U.S. patent application number 11/830550 was filed with the patent office on 2007-12-20 for electroluminescent iridium compounds having red-orange or red emission and devices made with such compounds.
Invention is credited to DANIEL DAVID LECLOUX, VIACHESLAV A. PETROV, YING WANG.
Application Number | 20070292718 11/830550 |
Document ID | / |
Family ID | 23365814 |
Filed Date | 2007-12-20 |
United States Patent
Application |
20070292718 |
Kind Code |
A1 |
LECLOUX; DANIEL DAVID ; et
al. |
December 20, 2007 |
ELECTROLUMINESCENT IRIDIUM COMPOUNDS HAVING RED-ORANGE OR RED
EMISSION AND DEVICES MADE WITH SUCH COMPOUNDS
Abstract
The present invention is generally directed to
electroluminescent Ir(III) complexes which have emission maxima in
the red-orange to red region of the visible spectrum, and devices
that are made with the Ir(III) complexes.
Inventors: |
LECLOUX; DANIEL DAVID;
(Wilmington, DE) ; PETROV; VIACHESLAV A.;
(Hockessin, DE) ; WANG; YING; (Wilmington,
DE) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY;LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
23365814 |
Appl. No.: |
11/830550 |
Filed: |
July 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10284593 |
Oct 31, 2002 |
7250512 |
|
|
11830550 |
Jul 30, 2007 |
|
|
|
Current U.S.
Class: |
428/691 ;
428/690 |
Current CPC
Class: |
H01L 51/0038 20130101;
C09K 2211/1011 20130101; H01L 51/5016 20130101; H01L 51/0085
20130101; H01L 51/0035 20130101; H01L 51/0086 20130101; H01L
51/0042 20130101; C07F 15/0033 20130101; H01L 51/5048 20130101;
C09K 11/06 20130101; Y10S 428/917 20130101; C09K 2211/1092
20130101; C09K 2211/185 20130101; H01L 51/0094 20130101; H01L
51/0039 20130101; C07D 409/04 20130101; C09K 2211/1029 20130101;
H05B 33/14 20130101; H01L 51/0036 20130101; H01L 51/5012 20130101;
H01L 51/0059 20130101; C09K 2211/1007 20130101 |
Class at
Publication: |
428/691 ;
428/690 |
International
Class: |
B32B 9/00 20060101
B32B009/00 |
Claims
1. An organic electronic device comprising an active layer
comprising a light-emitting layer having an emission maximum in the
range of 570 to 700 nm, wherein the active layer comprises at least
one compound having a formula according to Formula I: IrL.sub.3 (I)
where: L is selected from Formula III, Formula IV, Formula V,
Formula VI, and Formula VII in FIG. 1, and Formula VIII, Formula IX
and Formula X in FIG. 2, where: in Formula III: R.sup.3 through
R.sup.6 are the same or different and at least one of R.sup.3
through R.sup.6 is selected from D, F, C.sub.nF.sub.2n+1,
OC.sub.nF.sub.2n+1, and OCF.sub.2Y; at each occurrence in any of
Formulae III through VII: R.sup.1 is the same or different at each
occurrence and is selected from D, C.sub.nH.sub.2n+1, OR.sup.11,
SR.sup.11, N(R.sup.11).sub.2, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or adjacent pairs of
R.sup.1 can be joined to form a five- or six-membered ring; Y is H,
Cl, or Br; and A is S or NR.sup.11; at each occurrence in any of
Formulae III through X: R.sup.11 is the same or different at each
occurrence and is H or C.sub.nH.sub.2n+1; n is an integer from 1
through 12; and .alpha. is 0, 1 or 2; at each occurrence in any of
Formulae IV through X: .delta. is 0 or an integer from 1 through 4;
in Formula VII: E.sup.1 through E.sup.4 are the same or different
and are N or CR.sup.12, with the proviso that at least one E is N;
and R.sup.12 is the same or different at each occurrence and is
selected from H, D, SR.sup.11, N(R.sup.11).sub.2, F,
C.sub.n(H+F).sub.2n+1, OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or
adjacent pairs of R.sup.12 can be joined to form a five- or
six-membered ring, with the proviso that at least one of R.sup.12
is selected from D, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y; at each occurrence in any
of Formulae VIII through X: R.sup.2 and R.sup.7 through R.sup.10
are the same or different at each occurrence and are selected from
H, D, C.sub.nH.sub.2n+1, OR.sup.11, SR.sup.11, and
N(R.sup.11).sub.2, or adjacent pairs of R groups can be joined to
form a five- or six-membered ring provided that, where the active
layer contains less than 20% by weight of the at least one
compound, a diluent is also present.
2. The device of claim 1 wherein R.sup.5 is CF.sub.3.
3. The device of claim 1 wherein R.sup.8 is selected from OCH.sub.3
and OH.
4. The device of claim 1 wherein R.sup.9 is t-butyl.
5. The device of claim 1 wherein the diluent is selected from
poly(N-vinyl carbazole); polysilane; 4,4'-N,N'-dicarbazole
biphenyl; and tertiary aromatic amines.
6. The device of claim 1, further comprising a hole transport layer
selected from
N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine;
1,1-bis[(di-4-tolylamino) phenyl]cyclohexane;
N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)bip-
henyl]-4,4'-diamine;
tetrakis-(3-methylphenyl)-N,N,N',N'-2,5-phenylenediamine;
.alpha.-phenyl-4-N,N-diphenylaminostyrene;
p-(diethylamino)benzaldehyde diphenylhydrazone; triphenylamine;
bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane;
1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]pyrazoline;
1,2-trans-bis(9H-carbazol-9-yl)cyclobutane;
N,N,N',N'-tetrakis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine;
porphyrinic compounds; and combinations thereof.
7. The device of claim 1, further comprising an electron transport
layer selected from tris(8-hydroxyquinolato)aluminum;
2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline;
4,7-diphenyl-1,10-phenanthroline;
2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole;
3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole; and
combinations thereof.
8. A compound selected from complex 1-a through 1-f, as shown in
Table 1.
9. An organic electronic device comprising an active layer that
comprises a compound selected from complex 1-a through 1-f, as
shown in Table 1.
10. The device of claim 9 wherein the active layer further
comprises a diluent.
11. The device of claim 10 wherein the diluent is selected from
poly(N-vinyl carbazole); polysilane; 4,4'-N,N'-dicarbazole
biphenyl; and tertiary aromatic amines.
12. The device of claim 1 wherein the diluent is a conjugated
polymer selected from polyarylenevinylenes, polyfluorenes,
polyoxadiazoles, polyanilines, polythiophenes, polypyridines,
polyphenylenes, copolymers thereof, and combinations thereof.
13. The device of claim 12 wherein the diluent is a conjugated
polymer selected from polyarylenevinylenes, polyfluorenes,
polyoxadiazoles, polyanilines, polythiophenes, polypyridines,
polyphenylenes, copolymers thereof, and combinations thereof.
14. An active layer comprising at least one compound having a
formula according to Formula I: IrL.sub.3 (I) where: L is selected
from Formula III, Formula IV, Formula V, Formula VI, and Formula
VII in FIG. 1, and Formula VIII, Formula IX and Formula X in FIG.
