithiolate and
1,3-propylene dithiolate. Preferably, L is a .beta.-diketonate,
pyridine-2-carboxylate, a salicyliminate, or a derivative of
8-hydroquinoline or quinoline-2-carboxylic acid.
Conjugated Luminescent Polymers Containing Metal Complexes
[0021] The halogenated aromatic monomer-metal complex is a
precursor for a metal-complexed conjugated luminescent polymer,
which can be a homopolymer, a copolymer, a terpolymer, etc., and
which can be prepared by any of a number of means. For example, the
polymer can be prepared by a Suzuki coupling reaction, described in
U.S. Pat. No. 6,169,163 (the '163 patent), column 41, lines 50-67
to column 42, lines 1-24, which description is incorporated herein
by reference.
[0022] In the present case, the Suzuki coupling reaction can be
carried out by reacting, in the presence of a catalyst, preferably
a Pd/triphenylphosphine catalyst such as
tetrakis(triphenylphosphine)palladium(0), the halogenated aromatic
monomer-metal complex, preferably the bis(monohalogenated aromatic)
complex, with a diboronated aromatic compound. The aromatic group
of the co-monomer--which form structural units of the resultant
polymer--may be the same as or different from, preferably different
from, the aromatic group associated with the halogenated aromatic
monomer-metal complex.
[0023] It is also possible, and sometimes preferable, to prepare a
polymer having structural units of more than two monomers by
including in the reaction mixture a variety of halogenated and
boronated co-monomers along with the halogenated aromatic
monomer-metal complex.
[0024] Polymerization can also be carried out by coupling one or
more dihalogenated aromatic monomer-metal complexes with one or
more dihalogenated aromatic compounds in the presence of a nickel
salt, as described in the '163 patent, column 11, lines 9-34, which
description is incorporated herein by reference.
[0025] The aromatic co-monomers that can be used to couple with the
halogenated aromatic monomer-metal complex is nearly endless but a
representative list includes, 1,4-diXbenzenes, 1,3-diXbenzenes,
1,2-diXbenzenes 4,4'-diXbiphenyls, 1,4-diXnaphthalenes,
2,6-diXnaphthalenes, 2,5-diXfurans, 2,5-diXthiophenes,
5,5-diX-2,2'-bithiophenes, 9,10-diXanthracenes,
4,7-diX-2,1,3-benzothiadiazoles, diX triarylamines including
N,N-di(4-Xphenyl) anilines, N,N-di(4-Xphenyl)-p-tolylamines, and
N-diXphenyl-N-phenylanilines, 3,6-diX-N-substituted carbazoles,
2,7-diX-N-substituted carbazoles, 3,6-diX-dibenzosiloles,
2,7-diX-dibenzosiloles, N-substituted-3,7-diXphenothiazines,
N-substituted-3,7-diXphenoxazines,
diX-N,N,N',N'-tetraaryl-1,4-diaminobenzenes,
diX-N,N,N',N'-tetraarylbenzidines, diXarylsilanes, and
2,7-diX-9,9-disubstituted fluorenes, including fluorenes in which
the 9,9-substituents combine to form a ring structure, and
combinations thereof, where each X is independently a halogen or a
boronate, preferably bromo or chloro or boronate, more preferably
bromo or boronate. As used herein, "boronate" refers to an aromatic
fragment or compound that is substituted with a borane group, a
boronic acid ester group, or a boronic acid group.
