Infrared-emitting poly(norbornene)s and poly(cyclooctene)s

Article abstract of DOI:10.1021/ma050923k

Poly(norbornene)- and poly(cyclooctene)-based copolymers, bearing carbazole and 8-hydroxy-quinoline side chains, were prepared. Upon complexation of the pendant quinoline ligands in the side chain with ytterbium followed by the addition of 2 equiv of additional quinolines, infrared-emitting copolymers that emit around 970 nm were obtained. The emission intensities increased linearly as the density of lanthanide-quinolate complexes increased in the copolymers. Finally, we were able to prove that the polymer backbones do not interfere with the optical properties of the polymers, suggesting that these polymers are outstanding materials as IR emitters.

Full text of DOI:10.1021/ma050923k

Macromolecules 2005, 38, 8671-8678
8671
Infrared-Emitting Poly(norbornene)s and Poly(cyclooctene)s
Amy Meyers, Alpay Kimyonok, and Marcus Weck*
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
Received May 2, 2005; Revised Manuscript Received August 15, 2005
ABSTRACT: Poly(norbornene)- and poly(cyclooctene)-based copolymers, bearing carbazole and 8-hydroxy-
quinoline side chains, were prepared. Upon complexation of the pendant quinoline ligands in the side
chain with ytterbium followed by the addition of 2 equiv of additional quinolines, infrared-emitting
copolymers that emit around 970 nm were obtained. The emission intensities increased linearly as the
density of lanthanide-quinolate complexes increased in the copolymers. Finally, we were able to prove
that the polymer backbones do not interfere with the optical properties of the polymers, suggesting that
these polymers are outstanding materials as IR emitters.
Introduction
into polymer matrices, producing emission ranging from
0.98 µm for ytterbium complexes to 1.53 µm for erbium
complexes, with lifetimes as long as 230 µs.30 However,
one of the challenges in the optimization of lanthanide-
quinolate materials is the limited processability of the
material. We recently reported a polymer-quinolate
material that can be solution processed, suggesting a
new strategy to overcome this limitation.32-34
In this contribution, we report the utilization of the
next generation of our polymer-quinolate material to
fabricate polymer-supported lanthanide-quinolate com-
plexes. The research design includes the attachment of
one 8-hydroxyquinoline ligand to a norbornene or cy-
clooctene monomer that can then be polymerized using
ring-opening metathesis polymerization (ROMP), a po-
lymerization method that allows for controlled polymer-
izations under mild conditions at room temperature.
Furthermore, the tolerance of the Grubbs’ ruthenium-
based ROMP catalysts toward most functional groups
and the ability to form copolymers make this polymer-
ization method highly desirable.35-39 The quinolate
monomers are copolymerized with a carbazole-based
comonomer in order to alleviate solubility problems
while providing another potential route for energy
transfer to the lanthanide complex.
We demonstrate our new strategy by employing two
diverse polymerizable units, norbornene and cyclooctene.
By changing the polymer backbone from a poly(nor-
bornene) to a poly(cyclooctene), we can potentially tune
the refractive index of the material, thereby giving us
yet another means for adjusting the properties of the
polymers. Furthermore, by altering the polymer back-
bone, we will alter the polymer morphology that has a
direct effect on the polymer properties such as process-
ability and might have a profound effect on the emission
properties of the polymers. While poly(cyclooctene)s are
known to have a random coil configuration, poly-
(norbornene)s are significantly more rigid.40 This con-
tribution describes the synthesis and detailed charac-
terization of poly(norbornene)s and poly(cyclooctene)s
containing ytterbium-quinolate complexes.