2, where: in Formula III: R.sup.3 through R.sup.6 are the same or
different and at least one of R.sup.3 through R.sup.6 is selected
from D, F, C.sub.nF.sub.2n+1, OC.sub.nF.sub.2n+1, and OCF.sub.2Y;
at each occurrence in any of Formulae III through VII: R.sup.1 is
the same or different at each occurrence and is selected from D,
C.sub.nH.sub.2n+1, OR.sup.11, SR.sup.11, N(R.sup.11).sub.2, F,
C.sub.n(H+F).sub.2n+1, OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or
adjacent pairs of R.sup.1 can be joined to form a five- or
six-membered ring; Y is H, Cl, or Br; and A is S or NR.sup.11; at
each occurrence in any of Formulae III through X: R.sup.11 is the
same or different at each occurrence and is H or C.sub.nH.sub.2n+1;
n is an integer from 1 through 12; and .alpha. is 0, 1 or 2; at
each occurrence in any of Formulae IV through X: .delta. is 0 or an
integer from 1 through 4; in Formula VII: E.sup.1 through E.sup.4
are the same or different and are N or CR.sup.12, with the proviso
that at least one E is N; and R.sup.12 is the same or different at
each occurrence and is selected from H, D, SR.sup.11,
N(R.sup.11).sub.2, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or adjacent pairs of
R.sup.12 can be joined to form a five- or six-membered ring, with
the proviso that at least one of R.sup.12 is selected from D, F,
C.sub.n(H+F).sub.2n+1, OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y; at
each occurrence in any of Formulae VIII through X: R.sup.2 and
R.sup.7 through R.sup.10 are the same or different at each
occurrence and are selected from H, D, C.sub.nH.sub.2n+1,
OR.sup.11, SR.sup.11, and N(R.sup.11).sub.2, or adjacent pairs of R
groups can be joined to form a five- or six-membered ring provided
that, where the active layer contains less than 20% by weight of
the at least one compound, a diluent is also present.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to electroluminescent complexes of
iridium(III) which have emission spectra in the red-orange and red
region of the visible spectrum. It also relates to electronic
devices in which the active layer includes an electroluminescent
Ir(III) complex.
[0003] 2. Description of the Related Art
[0004] Organic electronic devices that emit light, such as
light-emitting diodes that make up displays, are present in many
different kinds of electronic equipment. In all such devices, an
organic active layer is sandwiched between two electrical contact
layers. At least one of the electrical contact layers is
light-transmitting so that light can pass through the electrical
contact layer. The organic active layer emits light through the
light-transmitting electrical contact layer upon application of
electricity across the electrical contact layers.
[0005] It is well known to use organic electroluminescent compounds
as the active component in light-emitting diodes. Simple organic
molecules such as anthracene, thiadiazole derivatives, and coumarin
derivatives are known to show electroluminescence. Semiconductive
conjugated polymers have also been used as electroluminescent
components, as has been disclosed in, for example, Friend et al.,
U.S. Pat. No. 5,247,190, Heeger et al., U.S. Pat. No. 5,408,109,
and Nakano et al., Published European Patent Application 443 861.
Complexes of 8-hydroxyquinolate with trivalent metal ions,
particularly aluminum, have been extensively used as
electroluminescent components, as has been disclosed in, for
example, Tang et al., U.S. Pat. No. 5,552,678.
[0006] Electroluminescent devices with an active layer of polymer
doped with organometallic complexes of iridium have been described
by Burrows and Thompson in published PCT applications WO 00/70655
and WO 01/41512. Most of these complexes have emission spectra with
peaks in the green or blue-green region.
[0007] There is a continuing need for efficient electroluminescent
compounds which emit light in the red region of the visible
spectrum (625-700 nm)
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a metal complex having
a formula selected from Formula I and Formula II: IrL.sub.3 (I)
IrL.sub.2Z (II) Where: [0009] Z is selected from .beta.-dienolates,
aminocarboxylates, iminocarboxylates, salicylates,
hydroxyquinolates, and diarylphosphinoalkoxides; and [0010] L is
selected from Formula III, Formula IV, Formula V, Formula VI, and
Formula VII in FIG. 1, and Formula VIII, Formula IX and Formula X
in FIG. 2, where: In Formula III: [0011] R.sup.3 through R.sup.6
are the same or different and at least one of R.sup.3 through
R.sup.6 is selected from D, F, C.sub.nF.sub.2n+1,
OC.sub.nF.sub.2n+1, and OCF.sub.2Y; At each Occurrence in any of
Formulae III Through VII: [0012] R.sup.1 is the same or different
at each occurrence and is selected from D, C.sub.nH.sub.2n+1,
OR.sup.11, SR.sup.11, N(R.sup.11).sub.2, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or adjacent pairs of
R.sup.1 can be joined to form a five- or six-membered ring; [0013]
Y is H, Cl, or Br; and [0014] A is S or NR.sup.11; At each
Occurrence in any of Formulae III Through X: [0015] R.sup.11 is the
same or different at each occurrence and is H or C.sub.nH.sub.2n+1;
[0016] n is an integer from 1 through 12; and [0017] .alpha. is 0,
1 or 2; At each Occurrence in any of Formulae IV Through X: [0018]
.delta. is 0 or an integer from 1 through 4; In Formula VII: [0019]
E.sup.1 through E.sup.4 are the same or different and are N or
CR.sup.12, with the proviso that at least one E is N; and [0020]
R.sup.12 is the same or different at each occurrence and is
selected from H, D, SR.sup.11, N(R.sup.11).sub.2, F,
C.sub.n(H+F).sub.2n+1, OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, or
adjacent pairs of R.sup.12 can be joined to form a five- or
six-membered ring, with the proviso that at least one of R.sup.12
is selected from D, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y; At each Occurrence in Any
of Formulae VIII Through X: [0021] R.sup.2 and R.sup.7 through
R.sup.10 are the same or different at each occurrence and are
selected from H, D, C.sub.nH.sub.2n+1, OR.sup.11, SR.sup.11, and
N(R.sup.11).sub.2, or adjacent pairs of R groups can be joined to
form a five- or six-membered ring.
[0022] In another embodiment, the present invention is directed to
an organic electronic device having at least one active layer
comprising a light-emitting layer having an emission maximum in the
range of from 570 to 700 nm, wherein at least 20% by weight of the
active layer comprises the above metal complex, or combinations of
the above metal complexes.
[0023] As used herein, the term "compound" is intended to mean an
electrically uncharged substance made up of molecules that further
consist of atoms, wherein the atoms cannot be separated by physical
means. The term "ligand" is intended to mean a molecule, ion, or
atom that is attached to the coordination sphere of a metallic ion.
