Synthesis and characterization of polymerizable phosphorescent platinum(II) complexes for solution-processible organic light-emitting diodes

Article abstract of DOI:10.1021/om700373c

A norbornene-functionalized derivative of acetylacetone has been used to synthesize a series of new polymerizable norbornene-derivatized phosphorescent platinum complexes of the form Pt(C∧N)(O∧O*) where C∧N represents a cyclometalated ligand and O∧O* represents the functionalized acetylacetonate ligand. The complexes have been fully characterized, and the structures of three examples have been determined by X-ray diffraction. Solution absorption and luminescence spectra and electrochemical data are very similar to those for analogues without these polymerizable groups. A 9,9-dialkyl-2,7-di(carbazol-9-yl)fluorene material, in which one of the alkyl groups bears a norbornene group, has been synthesized and copolymerized with the Pt(C∧N)(O∧O*) complexes using Grubbs ruthenium catalysts, resulting in copolymers with broad molecular weight distributions. The copolymers have been used as lumophores in organic light-emitting diodes, thus demonstrating that platinum phosphors can be successfully integrated into the "hybrid" approach to organic light-emitting diodes, in which molecules with transport or luminescent properties are covalently attached to electronically inert polymer backbones to give solution-processible materials. Emission from aggregate states appears to play a similar role in these copolymers to that seen in vapor-deposited devices based on small phosphor and host molecules; in particular, considerable aggregate emission is observed when a phosphor with blue solution emission is used in the devices.

Full text of DOI:10.1021/om700373c

4816
Organometallics 2007, 26, 4816-4829
Synthesis and Characterization of Polymerizable Phosphorescent
Platinum(II) Complexes for Solution-Processible Organic
Light-Emitting Diodes
Jian-Yang Cho,† Benoit Domercq,‡ Stephen Barlow,† Kyrill Yu. Suponitsky,§, Jennifer Li,§
Tatiana V. Timofeeva,§ Simon C. Jones,† Lauren E. Hayden,† Alpay Kimyonok,†
Clinton R. South,† Marcus Weck,† Bernard Kippelen,‡ and Seth R. Marder*,†
Center for Organic Photonics and Electronics (COPE), School of Chemistry and Biochemistry, and School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332,
Department of Natural Sciences, New Mexico Highlands UniVersity, Las Vegas, New Mexico 87701, and
Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russian Federation
ReceiVed April 16, 2007
A norbornene-functionalized derivative of acetylacetone has been used to synthesize a series of new
polymerizable norbornene-derivatized phosphorescent platinum complexes of the form Pt(C∧N)(O∧O*)
where C∧N represents a cyclometalated ligand and O∧O* represents the functionalized acetylacetonate
ligand. The complexes have been fully characterized, and the structures of three examples have been
determined by X-ray diffraction. Solution absorption and luminescence spectra and electrochemical data
are very similar to those for analogues without these polymerizable groups. A 9,9-dialkyl-2,7-di(carbazol-
9-yl)fluorene material, in which one of the alkyl groups bears a norbornene group, has been synthesized
and copolymerized with the Pt(C∧N)(O∧O*) complexes using Grubbs ruthenium catalysts, resulting in
copolymers with broad molecular weight distributions. The copolymers have been used as lumophores
in organic light-emitting diodes, thus demonstrating that platinum phosphors can be successfully integrated
into the “hybrid” approach to organic light-emitting diodes, in which molecules with transport or
luminescent properties are covalently attached to electronically inert polymer backbones to give solution-
processible materials. Emission from aggregate states appears to play a similar role in these copolymers
to that seen in vapor-deposited devices based on small phosphor and host molecules; in particular,
considerable aggregate emission is observed when a phosphor with blue solution emission is used in the
devices.
efficiencies have been obtained in OLEDs incorporating com-
plexes of iridium(III),3 platinum(II),4 osmium(II),5 rhenium(I),6
and ruthenium(II).7
Organic light-emitting diodes (OLEDs) fall into two main
classes: those based on vacuum-deposited small molecules and
those based on solution-processible conjugated polymers.
Phosphorescent lumophores have been incorporated into both
vacuum-deposited small-molecule devices8 and conjugated
polymer systems.9 However, there are some problems associated
Introduction
Organic light-emitting diodes (OLEDs) are a promising
technology for thin-film displays due to recent rapid progress
in material design and device fabrication.1 Recombination of a
hole and an electron can give rise to either singlet or triplet
excited states of the lumophore. In typical organic materials,
the triplet is nonluminescent and so only the charge-recombina-
tion events that form singlets can result in luminescence.
However, due to strong spin-orbit coupling, complexes of the
5d metals display rapid intersystem crossing from the lowest
excited singlet state to the lowest triplet state, which often has
a sufficiently short phosphorescence lifetime that it can lumi-
nesce with high efficiency; thus, formation of either singlet or
triplet excited states of the complex results in luminescence.
Hence, complexes of this type have been incorporated into
OLEDs to harvest both singlet and triplet charge recombinations;
theoretically, the internal quantum efficiency of such phospho-
rescent devices can approach 100%.2 High phosphorescence
(2) Adachi, C.; Baldo, M. A.; Thompson, M. E.; Forrest, S. R. J. Appl.
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Peng, S. E.-M. G.; Lee, G.-H. Inorg. Chem. 2005, 44, 1344. (c) Su, Y.-J.;
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† COPE and School of Chemistry and Biochemistry, Georgia Institute
of Technology.
‡ COPE and School of Electrical and Computer Engineering, Georgia
Institute of Technology.
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Y.; Shen, J. AdV. Funct. Mater. 2003, 13, 603. (b) Ranjan, S.; Lin, S.-Y.;
Hwang, K.-C.; Chi, Y.; Ching, W.-L.; Liu, C.-S.; Tao, Y.-T.; Chien, C.-
H.; Peng, S.-M.; Lee, G.-H. Inorg. Chem. 2003, 42, 1248.
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17, 1059. (b) Xia, H.; Zhang, C.; Qiu, S.; Lu, P.; Zhang, J.; Ma, Y. Appl.
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§ New Mexico Highlands University.
Russian Academy of Sciences.
(1) (a) Tang, C. W.; Vanslyke, S. A. Appl. Phys. Lett. 1987, 51, 913.
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10.1021/om700373c CCC: $37.00 © 2007 American Chemical Society
Publication on Web 08/09/2007

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4817
Chart 1. Structure of CBP, 1
with phase separation in blends of small-molecule phosphors
and polymers; this can lead to aggregation and subsequent
luminescence quenching and device degradation. To reduce
these effects, iridium phosphors have been covalently attached
to the side chains of a fully conjugated polyfluorene backbone,10
and bis-cyclometalated iridium acetylacetonate units have been
incorporated into the conjugated main chains of oligomeric 9,9-
dialkylfluorenes.11
Brooks et al.17 reported the synthesis and characterization of
a series of phosphorescent cyclometalated organometallic
platinum complexes of the general structure Pt(C∧N)(O∧O),
where C∧N is a cyclometalated ligand such as 2-phenylpyridi-
nato-N,C2′ (ppy) and O∧O is a â-diketonate ligand. These
platinum complexes have been used as phosphorescent dopants
in vacuum-deposited OLEDs in conjunction with 4,4′-di-
(carbazol-9-yl)biphenyl (CBP, 1, Chart 1) as a host material.18
A styryl derivative of acetylacetonate has been incorporated into
copolymers with triphenylamine-based hole-transport monomers
and oxadiazole-based electron-transport monomers; Pt(C∧N)
building blocks were then bound to the O∧O ligands in the
polymer, and the resulting Pt-containing copolymers were used
in single-layer solution-processible near-white OLEDs.19
For some years now, we have been interested in the side-
chain polymeric approach to OLEDs.12 An important aspect of
such work is to establish the extent to which devices based on
side-chain polymers resemble or differ from vapor-deposited
small-molecule devices. Here we investigate monomers and
copolymers containing Pt(C∧N)(O∧O) phosphors and modified
CBP as side chains, compare the photophysical properties of
these monomers and polymers with those of the previously
reported small-molecule species, and describe preliminary
evaluation of these materials in organic light-emitting diodes
with structures similar to those reported for analogous small
molecules.18 We have recently been interested in ring-opening
metathesis polymerization (ROMP) of substituted norbornenes
for side-chain polymeric OLED materials16,20 and have used
the same approach in the present work. In many cases, ROMP
offers the possibility of obtaining polymers with narrow
polydispersity indices, of obtaining well-defined block copoly-
mers, and of incorporating a wide range of other chemical
functionalities into polymers.21 Second, the nonpolar poly-
(norbornene) backbone should have relatively little adverse
affect on charge mobility in attached transport materials
according to the disorder formalism of Borsenberger and
Ba¨ssler;22 indeed we have measured higher hole mobilities in
A third approach to OLEDs utilizes solution-processible side-
chain polymers or dendrimers in which the side chains are
functionalized with small molecules that have transport or
luminescent properties;12,13 here the ease of solution processing
is retained, while the electronic properties of materials can be
tuned through the choice of small molecule from among the
wide range of well-studied examples and the rheological
properties of the polymer may be tuned through the choice of
polymer backbone and through copolymerization with other
monomers. Tokito et al.14 have reported random copolymers in
which phosphorescent iridium complexes and carbazole units
are attached as pendant groups to a polyethylene backbone.
Dendritic frameworks have been utilized to lead to solution-
processible phosphorescent light-emitting films.15 The synthesis
of norbornene monomers with covalently attached phosphores-
cent iridium complexes has recently been reported, along with
homopolymers and coolymers with norbornenes functionalized
with long alkyl chains.16
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4818 Organometallics, Vol. 26, No. 19, 2007
Scheme 1. Synthesis of 3-(5-(Bicyclo[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dione (4)
Cho et al.
Chart 2. Structures of Norbornene-Functionalized Organoplatinum Phosphors (10-14) and Small-Molecule Analogues (23-27)
Scheme 2. Synthesis of Platinum(II) (2-Phenylpyridinato-N,C2′)(3-(5-bicyclo[2.2.1]hept-5-en-2-ylpentyl)pentane-2,4-dionato-O,O)
(10)
poly(norbornene)s with bis(diarylamino)fluorene side groups
than for analogous poly(acrylate)s.20a
2-benzo[b]thiophen-2-ylpyridine (Hbtp), 1-phenylisoquinoline
(Hpiq), and 2-phenylbenzothiazole (Hbt) and HO∧O* is 3-(5-
(bicyclo[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dione} were
prepared in a two-step procedure. The intermediate Pt complexes
are mononuclear species of the general type Pt(C∧N)(HC∧N)-
(Cl) (5-9) obtained from the reaction of K2PtCl4 and HC∧N.25
Norbornene-functionalized Pt(C∧N)(O∧O*) species, 10-14,
shown in Chart 2 along with their nonfunctionalized analogues,
23-27 (Vide infra), were obtained from the reactions of these
intermediate Pt complexes with the appropriate diketone (4 or
acetylacetone) in the presence of excess Na2CO3 in 2-ethoxy-
ethanol. Scheme 2 illustrates the synthesis for the example of
platinum(II) (2-phenylpyridinato-N,C2′)(3-(5-bicyclo[2.2.1]hept-
5-en-2-ylpentyl)pentane-2,4-dionato-O,O) (10). Platinum(II) (2-
(4′,6′-difluorophenylpyridinato-N,C2′)(3-(5-bicyclo[2.2.1]hept-
5-en-2-ylpentyl)pentane-2,4-dionato-O,O) (11), platinum(II) (2,2′-
(4′,5′-benzo)thienyl)pyridinato-N,C3′)(3-(5-bicyclo[2.2.1]hept-
5-en-2-ylpentyl)pentane-2,4-dionato-O,O) (12), platinum(II) (1-
phenylisoquinolinato-N,C2′)(3-(5-bicyclo[2.2.1]hept-5-en-2-
ylpentyl)pentane-2,4-dionato-O,O) (13), and platinum(II) (2-
phenylbenzothiozolato-N,C2′)(3-(5-bicyclo[2.2.1]hept-5-en-2-
ylpentyl)pentane-2,4-dionato-O,O) (14) were prepared from their
corresponding Pt intermediates using the same synthetic pro-
cedure.
Results and Discussion
Synthesis of Norbornene-Substituted Acetylacetonate
Ligands. Potentially one could incorporate the norbornene
moiety into a variety of cyclometalating ligands in order to
prepare phosphors with different color emissions; however, a
simpler way to create a library of polymerizable phosphorescent
platinum complexes is to attach a norbornene moiety to the
common acetylacetonate ancillary ligand in the 3-position. The
reaction scheme for the preparation of norbornene-substituted
acetylacetonate ligands is shown in Scheme 1. The synthesis
of 5-(5-bromopentyl)bicyclo[2.2.1]hept-2-ene (2) was carried
out according to a published procedure.23 Compound 2 was
converted to 5-(5-iodopentyl)bicyclo[2.2.1]hept-2-ene (3) by
reacting with NaI in refluxing acetone and was used directly
for the next step without further purification. 3-(5-(Bicyclo-
[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dione (4) was prepared,
by analogy to a method reported by Ono et al.24 for the selective
monoalkylation of acetylacetone, using 3 as an alkylating agent
and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a base; 4 was
purified by column chromatography and was obtained as a light
1
yellow liquid. H NMR data suggest that 4 is formed as an
Synthesis of Norbornene-Functionalized Host Material for
Phosphors. 4,4′-Di(carbazol-9-yl)biphenyl (CBP) has been used
extensively as a host material for phosphors with different color
emissions in OLEDs due it its high triplet energy of 2.56 eV
(484 nm),26 both host and phosphor typically being deposited
equilibrium mixture of its keto and enol isomers. On the basis
of DEPT, COSY, and HETCOR experiments, the resonances
of 4 (both keto and enol forms) in 1H and 13C{1H} NMR spectra
were assigned (see Supporting Information). The ratio of keto
form to enol form at room temperature is approximately 62:38
1
based on integration values in the H NMR spectrum of 4.
(23) Stubbs, L. P.; Weck, M. Chem.-Eur. J. 2003, 9, 992.
(24) Ono, N.; Yoshimura, T.; Tanikaga, R.; Kaji, A. Chem. Lett. 1977,
871.
(25) Cho, J.-Y.; Suponitsky, K. Y.; Li, J.; Timofeeva, T. V.; Barlow, S.;
Marder, S. R. J. Organomet. Chem. 2005, 690, 4090.
(26) Baldo, M. A.; Forrest, S. R. Phys. ReV. B 2000, 62, 10958.
Synthesis of Norbornene Monomers Containing Platinum
Complexes. The monomers of phosphorescent cyclometalated
platinum complexes of the general structure Pt(C∧N)(O∧O*)
{HC∧N ) Hppy, 2-(2,4-difluorophenyl)pyridine (H-4,6-dfppy),