The trend in the development of future technologies,
such as molecular electronics and electrooptics for
display technologies, is moving toward the use of organic
materials. Over the past two decades, electrooptical
materials with emissions in the visible region have been
well established (for examples see refs 1-13). In con-
trast, organic materials that emit light in the infrared
region have only recently started to be explored.14-26
Infrared-emitting materials have potential applications
in electronic devices, such as organic light-emitting
diodes, and in photonic communication networks, es-
pecially silica optical fibers.14-20,24-28 Optical fibers
based on these materials are potentially useful for high-
speed data transmission by confining light in a region
of high refractive index between regions of low refractive
index.28 The optimal wavelength of light traveling
through the fibers that coincides with the least amount
of transmission loss is in the infrared region between
1.3 and 1.5 µm.18-20,25,26,28,29
Recent literature reports of materials emitting infra-
red radiation include conjugated polymers and com-
pounds containing lanthanide complexes.14-20,24-28 Lan-
thanide complexes have low band gaps and narrow
emission bands due to their f-f transitions that are
shielded from external forces by the 5s and 5p elec-
trons.17-19,30,31 However, because of the forbidden nature
of the f-f transitions, in most cases, the lanthanide
metal is excited by intramolecular energy transfer from
its surrounding ligands. Since this energy transfer is
usually through the triplet state of the ligands, the
theoretical internal quantum efficiencies can reach
100%, which is significantly higher than systems based
only on the recombination of singlet excitons.18,19,30
The design of lanthanide-based infrared emitters
includes ligands with energy levels that overlap with
the energy levels of the lanthanide metal in order for
the energy transfer to occur. This is known as the
“antenna effect”.18-21,25,27,28,30 A wide variety of ligands
have been coordinated to different lanthanide metals
in order to optimize this antenna effect.18-21,25,27,28,30 One
ligand that has been used repeatedly in these studies
is 8-hydroxyquinoline.14,16,25,29-31 Lanthanide-quinolate
complexes have been sublimed into thin films and doped
Experimental Section
General. All chemicals were purchased from Acros Organ-
ics or Aldrich and used without further purification. Flash
column chromatography was carried out on silica gel 60, 230-
400 mesh (Sorbent Technology). NMR spectra were acquired
* Corresponding
chemistry.gatech.edu.
author.
E-mail:
marcus.weck@
10.1021/ma050923k CCC: $30.25 © 2005 American Chemical Society
Published on Web 09/22/2005

8672 Meyers et al.
Macromolecules, Vol. 38, No. 21, 2005
with a Varian Mercury 400 (1H, 400.0 MHz; 13C, 100.6 MHz)
spectrometer. Chemical shifts are reported in ppm and refer-
enced to the corresponding residual nuclei in deuterated
solvents. Gel-permeation chromatography (GPC) analyses
were carried out using a Shimadzu instrument and linear
mixed bed column packed with 10 µm AM gel using THF as
the eluent and a multidiode array UV detector. All GPC data
were standardized against poly(styrene). Differential scanning
calorimetry (DSC) was performed under nitrogen using a
Mettler Toledo DSC 822e cooled by liquid nitrogen. The
temperature program provided heating and cooling cycles
between -50 and 360 °C at 10 °C/min. UV/vis spectra were
obtained on a Perkin-Elmer Lambda 19 UV/vis/NIR spectrom-
eter. The fluorescence spectra were obtained on a Spex
FluoroLog-3 spectrofluorimeter.
7.40 (2H, dd, J ) 7.69, 14.83); 6.25 (1H, endo, m); 6.17 (2H,
exo, m); 6.04 (1H, endo, m); 4.37 (2H, t, J ) 7.14); 2.87 (2H, s,
broad); 2.08 (4H, m); 1.56 (6H, m); 1.18 (2H, m); 0.62 (1H, m).
13C NMR (75 MHz, CDCl3) δ: 140.7; 137.2; 132.6; 125.9; 123.1;
120.6; 119.0; 109.1; 50.0; 45.9; 43.4; 39.2; 35.1; 32.9; 29.5; 28.9;
28.0. MS (EI): m/z ) 329.3. Anal. Calcd for C24H27N1: C, 87.53;
H, 8.21; N, 4.30. Found: C, 88.30; H, 7.93; N, 4.50.