The letter "L" is used to designate a ligand having a nominal (-1)
charge formed from the neutral parent compound, "HL", by the loss
of a hydrogen ion. The letter "Z" is used to designate a bidentate
ligand having a nominal (-1) charge formed from the neutral parent
compound, "HZ", by the loss of a hydrogen ion. The term "complex",
when used as a noun, is intended to mean a compound having at least
one metallic ion and at least one ligand. The term
".beta.-dicarbonyl" is intended to mean a neutral compound in which
two ketone groups are present, separated by a CHR group. The term
".beta.-enolate" is intended to mean the anionic form of the
.beta.-dicarbonyl in which the H from the CHR group between the two
carbonyl groups has been abstracted. The term "group" is intended
to mean a part of a compound, such a substituent in an organic
compound or a ligand in a complex. The term "facial" is intended to
mean one isomer of a complex, Ma.sub.3b.sub.3, having octahedral
geometry, in which the three "a" groups are all adjacent, i.e. at
the corners of one face of the octahedron. The term "meridional" is
intended to mean one isomer of a complex, Ma.sub.3b.sub.3, having
octahedral geometry, in which the three "a" groups occupy three
positions such that two are trans to each other. The phrase
"adjacent to," when used to refer to layers in a device, does not
necessarily mean that one layer is immediately next to another
layer. On the other hand, the phrase "adjacent R groups," is used
to refer to R groups that are next to each other in a chemical
formula (i.e., R groups that are on atoms joined by a bond). The
term "photoactive" refers to any material that exhibits
electroluminescence and/or photosensitivity. In addition, the IUPAC
numbering system is used throughout, where the groups from the
Periodic Table are numbered from left to right as 1 through 18 (CRC
Handbook of Chemistry and Physics, 81.sup.st Edition, 2000). In the
Formulae and Equations, the letters A, E, L, R, Q, Y and Z are used
to designate atoms or groups which are defined within. All other
letters are used to designate conventional atomic symbols. The term
"(H+F)" is intended to mean all combinations of hydrogen and
fluorine, including completely hydrogenated, partially fluorinated
or perfluorinated substituents. By "emission maximum" is meant the
wavelength, in nanometers, at which the maximum intensity of
electroluminescence is obtained. Electroluminescence is generally
measured in a diode structure, in which the material to be tested
is sandwiched between two electrical contact layers and a voltage
is applied. The light intensity and wavelength can be measured, for
example, by a photodiode and a spectrograph, respectively.
DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 shows Formulae III through VII for the ligand L
useful in the metal complex of the invention.
[0025] FIG. 2 shows Formulae VII through X for the ligand L useful
in the metal complex of the invention.
[0026] FIG. 3 shows Formula XI for the .beta.-enolate ligand and
Formula XII for the phosphino alkoxide ligand, useful in the
invention.
[0027] FIG. 4 shows Equation (1) for synthesis of the parent ligand
compounds, HL, useful in the invention.
[0028] FIG. 5 shows Equations (2) through (4) for forming the
complexes useful in the invention.
[0029] FIG. 6 is a schematic diagram of a light-emitting device
(LED).
[0030] FIG. 7 is a schematic diagram of an LED testing
apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The metal complexes of the invention have one of Formulae I
and II, given above, and are referred to as cyclometallated
complexes. The iridium in Formulae I and II is in the +3 oxidation
state and is hexacoordinate. In Formula I, the complex is a
tris-cyclometallated complex with no additional ligands. The tris
complexes may exhibit a facial or a meridional geometry, but most
often the facial isomer is formed. In Formula II, the complex is a
bis-cyclometallated complex with an additional monoanionic
bidentate ligand, Z. These cyclometallated iridium complexes are
neutral and non-ionic, and can be sublimed intact. Thin films of
these materials obtained via vacuum deposition exhibit good to
excellent electroluminescent properties.
[0032] The complexes of the invention have emission spectra with
maxima in the range of 570 to 700 nm, which is in the red-orange to
red region of the visible spectrum. The preferred red emission is
at 620 nm and above.
[0033] Ligand L having Formula III, shown in FIG. 1, is derived
from a thienyl-pyridine (when A is S) or pyrrolyl-pyridine (when A
is NR.sup.11) compound in which there is at least one
fluorine-containing substituent on the pyridine ring. The R.sup.3
through R.sup.6 groups may be chosen from conventional
substitutents for organic compounds, such as alkyl, alkoxy,
halogen, nitro, and cyano groups, as well as deutero, fluoro,
fluorinated alkyl and fluorinated alkoxy groups. The groups can be
partially or fully fluorinated (perfluorinated). It is preferred
that .alpha. is 0, and that R.sup.3 and/or R.sup.5 is a
fluorine-containing substituent. Most preferred is CF.sub.3. When A
is NR.sup.11, it is preferred that R.sup.11 is CH.sub.3.
[0034] Ligand L having Formula IV, shown in FIG. 1, is derived from
a thienyl- or a pyrrolyl-quinoline compound. Ligand L having
Formula V or Formula VI, shown in FIG. 1, is derived from a
thienyl- or a pyrrolyl-isoquinoline compound. It is preferred that
alpha is 0. When A is NR.sup.11, it is preferred that R.sup.11 is
CH.sub.3.
[0035] Ligand L having Formula VII, shown in FIG. 1, is derived
from a thienyl- or a pyrrolyl-diazine compound, or the analog with
3 or more nitrogens. There is at least one substituent on the
6-membered ring that is selected from D, F, C.sub.n(H+F).sub.2n+1,
OC.sub.n(H+F).sub.2n+1, and OCF.sub.2Y, most preferably CF.sub.3.
It is preferred that .alpha. is 0. When A is NR.sup.11, it is
preferred that R.sup.11 is CH.sub.3.
[0036] Ligand L having Formula VIII, shown in FIG. 2, is derived
from a phenyl-quinoline compound. Ligand L having Formulae IX or X,
shown in FIG. 2, is derived from a phenyl-isoquinoline compound.
The R.sup.7 through R.sup.10 groups may be chosen from conventional
substitutents for organic compounds, such as alkyl, alkoxy,
halogen, nitro, and cyano groups, as well as deutererium. It is
preferred that the R.sup.8 and/or R.sup.10 is a substituent bonded
through a heteroatom having non-bonding pi electrons, most
preferably oxygen. It is preferred that the R.sup.9 substituent is
an alkyl, preferably a tertiary alkyl.
[0037] The parent ligand compounds, HL, can generally be prepared
by standard palladium-catalyzed Suzuki or Kumada cross-coupling of
the corresponding heterocyclic aryl chloride with an organoboronic
acid or organomagnesium reagent, as described in, for example, O.
Lohse, P. Thevenin, E. Waldvogel Synlett, 1999, 45-48. This
reaction is illustrated for a phenyl-isoquinoline, where R and R'
represent substituents, in Equation (1) in FIG. 4.
[0038] The Z ligand is a monoanionic bidentate ligand. In general
these ligands have N, O, P, or S as coordinating atoms and form 5-
or 6-membered rings when coordinated to the iridium. Suitable
coordinating groups include amino, imino, amido, alkoxide,
carboxylate, phosphino, thiolate, and the like. Examples of
suitable parent compounds for these ligands include
.beta.-dicarbonyls (.beta.-enolate ligands), and their N and S
analogs; amino carboxylic acids (aminocarboxylate ligands);
pyridine carboxylic acids (iminocarboxylate ligands); salicylic
acid derivatives (salicylate ligands); hydroxyquinolines
(hydroxyquinolinate ligands) and their S analogs; and
diarylphosphinoalkanols (diarylphosphinoalkoxide ligands).
[0039] The .beta.-enolate ligands generally have Formula XI shown
in FIG. 3, where R.sup.13 is the same or different at each
occurrence. The R.sup.13 groups can be hydrogen, halogen,
substituted or unsubstituted alkyl, aryl, alkylaryl or heterocyclic
groups. Adjacent R.sup.13 groups can be joined to form five- and
six-membered rings, which can be substituted. Preferred R.sup.13
groups are selected from H, F, C.sub.n(H+F).sub.2n+1,
--C.sub.6H.sub.5, --C.sub.4H.sub.3S, and --C.sub.4H.sub.3O, where n
is an integer from 1 to 12, preferably from 1 to 6.