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4819
Scheme 3. Synthesis of 9-[3-(Bicyclo[2.2.1]hept-5-en-2-ylmethoxy)propyl]-2,7-biscarbazol-9-yl-9-methyl-9H-fluorene (22)
Table 1. Polymer Characterization Data
together under vacuum. Previously we have compared the
polymer
poly-22
poly-22-co-10
poly-22-co-11 13 500 46 000 3.47
poly-22-co-12 12 000 44 000 3.59
Mn
Mw
PDI
Tg/°C Grubbs cat. used
thermal, spectroscopic, electrochemical, and hole-mobility
properties of 2,7-bis(diarylamino)-9,9-dimethylfluorenes with
their 4,4′-bis(diarylamino)biphenyl analogues and their behavior
in OLEDs;27 we found that fluorescence spectra and quantum
yields for the two classes of compounds are similar, despite
significant differences in the structure of the absorption spectra.
Moreover, DFT calculations suggest that 2,7-di(carbazol-9-yl)-
fluorene has a triplet energy only slightly lower (0.03 eV) than
that of 1.28 Therefore, due to the ease of functionalization of
fluorenes at the 9-position, we chose a functionalized norbornene
monomer linked to a pendant 2,7-di(carbazol-9-yl)fluorene
moiety as a host material for copolymerization with our platinum
phosphor monomers. The synthesis (Scheme 3) involves
monomethylation of fluorene,29 followed by iodination. The
protected hydroxy-functionalized 2,7-diiodofluorene, 18, was
obtained by alkylation using 3-bromo-1-propanol with subse-
quent protection of the resulting alcohol 17 using tert-butyldim-
ethylchlorosilane; alternatively 18 can also be obtained directly
by alkylation of 16 with tert-butyldimethylsilyl-protected 3-bromo-
1-propanol, although the yield is slightly reduced in comparison
to the two-step procedure. The fluorene core was coupled to
carbazole using a copper-mediated Ullmann reaction30 with the
use of a phase-transfer reagent (18-crown-6) and a weak base
(K2CO3) at 185-190 °C for 3 days, followed by deprotection
using tetra-n-butylammonium fluoride in THF to give the
29 500 67 000 2.27
8800 26 000 2.96
190a
182
185
202
second
third
second
second
a For comparison, the monomer 22 shows a Tg of 94 °C, with no evidence
of other thermal process in the temperature range investigated (25-220
°C).
hydroxy-functionalized 2,7-di(carbazol-9-yl)fluorene, 20, in
excellent yield. Treatment of 20 with p-toluenesulfonyl chloride
and 2.1 equiv of pyridine in CH2Cl2 afforded the corresponding
tosylate, 21. The norbornene monomer, 22, was prepared at
ambient temperature, using excess potassium hydride to depro-
tonate 5-norbornene-2-methanol, and was isolated as a colorless
glassy solid.
Polymerization. Monomers 10, 11, 12, and 22 were polym-
erized using Grubbs’ second- or third-generation ruthenium
catalysts (2 mol %) in dry CH2Cl2. After the polymerization
was complete, the reaction mixture was quenched with a few
drops of ethyl vinyl ether before precipitation in cold methanol.
Table 1 summarizes molecular weights determined by GPC and
glass-transition temperatures (Tg) determined by DSC for the
homopolymer of 22 and random copolymers of 22 with 10 wt
% of phosphor monomers: poly-22-co-10, poly-22-co-11, and
poly-22-co-12. The synthesis of poly-10 was also attempted
using the second-generation catalyst; the resulting material was
found to have a Tg of 126 °C but was too poorly soluble for
characterization by GPC. The copolymers display significantly
broader molecular weight distributions than the homopolymer
(27) Hreha, R. D.; George, C. P.; Haldi, A.; Domercq, B.; Malagoli,
M.; Barlow, S.; Bre´das, J.-L.; Kippelen, B.; Marder, S. R. AdV. Funct. Mater.
2003, 13, 967.
(28) Marsal, P.; Avilov, I.; da Silva Filho, D. A.; Bre´das, J.-L.; Beljonne,
D. Chem. Phys. Lett. 2004, 392, 521.
1
of the host. Indeed, three different carbene H NMR signals
(29) Brisse, F.; Durocher, G.; Gauthier, S.; Gravel, D.; Marques, R.;
Vergelati, C.; Zelent, B. J. Am. Chem. Soc. 1986, 108, 6579.
(30) (a) Ullmann, F. Ber. Deutsch Chem. Ges. 1903, 36, 2382. (b)
Belfield, K. D.; Schafer, K. J.; Mourad, W.; Reinhardt, B. A. J. Org. Chem.
2000, 65, 4475.
are seen during the formation of the copolymers, whereas only
one is seen during the homopolymerization of 22. This suggests
that the ruthenium catalysts decompose at least partially during
the polymerization and that the catalysts are not fully functional