Copolymerization of Monomers 3 and 7 (Ratios of 3/7
) 1:5, 1:10, 1:20). Monomers 3 and 7 were dissolved in 5 mL
of chloroform. A chloroform solution of ruthenium catalyst 8
(5 mol % in 1 mL) was added to the monomer solution and
stirred for 5 min, followed by the addition of ethyl vinyl ether
(1 mL). After stirring for an additional 10 min, the solution
was concentrated down to 1 mL and added dropwise to 100
mL of methanol. The polymer, which precipitated out of
solution, was collected and redissolved in 1 mL of chloroform
and reprecipitated into methanol. This purification procedure
was repeated three times. The final product was collected as
a brown solid (9a-c).
Synthesis of 5-(Bicyclo[2.2.1]hept-5-en-2-yl-methoxy-
methyl)quinolin-8-ol (3). Chloromethylhydroxyquinoline hy-
drochloride (2) was prepared from 8-hydroxyquinoline (1)
according to literature procedures.41 Monomer 3 was prepared
by stirring 2 (2.0 g, 8.7 mmol) and sodium bicarbonate (0.8 g,
9.5 mmol) in a large excess of norbornene methanol (10 mL)
at 90 °C for 1 h. The excess alcohol was distilled off, and the
remaining solid was dissolved in water. The aqueous solution
was extracted with CH2Cl2; the organic layer was collected,
washed with a brine solution, and dried over sodium sulfate.
The solvent was removed, leaving a greenish-yellow solid that
was purified by column chromatography (silica gel, 4:1 hex-
anes/ethyl acetate) yielding an off-white solid (1.8 g, 72% yield).
Monomer 3 is an 80:20 mixture of the endo-exo isomers. These
isomers can be separated by column chromatography. While
we used both isomers for all polymerization studies, for
clarification and proof of purity, we report the 1H and 13C NMR
data of only the exo isomer. 1H NMR (300 MHz, CDCl3) δ: 8.81
(1H, dd, J ) 1.65, 4.39); 8.53 (1H, dd, J ) 1.65, 8.79); 7.52
(1H, dd, J ) 4.39, 8.79); 7.42 (1H, d, J ) 7.69); 7.11 (1H, d, J
) 7.69); 6.07 (2H, m); 4.84 (2H, s); 3.56-3.01 (2H, m); 2.86-
2.70 (2H, m); 1.74 (1H, m); 1.29 (3H, m); 1.19 (1H, m). 13C NMR
(75 MHz, CDCl3) δ: 152.5, 147.8, 138.8, 136.8, 136.7, 133.7,
128.7, 127.6, 124.9, 122.0, 108.9, 75.0, 71.5, 45.3, 44.1, 41.8,
39.1, 30.1. MS (EI): m/z ) 281.2. Anal. Calcd for C18H19O2N1:
C, 76.87; H, 6.76; N, 4.98. Found: C, 77.02; H, 7.01; N, 4.72.
Synthesis of 9-(4-Bromobutyl)-9H-carbazole (5). Car-
bazole 4 (3.2 g, 0.020 mol) was combined with an excess of
potassium carbonate and dissolved in 20 mL of acetone. An
acetone solution of 1,4-dibromobutane (10 g, 1.5 mmol/mL) was
added dropwise to the carbazole solution, and the combined
mixture was refluxed overnight. The solvent was removed, and
the remaining solid was purified by column chromatography
(silica gel, 3:1 hexanes/methylene chloride) yielding a white
solid (4.8 g, 81% yield). 1H NMR (300 MHz, CDCl3) δ: 8.19
(2H, d, J ) 7.69); 7.56 (2H, dd, J ) 7.14, 15.38); 7.45 (2H, d,
J ) 8.24); 7.35 (2H, dd, J ) 7.14, 14.83); 4.36 (2H, t, J ) 7.14);
3.40 (2H, t, J ) 6.59); 2.11 (2H, m); 1.96 (2H, m). 13C NMR
(75 MHz, CDCl3) δ: 140.4; 126.0; 123.1; 120.7; 119.2; 108.8;
42.5; 33.7; 30.6; 28.0. MS (EI): m/z ) 301. Anal. Calcd for
C16H16N1Br1: C, 63.78; H, 5.31; N, 4.65. Found: C, 64.02; H,
5.01; N, 4.71.