[0040] Examples of suitable .beta.-enolate ligands, Z, include the
compounds listed below. The abbreviation for the .beta.-enolate
form is given below in brackets.
[0041] 2,4-pentanedionate [acac]
[0042] 1,3-diphenyl-1,3-propanedionate [DI]
[0043] 2,2,6,6-tetramethyl-3,5-heptanedionate [TMH]
[0044] 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate [TTFA]
[0045] 7,7-dimethyl-1,1,1,2,2,3,3-heptafluoro-4,6-octanedionate
[FOD]
[0046] 1,1,1,3,5,5,5-heptafluoro-2,4-pentanedionate [F7acac]
[0047] 1,1,1,5,5,5-hexaflouro-2,4-pentanedionate [F6acac]
[0048] 1-phenyl-3-methyl-4-i-butyryl-pyrazolinonate [FMBP]
[0049] The .beta.-dicarbonyl parent compounds, HZ, are generally
available commercially. The parent compound of F7acac,
1,1,1,3,5,5,5-heptafluoro-2,4-pentanedione,
CF.sub.3C(O)CFHC(O)CF.sub.3, can be prepared using a two-step
synthesis, based on the reaction of perfluoropentene-2 with
ammonia, followed by a hydrolysis step. This compound should be
stored and reacted under anyhydrous conditions as it is susceptible
to hydrolysis.
[0050] The hydroxyquinoline parent compounds, HZ, can be
substituted with groups such as alkyl or alkoxy groups which may be
partially or fully fluorinated. In general, these compounds are
commercially available. Examples of suitable hydroxyquinolinate
ligands, Z, include: [0051] 8-hydroxyquinolinate [8hq] [0052]
2-methyl-8-hydroxyquinolinate [Me-8hq] [0053]
10-hydroxybenzoquinolinate [10-hbq] The parent hydroxyquinoline
compounds are generally available commercially.
[0054] The phosphino alkoxide parent compounds, HZ, generally have
Formula XII, shown in FIG. 3, where [0055] R.sup.14 can be the same
or different at each occurrence and is selected from
C.sub.n(H+F).sub.2n+1 and C.sub.6(H+F).sub.5, [0056] R.sup.15 can
be the same or different at each occurrence and is selected from H
and C.sub.n(H+F).sub.2n+1, and [0057] .lamda. is 2 or 3.
[0058] Examples of suitable phosphino alkoxide ligands listed
below. The abbreviation for these ligands is given below in
brackets.
[0059] 3-(diphenylphosphino)-1-oxypropane [dppO]
[0060] 1,1-bis(trifluoromethyl)-2-(diphenylphosphino)-ethoxide
[tfmdpeO]
The parent phosphino alkanol compounds are generally available
commercially.
[0061] Complexes of Formulae I and II are generally prepared from
the metal chloride salt by first forming the bridged chloride
dimer. This reaction is illustrated for a thienyl-pyridine ligand
in Equation (2) shown in FIG. 5. Complexes of Formula I are then
formed by adding an excess of the ligand parent compound HL,
without a solvent, in the presence of 2 equivalents of silver
trifluoroacetate, AgOCOCF.sub.3, per dimer. This reaction is
illustrated in Equation (3) in FIG. 5. Complexes of Formula II are
formed by adding the sodium salt of the Z ligand to the bridged
chloride dimer. This reaction is illustrated in Equation (4) in
FIG. 5.
[0062] Examples of metal complexes of the invention are given in
Table 1 below. At each occurrence, .alpha. and .delta. are zero.
TABLE-US-00001 TABLE 1 Complex Ligand R Complex Formula Formula A
substituents Z 1-a I III S R.sup.5 = CF.sub.3 -- 1-b I V S none --
1-c I IX -- R.sup.9 = t-butyl -- 1-d I IX -- R.sup.8 = OCH.sub.3 --
1-e I IX -- R.sup.8 = OH -- 1-f I VIII -- R.sup.9 = t-butyl -- 1-g
II III N--CH.sub.3 R.sup.5 = CF.sub.3 acac 1-h II V S none acac 1-i
II IX -- none acac 1-j II IX -- R.sup.9 = t-butyl acac 1-k II IX --
R.sup.8 = OCH.sub.3 acac 1-l II VIII -- R.sup.9 = t-butyl acac 1-m
II IX -- R.sup.7 = R.sup.8 = R.sup.9 = acac R.sup.10 = D
[0063] The complexes in Table 1 have electroluminescent emission
maxima from about 570 nm, for compound 1-a, to about 670 nm, for
compound 1-k.
Electronic Device
[0064] The present invention also relates to an electronic device
comprising at least one photoactive layer positioned between two
electrical contact layers, wherein the at least one photoactive
layer of the device includes the complex of the invention. As shown
in FIG. 6, a typical device 100 has an anode layer 110 and a
cathode layer 150 and layers 120, 130 and optionally 140 between
the anode 110 and cathode 150. Layers 120, 130, and 140 are
collectively referred to as the active layers. Adjacent to the
anode is a hole injection/transport layer 120. Adjacent to the
cathode is an optional layer 140 comprising an electron transport
material. Between the hole injection/transport layer 120 and the
cathode (or optional electron transport layer) is the photoactive
layer 130. Layers 120, 130, and 140 are individually and
collectively referred to as the active layers.
[0065] Depending upon the application of the device 100, the
photoactive layer 130 can be a light-emitting layer that is
activated by an applied voltage (such as in a light-emitting diode
or light-emitting electrochemical cell), a layer of material that
responds to radiant energy and generates a signal with or without
an applied bias voltage (such as in a photodetector). Examples of
photodetectors include photoconductive cells, photoresistors,
photoswitches, phototransistors, and phototubes, and photovoltaic
cells, as these terms are describe in Markus, John, Electronics and
Nucleonics Dictionary, 470 and 476 (McGraw-Hill, Inc. 1966).
[0066] The complexes of the invention are particularly useful as
the photoactive material in layer 130, or as electron transport
material in layer 140. When used in layer 130, it has been found
that the complexes of the invention do not need to be in a solid
matrix diluent in order to be effective. A layer that is greater
than 20% by weight metal complex, based on the total weight of the
layer, up to 100% metal complex, can be used as the emitting layer.
Additional materials can be present in the emitting layer with the
metal complex. For example, a fluorescent dye may be present to
alter the color of emission. A diluent may also be added.
Preferably, the diluent facilitates charge transport in the layer.
The diluent can be a polymeric material, such as poly(N-vinyl
carbazole) and polysilane. It can also be a small molecule, such as
4,4'-N,N'-dicarbazole biphenyl or tertiary aromatic amines. When a
diluent is used, the metal complex is generally present in a small
amount, usually less than 20% by weight, preferably less than 10%
by weight, based on the total weight of the layer.
[0067] One type of diluent which is useful with the iridium metal
complexes of the invention, is a conjugated polymer in which the
triplet excited state of the polymer is at a higher energy level
than the triplet excited state of the iridium complex. Examples of
suitable conjugated polymers include polyarylenevinylenes,
polyfluorenes, polyoxadiazoles, polyanilines, polythiophenes,
polypyridines, polyphenylenes, copolymers thereof, and combinations
thereof. The conjugated polymer can be a copolymer having
non-conjugated portions of, for example, acrylic, methacrylic, or
vinyl, monomeric units. Particularly useful are homopolymers and
copolymers of fluorene and substituted fluorenes.