4820 Organometallics, Vol. 26, No. 19, 2007
Cho et al.
Figure 2. Normalized photoluminescence spectra of 10-14 in THF
at room temperature.
Figure 1. Absorption spectra of platinum complexes 10-14 in
CH2Cl2.
Table 2. Redox Potentials (V vs FeCp2+/0, DMF/0.1 M
nBu4NPF6, 50 mV s-1) of Norbornene-Substituted Platinum
Complexes (10-14) and Their Corresponding Unsubstituted
Analogues (23-27)
norbornene monomers
small-molecule analogues
+/0
0/-
+/0
0/-
compound
Eox
E1/2
compound
Eox
E1/2
10
11
12
13
14
+0.35
+0.45
+0.45
+0.32
+0.41
-2.44
-2.27
-2.27
-2.02
-2.15
23
24
25
26
27
a
a
a
-2.39a
-2.29a
-2.25a
-2.00
-2.13
+0.29
+0.37
+/0
a From ref 17, where Eox values are not reported.
Figure 3. Photoluminescence spectra of 22, poly-22, and CBP (1)
group tolerant toward the platinum complexes, perhaps due to
transfer of the acetylacetonate ligand from platinum to ruthe-
nium. While the polymerization was complete for all copoly-
merizations studied and polymeric material could be obtained
easily, the polymerization is clearly not living.
in toluene.
Table 3. Absorption (CH2Cl2) and Emission (THF, 298 K)
Data for Platinum Complexes
complex
λmaxabs/nm (ꢀmax/103 cm-1 M-1
)
λmaxem/nm
10
255 (54.2), 279 (40.4), 313 (sh, 17.7),
327 (sh, 16.3), 346 (sh, 12.0), 372 (13.1),
387 (sh, 10.5), 395 (sh, 8.6), 415 (sh, 3.6)
253 (43.3), 273 (sh, 31.8), 305 (sh, 15.7),
320 (14.1), 342 (9.1), 368 (11.1),
405 (sh, 1.8)
267 (30.5), 278 (30.1), 286 (29.5),
320 (26.6), 345 (sh, 20.7), 380 (sh, 10.1),
424 (10.1), 445 (10.1)
259 (15.2), 272 (14.3), 297 (sh, 11.3),
321 (sh, 7.3), 344 (7.0), 360 (7.6),
413 (5.5), 445 (sh, 3.7)
259 (24.3), 308 (sh, 15.9), 317 (19.3),
330 (17.0), 397 (8.8)
486
Electrochemistry. The electrochemical properties of the
norbornene-substituted platinum complexes (10-14) were
studied using cyclic voltammetry; the data are compared with
those for their corresponding unsubstituted Pt complexes in
Table 2. In the case of 23-25, the small-molecule analogues
of 10-12, respectively, the values in the table are taken from
a previous literature report.17 Small-molecule analogues of 13
and 14, 2625 and 27,31 respectively, have recently been reported,
but without electrochemical data. All complexes show a single
reversible process with E1/2 between -2.00 and -2.44 V vs
FeCp2+/0; this can be attributed to molecular reduction, which
is generally considered to be localized on the cyclometalated
C∧N ligand. The complexes also show an irreversible, presum-
ably metal-based, oxidation peak with Eox between +0.29 and
+0.45 V; oxidation of square-planar complexes is typically
irreversible because of rapid solvolysis of the resultant platinum-
(III) species.32 Table 2 clearly shows that, as expected, the
electrochemical properties of these norbornene-substituted
platinum complexes are not significantly affected by the
incorporation of an alkylnorbornene moiety onto the backbone
of the acetylacetonate ligand. The host monomer 22 has
irreversible electrochemistry (Eox ) 0.58 V vs FeCp2+/0 in CH2-
Cl2 at 50 mV s-1) similar to that of 1.
11
12
13
468
607
595
14
26
543
595
252 (10.1), 271 (8.9), 290 (sh, 7.6),
343 (4.1), 360 (4.6), 401 (3.2),
422 (sh, 2.2), 431 (sh, 1.9)
256 (13.4.), 308 (sh, 8.4), 316 (10.5),
331 (9.5), 387 (4.5), 427 (sh, 1.9)
27
545
solid state and in dilute solution. The solution emission spectra
of 10-14, shown in Figure 2 and summarized in Table 3, are
also similar to those of the corresponding small molecules.17
The trends observed in the absorption and fluorescence
spectra of 22 or poly-22 and 1 parallel those seen for bis-
(diarylamino)fluorenes and bis(diarylamino)biphenyls;27 al-
though the absorption spectra of the fluorene- and biphenyl-
bridged compounds differ considerably, as shown in Figure 3
the fluorescence spectra are very similar. The similarity between
fluorescence spectra suggests that the singlet excited states of
22 and poly-22 have similar energy-transfer abilities as their
CBP analogues. If one assumes comparable singlet-triplet
splittings for the two systems, triplet energy transfer is also likely
to be similar in the two classes of compounds, consistent with
calculations suggesting similar triplet energies in 1 and a
Electronic Spectroscopy. Absorption spectra of 10-14 are
shown in Figure 1, and data are summarized in Table 3; the
spectra are similar to those of the respective small-molecule
analogues (23-27).17 All of these complexes show visible
emission under UV irradiation at room temperature, both in the
(31) Laskar, I. R.; Hsu, S.-F.; Chen, T.-M. Polyhedron 2005, 24, 881.
(32) Kvam, P. I.; Puzyk, M. V.; Balashev, K. P.; Songstad, J. Acta Chem.
Scand. 1995, 49, 335.

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4821
the emission in 22-based systems has been achieved through
the control of the phosphor/host ratio and the choice of host
materials. The greater tendency to observe aggregate emission
in 24 and 11-based systems is perhaps due to an increase in
π-π stacking interactions associated with the presence of the
difluorophenyl group.34
X-ray Crystallography. Single crystals of the complexes 10,
12, and 13 suitable for an X-ray diffraction study were obtained
from a mixture of dichloromethane and methanol. The asym-
metric unit in each case contains one molecule, the structures
of which are depicted in Figure 6. The selected geometric
parameters in Table 4 indicate that for all three complexes the
coordination environment of platinum is slightly distorted square
planar. The Pt-C bonds are shorter than the Pt-N bonds; the
Pt-O(2) bonds located trans to Pt-C bonds are significantly
elongated relative to the Pt-O(1) bonds trans to Pt-N bonds,
consistent with the expected relative trans influences of
aryl and pyridyl ligands.35 The bond lengths are generally
in the range of normally observed values for such com-
pounds.36 In the case of complex 10, the small differences
between Pt-C and Pt-N bonds and between the two Pt-O
bond lengths compared to those seen in 12 and 13 suggest
disorder between the pyridyl and phenyl rings of the ppy ligand;
however, poor crystal quality meant we were unable to model
this disorder in a satisfactory manner. The attached norbor-
nene moieties are disordered in all three structures, at least in
part due to the presence of both exo and endo isomers, and
were in each case modeled using two orientations with equal
occupancies.
Figure 4. Normalized photoluminescence spectra of films of poly-
10, poly-22-co-10, poly-22-co-11, and poly-22-co-12.
Figure 5. Photoluminescence spectra of a film of copolymer poly-
22-co-11 and monomer 11 (in a thin film sample and a dilute THF
solution).
In view of the observation of aggregate-based emission in
films of platinum monomers (see above) and of recent studies
emphasizing the influence of π-stacking on the luminescent
properties of both organic and organoplatinum compounds,37
we were interested in the nature of the aggregation in the crystal
structures of 10, 12, and 13. In all the structures under study,
stacking interactions are observed between π-conjugated ligands
of the neighboring molecules. The crystal structure of complex
10 can be described as being built up from columns in the
direction of the crystallographic screw axis; in the column,
molecules are related by translations along the shortest crystal-
lographic axis (b-) with equal distances of 3.43(2) Å between
conjugated planar fragments of adjacent molecules. Figure 7
shows the crystal packing and overlap between the substituted
acac ligand of one complex and the ppy ligand of its neigh-
bor. The shortest interatomic distance is 3.561(13) Å for the
C(12)‚‚‚C(1)[x, -1+y, z] atomic pair, implying weak interaction
between these π-systems.
fluorene-bridged analogue.28 Thus, 22 and poly-22 appear to
be suitable candidates as hosts for the platinum complexes.
The square-planar geometry of platinum(II) complexes has
previously been reported to promote intermolecular stacking and
excimer formation, leading to substantial differences between
solution and solid-state luminescence spectra.33 Photolumines-
cence spectra of thin-film samples of our platinum materials
obtained by spin-coating from CH2Cl2 show some evidence of
these aggregation effects (Figure 4). In particular, films of the
homopolymer poly-10 and of the monomer 10 show orange
em
emission (broad peaks characterized by λmax ) 633 and 609
nm, respectively), very different from the 486 nm emission
observed for the monomer in solution. The copolymers poly-
22-co-10 and poly-22-co-12, however, show thin-film emission
spectra (λmaxem ) 487 and 609 nm, respectively) similar to the
solution spectra of 10 and 12, respectively, thus suggesting that
copolymerization of monomers of phosphor (10 or 12) with 22
significantly reduces aggregation relative to that in the ho-
mopolymers or in neat films of corresponding small molecules,
presumably due, at least in part, to physically separating the
platinum complexes from one another. However, films of poly-
22-co-11 show near-white emission under UV irradiation; Figure
5 shows that this broad emission can be attributed to a
combination of higher energy structured emission from isolated
molecules, as seen for 11 in dilute solution, and a lower energy
unstructured emission from aggregate states, as seen in films
of 11 monomer. Thus, copolymerization of monomers of 11
and 22 fails to prevent emission from aggregate species. The
result is not too surprising; moderately efficient white elec-
troluminescence has been reported with the use of Pt(4,6-
dfppy)(O∧O), 24, as a single emissive dopant;18 balancing of
molecular and aggregate emission to optimize the whiteness of
In the crystal structure of 12, molecules form translational
columns along the a-axis. In contrast to complex 10, where
acac-ppy stacking is observed, the stacking interactions in 12
are formed between the cyclometalated ligands of adjacent
molecules. The interplanar distance is equal to 3.35(2) Å, and
the shortest interatomic distance is 3.333(11) Å between C(11)
(34) For π-π stacking between perfluorophenyl and phenyl groups,
see: Coates, G. W.; Dunn, A. R.; Henling, L. M.; Ziller, J. W.; Lobkovsky,
E. B.; Grubbs, R. H. J. Am. Chem. Soc. 1998, 120, 3641.
(35) Huheey, J. E.; Keiter, E. A.; Keiter, R. L., Inorganic Chemistry:
Principles of Structure and ReactiVity, 4th ed.; HarperCollins, 1993.
(36) (a) Allen, F. H.; Kennard, O.; Watson, D.; Brammer, L.; Orpen, A.
G.; Taylor, R. J. Chem. Soc., Perkin Trans. 2 1987, S1. (b) Allen, F. N.;
Kennard, O. Chem. Des. Autom. News 1993, 8, 31. (c) Cambridge Structural
Database, version 5.26, November, 2004.
(37) (a) Cornil, J.; dos Santos, D. A.; Crispin, X.; Silbey, R.; Bredas,
J.-L. J. Am. Chem. Soc. 1998, 120, 1289. (b) Xie, Z.; Yang, B.; Li, F.;
Cheng, G.; Liu, L.; Yang, G.; Xu, H.; Ye, L.; Hanif, M.; Liu, S.; Ma, D.;
Ma, Y. J. Am. Chem. Soc. 2005, 127, 14152. (c) Bai, D.-R.; Wang, S.
Organometallics 2006, 25, 1517.
(33) Ionkin, A. S.; Marshall, W. J.; Wang, Y. Organometallics 2005,
24, 619.