Synthesis of 9-(5-(Bicyclo[2.2.1]hept-5-en-2-yl-pentyl)-
9H-carbazole (7). 5-Bromomethylnorbornene (6), prepared
according to literature procedures42 (3.0 g, 0.015 mol), was
dissolved in 10 mL of anhydrous THF and added dropwise to
dried magnesium turnings (0.5 g, 0.020 mol) in 10 mL of
anhydrous THF under argon. After the addition was complete,
the mixture was warmed to 50 °C and stirred overnight under
argon. The resulting solution was then added dropwise to an
ice-cold solution of 5 (3.78 g, 0.012 mol), Li2CuCl4 (5 mL, 0.1
M solution in THF), and 10 mL of anhydrous THF. After the
addition was complete, the solution was warmed to room
temperature and stirred under argon overnight. The solution
was diluted with ether, washed with an aqueous solution of
NH4Cl and brine, and dried over Na2SO4. After removal of the
solvent, the yellow oil was purified by column chromatography
(silica gel, 5:1 hexanes/ethyl acetate) yielding a yellow solid
(3.5 g, 85% yield). 1H NMR (300 MHz, CDCl3) δ: 8.26 (2H, d,
J ) 7.69); 7.63 (2H, dd, J ) 8.24, 15.38); 7.52 (2H, d, J ) 7.69);
Quinoline-co-carbazole Copolymer 9a (1:5). 1H NMR (300
MHz, CDCl3) δ: 8.72 (1H, broad); 8.42 (1H, broad); 8.12 (10H,
broad); 7.45 (14H, broad); 7.05 (1H, broad); 5.14 (12H, m); 4.69
(2H, broad); 4.25 (10H, m); 3.35 (2H, m); 2.95 (5H, m); 2.65
(8H, m); 1.85 (20H, m); 1.30 (40H, m). 13C NMR (75 MHz,
CDCl3) δ: 152.4; 147.8; 140.5; 138.7; 137.2; 133.8; 132.6; 128.7;
127.5; 125.7; 124.9; 122.9; 120.5; 118.9; 108.8; 50.0; 45.9; 43.3;
39.2; 35.1; 31.9; 29.3; 28.7; 27.8.
1
Quinoline-co-carbazole Copolymer 9b (1:10). H NMR (300
MHz, CDCl3) δ: 8.72 (1H, broad); 8.42 (1H, broad); 8.12 (20H,
broad); 7.45 (28H, broad); 7.05 (1H, broad); 5.14 (22H, m); 4.69
(2H, broad); 4.25 (20H, m); 3.35 (2H, m); 2.95 (10H, m); 2.65
(16H, m); 1.85 (40H, m); 1.30 (80H, m). 13C NMR (75 MHz,
CDCl3) δ: 152.4; 147.7; 140.4; 138.7; 137.1; 133.7; 132.7; 128.5;
127.5; 125.7; 124.8; 122.8; 120.5; 118.8; 108.9; 50.2; 45.8; 43.2;
39.2; 35.3; 31.9; 29.5; 28.6; 27.7.
1
Quinoline-co-carbazole Copolymer 9c (1:20). H NMR (300
MHz, CDCl3) δ: 8.72 (1H, broad); 8.42 (1H, broad); 8.12 (40H,
broad); 7.45 (54H, broad); 7.05 (1H, broad); 5.14 (42H, m); 4.69
(2H, broad); 4.25 (40H, m); 3.35 (2H, m); 2.95 (20H, m); 2.65
(32H, m); 1.85 (80H, m); 1.30 (160H, m). 13C NMR (75 MHz,
CDCl3) δ: 152.3; 147.9; 140.4; 138.6; 137.2; 133.9; 132.5; 128.7;
127.4; 125.6; 124.8; 122.9; 120.5; 118.8; 108.8; 50.1; 45.8; 43.3;
39.1; 35.2; 31.8; 29.4; 28.7; 27.8.