[0068] In some cases the metal complexes of the invention may be
present in more than one isomeric form, or mixtures of different
complexes may be present. It will be understood that in the above
discussion of OLEDs, the term "the metal complex" is intended to
encompass mixtures of complexes and/or isomers.
[0069] The device generally also includes a support (not shown)
which can be adjacent to the anode or the cathode. Most frequently,
the support is adjacent the anode. The support can be flexible or
rigid, organic or inorganic. Generally, glass or flexible organic
films are used as a support. The anode 110 is an electrode that is
particularly efficient for injecting or collecting positive charge
carriers. The anode is preferably made of materials containing a
metal, mixed metal, alloy, metal oxide or mixed-metal oxide.
Suitable metals include the Group 11 metals, the metals in Groups
4, 5, and 6, and the Group 8-10 transition metals. If the anode is
to be light-transmitting, mixed-metal oxides of Groups 12, 13 and
14 metals, such as indium-tin-oxide, are generally used. The anode
110 may also comprise an organic material such as polyaniline as
described in "Flexible light-emitting diodes made from soluble
conducting polymers," Nature vol. 357, pp 477-479 (11 Jun.
1992).
[0070] The anode layer 110 is usually applied by a physical vapor
deposition process or spin-cast process. The term "physical vapor
deposition" refers to various deposition approaches carried out in
vacuo. Thus, for example, physical vapor deposition includes all
forms of sputtering, including ion beam sputtering, as well as all
forms of vapor deposition such as e-beam evaporation and resistance
evaporation. A specific form of physical vapor deposition which is
useful is rf magnetron sputtering.
[0071] There is generally a hole transport layer 120 adjacent the
anode. Examples of hole transport materials for layer 120 have been
summarized for example, in Kirk-Othmer Encyclopedia of Chemical
Technology, Fourth Edition, Vol. 18, p. 837-860, 1996, by Y. Wang.
Both hole transporting molecules and polymers can be used. Commonly
used hole transporting molecules, in addition to TPD and MPMP
mentioned above, are: 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane
(TAPC);
N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)bip-
henyl]-4,4'-diamine (ETPD);
tetrakis-(3-methylphenyl)-N,N,N',N'-2,5-phenylenediamine (PDA);
a-phenyl-4-N,N-diphenylaminostyrene (TPS);
p-(diethylamino)benzaldehyde diphenylhydrazone (DEH);
triphenylamine (TPA);
1-phenyl-3-[p-(diethylamino)styryl]-5-[p-(diethylamino)phenyl]pyrazoline
(PPR or DEASP); 1,2-trans-bis(9H-carbazol-9-yl)cyclobutane (DCZB);
N,N,N',N'-tetrakis(4-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine
(TTB); and porphyrinic compounds, such as copper phthalocyanine.
Commonly used hole transporting polymers are polyvinylcarbazole,
(phenylmethyl)polysilane; poly(3,4-ethylendioxythiophene) (PEDOT);
and polyaniline. It is also possible to obtain hole transporting
polymers by doping hole transporting molecules such as those
mentioned above into polymers such as polystyrene and
polycarbonate.
[0072] Optional layer 140 can function both to facilitate electron
transport, and also serve as a buffer layer or anti-quenching layer
to prevent quenching reactions at layer interfaces. Preferably,
this layer promotes electron mobility and reduces quenching
reactions. Examples of electron transport materials for optional
layer 140 include metal chelated oxinoid compounds, such as
tris(8-hydroxyquinolato)aluminum (Alq.sub.3); phenanthroline-based
compounds, such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline
(DDPA) or 4,7-diphenyl-1,10-phenanthroline (DPA), and azole
compounds such as
2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD) and
3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole
(TAZ).
[0073] The cathode 150 is an electrode that is particularly
efficient for injecting or collecting electrons or negative charge
carriers. The cathode can be any metal or nonmetal having a lower
work function than the first electrical contact layer (in this
case, an anode). Materials for the second electrical contact layer
can be selected from alkali metals of Group 1 (e.g., Li, Cs), the
Group 2 (alkaline earth) metals, the Group 12 metals, the
lanthanides, and the actinides. Materials such as aluminum, indium,
calcium, barium, samarium and magnesium, as well as combinations,
can be used.
[0074] It is known to have other layers in organic electronic
devices. For example, there can be a layer (not shown) between the
conductive polymer layer 120 and the active layer 130 to facilitate
positive charge transport and/or band-gap matching of the layers,
or to function as a protective layer. Similarly, there can be
additional layers (not shown) between the active layer 130 and the
cathode layer 150 to facilitate negative charge transport and/or
band-gap matching between the layers, or to function as a
protective layer. Layers that are known in the art can be used. In
addition, any of the above-described layers can be made of two or
more layers. Alternatively, some or all of inorganic anode layer
110, the conductive polymer layer 120, the active layer 130, and
cathode layer 150, may be surface treated to increase charge
carrier transport efficiency. The choice of materials for each of
the component layers is preferably determined by balancing the
goals of providing a device with high device efficiency.
[0075] It is understood that each functional layer may be made up
of more than one layer.
[0076] The device can be prepared by sequentially vapor depositing
the individual layers on a suitable substrate. Substrates such as
glass and polymeric films can be used. Conventional vapor
deposition techniques can be used, such as thermal evaporation,
chemical vapor deposition, and the like. Alternatively, the organic
layers can be coated from solutions or dispersions in suitable
solvents, using any conventional coating technique. In general, the
different layers will have the following range of thicknesses:
anode 110, 500-5000 .ANG., preferably 1000-2000 .ANG.; hole
transport layer 120, 50-2500 .ANG., preferably 200-2000 .ANG.;
light-emitting layer 130, 10-1000 .ANG., preferably 100-800 .ANG.;
optional electron transport layer 140, 50-1000 .ANG., preferably
100-800 .ANG.; cathode 150, 200-10,000 .ANG., preferably 300-5000
.ANG.. The location of the electron-hole recombination zone in the
device, and thus the emission spectrum of the device, is affected
by the relative thickness of each layer. For examples, when an
emitter, such as Alq.sub.3 is used as the electron transport layer,
the electron-hole recombination zone can be in the Alq.sub.3 layer.
The emission would then be that of Alq.sub.3, and not the desired
sharp lanthanide emission. Thus the thickness of the
electron-transport layer must be chosen so that the electron-hole
recombination zone is in the light-emitting layer. The desired
ratio of layer thicknesses will depend on the exact nature of the
materials used.
[0077] It is understood that the efficiency of the devices of the
invention made with metal complexes, can be further improved by
optimizing the other layers in the device. For example, more
efficient cathodes such as Ca, Ba, Mg/Ag, or LiF/Al can be used.
Shaped substrates and novel hole transport materials that result in
a reduction in operating voltage or increase quantum efficiency are
also applicable. Additional layers can also be added to tailor the
energy levels of the various layers and facilitate
electroluminescence.