4822 Organometallics, Vol. 26, No. 19, 2007
Cho et al.
Figure 6. ORTEP views (50% probability) of complexes 10, 12, and 13. Only one orientation of the disordered norbornene side chains
is shown.
Table 4. Selected Bond Lengths (Å) and Angles (deg) for
Platinum Monomers
The structure of the columns in the crystal structure of 13 is
different from those in crystals of 10 and 12; here molecules
within a column are related by the center of symmetry. The
columns are parallel to the [1 1 0] crystallographic direction
and are built up of stacked dimers, which are connected to each
other by C-H‚‚‚π interactions. The stacking interaction is
facilitated by substantial overlap of both ligands with an
interplanar distance of 3.46(2) Å (Figure 11). The shortest
interatomic interaction is 3.327(10) Å between C(1) and
C(15)[-x, -1-y, -z]. There is also a Pt(1)‚‚‚C(7) contact of
3.434(6) Å. The interatomic distances together suggest that this
complex probably has the strongest intermolecular interactions
of the molecules considered here. The C-H‚‚‚π contact is
formed by the H(17b) hydrogen and π-system of the acac ligand.
The H(17b)‚‚‚M distance is 2.48 Å, the C(17)-H(17b)‚‚‚M angle
10
12
13
Pt(1)-C(1)
2.002(8)
2.020(9)
2.058(6)
2.070(7)
93.5(3)
174.6(3)
81.4(4)
90.8(3)
1.978(7)
2.001(6)
1.972(5)
2.056(4)
96.4(3)
176.8(2)
80.4(3)
88.91(19)
174.4(3)
94.3(2)
1.959(5)
1.978(4)
1.986(4)
2.061(4)
95.02(18)
176.08(16)
81.2(2)
89.73(15)
175.3(2)
94.01(16)
Pt(1)-N(1)
Pt(1)-O(1)
Pt(1)-O(2)
O(1)-Pt(1)-C(1)
O(1)-Pt(1)-N(1)
C(1)-Pt(1)-N(1)
O(1)-Pt(1)-O(2)
C(1)-Pt(1)-O(2)
N(1)-Pt(1)-O(2)
175.0(3)
94.2(3)
and C(2)[1+x, y, z] atoms. The overlap area (which does not
involve the sulfur atom of the cyclometalated ligand) and the
crystal packing are shown in Figure 8.

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4823
Figure 7. Crystal packing of 10. (a) Fragment of crystal packing as a projection onto the ac plane. (b) Stacking interaction between [x, y,
z] and [x, -1+y, z] (denoted by primed atomic labels and open bond lines).
is 142°, and the angle between the mean plane of the ligand
and the H(17b)‚‚‚M vector is 80°. The crystal structure of 13
has a molecular packing of head-to-tail dimers similar to
Pt(thpy)(dpm) {thpy ) 2-(2′-thienyl)pyridinato-N,C3′; dpm )
1,3-di-tert-butyl-1,3-propandionato-O,O}.17 The π-stacking in-
teractions seen in these structures and those previously reported
may be related to the origins of aggregate-based photo- and
electroluminescence seen in the solid state for some of these
species.
22/small-molecule and the corresponding copolymer devices are
shown in Figures 10 and 11, respectively. The devices have
broad EL spectra throughout the visible, similar to those
previously seen in vapor-deposited OLEDs and attributed to a
combination of emissions from aggregates or excimers and from
monomers. Typically, the appearance of these EL spectra
depends on the concentration of phosphor in the host and on
the driving voltage of the device.16b Our EL spectra differ to
varying degrees from the solid-state PL spectra of the copoly-
mers. The EL spectra of the copolymer and the corresponding
poly-22/small-molecule devices are broadly similar in each case,
but there are significant differences in the detailed structure of
the spectra seen in the comparisons of poly-22-co-10 vs poly-
22/23 and of poly-22-co-11 vs poly-22/24. In both types of
devices, the peak at 440 nm can presumably be attributed to
fluorescence from the photo-cross-linkable TPD-based polymer
28,38 by analogy with similar emission observed by Thompson
et al. and attributed to emission from the NPD hole-transport
layer used, which results from incomplete electron-hole
recombination in the host/phosphor layer.18 However, the
relative contribution of this luminescence to the total emission
appears to be reduced in the copolymer devices, at least in the
poly-22-co-11 vs poly-22/24 comparison. The results clearly
indicate the side-chain polymer approach to OLEDs can be
successfully adapted to incorporate phosphorescent lumophores.
However, while the details of the observed aggregate emissions
change somewhat depending on whether copolymers or small
molecules are used in conjunction with the polymer host, the
copolymer approach evidently does not disrupt the aggregation
of platinum(II) 2-(4′,6′-difluorophenylpyridinato-N,C2′) com-
Electroluminescence Behavior. Multilayer OLEDs incor-
porating small-molecule platinum phosphors have been fabri-
cated by Thompson and co-workers with the structure ITO/
PEDOT:PSS/NPD/CBP:Pt-complex/BCP/AlQ3/LiF/Al, where
ITO ) indium tin oxide, PEDOT:PSS ) poly(ethylenediox-
ythiophene)-polystyrenesulfonic acid (not used in all devices);
NPD ) 4,4′-bis(phenyl-R-napthylamino)biphenyl; BCP ) ba-
thocuproine (2,9-dimethyl-4,7-diphenyl[1,10]phenanthroline);
and AlQ3 ) aluminum tris(8-hydroxyquinolate).18 We fabricated
OLEDs in which our platinum-containing copolymers act as
lumophores using similar device structures. Specifically, the
photo-cross-linkable hole-transport polymer 25 (Chart 3), which
we have previously reported,12d was spin-coated onto ITO and
cross-linked by exposure to UV irradiation (λmax ≈ 310 nm, 1
min). Onto this hole-transport layer, a platinum-containing
copolymer, with the loading of the platinum complex in each
copolymer being approximately 10 wt %, was then spin-coated.
Finally, BCP (15 nm), AlQ3 (20 nm), and LiF (1 nm) were
evaporated on top of the polymers, followed by the metal
cathode (Al). For comparison we also fabricated devices in
which the phosphor copolymer layer was replaced with a spin-
coated layer of poly-22 and small-molecule platinum complexes
(at 10 wt %). The electroluminescence (EL) spectra of the poly-
(38) The solid-state PL spectrum of 28 shows emission λmax of 435 nm.

4824 Organometallics, Vol. 26, No. 19, 2007
Cho et al.
Figure 8. Crystal packing of 12. (a) Fragment of crystal packing as a projection onto the bc plane. (b) Stacking interaction between [x, y,
z] and [1+x, y, z] (denoted by primed atomic labels and open bond lines).
plexes sufficiently to enable simple blue phosphorescence to
be achieved using poly-22-co-11.
may be used in other multilayer polymeric phosphorescent
OLEDs, for example, copolymerized with recently described
iridium norbornene monomers.16
Conclusions
Experimental Section
We have described the synthesis of a series of new phos-
phorescent Pt complexes of the form Pt(C∧N)(O∧O*), where
C∧N is a cyclometalated aryl pyridine and O∧O* is a
norbornene-functionalized acetylacetonate ligand, which show
solution absorption and luminescence spectra and electrochemi-
cal behavior very similar to analogues without the norbornene
group. We have also synthesized a polymerizable host material;
this compound is based on a norbornene-functionalized analogue
of N,N′-dicarbazolyl-4,4′-biphenyl, which is widely used as a
host material for platinum- and iridium-based phosphors since
it is capable of transferring both singlet and triplet excitation
to a wide variety of phosphorescent dopants. Copolymers of
our phosphor monomers and the host monomer can be synthe-
sized using Grubbs’ ruthenium catalysts; however, the platinum
complexes appear to interfere with the polymerization process
and broad molecular-weight distributions are obtained. Never-
theless, the copolymers can be used to fabricate functioning
OLEDs, thus demonstrating extension of the possibility of
phosphorescent multilayer devices based on side-chain poly-
mers. OLED data suggest that aggregate-based emission in these
copolymers has comparable importance to that in vapor-
deposited devices based on small host and phosphor molecules,
with aggregate emission being particularly important for phos-
phors with the shortest wavelength emission. Although the
copolymer approach seems to provide no clear advantage in
controlling aggregate emission, it may be advantageous when
solution processibility is desirable. Moreover, the host monomer
General Considerations. All experiments with air- and moisture-
sensitive intermediates and compounds were carried out under an
inert atmosphere of dry nitrogen using standard Schlenk techniques.
1H and 13C{1H} NMR spectra (solution) were recorded on Varian
Mercury-300 spectrometers and referenced to residual proton
solvent signals. Elemental analyses were performed at Atlantic
Microlab, Inc. High-resolution mass spectral analyses were per-
formed by the Bioanalytical Mass Spectrometry Facility at Georgia
Institute of Technology. Electrochemical measurements were carried
out under dinitrogen for deoxygenated DMF solutions of tetra-n-
butylammonium hexafluorophosphate (0.1 M) using a computer-
controlled BAS 100B electrochemical analyzer, a glassy-carbon
working electrode, a platinum-wire auxiliary electrode, and an Ag
wire anodized with AgCl as a pseudoreference electrode. Potentials
were referenced to the ferrocenium/ferrocene (FeCp2+/0) couple
using ferrocene as an internal standard. UV-vis absorption spectra
were recorded on a Varian Cary 5E UV-vis-NIR spectropho-
tometer, while solution and thin-film PL spectra were recorded on
a Shimadzu FP-5301PC spectrofluorometer or a Fluorolog III ISA
spectrofluorometer.
K2PtCl4 (Strem), 2-phenylpyridine (Hppy), 2-phenylbenzothia-
zole (Hbt), 2,4-pentanedione, potassium hydride, 1,8-diazabicyclo-
[5.4.0]undec-7-ene (DBU), sodium carbonate, iodine, iodic acid,
3-bromo-1-propanol, fluorene, sodium thiosulfate, carbon tetra-
chloride, tert-butyldimethylchlorosilane, imidazole, p-toluenesulfo-
nyl chloride, tetrabutylammonium fluoride (TBAF), 18-crown-6,
potassium carbonate, sodium iodide, anhydrous 1,2-dichloroben-

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4825
Figure 9. Crystal packing of 13. (a) Fragment of crystal packing as a projection onto the (1 1 0) plane. (b) Stacking interaction between
[x, y, z] and [-x, -1-y, -z] (denoted by primed atomic labels and open bond lines).
Figure 11. Electroluminescence spectra for devices with structure
ITO/cross-linked-28/poly-22-co-10, poly-22-co-11, or poly-22-co-
12/BCP/AlQ3/LiF/Al at an applied voltage of 12 V.
Figure 10. Electroluminescence spectra for devices with structure
ITO/cross-linked-28/poly-22:10%phosphor/BCP/AlQ3/LiF/Al at an
applied voltage of 12 V.
zene, and 2-ethoxyethanol (Aldrich) were used as received without
further purification. H-4,6-dfppy, Hbtp, and Hpiq were prepared
via the Suzuki coupling reactions of commercially available boronic
acids with 2-bromopyridine or 1-chloroisoquinoline. Carbazole was
recrystallized from ethanol. 2,23 5-8,25 23-25,17 and 2812d were
prepared according to the literature.
isomer: 1H NMR (300 MHz, CDCl3) δ 6.09 (dd, J ) 5.5 Hz, 3.0
Hz, 1H), 5.88 (dd, J ) 5.8 Hz, 3.3 Hz, 1H), 3.16 (t, J ) 7.1 Hz,
2H), 2.72 (m, 2H), 0.42-2.00 (m, 13H); 13C{1H} NMR (75 MHz,
CDCl3) δ 136.85, 132.21, 49.59, 45.41, 42.54, 38.69, 34.61, 33.60,
32.45, 30.81, 27.62, 7.48; HRMS-EI (m/z) [M]+ calcd for C12H19I,
290.05315; found, 290.05315.
5-(5-Iodopentyl)bicyclo[2.2.1]hept-2-ene (mixture of endo and
exo isomers) (3). 2 (5.0 g, 20.6 mmol) and NaI (6.16 g, 41.1 mmol)
were refluxed in acetone at 80 °C overnight. Volatiles were removed
under reduced pressure. H2O was added to the residue, and the
mixture was extracted with diethyl ether. The organic layer was
dried over anhydrous MgSO4, and volatiles were removed under
reduced pressure to give a yellowish oil (5.70 g, 95%). Endo
3-(5-(Bicyclo[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dione (4).
5-(5-Iodopentyl)bicyclo[2.2.1]hept-2-ene (3) (15.0 g, 51.7 mmol)
was added to a solution of 2,4-pentanedione (5.18 g, 51.7 mmol)
and DBU (7.87 g, 51.7 mmol) in C6H6 (120 mL). The reaction
mixture was stirred at room temperature overnight, after which the
DBU‚HI salt was filtered and the filtrate was concentrated under
reduced pressure. The crude product was purified by column