Formation of Ybq3 Copolymers 10a-c. Excess Ybq3,
prepared according to literature procedures23 was dissolved
in a minimum amount of methanol and added to a chloroform
solution of 9 (0.1 g/10 mL). After stirring overnight, the
solution was concentrated down to 1 mL and added dropwise
to 100 mL of methanol. The polymer, which precipitated out
of solution, was collected and redissolved in 1 mL of chloroform
and precipitated into methanol. This purification procedure
was repeated three times. The final product was collected as
a brown solid 10a-c.
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
1
10a (1:5). H NMR (300 MHz, CDCl3) δ: 8.75 (m); 8.39 (m);
8.12 (10H, m); 7.83 (m); 7.45 (15H, m); 6.96 (m); 5.28 (12H,
m); 4.25 (10H, m); 2.89 (5H, m); 2.52 (8H, m); 1.85 (20H, m);
1.32 (40H, m). 13C NMR (75 MHz, CDCl3) δ: 140.4; 137.1;
132.7; 125.7; 122.8; 120.5; 118.8; 108.9; 50.2; 45.8; 43.2; 39.2;
35.3; 31.9; 29.5; 28.6; 27.7.
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
1
10b (1:10). H NMR (300 MHz, CDCl3) δ: 8.75 (m); 8.38 (m);
8.11 (20H, m); 7.82 (m); 7.44 (30H, m); 6.98 (m); 5.25 (22H,
m); 4.24 (20H, m); 2.87 (10H, m); 2.51 (16H, m); 1.82 (40H,
m); 1.30 (80H, m). 13C NMR (75 MHz, CDCl3) δ: 140.5; 137.2;
132.6; 125.7; 122.9; 120.5; 118.9; 108.8; 50.0; 45.9; 43.3; 39.2;
35.1; 31.9; 29.3; 28.7; 27.8.
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
1
10c (1:20). H NMR (300 MHz, CDCl3) δ: 8.72 (m); 8.42 (m);
8.12 (40H, broad); 7.45 (54H, broad); 7.05 (m); 5.24 (42H, m);
4.25 (40H, m); 2.95 (20H, m); 2.65 (32H, m); 1.84 (80H, m);
1.32 (160H, m). 13C NMR (75 MHz, CDCl3) δ: 140.4; 137.2;
132.5; 125.6; 122.9; 120.5; 118.8; 108.8; 50.1; 45.8; 43.3; 39.1;
35.2; 31.8; 29.4; 28.7; 27.8.

Macromolecules, Vol. 38, No. 21, 2005
Poly(norbornene)s and Poly(cyclooctene)s 8673
Synthesis of 5-(Cyclooct-4-enyloxymethyl)quinolin-8-
ol (12). 5-Hydroxycyclooctene (11) was prepared according to
literature procedure.43 Monomer 12 was synthesized by stir-
ring chloromethylhydroxyquinoline hydrochloride (2) (1.5 g,
0.0065 mol) and 11 (6.8 g, 0.054 mol) in the presence of excess
NaHCO3 at 110 °C for 1.5 h. Upon cooling, a solid precipitated
that was dissolved in CH2Cl2 and washed with water. The
solvent and the excess alcohol were removed by distillation.
The resulting green solid was recrystallized from hexanes to
give a white solid (0.87 g, 46% yield). 1H NMR (300 MHz,
CDCl3) δ: 8.79 (1H, dd, J ) 1.65, 4.12); 8.49 (1H, dd, J ) 1.65,
8.52); 7.47 (1H, dd, J ) 4.12, 8.52); 7.40 (1H, d, J ) 7.69);
7.10 (1H, d, J ) 7.69); 5.62 (2H, m); 4.80 (2H, dd, J ) 11.26,
22.25); 3.51 (1H, m); 2.35-1.40 (10H, m). 13C NMR (75 MHz,
CDCl3) δ: 152.4, 147.6, 138.6, 133.9, 130.2, 129.6, 128.7, 127.7,
125.2, 121.9, 109.2, 80.1, 68.7, 34.6, 33.6, 26.1, 25.9, 23.1. MS
m/z Calcd (M+): 284.2. Found (ESI): 284.2 (M+).