[0026] The resultant polymer has a backbone having structural units
of a) an aromatic group which is also attached to a linking group
that disrupts conjugation between the aromatic group and the metal
complex fragment; and b) an aromatic comonomer, which forms a
conjugated system with the aromatic group. The term "structural
units" is used herein to refer to the remnant of the monomer after
polymerization. A structural unit of the aromatic group that is
attached to the metal complex through a linking group is
represented by the following structure:
##STR00007##
where L, M, Ar', and Ar'' are as previously defined, and at least
one of R'.sub.a and R'.sub.b, preferably only one of R'.sub.a and
R'.sub.b, contains an aromatic group that is part of the polymer
backbone, preferably a phenyl group, a naphthalenyl group, or an
anthracenyl group, more preferably a phenyl group; and a linking
group, G, that disrupts conjugation between the aromatic group and
the metal complex fragment. The other of R'.sub.a and R'.sub.b is
preferably a monovalent substituent, including H. Thus, where Ar is
phenyl and R.sub.b is H, the following structural unit is
formed:
##STR00008##
[0027] Similarly, a structural unit of a benzene-containing
comonomer that is incorporated into the polymer backbone through
the 1,4-positions is a 1,4-phenylene group; a structural unit of a
9,9-disubstituted fluorene-containing comonomer that is
incorporated into the polymer backbone through the 2,7-positions is
a 9,9-disubstituted fluorene-2,7-diyl group, where each R is a
substituent, as illustrated:
##STR00009##
[0028] Accordingly, the structural units corresponding to the above
listed co-monomers are 1,4-phenylenes, 1,3-phenylenes,
1,2-phenylenes, 4,4'-biphenylenes, naphthalene-1,4-diyls,
naphthalene-2,6-diyl, furan-2,5-diyls, thiophene-2,5-diyls,
2,2'-bithiophene-5,5-diyls, anthracenes-9,10-diyls,
2,1,3-benzothiadiazoles-4,7-diyls, N-substituted
carbazole-3,6-diyls, N-substituted carbazole-2,7-diyls,
N-substituted-phenothiazine-3,7-diyls,
N-substituted-phenoxazines-3,7-diyls, triarylamine-diyls including
triphenylamine-4,4'-diyls, diphenyl-p-tolylamine-4,4'-diyls, and
N,N-diphenylaniline-3,5-diyls, dibenzosilole-3,6-diyls,
dibenzosilole-2,7-diyls,
N,N,N',N'r-tetraaryl-1,4-diaminobenzene-diyls,
N,N,N',N'-tetraarylbenzidine-diyls, arylsilane-diyls, and
9,9-disubstituted fluorenes-2,7-diyls. It is to be understood that
the polymer, copolymer, etc. is not limited by the manner in which
it is made.
[0029] The resultant polymer has a conjugated backbone with metal
complexation that can be precisely controlled because preferably at
least 90%, more preferably at least 95%, and most preferably 100%
of the structural units of the aromatic monomer-metal complex
contain a metal complex that is incorporated within the polymer
backbone. Moreover, the metal complex is insulated from the
conjugated polymer backbone due to the absence of direct
delocalization between the ligand and the polymer backbone, which
insulation preserves the luminescent properties of the metal
complex. The terms "conjugated polymer" and "conjugated polymer
backbone" are used to mean that the polymer backbone has electrons
that are delocalized throughout at least two adjacent structural
units, preferably at least five adjacent structural units, more
preferably at least ten adjacent structural units.
[0030] Preferably, the ratio of structural units of halogenated
aromatic monomer-metal complex to structural units of the comonomer
is preferably at least 0.01:99.99, more preferably at least
0.1:99.9, and most preferably at least 1:99; and preferably not
greater than 20:80, more preferably not greater than 10:90.
[0031] The polymer of the present invention preferably has a weight
average molecular weight M.sub.w of at least 5000 Daltons, more
preferably at least 10,000 Daltons, more preferably at least 50,000
Daltons, and most preferably at least 100,000 Daltons; and
preferably less than 2,000,000 Daltons. M.sub.w is determined using
gel permeation chromatography against polystyrene standards.
[0032] The polymer of the present invention can be combined with
one or more other polymers to make a blend. Examples of suitable
blending polymers include homo- or co-polymers (including
terpolymers or higher) of polyacrylates, polymethacrylates,
polystyrenes, polyesters, polyimides, polyvinylenes,
polycarbonates, polyvinyl ethers and esters, fluoropolymers,
polycarbazoles, polyarylene vinylenes, polyarylenes,
polythiophenes, polyfurans, polypyrroles, polypyridines,
polyfluorenes, and combinations thereof.
[0033] The polymer or blend of the present invention can be
combined with a sufficient amount of one or more solvents
(hereinafter "solvent") to make a solution which is useful, for
example, as an ink. The amount of solvent varies depending upon the
solvent itself and the application, but is generally used at a
concentration of at least 80 weight percent, more preferably at
least 90 weight percent, and most preferably at least 95 weight
percent, based on the weight of the luminescent polymer, the
optional additives or modifiers, and the solvent.
[0034] Examples of suitable solvents for the polymer include
benzene; mono-, di- and trialkylbenzenes including C.sub.1-12-alkyl
benzenes, xylenes, mesitylene, cyclohexylbenzene, and
diethylbenzene; furans including tetrahydrofuran and
2,3-benzofuran; 1,2,3,4-tetrahydronaphthalene; cumene; decalin;
durene; chloroform; limonene; dioxane; alkoxybenzenes including
anisole, and methyl anisoles; alkyl benzoates including methyl
benzoate; biphenyls including isopropyl biphenyl; pyrrolidinones
including cyclohexylpyrrolidinone; imidazoles including
dimethylimidazolinone; and fluorinated solvents; and combinations
thereof. More preferred solvents include C.sub.1-8-alkyl benzenes,
cyclohexylbenzene, xylenes, mesitylene,
1,2,3,4-tetrahydronaphthalene, methyl benzoate, isopropyl biphenyl,
and anisole, and combinations thereof.