4826 Organometallics, Vol. 26, No. 19, 2007
Cho et al.
Chart 3. Structure of Photo-cross-linkable Hole-Transport
J ) 5.5 Hz, 2.7 Hz, 1H), 2.73 (br, 2H), 2.24-2.30 (m, 2H), 2.11
(s, 3H), 2.10 (s, 3H), 1.00-2.01 (m, 12H), 0.44-0.50 (m, 1H).
HRMS-EI (m/z): [M]+ calcd for C28H31NO2PtF2, 646.19707; found,
646.19358. Anal. Calcd for C28H31NO2PtF2: C, 52.01; H, 4.83; N,
2.17. Found: C, 52.28; H, 4.87; N, 2.05.
Polymer 28; n/m ) ca. 4
Platinum(II) (2,2′-(4′,5′-Benzo)thienyl)pyridinato-N,C3′)(3-(5-
(bicyclo[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dionato-O,O) (12).
A mixture of 7 (1.0 g, 1.53 mmol), 4 (0.89 g, 3.4 mmol), and Na2-
CO3 (1.20 g, 11.3 mmol) in 2-ethoxyethanol (60 mL) was heated
at 100 °C overnight under a N2 atmosphere. The reaction mixture
was allowed to cool to room temperature, and H2O was added.
The mixture was extracted with CH2Cl2. The organic layer was
washed with H2O and dried over anhydrous MgSO4. Volatiles were
removed under reduced pressure. The crude product was purified
by column chromatography (silica gel, dichloromethane as eluting
solvent) to give an orange-brown solid (0.76 g, 75%), mp 184-
185 °C. 1H NMR (300 MHz, CDCl3): δ 8.73-8.87 (m, 2H), 7.76-
7.80 (m, 1H), 7.62 (t, J ) 7.7 Hz, 1H), 7.28-7.35 (m, 2H), 7.23
(d, J ) 8.2 Hz, 1H), 6.86 (t, J ) 6.3 Hz, 1H), 6.10 (dd, J ) 5.8
Hz, 3.0 Hz, 1H), 5.91 (dd, J ) 5.5 Hz, 2.7 Hz, 1H), 2.74 (br, 2H),
2.26-2.32 (m, 2H), 2.15 (s, 3H), 2.10 (s, 3H), 1.00-2.02 (m, 12H),
0.45-0.51 (m, 1H). 13C{1H} NMR (75 MHz, CDCl3): δ 183.66,
181.31, 164.48, 146.55, 145.35, 142.21, 140.27, 138.37, 138.07,
136.81, 132.28, 126.57, 125.18, 123.92, 122.20, 118.56, 117.97,
111.94, 49.60, 45.46, 42.56, 38.80, 34.92, 32.51, 31.07, 30.87,
30.23, 28.55, 27.55, 25.85. HRMS-EI (m/z): [M]+ calcd for C30H33-
NO2PtS, 666.18799; found, 666.18380. Anal. Calcd for C30H33-
NO2PtS: C, 54.04; H, 4.99; N, 2.10. Found: C, 54.08; H, 5.00; N,
2.01.
chromatography (silica gel, hexanes/dichloromethane ) 1:3 (v/v))
to give a light yellow liquid (7.75 g, 57%). Endo isomer (keto
form): 1H NMR (300 MHz, CDCl3) δ 6.05-6.08 (m, 1H), 5.84-
5.87 (m, 1H), 3.56 (t, J ) 7.4 Hz, 1H), 2.70 (br, 2H), 2.13 (s, 6H),
0.40-2.00 (m, 15H). (Enol form): 1H NMR (300 MHz, CDCl3) δ
16.63 (s, 1H), 6.05-6.08 (m, 1H), 5.84-5.87 (m, 1H), 2.70 (br,
2H), 2.09 (s, 6H), 0.40-2.00 (m, 14H). 13C{1H} NMR (75 MHz,
CDCl3): δ 204.31, 190.71, 136.77, 132.19, 110.50, 69.05, 49.56,
45.41, 45.38, 42.51, 38.75, 38.69, 34.82, 34.67, 32.45, 32.42, 30.72,
29.92, 29.72, 29.10, 28.50, 28.38, 28.35, 27.65, 27.62, 22.93.
HRMS-EI (m/z): [M]+ calcd for C17H26O2, 262.19328; found,
262.19483. Anal. Calcd for C17H26O2: C, 77.82; H, 9.99. Found:
C, 77.26; H, 9.90.
Platinum(II) (2-Phenylpyridinato-N,C2′)(3-(5-(bicyclo[2.2.1]-
hept-5-en-2-yl)pentyl)pentane-2,4-dionato-O,O) (10). A mixture
of 5 (1.0 g, 1.85 mmol), 4 (1.02 g, 3.9 mmol), and Na2CO3 (1.38
g, 13.0 mmol) in 2-ethoxyethanol (100 mL) was heated at 100 °C
overnight under a N2 atmosphere. The reaction mixture was allowed
to cool to room temperature, and H2O was added. The mixture was
extracted with CH2Cl2. The organic layer was washed with H2O
and dried over anhydrous MgSO4. Volatiles were removed under
reduced pressure to give a brown oil. The crude product was purified
by column chromatography (silica gel, hexanes/dichloromethane
) 1:1 (v/v)) to give a yellow crystalline solid (0.88 g, 78%), mp
Platinum(II) (1-Phenyl-isoquinolinato-N,C2′)(3-(5-(bicyclo-
[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dionato-O,O) (13). A
mixture of 8 (0.4 g, 0.62 mmol), 4 (0.33 g, 1.2 mmol), and Na2-
CO3 (0.66 g, 6.2 mmol) in 2-ethoxyethanol (15 mL) was heated at
100 °C overnight under a N2 atmosphere. The reaction was allowed
to cool to room temperature, and H2O was added. The mixture was
extracted with CH2Cl2. The organic layer was washed with H2O
and dried over anhydrous MgSO4. Volatiles were removed under
reduced pressure. The crude product was purified by column
chromatography (silica gel, dichloromethane as eluting solvent) to
give an orange-red solid. The product was recrystallized from a
dichloromethane/methanol solvent mixture to give red crystals (82
1
160-162 °C. H NMR (300 MHz, CDCl3): δ 8.93 (dd, J ) 5.8
Hz, 0.8 Hz, 1H), 7.76 (td, J ) 7.4 Hz, 1.6 Hz, 1H), 7.60 (dd, J )
7.7 Hz, 1.1 Hz, 1H), 7.56 (d, J ) 7.7 Hz, 1H), 7.41 (dd, J ) 7.7
Hz, 1.1 Hz, 1H), 7.18 (td, J ) 7.4 Hz, 1.4 Hz, 1H), 7.02-7.08 (m,
2H), 6.09 (dd, J ) 5.8 Hz, 3.0 Hz, 1H), 5.90 (dd, J ) 5.5 Hz, 2.7
Hz, 1H), 2.74 (br, 2H), 2.26-2.32 (m, 2H), 2.114 (s, 3H), 2.105
(s, 3H), 0.98-2.02 (m, 12H), 0.44-0.50 (m, 1H). 13C{1H} NMR
(75 MHz, CDCl3): δ 184.42, 182.19, 168.29, 146.91, 144.61,
139.96, 137.84, 136.79, 132.30, 130.55, 129.08, 123.28, 122.87,
120.97, 118.23, 111.94, 49.60, 45.46, 42.57, 38.81, 34.94, 32.51,
31.15, 31.05, 30.25, 28.58, 27.87, 26.99. HRMS-EI (m/z): [M]+
calcd for C28H33NO2Pt, 609.21381; found, 609.21258. Anal. Calcd
for C28H33NO2Pt: C, 55.07; H, 5.45; N, 2.29. Found: C, 55.10;
H, 5.40; N, 2.27.
1
mg, 20%). H NMR (300 MHz, CDCl3): δ 8.92 (d, J ) 6.6 Hz,
1H), 8.87 (d, J ) 8.5 Hz, 1H), 8.08 (d, J ) 7.7 Hz, 1H), 7.60-
7.82 (m, 4H), 7.39 (d, J ) 6.6 Hz, 1H), 7.22 (td, J ) 7.4 Hz, 1.4
Hz, 1H), 7.14 (td, J ) 7.4 Hz, 1.4 Hz, 1H), 6.09(dd, J ) 5.5 Hz,
3.0 Hz, 1H), 5.90 (dd, J ) 5.5 Hz, 2.7 Hz, 1H), 2.74 (br s, 2H),
2.31 (m, 2H), 2.15 (s, 3H), 2.13 (s, 3H), 1.91-2.02 (m, 1H), 1.78-
1.86 (m, 1H), 1.06-1.37 (m, 10H), 0.44-0.50 (m, 1H). 13C{1H}
NMR (75 MHz, CDCl3): δ 184.71, 182.36, 168.59, 146.25, 142.68,
139.07, 137.23, 136.81, 132.31, 130.93, 130.60, 129.23, 128.35,
128.09, 127.39, 126.09, 125.92, 122.99, 119.38, 112.02, 49.62,
45.49, 42.59, 38.83, 34.96, 32.53, 31.16, 31.01, 30.26, 28.60, 27.91,
27.00. HRMS-EI (m/z): [M]+ calcd for C32H35NO2Pt, 660.23156;
found, 660.23283. Anal. Calcd for C32H35NO2Pt: C, 58.17; H, 5.34;
N, 2.12. Found: C, 57.81; H, 5.31; N, 2.13.
Platinum(II) (2-(4′,6′-Difluorophenylpyridinato-N,C2′)(3-(5-
(bicyclo[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dionato-O,O) (11).
A mixture of 6 (1.0 g, 1.63 mmol), 4 (0.935 g, 3.6 mmol), and
Na2CO3 (1.26 g, 11.9 mmol) in 2-ethoxyethanol (60 mL) was heated
at 100 °C overnight under a N2 atmosphere. The reaction mixture
was allowed to cool to room temperature, and H2O was added.
The mixture was extracted with CH2Cl2. The organic layer was
washed with H2O and dried over anhydrous MgSO4. Volatiles were
removed under reduced pressure. The crude product was purified
by column chromatography (silica gel, dichloromethane as eluting
solvent) to give a yellow-brown solid (0.81 g, 77%), mp 148-149
°C. 1H NMR (300 MHz, CDCl3): δ 8.91 (d, J ) 5.5 Hz, 1H), 7.90
(d, J ) 8.0 Hz, 1H), 7.77 (t, J ) 7.7 Hz, 1H), 7.03-7.09 (m, 2H),
6.49-6.56 (m, 1H), 6.09 (dd, J ) 5.5 Hz, 3.0 Hz, 1H), 5.90 (dd,
Platinum(II) (2-Phenylbenzothiozolato-N,C2′)(3-(5-bi(cyclo-
[2.2.1]hept-5-en-2-yl)pentyl)pentane-2,4-dionato-O,O) (14). 9 was
prepared from K2PtCl4 and 2-phenylbenzothiazole (Hbt) in a 3:1
(v/v) mixture of 2-ethoxyethanol and H2O at 80 °C. However, poor
solubility of 9 prevented its further purification. Therefore, crude
9 was used directly in the following step. A mixture of 9 (1.0 g,
1.53 mmol), 4 (0.885 g, 3.37 mmol), and Na2CO3 (1.19 g, 11.2
mmol) in 2-ethoxyethanol (20 mL) was heated at 100 °C for 1 day
under a N2 atmosphere. The reaction mixture was allowed to cool
to room temperature, and H2O was added. The mixture was
extracted with CH2Cl2. The organic layer was washed with H2O
and dried over anhydrous MgSO4. Volatiles were removed under