broad); 7.45 (42H, broad); 7.26 (20H, broad); 7.14 (1H, broad);
5.40 (22H, broad); 4.91 (12H, broad); 4.31 (20H, broad); 3.57
(1H, m); 2.2-1.4 (190 H, m). 13C NMR (75 MHz, CDCl3) δ:
173.3, 152.5, 147.8, 140.5, 138.8, 133.9, 130.6, 130.4, 130.0,
129.8, 129.6, 128.9, 128.7, 127.7, 126.2, 125.9, 125.3, 123.0,
121.9, 120.6, 119.0, 108.9, 73.8, 68.8, 60.3, 43.1, 34.7, 34.4, 34.1,
33.5, 33.2, 33.0, 32.8, 29.1, 28.9, 27.4, 27.2, 25.7, 25.2, 23.7.
Quinoline-co-carbazole Copolymer 15c (1:20). 1H NMR (300
MHz, CDCl3) δ: 8.77 (1H, broad); 8.44 (1H, broad); 8.13 (40H,
broad); 7.45 (82H, broad); 7.26 (40H, broad); 7.14 (1H, broad);
5.38 (42H, broad); 4.89 (22H, broad); 4.28 (40H, broad); 3.54
(1H, m); 2.2-1.4 (370H, m). 13C NMR (75 MHz, CDCl3) δ:
173.3, 152.5, 147.8, 140.5, 138.8, 133.9, 130.6, 130.4, 130.0,
129.8, 129.6, 128.9, 128.7, 127.7, 126.2, 125.9, 125.3, 123.0,
121.9, 120.6, 119.0, 108.9, 73.8, 68.8, 60.3, 43.1, 34.7, 34.4, 34.1,
33.5, 33.2, 33.0, 32.8, 29.1, 28.9, 27.4, 27.2, 25.7, 25.2, 23.7.
Formation of Ybq3 Copolymers 16a-c. Excess Ybq3 was
dissolved in a minimum amount of methanol and added to a
chloroform solution of 15 (0.1 g/10 mL). After stirring over-
night, the solution was concentrated down to 1 mL and added
dropwise to 100 mL of cold methanol. The polymer, which
precipitated out of solution, was collected and redissolved in
1 mL of chloroform and precipitated into cold methanol. This
purification procedure was repeated three times. The final
product was collected as a brown solid 16a-c.
Synthesis of 6-Bromohexanoic Acid Cyclooct-4-enyl
Ester (13). Dicyclocarbodiimide (7.5 g, 0.036 mol) and N,N-
(dimethylamino)pyridine (0.4 g, 0.0033 mol) were dissolved in
40 mL of anhydrous CH2Cl2 and added dropwise to a solution
of 11 (3.9 g, 0.031 mol) and 6-bromohexanoic acid (7.6 g, 0.039
mol) in 40 mL of anhydrous CH2Cl2 under argon. The solution
was stirred overnight at room temperature. The white pre-
cipitate that formed during the reaction was filtered off, the
filtrate was reduced, and the remaining oil was purified by
column chromatography (silica gel, 4:1 hexanes/ethyl acetate)
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
16a (1:5). 1H NMR (300 MHz, CDCl3) δ: 8.79 (broad); 8.13
(broad); 7.37 (broad); 5.40 (broad); 4.85 (broad); 4.30 (broad);
3.64 (broad); 2.4-1.2 (broad). 13C NMR (75 MHz, CDCl3) δ:
173.3, 151.8, 147.6, 140.5, 138.1, 133.6, 130.7, 130.6, 130.5,
130.4, 130.1, 130.0, 129.9, 129.7, 126.2, 125.8, 122.9, 120.6,
118.9, 108.8, 73.8, 66.4, 43.1, 37.3, 34.7, 34.3, 34.1, 32.8, 29.0,
28.8, 27.2, 25.6, 25.2.
1
to yield a colorless oil (7.5 g, 79% yield). H NMR (300 MHz,
CDCl3) δ: 5.61 (2H,m); 4.80 (1H,m); 3.37 (2H, t, J ) 6.87);
2.36-1.40 (18H, m). 13C NMR (75 MHz, CDCl3) δ: 172.8; 129.9;
129.7; 75.7; 34.8; 34.1; 34.0; 33.8; 32.7; 27.9; 25.9; 25.2; 24.5;
22.7.