[0078] The iridium complexes of the invention often are
phosphorescent and photoluminescent and may be useful in other
applications. For example, organometallic complexes of iridium have
been used as oxygen sensitive indicators, as phosphorescent
indicators in bioassays, and as catalysts. The bis cyclometallated
complexes can be used to sythesize tris cyclometalated complexes
where the third ligand is the same or different.
EXAMPLES
[0079] The following examples illustrate certain features and
advantages of the present invention. They are intended to be
illustrative of the invention, but not limiting. All percentages
are mole percents, unless otherwise indicated.
Examples 1
[0080] This example illustrates the preparation of a ligand parent
compound (HL), 2-(2-thienyl)-5-(trifluoromethyl)pyridine.
[0081] 2-thienylboronic acid (Lancaster Synthesis, Inc., 1.00 g,
7.81 mmmol), 2-chloro-5-trifluoromethylpyrdine (Aldrich Chemical
Co., 1.417 g, 7.81 mmol), tetrakistriphenylphosphine palladium(0)
(Aldrich, 451 mg, 0.391 mmol), potassium carbonate (EM Science,
3.24 g, 23.4 mmol), water (20 mL), and dimethoxyethane (Aldrich, 20
mL) were allowed to stir at reflux for 20 hours under N.sub.2,
after which time the mixture was cooled to room temperature and the
organic and aqueous layers were separated. The aqueous layer was
extracted with 3.times.50 mL of diethyl ether, and the combined
organic fractions were dried with sodium sulfate, filtered, and the
filtrate was evaporated to dryness. The crude product was purified
by silica gel flash chromatography with CH.sub.2Cl.sub.2/hexanes
(1:1) as the eluent (product Rf=0.5), to afford the product as a
white crystalline solid (yield=5.2 g, 73% isolated yield). .sup.1H
NMR (CDCl.sub.3, 296 K, 300 MHz): .delta.=7.73-7.57 (2H, m), 7.55
(1H, d, J=8.5 Hz), 7.34 (1H, d, J=4.8 Hz), 6.88 (1H d, J=4.8 Hz)
ppm. .sup.19F NMR (CDCl.sub.3, 296K, 282 MHz) .delta.=-62.78
ppm.
Example 2
[0082] This example illustrates the preparation of the intermediate
dichloro bridged dimer,
[IrCl{2-(2-thienyl)-5-(trifluoromethyl)pyridine}2]2.
[0083] 2-(2-thienyl)-5-(trifluoromethyl)pyridine from Example 1
(555 mg, 2.42 mmol), iridium trichloride (Strem Chemicals, 401 mg,
1.13 mmol), 2-ethoxyethanol (Aldrich Chemical Co., 10 mL) and water
(1 mL) were allowed to reflux under nitrogen for 15 hours, after
which time the reaction was allowed to cool to room temperature.
The resulting precipitated product was collected by filtration,
washed with hexanes, and dried in vacuo, to afford 575 mg (37%) of
the product as a red-orange solid. .sup.1H NMR (CDCl.sub.3, 296 K,
300 MHz): .delta.=9.30 (4H, d, J=1.5 Hz), 7.80 (4H, dd, J=2.0 Hz
and 8.5 Hz), 7.59 (4H, d, J=8.5 Hz), 7.21 (8H, d, J=4.8 Hz), 5.81
(d, 4H, J=4.9 Hz). .sup.19F NMR (CDCl.sub.3, 296K, 282 MHz)
.delta.=-62.07 ppm.
Example 3
[0084] This example illustrates the preparation of a
tris-cyclometallated iridium complex,
[Ir{2-(2-thienyl)-5-(trifluoromethyl)pyridine}.sub.3], compound 1-a
from Table 1.
[0085]
[IrCl{2-(2-thienyl)-5-(trifluoromethyl)pyridine}.sub.2].sub.2 from
Example 2 (100 mg, 0.073 mmol),
2-(2-thienyl)-5-(trifluoromethyl)pyridine from Example 1 (201 mg,
0.88 mmol), and silver trifluoroacetate (Aldrich, 40 mg, 0.18 mmol)
were combined and allowed to stir at 170-180.degree. C. under
nitrogen for 10 min. Then the mixture was allowed to cool to room
temperature and it was redissolved in a minimum amount
dichloromethane. The solution was passed through a silica gel
column with dichloromethane/hexanes (1:1) as the eluting solvent.
The first red-orange fraction to come down the column (product
Rf=0.5) was collected and evaporated to dryness. The residue was
suspended in hexanes, and the precipitated product was filtered and
washed with excess hexanes to remove any residual
2-(2-thienyl)-5-(trifluoromethyl)pyridine, to afford the product as
a red-orange solid. Isolated yield .apprxeq.50 mg (39%). .sup.1H
NMR (CDCl.sub.3, 296 K, 300 MHz): .delta.=7.73-7.57 (6H, m), 7.55
(3H, d, J=8.5 Hz), 7.34 (3H, d, J=4.8 Hz), 6.88 (3H, d, J=4.8 Hz).
.sup.19F NMR (CDCl.sub.3, 296K, 282 MHz) .delta.=-62.78.
[0086] Compounds 1-b through 1-f in Table 1 were made using a
similar procedure.
Example 4
[0087] This example illustrates the preparation of the ligand
parent compound, 1-(4-tert-butylphenyl)-isoquinoline.
[0088] 4-tert-butylphenylboronic acid (Aldrich Chemical Co., 5.00
g, 30.56 mmmol), 1-chloroisoquinoline (Aldrich Chemical Co., 5.44
g, 30.56 mmol), tetrakistriphenylphosphine palladium(0) (Aldrich,
800 mg, 0.69 mmol), potassium carbonate (EM Science, 12.5 g, 23.4
mmol), water (50 mL), and dimethoxyethane (Aldrich, 75 mL) were
allowed to stir at reflux for 20 h under N.sub.2, after which time
the mixture was cooled to room temperature and the organic and
aqueous layers were separated. The aqueous layer was extracted with
3.times.75 mL of diethyl ether, and the combined organic fractions
were dried with sodium sulfate, filtered, and the filtrate was
evaporated to dryness. The crude material was chromatographed on a
silica gel column, first by eluting the catalyst byproduct with 4:1
hexanes/dichloromethane, and finally the product was eluted with
dichloromethane/MeOH (9.5:0.5, product R.sub.f=0.7). The pure
product fractions were collected and dried in vacuo, to afford 4.5
g (56% isolated yield) of a light yellow solid, >95% pure NMR
spectroscopy. .sup.1H NMR (CDCl.sub.3, 296 K, 300 MHz):
.delta.=8.58 (1H, d, J=5.70 Hz), 8.15 (1H, d, J=8.5 Hz), 7.83 (1H,
d, J=8.5 Hz), 7.5-7.7 (7H, m), 1.38 (9H, s) ppm.
Example 5
[0089] This example illustrates the preparation of the dichloro
bridged dimer,
IrCl{1-(4-t-Bu-phenyl)-isoquinoline}.sub.2].sub.2.