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4827
reduced pressure. The crude product was purified by column
chromatography (silica gel, dichloromethane as eluting solvent) to
give a yellow solid. The product was recrystallized twice from a
dichloromethane/methanol solvent mixture to give a yellow solid
1.99 (m, 2H), 1.44 (s, 3H), 1.39 (s, 1H), 0.88 (m, 2H). 13C{1H}
NMR (75 MHz, CDCl3): δ 153.14, 138.66, 136.18, 131.89, 121.63,
93.20, 62.79, 50.79, 36.49, 27.61, 26.50. HRMS-EI (m/z): [M]+
calcd for C17H16I2O, 489.92907; found, 489.92876. Anal. Calcd
for C17H16I2O: C, 41.66; H, 3.29. Found: C, 42.20; H, 3.37.
1
(0.17 g, 17% overall yield for two steps). H NMR (300 MHz,
CDCl3): δ 9.16 (d, J ) 8.2 Hz, 1H), 7.77 (d, J ) 8.0 Hz, 1H),
7.69 (d, J ) 7.7 Hz, 1H), 7.53 (ddd, J ) 8.2 Hz, 7.1 Hz, 1.1 Hz,
1H), 7.46 (dd, J ) 7.7 Hz, 1.1 Hz, 1H), 7.38 (m, 1H), 7.18 (td, J
) 7.4 Hz, 1.4 Hz, 1H), 7.07 (td, J ) 7.7 Hz, 1.4 Hz, 1H), 6.09
(dd, J ) 5.8 Hz, 3.0 Hz, 1H), 5.91 (dd, J ) 5.8 Hz, 3.0 Hz, 1H),
2.74 (br, 2H), 2.29-2.34 (m, 2H), 2.18 (s, 3H), 2.12 (s, 3H), 1.77-
2.02 (m, 2H), 1.00-1.05 (m, 10H), 0.45-0.51 (m, 1H). 13C{1H}
NMR (75 MHz, CDCl3): δ 183.78, 181.64, 181.48, 150.66, 140.87,
139.43, 136.82, 132.30, 130.69, 130.10, 129.99, 127.26, 125.10,
124.50, 123.43, 121.91, 120.50, 111.64, 49.62, 45.49, 42.59, 38.83,
34.94, 32.53, 31.15, 30.86, 30.25, 28.60, 27.32, 26.76. HRMS-EI
(m/z): [M]+ calcd for C30H33NO2PtS, 666.18799; found, 666.18721.
Anal. Calcd for C30H33NO2PtS: C, 54.04; H, 4.99; N, 2.10; S, 4.81.
Found: C, 53.87; H, 4.91; N, 2.31; S, 4.90.
tert-Butyl-[3-(2,7-diiodo-9-methyl-9H-fluoren-9-yl)propoxy]-
dimethylsilane (18). A round-bottom flask was charged with 17
(11.8 g, 24.1 mmol) and DMF (150 mL). tert-Butyldimethylchlo-
rosilane (4.67 g, 31 mmol) and imidazole (2.11 g, 31 mmol) were
added. The reaction mixture was stirred at room temperature
overnight. The reaction mixture was poured into a mixture of H2O
and diethyl ether. The aqueous layer was extracted with diethyl
ether. The combined organic layers were dried over anhydrous
MgSO4. Volatiles were removed under reduced pressure to give a
yellow oil. The product was purified by column chromatography
(silica gel, hexanes/dichloromethane ) 6:1) to give a white solid
1
(13.68 g, 94%). H NMR (300 MHz, CDCl3): δ 7.71 (d, J ) 1.4
Hz, 2H), 7.64 (dd, J ) 8.0 Hz, 1.6 Hz, 2H), 7.38 (d, J ) 8.0 Hz,
2H), 3.36 (t, J ) 6.3 Hz, 2H) 2.02 (m, 2H), 1.43 (s, 3H), 1.39 (s,
1H), 0.88 (s, 9H), 0.83 (m, 2H), -0.03 (s, 6H). 13C{1H} NMR (75
MHz, CDCl3): δ 153.52, 138.80, 136.21, 132.08, 121.66, 93.17,
62.85, 50.85, 36.42, 27.60, 26.63, 25.95, 18.30, -5.33. HRMS-EI
(m/z): [M]+ calcd for C23H30I2OSi, 604.01555; found, 604.01507.
Anal. Calcd for C23H30I2OSi: C, 45.71; H, 5.00. Found: C, 45.94;
H, 5.14.
9-Methyl-9H-fluorene (15).29 A solution of fluorene (20.0 g,
0.12 mol) in dry THF (250 mL) was allowed to cool to -78 °C.
nBuLi (48.1 mL of 2.5 M solution in hexanes, 0.12 mmol) was
added. The reaction mixture was stirred at -78 °C for 30 min.
Methyl iodide (17.08 g, 0.12 mol) in dry THF (40 mL) was added
at -78 °C. The resulting mixture was stirred at -78 °C for 2 h,
slowly warmed to room temperature, and stirred at room temper-
ature overnight. The reaction mixture was neutralized with a
saturated aqueous NH4Cl solution. The mixture was extracted with
CH2Cl2. The organic layer was washed with H2O and brine and
dried over anhydrous MgSO4. Volatiles were removed under
reduced pressure. The crude product was purified by column
chromatography (silica gel, hexanes as eluting solvent) to give a
tert-Butyl-[3-(2,7-diiodo-9-methyl-9H-fluoren-9-yl)propoxy]-
dimethylsilane (18), Alternative One-Step Procedure. A mixture
of 16 (28.0 g, 65.1 mmol), (3-bromopropoxy)(tert-butyl)dimeth-
ylsilane (19.1 g, 75.3 mmol), potassium hydroxide (4.42 g,78.8
mmol), DMSO (150 mL), and 18-crown-6 (1.72 g, 6.5 mmol) was
stirred at room temperature overnight. The reaction mixture was
extracted with Et2O (100 mL), and the organic layer was washed
with saturated NaCl aqueous solution (4 × 100 mL) and water (3
× 100 mL). The organic layer was dried over MgSO4, after which
volatiles were removed under reduced pressure. The product was
purified by column chromatography (silica gel, hexanes, then
hexanes/dichloromethane ) 5:1 as eluting solvent), followed by
removal of excess (3-bromopropoxy)(tert-butyl)dimethylsilane by
vacuum distillation (0.04 Torr, 56 °C) to give a pale yellow solid
(17.17 g, 44%).
1
colorless semisolid (20.8 g, 96%). H NMR (300 MHz, CDCl3):
δ 7.74-7.78 (m, 2H), 7.49-7.54 (m, 2H), 7.28-7.40 (m, 4H), 3.95
(q, J ) 7.4 Hz, 1H), 1.53 (d, J ) 7.4 Hz, 3H). 13C{1H} NMR (75
MHz, CDCl3): δ 148.83, 140.37, 126.82, 123.90, 119.74, 42.47,
18.27.
2,7-Diiodo-9-methyl-9H-fluorene (16). A solution of 15 (9.24
g, 51.3 mmol), iodine (9.58 g, 37.7 mmol), iodic acid (4.22 g, 24
mol), concentrated H2SO4 (4 mL), and CCl4 (6 mL) in acetic acid
(80 mL) was heated at 80 °C overnight. The resulting precipitate
was collected by vacuum filtration and dissolved in CH2Cl2. The
organic layer was washed with aqueous sodium thiosulfate (0.1
M) solution and dried over anhydrous MgSO4. Volatiles were
removed under reduced pressure. The crude product was purified
by column chromatography (silica gel, hexanes as eluting solvent)
to give a yellow solid (13.53 g, 61%). 1H NMR (300 MHz,
CDCl3): δ 7.80 (dd, J ) 1.6 Hz, 0.8 Hz, 2H), 7.66 (ddd, J ) 8.0
Hz, 1.6 Hz, 0.8 Hz, 2H), 7.43 (d, J ) 8.0 Hz, 2H), 3.86 (q, J ) 7.4
Hz, 1H), 1.46 (d, J ) 7.4 Hz, 3H). 13C{1H} NMR (75 MHz,
CDCl3): δ 150.41, 139.04, 136.02, 133.18, 121.50, 92.73, 42.23,
17.94. HRMS-EI (m/z): [M]+ calcd for C14H10I2, 431.88720; found,
431.88551. Anal. Calcd for C14H10I2: C, 38.92; H, 2.33. Found:
C, 39.24; H, 2.33.
tert-Butyl-[3-(2,7-biscarbazol-9-yl-9-methyl-9H-fluoren-9-yl)-
propoxy]dimethylsilane (19). A mixture 18 (20.7 g, 34.2 mmol),
carbazole (11.45 g, 68.5 mmol), copper (8.71 g, 137 mmol), K2-
CO3 (37.87 g, 274 mmol), and 18-crown-6 (1.81 g, 6.8 mmol) in
1,2-dichlorobenzene (500 mL) was refluxed at 185 °C under argon
for 3 days. The reaction mixture was filtered, and the filtrate was
concentrated under reduced pressure. The crude product was
purified by two consecutive column chromatographies (silica gel,
hexanes/dichloromethane ) 3:1 (first), then hexanes/dichlo-
romethane ) 1:1 (second)) to give a white solid (20.75 g, 89%).
1H NMR (300 MHz, CDCl3, δ): 8.26 (d, J ) 7.4 Hz, 4H), 8.03 (d,
J ) 7.7 Hz, 2H), 7.73 (d, J ) 1.4 Hz, 2H), 7.67 (dd, J ) 8.0 Hz,
1.9 Hz, 2H), 7.50-7.60 (m, 8H), 7.37-7.43 (m, 4H), 3.54 (t, J )
6.6 Hz, 2H), 2.20 (m, 2H), 1.70 (s, 3H), 1.23 (m, 2H), 0.89 (s,
9H), 0.05 (s, 6H). 13C{1H} NMR (75 MHz, CDCl3): δ 153.99,
140.97, 138.63, 136.95, 126.21, 126.00, 123.43, 121.69, 121.23,
120.37, 119.97, 109.78, 63.32, 51.08, 36.93, 28.21, 26.69, 25.91,
18.29, -5.33. LRMS-EI (m/z): [M]+ calcd for 682.9; found, 682.4.
Anal. Calcd for C47H46N2OSi: C, 82.65; H, 6.79; N, 4.10. Found:
C, 82.94; H, 6.91; N, 4.06.
3-(2,7-Diiodo-9-methyl-9H-fluoren-9-yl)propan-1-ol (17). A
mixture of 16 (18.6 g, 43.1 mmol), 3-bromo-1-propanol (7.18 g,
51.7 mmol), potassium hydroxide (2.90 g, 51.7 mmol), H2O (4 mL),
DMSO (100 mL), and 18-crown-6 (1.14 g, 4.3 mmol) was stirred
at room temperature overnight. The reaction mixture was extracted
with CH2Cl2, and the organic layer was washed with saturated NaCl
aqueous solution and water. The organic layer was dried over
MgSO4, after which volatiles were removed under reduced pressure.
The product was purified by column chromatography (silica gel,
hexanes/dichloromethane ) 1:1, then dichloromethane as eluting
solvent) to give a pale yellow solid (12.15 g, 58%). 1H NMR (300
MHz, CDCl3): δ 7.68 (d, J ) 1.1 Hz, 2H), 7.64 (dd, J ) 8.0 Hz,
1.6 Hz, 2H), 7.40 (d, J ) 8.0 Hz, 2H), 3.39 (t, J ) 6.6 Hz, 2H),
3-(2,7-Biscarbazol-9-yl-9-methyl-9H-fluoren-9-yl)propan-1-
ol (20). 19 (20.75 g, 30.4 mmol) was dissolved in THF, and
tetrabutylammonium fluoride (70 mL of a 1.0 M solution in THF,
70 mmol) was added to the mixture. The resulting mixture was
stirred at room temperature, and the reaction progress was monitored
by TLC. After the starting material was consumed, the reaction
mixture was poured into water and extracted with CH2Cl2. The