[0035] In a typical application, the ink formulation can be
deposited on a substrate such as indium-tin-oxide (ITO) glass
having a hole transporting material disposed thereon. The solvent
is then evaporated, whereupon the ink forms a thin film of the
luminescent polymer. The film is used as an active layer in an
organic light-emitting diode (OLED) device, which can be used to
make a display such as a self-emissive flat panel display. The film
is also useful in other electronic devices including light sources,
photovoltaic cells, and field effect transistor devices.
[0036] The following examples are for illustrative purposes only
and are not intended to limit the scope of the invention.
Example 1
Preparation of Iridium (III)
bis{2-[4'-(4''-bromophenoxy)phenyl]pyridinato-N,C.sup.2'}(acetylacetonate
A. Preparation of 2-(4'-Phenoxy)phenylpyridine
[0037] 4-Phenoxyphenylboronic acid (10.7 g, 0.05 mol) and
2-bromopyridine (11.58 g, 0.075 mol) were dissolved in 250 mL of
THF followed by addition of 2M NaCO.sub.3 (60 mL) and
tetrakis(triphenylphosphine)palladium (0) (0.29 g). The reaction
mixture was boiled at reflux overnight and then transferred into a
separation funnel to remove the aqueous layer. The organic layer
was removed in vacuo and the residue was eluted through a silica
gel column, first with 1:1 chloroform and hexane mixture and then
with pure chloroform to afford a pale yellow oil. HPLC showed a
purity of 99.5%. GCMS: M.sup.+=247.
B. Preparation of 2-[4'-(4''-Bromophenoxy)phenyl]pyridine
[0038] A solution of N-bromosuccinimide (NBS, 3.95 g, 22.2 mmol) in
DMF (10 mL) was added to a solution of 2-(4'-Phenoxy)phenylpyridine
(5.8 g, 23.4 mmol) in DMF (100 mL) at room temperature. The
reaction mixture was stirred at 80.degree. C. for 1 h. HPLC showed
about 40% of the starting material was converted. Additional NBS
(1.55 g) was added and the reaction continued at 80.degree. C.
overnight. HPLC indicated a conversion of 55%. Additional NBS (5 g)
was added and the reaction was continued at 80.degree. C. for 1 h.
HPLC showed complete conversion of the starting material. After
being cooled to room temperature, the reaction mixture was poured
into water (300 mL) with stirring whereupon NaOH solution (15 mL of
50% (w/w)) was added into the mixture. The mixture was stirred at
room temperature for 2 h and was then filtered to collect the
solid. The solid was washed with water and was re-crystallized from
ethanol to provide 5.5 g of the titled compound in white crystals.
HPLC showed a purity of 98.6%. GCMS: M.sup.+=327.
C. Preparation of Iridium (III)
bis{2-[4'-(4''-bromophenoxy)phenyl]pyridinato-N,C.sup.2'}
.mu.-chloro-bridged dimer
[0039] Iridium (III) chloride (% Ir=54.11, 1.5 g, 4.25 mmol) and
2-[4'-(4''-bromophenoxy)phenyl]pyridine (3.5 g) were dispersed in
2-ethoxyetanol (30 mL) at room temperature. The mixture was boiled
at reflux under nitrogen for 20 h, at which time, a yellow solid
precipitated from solution. Methanol (100 mL) was added to the
reaction mixture to complete the precipitation. The solid was
collected by filtration and was washed with methanol, 1N HCl, and
ethanol successively and then was dried in vacuo at 40.degree. C.
to provide 3.27 g of yellow powder.
D. Preparation of Iridium (III)
bis{2-[4'-(4''-bromophenoxy)phenyl]pyridinato-N,C.sup.2'}(acetylacetonate-
)
[0040] Iridium (III)
bis{2-[4'-(4''-bromophenoxy)phenyl]pyridinato-N,C.sup.2'}
.mu.-chloro-bridged dimer (1.05 g, 0.6 mmol) and sodium carbonate
(1.0 g) were dispersed in 2-ethoxyethanol (60 mL). The mixture was
degassed with nitrogen at room temperature for 15 min, whereupon
2,4-pentanedione (0.132 g, 1.32 mmol) was added together with
2-ethoxyethanol (20 mL). The mixture was refluxed for 1 h. TLC
showed no dimer starting material and the main product was found to
be a green emissive material. After being cooled to room
temperature, water (100 mL) was added to precipitate the product.