[0090] 1-(4-t-Bu-phenyl)-isoquinoline from Example 4 (1.00 g, 3.82
mmol), IrCl.sub.3(H.sub.2O).sub.3 (Strem Chemicals, 633 mg, 1.79
mmol), and 2-ethoxyethanol (Aldrich Chemical Co., 40 mL) were
allowed to stir at reflux for 15 h, after which time the mixture
was poured into an equal volume of water. The resulting orange
precipitate was isolated by filtration, washed with water, and
allowed to dry in vacuo. Then the solid was re-dissolved in
dichloromethane and passed through a silica gel pad. The red eluted
dichloromethane solution was evaporated to dryness, and the
resulting solid was suspended in hexanes. The solid was isolated by
filtration to afford 650 mg (49%) of a red-orange solid, >95%
pure by NMR spectroscopy..sup.1H NMR (CD.sub.2Cl.sub.2, 296 K, 300
MHz): .delta.=9.37 (4H, d, J=6.5 Hz), 8.95 (4H, d, J=8.2 Hz), 8.07
(4H, d, J=8.5 Hz), 7.90 (4H, dd, J=1.4 and 8.2 Hz), 7.7-7.9 (8H,
m), 6.94 (4H, dd, J=2.0 and 8.4 Hz), 6.86 (4H, d, J=6.4 Hz), 5.92
(4 H, d, J=2.0 Hz), 0.81 (36H, s) ppm.
Example 6
[0091] This example illustrates the preparation of a bis
cyclometallated iridium complex,
[Ir(acac){1-(4-t-Bu-phenyl)-isoquinoline}.sub.2], compound 1-j,
from Table 1.
[0092] [IrCl{1-(4-t-Bu-phenyl)-isoquinoline}.sub.2].sub.2 from
Example 5 (200 mg, 0.135 mmol), sodium acetylacetonate (Aldrich, 80
mg, 0.656 mmol), and 2-ethoxyethanol (Aldrich, 5 mL) were allowed
to stir at 120.degree. C. for 10 min, then the volatile components
were removed in vacuo. The residue was redissolved in
dichloromethane and passed through a pad of silica gel on a
sintered glass funnel with CH.sub.2Cl.sub.2 as the eluting solvent.
The red-luminescent filtrate was evaporated to dryness to afford
190 mg (87% isolated yield) of the desired product, >95% by
.sup.1H NMR. .sup.1H NMR (CDCl.sub.3, 296 K, 300 MHz): .delta.=8.94
(2H, dd, J=2.1 and 8.2 Hz), 8.49 (2H, d, J=6.4 Hz), 8.11 (2H, d,
J=8.50 Hz), 7.98 (2H, d, J=3.9 and 9.6 Hz), 7.6-7.8 (4H, m), 7.55
(2H, d, J=6.4 Hz), 6.99 (2H, d, J=2.1 and 8.5 Hz), 6.21 (2H, d,
J=2.0 Hz), 5.35 (1H, s), 1.84 (6H, s), 0.95 (18H, s) ppm.
[0093] Compounds 1-g through 1-i and 1-k through1-l in Table 1 were
made using a similar procedure.
Example 7
[0094] This example illustrates the preparation of the ligand
parent compound, 1-(perdeuterophenyl)-isoquinoline.
[0095] Perdeutero-benzeneboronic acid, dimethylester: To a solution
of bromobenzene-d5 (Aldrich Chemical Co., 10.0 g, 61.7 mmol) in dry
diethyl ether (50 mL) at -78.degree. C. under nitrogen was added
n-BuLi (Aldrich, 1.6 M in hexanes, 38.6 mL) slowly over two
minutes. The stirred mixture was allowed to warm to room
temperature for 2 hours, and then it was transferred to another
flask which contained a stirred solution of trimethylborate
(Aldrich, 50 mL, 494 mmol) and dry diethylether (200 mL) at
-78.degree. C. under N.sub.2. The resulting mixture was allowed to
warm to room temperature and stirred for 15 hours, after which time
ice-cold 2 M HCl (50 mL) was added to quench the reaction mixture.
The organic phase was separated, dried with sodium sulfate,
filtered, and evaporated to dryness, to afford 4.9 g (52% yield) of
the desired product as a white solid. .sup.1H NMR (CDCl.sub.3, 296
K, 300 MHz) .delta. 3.73 (br s) ppm.
[0096] 1-(perdeuterophenyl)-isoquinoline: 1-Chloroisoquinoline
(Aldrich Chemical Co., 5.00 g, 30.6 mmol), perdeuterobenzeneboronic
acid, dimethyl ester from the synthesis above (4.87 g, 31.4 mmol),
potassium carbonate (EM Science, 8.4 g, 61.2 mmol),
tetrakistriphenylphosphine palladium(0) (Aldrich, 707 mg, 0.611
mmol), dimethoxymethane (Aldrich, 100 mL) and water (100 mL) were
combined under nitrogen, and the mixture was allowed to reflux for
15 hours. After this time, the organic layer was separated, and the
aqueous layer was extracted with 3.times.50 mL of diethyl ether.
The combined organic components were dried with sodium sulfate,
filtered, and evaporated to dryness. The resulting crude product
was purified by silica gel chromatography. The phosphine catalyst
was first eluted with 4:1 dichloromethane/hexanes, and then the
desired product was eluted with 100% dichloromethane and then
dichloromethane/methanol (95:5, product Rf=0.6). The product
fractions were combined and evaporated to dryness, to afford 4.5 g
(70%) of the desired product as a white solid. .sup.1H NMR
(CDCl.sub.3, 296 K, 300 MHz): .delta.=8.60 (1H, d, J=5.7 Hz), 8.10
(1H, d, J=8.5 Hz), 7.88 (1H, d, J=8.4 Hz), 7.67 (2H, m), 7.53 (1H,
m) ppm.
Example 8
[0097] This example illustrates the preparation of the dichloro
bridged dimer,
[IrCl{1-(perdeuterophenyl)-isoquinoline}.sub.2].sub.2.
[0098] 1-(Perdeuterophenyl)-isoquinoline from Example 7 (3.00 g,
14.3 mmol), IrCl.sub.3(H.sub.2O).sub.3 (Strem Chemicals, Inc.) 2.42
g, 6.80 mmol), 2-ethoxyethanol (Aldrich Chemical Co., 45 mL), and
water (5 mL) were allowed to stir at reflux for 15 hours under
nitrogen, after which time the resulting precipitated product was
isolated via filtration. It was then washed with excess methanol,
then diethyl ether, and finally dried in vacuo, to afford the
desired product as a red-orange solid. Yield=2.12 g (48%).
Example 9
[0099] This example illustrates the preparation of a bis
cyclometallated iridium complex,
Ir(acac){1-(perdeuterophenyl)-isoquinoline}.sub.2, compound 1-m,
from Table 1.
[0100] [IrCl{1-(perdeuterophenyl)-isoquinoline}.sub.2].sub.2 from
Example 8 (300 mg, 0.232 mmol), acetylacetone, sodium salt (Aldrich
Chemical Co., 71 mg, 0.581 mmol), and 2-ethoxyethanol (Aldrich, 15
mL) were allowed to stir at 120.degree. C. for 45 min, after which
time the volatile components were removed in vacuo. The resulting
residue was taken up in dichloromethane and passed through a silica
gel pad with dichloromethane as the eluting solvent. The first red
fraction (Rf=1.0) was collected and evaporated to dryness, to
afford the desired product as a red-orange solid. Yield=230 (70%).
.sup.1H NMR (CDCl.sub.3, 296 K, 300 MHz) .delta.=8.99 (1H, m), 8.45
(1H, d, J=6.4 Hz), 7.98 (1H, m), 7.75 (2H, m), 7.55 (1H, d, J=6.3
Hz), 5.29 (1H, s), 1.79 (6H, s) ppm. Additional signals observed
that are due to small amounts of H/D exchange that occurred in the
cyclometallation reaction: 8.24 (0.5 H, m), 6.96 (0.20 H, d, J=9.8
Hz).