4828 Organometallics, Vol. 26, No. 19, 2007
Cho et al.
Table 5. Crystallographic Data for 10, 12, and 13
10
12
13
formula
fw
C28H33O2NPt
610.64
C30H33O2NSPt
666.72
C32H35O2NPt
660.70
cryst color
cryst habit
cryst size, mm
cryst syst
space group
a, Å
yellow
prism
yellow
plate
dark red
Plate
0.1 × 0.1 × 0.05
monoclinic
P21/c
20.193(6)
5.6385(17)
21.971(7)
90
100.012(8)
90
2463.5(13)
4
0.2 × 0.1 × 0.02
monoclinic
P21/n
6.903(2)
9.395(3)
39.788(12)
90
93.562(7)
90
2575.5(14)
4
0.2 × 0.15 × 0.05
triclinic
P1h
10.582(4)
10.823(4)
12.847(5)
97.877(6)
98.863(6)
115.270(5)
1280.3(8)
2
b, Å
c, Å
R, deg
â, deg.
γ, deg
V, Å3
Z
F
calc, g‚cm-3
1.646
1208
5.720
1.719
1320
5.557
1.714
656
5.510
F(000)
µ, mm-1
Tmax/Tmin
0.751/0.471
1.88-26.00
-24 e h e 24
-6 e k e 5
-27 e l e 20
12 826
4762/0.0779
98.7
283/20
0.591/0.895
2.05-27.02
-8 e h e 8
-11 e k e 11
-50 e l e 50
23 085
5576/0.0899
99.2
310/7
0.896/0.316
2.19 to 26.00
-13 e h e 13
-13 e k e 13
-15 e l e 15
10 861
4869/0.0477
96.9
313/3
θ range, deg
index ranges
no. of rflns collected
no. of indep rflns/Rint
completeness to θ, %
no. of refined params/restraints
GOF (F2)
0.964
1.084
0.973
no. of rflns with I > 2σ(I)
2657
0.0517
0.1111
2.579/-0.777
3591
0.0524
0.0847
1.494/-0.857
3854
0.0370
0.0664
1.094/-1.232
R1(F) (I > 2σ(I))a
wR2(F2) (all data)b
largest diff peak/hole, e‚Å-3
b
2
2
2
a R1 ) ∑|Fo - |Fc||/∑(Fo). wR2 ) (∑[w(Fo - Fc )2]/∑[w(Fo )2 ]1/2
.
organic layer was dried over anhydrous MgSO4. Volatiles were
removed under reduced pressure. The crude product was purified
by column chromatography (silica gel, hexanes/dichloromethane
26.56, 24.57, 21.55. HRMS-EI (m/z): [M]+ calcd for C48H38N2O3S,
722.2603; found, 722.2607. Anal. Calcd for C48H38N2O3S: C,
79.75; H, 5.30; N, 3.88; S, 4.44. Found: C, 79.55; H, 5.60; N,
3.90; S, 4.34.
1
) 1:1) to give a light yellowish solid (17.28 g, quantitative). H
NMR (300 MHz, CDCl3): δ 8.19 (d, J ) 7.7 Hz, 4H), 7.98 (d, J
) 7.4 Hz, 2H), 7.65 (d, J ) 1.4 Hz, 2H), 7.62 (dd, J ) 8.0 Hz, 1.9
Hz, 2H), 7.42-7.53 (m, 8H), 7.30-7.35 (m, 4H), 3.46 (t, J ) 6.6
Hz, 2H), 2.14 (m, 2H), 1.63 (s, 3H), 1.14 (m, 2H). 13C{1H} NMR
(75 MHz, CDCl3): δ 153.59, 140.78, 138.47, 136.88, 126.12,
125.92, 123.34, 121.52, 121.17, 120.32, 119.94, 109.71, 62.84,
51.06, 36.67, 28.08, 26.76. HRMS-EI (m/z): [M]+ calcd for
C41H32N2O, 568.25146; found, 568.25112. Anal. Calcd for
C41H32N2O: C, 86.59; H, 5.67; N, 4.93. Found: C, 86.33; H, 5.65;
N, 4.91.
9-[3-(Bicyclo[2.2.1]hept-5-en-2-ylmethoxy)propyl]-2,7-biscar-
bazol-9-yl-9-methyl-9H-fluorene (22). A Schlenk tube was charged
with dry THF (25 mL) and excess KH. 5-Norbornene-2-methanol
(0.18 g, 1.44 mmol) and 21 (1.2 g, 1.66 mmol) were added to the
Schlenk tube sequentially. The resulting mixture was stirred at room
temperature for 2 h. The reaction mixture was then quenched with
water and extracted with ether. The organic layer was washed with
water and dried over anhydrous MgSO4. Volatiles were removed
under reduced pressure. The crude product was purified by two
consecutive column chromatographies (silica gel, hexanes/dichlo-
romethane ) 1:1 (first), then hexanes/dichloromethane ) 3:1
(second)) to give a colorless glassy solid. The solid was dissolved
in THF and precipitated in cold MeOH. The resulting solid was
collected by filtration and dried under vacuum to give a white solid
(0.57 g, 59%). Endo isomer: 1H NMR (300 MHz, CD2Cl2) δ 8.20
(d, J ) 7.7 Hz, 4H), 7.99 (d, J ) 8.0 Hz, 2H), 7.66 (d, J ) 0.80
Hz, 2H), 7.62 (dd, J ) 8.0 Hz, 1.9 Hz, 2H), 7.43-7.54 (m, 8H),
7.30-7.36 (m, 4H), 6.00 (dd, J ) 5.8 Hz, 3.0 Hz, 1H), 5.82 (dd,
J ) 5.8 Hz, 3.0 Hz, 1H), 2.80-3.36 (m, 5H), 2.71 (br, 1H), 2.20-
2.30 (m, 1H), 2.10-2.20 (m, 2H), 1.71 (ddd, J ) 11.5 Hz, 9.1 Hz,
3.8 Hz, 1H), 1.64 (s, 3H), 1.10-1.38 (m, 4H), 0.38 (ddd, J ) 11.5
Hz, 4.4 Hz, 2.5 Hz, 1H). Endo and exo isomers: 13C{1H} NMR
(75 MHz, CD2Cl2) δ 153.76, 140.84, 138.54, 136.93, 136.84,
136.40, 136.38, 132.22, 126.10, 125.91, 123.36, 121.60, 121.16,
120.31, 119.91, 109.73, 75.44, 74.51, 70.91, 70.84, 51.17, 49.36,
44.91, 43.96, 43.64, 42.15, 41.50, 38.80, 38.72, 37.05, 29.73, 29.14,
26.74, 25.23. HRMS-EI (m/z): [M]+ calcd for C49H42N2O, 674.3297;
found, 674.3292. Anal. Calcd for C49H42N2O: C, 87.21; H, 6.27;
N, 4.15. Found: C, 86.98; H, 6.20; N, 4.08.
Toluene-4-sulfonic Acid 3-(2,7-Biscarbazol-9-yl-9-methyl-9H-
fluoren-9-yl)propyl Ester (21). To a solution of 20 (5.0 g, 8.8
mmol) in dry CH2Cl2 (40 mL) were added p-toluenesulfonyl
chloride (1.84 g, 9.7 mmol) and pyridine (1.5 mL, 18.5 mmol) at
0 °C. The reaction mixture was gradually warmed to room
temperature and stirred at room temperature. The reaction progress
was monitored by TLC. After stirring at room temperature for 3
days, the reaction mixture was washed with 1 N HCl. The organic
layer was washed with aqueous Na2CO3 solution and water and
dried over anhydrous MgSO4. Volatiles were removed under
reduced pressure. The crude product was purified by column
chromatography (silica gel, hexanes/dichloromethane ) 1:1) to give
a light yellow solid. The solid was triturated and washed with hot
MeOH to give a white solid (4.17 g, 66%) after drying under
1
vacuum overnight. H NMR (300 MHz, CDCl3): δ 8.19 (d, J )
7.7 Hz, 4H), 7.97 (d, J ) 8.0 Hz, 2H), 7.67 (d, J ) 8.2 Hz, 2H),
7.63 (dd, J ) 8.0 Hz, 1.7 Hz, 2H), 7.59 (d, J ) 1.6 Hz, 2H), 7.46-
7.52 (m, 8H), 7.30-7.38 (m, 4H), 7.16 (d, J ) 8.0 Hz, 2H), 3.85
(t, J ) 6.3 Hz, 2H), 2.30 (s, 3H), 2.09 (m, 2H), 1.59 (s, 3H), 1.23
(m, 2H). 13C{1H} NMR (75 MHz, CDCl3): δ 152.91, 144.50,
140.71, 138.34, 137.03, 132.81, 129.63, 127.64, 126.29, 126.03,
123.37, 121.34, 121.25, 120.31, 120.02, 109.65, 70.32, 50.77, 36.44,
Platinum(II) (1-Phenylisoquinolinato-N,C2′)(2,4-pentanedi-
onato-O,O) (26). A mixture of 8 (1.0 g, 1.56 mmol), 2,4-
pentanedione (0.344 g, 3.44 mmol), and Na2CO3 (1.65 g, 15.6