The yellow solid was collected by filtration and dried in vacuo at
40.degree. C. overnight. The crude product was re-dissolved in
methylene chloride and purified on a silica gel column eluted by
methylene chloride to give 0.48 g of yellow powder, purtiy of 99.5%
by HPLC:
Example 2
Preparation of a Co-polymer Containing Iridium (III)
bis[2-(4'-phenoxyphenyl)pyridinato-N,C.sup.2'](acetylacetonate)
[0041] Tetrakis(triphenylphosphine)palladium(0) (5 mg) and 2M
aqueous sodium carbonate solution (11 mL) were added under nitrogen
to a stirred mixture of 9,9-di(1-octyl)fluorene-2,7-diboronic acid
ethylene glycol ester (2.149 g, 4.04 mmol),
2,7-dibromo-9,9-di(1-octyl)fluorene (1.647 g, 3.00 mmol),
3,7-dibromo-N-(4-n-butyl)-phenyl-phenoxazine (0.190 g, 0.40 mmol),
N,N'-(di(bromophenyl)-N,N'-di(9,9-dibutyl)fluorene-1,4-phenylenedi-
amine (0.390 g, 0.40 mmol), iridium (III)
bis{2-[4'-(4''-bromophenoxy)phenyl]pyridinato-N,C.sup.2'}(acetylacetonate-
) (0.188 g, 0.20 mmol), and Aliquat 336 (0.75 g) phase transfer
catalyst in toluene (50 mL). The reaction mixture was stirred at
101.degree. C. under nitrogen for 16 h. Then,
9,9-di(1-octyl)fluorene-2,7-diboronic acid ethylene glycol ester
(20 mg) was added and the polymerization was continued under the
same conditions for another 3 h. Bromobenzene (0.15 g dissolved in
10 mL of toluene) was then added under the same reaction conditions
for 2 h. Phenylboronic acid (0.4 g) and
tetrakis(triphenylphosphine)palladium(0) (3 mg dissolved in 10 mL
of toluene) was added under the same reaction conditions for 4 h.
The mixture was allowed to cool to about 50.degree. C., the aqueous
layer removed, and the organic layer washed with water. The
resultant polymer solution was then poured into methanol (1.5 L)
with stirring to precipitate pale yellow polymer fibers. These
fibers were collected by filtration, washed with methanol, and
dried in vacuo at 50.degree. C. overnight. The polymer was
re-dissolved in toluene and the solution passed through a column
packed with layers of celite and silica gel. The combined eluates
were concentrated to about 100 mL, then poured into methanol (1.5
L) with stirring. The polymer fibers were collected and dried in
vacuo at 50.degree. C. overnight. The polymer was re-dissolved in
toluene and re-precipitated in methanol. After further filtration
and drying, 2.26 g of pale yellow fibers were obtained. The weight
average molecular weight (M.sub.w) of the polymer was measured by
gel permeation chromatography (GPC) against the polystyrene
standards as 121,000 with a polydispersity index (M.sub.w/M.sub.n)
of 3.78.
Example 3
Iridium (III)
bis[2-(4'-phenoxyphenyl)pyridinato-N,C.sup.2'](acetylacetonate)
Containing a Fluorene copolymer II
[0042] The procedure described in Example 2 was followed except
that N,N-aiphenyl-3,5-dibromoaniline (0.3248 g, 0.80 mmol) was used
instead of dibromo-N-(4-n-butyl)-phenyl-phenoxazine and
N,N'-(di(bromophenyl)-N,N'-di(9,9-dibutyl)fluorene-1,4-phenylenediamine
(0.390 g, 0.40 mmol); the copolymer II was prepared in the yield of
2.13 g.
Example 4
Light-Emitting Devices of a Metal Complex-Containing Polymer
[0043] A thin film of
poly(ethylenedioxythiophene)/polystyrenesulfonic acid (commercially
available from H. C. Starck and BAYTRON.TM. P conducting polyer)
was spin-coated on a ITO (indium tin oxide)-coated glass substrate,
at a thickness of 80 nm. Then, a film of the metal
complex-containing polymer described in Example 3 was spin-coated
on the PEDOT film at a thickness of 80 nm from a solution in
xylenes. After drying, a thin layer (3 nm) of LiF was deposited on
the top of the polymer layer by thermal evaporation, followed by
the deposition of a calcium cathode (10-nm thick). An additional
aluminum layer was applied by evaporation to cover the calcium
cathode. By applying a bias (ITO wired positively) on the resultant
device, bluish green light emission was obtained. The
electroluminescent spectrum recorded at 200 cd/m.sup.2 corresponds
to the chromaticity coordinates of (x=0.240, y=0.270) in the CIE
1931 diagram. The brightness of the emission reached 200 cd/m.sup.2
at about 13 V with the luminance efficiency of 0.08 cd/A.
* * * * *