Example 10
[0101] This example illustrates the formation of OLEDs using the
iridium complexes of the invention.
[0102] Thin film OLED devices including a hole transport layer (HT
layer), electroluminescent layer (EL layer) and at least one
electron transport layer (ET layer) were fabricated by the thermal
evaporation technique. An Edward Auto 306 evaporator with oil
diffusion pump was used. The base vacuum for all of the thin film
deposition was in the range of 10.sup.-6 torr. The deposition
chamber was capable of depositing five different films without the
need to break up the vacuum.
[0103] An indium tin oxide (ITO) coated glass substrate was used,
having an ITO layer of about 1000-2000 .ANG.. The substrate was
first patterned by etching away the unwanted ITO area with 1N HCl
solution, to form a first electrode pattern. Polyimide tape was
used as the mask. The patterned ITO substrates were then cleaned
ultrasonically in aqueous detergent solution. The substrates were
then rinsed with distilled water, followed by isopropanol, and then
degreased in toluene vapor for .about.3 hours. Alternatively,
patterned ITO from Thin Film Devices, Inc was used. These ITO's are
based on Corning 1737 glass coated with 1400 .ANG. ITO coating,
with sheet resistance of 30 ohms/square and 80% light
transmission.
[0104] The cleaned, patterned ITO substrate was then loaded into
the vacuum chamber and the chamber was pumped down to 10.sup.-6
torr. The substrate was then further cleaned using an oxygen plasma
for about 5-10 minutes. After cleaning, multiple layers of thin
films were then deposited sequentially onto the substrate by
thermal evaporation. Finally, patterned metal electrodes of Al were
deposited through a mask. The thickness of the film was measured
during deposition using a quartz crystal monitor (Sycon STC-200).
All film thicknesses reported in the Examples are nominal,
calculated assuming the density of the material deposited to be
one. The completed OLED device was then taken out of the vacuum
chamber and characterized immediately without encapsulation.
[0105] A summary of the device layers and thicknesses are given in
Table 2. In all cases the anode was ITO as discussed above, and the
cathode was Al having a thickness in the range of 700-760 .ANG..
TABLE-US-00002 TABLE 2 HT layer EL layer ET layer Cathode Sample
Thickness, .ANG. thickness, .ANG. thickness, .ANG. thickness, .ANG.
1 MPMP Compound 1-a DPA Al 504 411 418 737 2 MPMP Compound 1-i DPA
Al 513 420 412 737 3 MPMP Compound 1-j DPA Al 513 414 400 721 4
MPMP Compound 1-k DPA Al 530 407 407 732 5 MPMP Compound 1-l DPA Al
533 411 414 727 6 MPMP Compound 1-f DPA Al 563 305 408 725 7 MPMP
Compound 1-h DPA Al 538 409 418 734 8 MPMP Compound 1-c DPA Al 526
428 402 728 9 MPMP Compound 1-m DPA Al 530 404 415 725 DPA =
4,7-diphenyl-1,10-phenanthroline ET = electron transport EL =
electroluminescence HT = hole transport MPMP =
bis[4-(N,N-diethylamino)-2-methylphenyl](4-methylphenyl)methane
[0106] The OLED samples were characterized by measuring their (1)
current-voltage (I-V) curves, (2) electroluminescence radiance
versus voltage, and (3) electroluminescence spectra versus voltage.
The apparatus used, 200, is shown in FIG. 7. The I-V curves of an
OLED sample, 220, were measured with a Keithley Source-Measurement
Unit Model 237, 280. The electroluminescence radiance (in the unit
of Cd/m.sup.2) vs. voltage was measured with a Minolta LS-110
luminescence meter, 210, while the voltage was scanned using the
Keithley SMU. The electroluminescence spectrum was obtained by
collecting light using a pair of lenses, 230, through an electronic
shutter, 240, dispersed through a spectrograph, 250, and then
measured with a diode array detector, 260. All three measurements
were performed at the same time and controlled by a computer, 270.
The efficiency of the device at certain voltage is determined by
dividing the electroluminescence radiance of the LED by the current
density needed to run the device. The unit is in Cd/A.
[0107] The results are given in Table 3 below. TABLE-US-00003 TABLE
3 Electroluminescent Properties of Iridium Compounds Approximate
Peak Peak Peak Radiance, efficiency, Wavelengths, Sample Cd/m.sup.2
Cd/A nm 1 200 Cd/m.sup.2 1.5 570 at 25 V 2 100 Cd/m.sup.2 0.65 620
at 22 V 3 200 1.2 625 at 22 V 4 1 0.04 >670 at 21 V 5 400 1.6
605 and 640 at 22 V 6 5 0.3 585 at 20 V 7 7 0.06 620 at 23 V 8 2.5
0.3 625 at 23 V 9 350 0.6 625 at 19 V
Example 11
[0108] This example illustrates the formation of OLED's using a
red-emissive material of the invention as a dopant in a
poly(fluorene) polymer matrix. The resulting blend will be used as
the active red-emissive layer in an OLED. The iridium complex,
[Ir(acac){1-(4-t-Bu-phenyl)-isoquinoline}.sub.2], compound 1-j,
from Table 1, will be prepared as described in Example 6. The
polyfluorene polymer will be prepared as described in Yamamoto,
Progress in Polymer Science, Vol. 17, p 1153 (1992), where the
dihalo, preferably dibromo, derivatives of the monomeric units are
reacted with a stoichiometric amount of a zerovalent nickel
compound, such as bis(1,5-cyclooctadiene)nickel(0).
[0109] The organic film components in this OLED example will all be
solution processed. Device assembly will be as follows: ITO/glass
substrate (Applied Films) will be patterned (device active
area=entire 3 cm.sup.2) and cleaned as described in Example 10. The
substrate will then be further cleaned by placing in a 300 W plasma
oven for 15 min. A poly(ethylenedioxythiophene)-poly(styrenesufonic
acid) (PEDOT-PSSA, Bayer Corp.) buffer layer (i.e. hole
transport/injection layer) will then be spin-coated to a thickness
of 90 nm. The film will be dried on a hotplate at 200.degree. C.
for 3 min. The substrate will be then transferred to a
nitrogen-filled glovebox, at which point a solution of
poly(fluorene) polymer,
[Ir(acac){1-(4-t-Bu-phenyl)-isoquinoline}.sub.2] (1.6 .mu.mol), and
anhydrous toluene (7.5 mL) will be spin coated on the substrate to
a thickness of 70 nm. The substrate will be then transferred to a
high vacuum chamber, where Ba (3.5 nm) followed by Al (400 nm) will
be thermally deposited at 2.0.times.10.sup.-6 torr. The resulting
OLED device will then be sealed from air by gluing a glass slide on
top of the cathode with the use of a UV-curable epoxy resin.
[0110] The device will be fully characterized by acquiring
current-voltage, luminance-voltage, luminance-current,
efficiency-voltage, and efficiency-current profiles. This will be
accomplished with the use of a computer-driven (Labview software)
Keithley Source-Measurement Unit and a photodiode, the latter which
integrated light output over the entire 3 cm.sup.2 device active
area.
* * * * *