Polymerizable Phosphorescent Platinum(II) Complexes
Organometallics, Vol. 26, No. 19, 2007 4829
mmol) in 2-ethoxyethanol (20 mL) was heated at 100 °C overnight
under N2 atmosphere. The reaction was allowed to cool to room
temperature, and H2O was added. The mixture was extracted with
CH2Cl2. The organic layer was washed with H2O and dried over
anhydrous MgSO4. Volatiles were removed under reduced pressure.
The crude product was purified by column chromatography (silica
gel, dichloromethane as eluting solvent) to give an orange-brown
solid (0.50 g, 64%). 1H NMR (300 MHz, CDCl3): δ 8.93 (d, J )
6.6 Hz, 1H), 8.85 (d, J ) 8.5 Hz, 1H), 8.07 (dd, J ) 8.0 Hz, 1.4
Hz, 1H), 7.59-7.82 (m, 4H), 7.40 (d, J ) 6.3 Hz, 1H), 7.23 (td, J
) 7.1 Hz, 1.4 Hz, 1H), 7.15 (td, J ) 7.1 Hz, 1.4 Hz, 1H), 5.47 (s,
1H), 2.010 (s, 3H), 2.005 (s, 3H). 13C{1H} NMR (75 MHz,
CDCl3): δ 185.76, 184.00, 168.44, 146.09, 141.43, 139.10, 137.25,
131.01, 130.45, 129.25, 128.41, 128.09, 127.36, 126.10, 125.80,
123.14, 119.44, 102.49, 28.43, 27.26. HRMS-EI (m/z): [M]+ calcd
for C20H17NO2Pt, 498.0907; found, 498.0902. Anal. Calcd for
C20H17NO2Pt: C, 48.19; H, 3.44; N, 2.81. Found: C, 48.13; H,
3.36; N, 2.71.
Calcd for (C49H42N2O)n: C, 87.21; H, 6.27; N, 4.15. Found: C,
86.63; H, 6.36; N, 4.08.
Poly-10. To a solution of 10 (0.19 g, 0.16 mmol) in dry CH2Cl2
(2 mL) was added second-generation Grubbs initiator (2.8 mg,
0.0033 mmol) in CH2Cl2 (1 mL). The reaction mixture was stirred
at room temperature and monitored by TLC. After stirring at room
temperature for 40 h, the reaction mixture was quenched with few
drops of ethyl vinyl ether and stirred for additional 20 min. The
reaction mixture was poured into MeOH and the resulting mixture
was concentrated under reduced pressure; the resulting solid was
collected by vacuum filtration (0.063 g, 63%). 1H NMR (300 MHz,
CDCl3) δ 8.85 (br, 1 H), 7.72 (br, 1H), 7.59 (br, 1H), 7.56 (br,
1H), 7.38 (br, 1H), 7.18 (br, 1H), 7.05 (br, 1H), 5.30 (br m, 2H),
1.13-2.95 (br m, 23H).
Poly-22-co-10. To a solution of 22 (0.19 g, 0.148 mmol) and
10 (11.2 mg, 0.018 mmol) in dry CH2Cl2 (2 mL), second-generation
Grubbs initiator (2.8 mg, 0.0033 mmol) in CH2Cl2 (1 mL) was
added. The reaction mixture was stirred at room temperature and
monitored by TLC. After stirring at room temperature for 1 h, the
reaction mixture was quenched with few drops of ethyl vinyl ether
and stirred for additional 20 min. The reaction mixture was poured
into MeOH and a white solid was formed. The solid was collected
by filtration to give a white solid. The solid was dissolved in CH2Cl2
and re-precipitated in MeOH (79 mg, 71%). This polymer was also
obtained (58 mg, 52%) in an analogous method using the third-
Platinum(II) (2-Phenylbenzothiozolato-N,C2′)(2,4-pentanedi-
onato-O,O) (27). A mixture of 9 (0.5 g, 0.77 mmol), 2,4-
pentanedione (0.17 g, 1.7 mmol), and Na2CO3 (0.81 g, 7.67 mmol)
in 2-ethoxyethanol (15 mL) was heated at 100 °C for 20 h. The
reaction mixture was allowed to cool to room temperature, and H2O
was added. The mixture was extracted with CH2Cl2. The organic
layer was washed with H2O and dried over anhydrous MgSO4.
Volatiles were removed under reduced pressure. The crude product
was purified by column chromatography (silica gel, dichlo-
romethane as eluting solvent) to give an orange solid (0.168 g,
1
generation Grubbs initiator (3 mg, 0.0033 mmol). H NMR (300
MHz, CDCl3) δ 8.84 (br, ca. 0.15H), 8.01 (br, 4H), 7.75 (br, 2H),
7.20-7.60 (br, m, 12H), 7.18 (br, 4H), 6.80-7.10 (br m, ca. 0.45H),
4.90 (br m, 2H), 0.60-3.20 (br m, 18H).
1
43%). H NMR (300 MHz, CDCl3): δ 9.17 (d, J ) 8.5 Hz, 1H),
Poly-22-co-11. This polymer was obtained (44 mg, 40%) in the
same way as poly-22-co-10 using second-generation Grubbs initiator
and using 11 (11.1 mg) in place of 10, 1H NMR (300 MHz, CDCl3)
7.77 (m, 1H), 7.67 (m, 1H), 7.52 (ddd, J ) 8.5 Hz, 7.1 Hz, 1.4 Hz,
1H), 7.45 (dd, J ) 7.4 Hz, 1.4 Hz, 1H), 7.39 (ddd, J ) 8.2 Hz, 7.4
Hz, 1.4 Hz, 1H), 7.18 (td, J ) 7.4 Hz, 1.4 Hz, 1H), 7.07 (td, J )
7.4 Hz, 1.1 Hz, 1H), 5.53 (s, 1H), 2.05 (s, 3H), 2.00 (s, 3H).
13C{1H} NMR (75 MHz, CDCl3): δ 184.97, 183.39, 181.1, 150.68,
140.75, 138.16, 130.63, 130.17, 129.82, 127.35, 125.16, 124.57,
123.61, 121.91, 120.64, 102.05, 28.11, 27.21. HRMS-EI (m/z):
[M]+ calcd for C18H15NO2PtS, 504.0471; found, 504.0446. Anal.
Calcd for C18H15NO2PtS: C, 42.86; H, 3.00; N, 2.78; S, 6.36.
Found: C, 43.12; H, 3.12; N, 2.96; S, 6.42.
1
δ H NMR (300 MHz, CDCl3) δ 8.82 (br, ca. 0.15H), 8.01 (br,
4H), 7.75 (br, 2H), 7.20-7.60 (br, m, 12H), 7.18 (br, 4H), 6.90
(br, 0.3H), 6.47 (br, 0.3H), 4.90 (br m, 2H), 0.60-3.20 (br m, 18H).
Poly-22-co-12. This polymer was obtained (89.3 mg, 79%) in
the same way as poly-22-co-11 using 12 (11.1 mg) in place of 11.
1H NMR (300 MHz, CDCl3) δ 8.76 (br, ca. 0.15H), 8.01 (br, 4H),
7.75 (br, 2H), 7.20-7.60 (br, m, 12H), 7.18 (br, 4H), 6.70 (br, ca.
0.15H), 4.90 (br m, 2H), 0.60-3.20 (br m, 18H).
Poly-22. To a solution of 22 (0.400 g, 0.59 mmol) in dry CH2Cl2
(10 mL), second-generation Grubbs initiator (10 mg, 0.012 mmol)
in CH2Cl2 (1.5 mL) was added. The reaction mixture was stirred
at room temperature and monitored by TLC. After stirring at room
temperature for 65 min, the reaction mixture was quenched with
few drops of ethyl vinyl ether. The resulting mixture was stirred
for additional 30 min. The reaction mixture was poured into MeOH
and the resulting solid was collected by filtration, re-dissolved in
X-ray Diffraction. X-ray experiments were carried out using a
SMART 1000 CCD diffractometer (λ(Mo KR) ) 0.71073 Å,
graphite monochromator, ω-scans) at 120 K. The details of data
collection and crystal structure refinement, for which we used
SAINT Plus,39 SADABS,40 and SHELXTL-9741 program packages,
are summarized in Table 5.
Acknowledgment. This material is based on work supported
in part by the National Science Foundation STC Program under
agreement no. DMR-0120967. We also thank the NSF for
support through CHE-0342321 and the NIH for support through
the RIMI program, award no. 1P20MD001104-01.
1
THF and re-precipitated in MeOH (0.305 g, 76%). H NMR (300
MHz, CDCl3) δ 8.01 (br, 4H), 7.75 (br, 2H), 7.20-7.60 (br, m,
12H), 7.18 (br, 4H), 4.90 (br m, 2H), 0.60-3.20 (br m, 18H). Anal.
(39) SMART and SAINT, Release 5.0, Area Detector Control and
Integration Software; Bruker AXS, Analytical X-Ray Instruments: Madison,
WI, 1998.
(40) Sheldrick, G. M. SADABS, A Program for Exploiting the Redun-
dancy of Area-detector X-Ray Data; University of Go¨ttingen: Go¨ttingen,
Germany, 1999.
Supporting Information Available: Figures showing NMR
characterization of 4 and polymers and showing disorder models
used for crystals of 10, 12, and 13 (PDF format). Crystallographic
data for 10, 12, and 13 (CIF format). This material is available
free of charge via the Internet at http://pubs.acs.org.
(41) Sheldrick, G. M. SHELXTL-97, Program for Solution and Refine-
ment of Crystal Structures; Bruker AXS Inc.: Madison, WI, 1997.
OM700373C