Synthesis of 6-Carbazol-9-ylhexanoic Acid Cyclooct-
4-enyl Ester (14). Carbazole 4 (3.7 g, 0.022 mol) was dissolved
in anhydrous THF and added dropwise to an ice-cold mixture
of NaH (0.5 g, 0.021 mol) in THF and stirred for 1 h. Then, 13
(4.8 g, 0.016 mol), dissolved in 50 mL of anhydrous THF, was
added dropwise to the reaction mixture. After the addition was
complete, the mixture was refluxed overnight. After filtration,
the solution was diluted with ether, washed with an aqueous
solution of NaHCO3 and brine, and dried over Na2SO4. The
solvent was removed, and the crude product was purified by
column chromatography (silica gel, 9:1 hexanes/ethyl acetate)
yielding a viscous, colorless oil (3.7 g, 60% yield). 1H NMR (300
MHz, CDCl3) δ: 8.12 (2H, d, J ) 7.69); 7.48 (2H, dd, J ) 6.89,
15.11); 7.40 (2H, d, J ) 7.97); 7.26 (2H, dd, J ) 6.89, 14.83);
5.65 (2H, m); 4.81 (1H, m); 4.31 (2H, t, J ) 7.14); 2.32-1.44
(18H, m). 13C NMR (75 MHz, CDCl3) δ: 172.9, 140.5, 129.9,
129.8, 125.8, 123.0, 120.6, 118.9, 108.8, 75.8, 75.7, 43.2, 34.8,
34.1, 33.9, 29.1, 27.2, 25.9, 25.2, 22.7. MS m/z Calcd (M+):
390.2. Found (ESI): 390.2 (M+).
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
1
16b (1:10). H NMR (300 MHz, CDCl3) δ: 8.79 (broad); 8.13
(broad); 7.37 (broad); 5.40 (broad); 4.85 (broad); 4.30 (broad);
3.64 (broad); 2.4-1.2 (broad). 13C NMR (75 MHz, CDCl3) δ:
173.3, 151.8, 147.6, 140.5, 138.1, 133.6, 130.7, 130.6, 130.5,
130.4, 130.1, 130.0, 129.9, 129.7, 126.2, 125.8, 122.9, 120.6,
118.9, 108.8, 73.8, 66.4, 43.1, 37.3, 34.7, 34.3, 34.1, 32.8, 29.0,
28.8, 27.2, 25.6, 25.2.
Ytterbium Tris(8-hydroxyquinoline)-co-carbazole Copolymer
1
16c (1:20). H NMR (300 MHz, CDCl3) δ: 8.79 (broad); 8.13
(broad); 7.37 (broad); 5.40 (broad); 4.85 (broad); 4.30 (broad);
3.64 (broad); 2.4-1.2 (broad). 13C NMR (75 MHz, CDCl3) δ:
173.3, 151.8, 147.6, 140.5, 138.1, 133.6, 130.7, 130.6, 130.5,
130.4, 130.1, 130.0, 129.9, 129.7, 126.2, 125.8, 122.9, 120.6,
118.9, 108.8, 73.8, 66.4, 43.1, 37.3, 34.7, 34.3, 34.1, 32.8, 29.0,
28.8, 27.2, 25.6, 25.2.
Solution Photoluminescence Studies. Approximately 5
mg of each copolymer was dissolved in a minimum amount of
chloroform. The solution was then diluted with DMSO until a
precipitate formed followed by the addition of chloroform until
the solution became clear again. This procedure was repeated
as necessary until a volume of 3 mL was reached. Note that
the amount of chloroform and DMSO was different for each
copolymer ratio.
Copolymerization of 12 and 14 (Ratios of 12/14 ) 1:5,
1:10, 1:20). Monomer 12 was dissolved in 1 mL of chloroform.
A chloroform solution of the ruthenium catalyst 8 in 1 mL of
chloroform was added to the monomer solution and stirred for
30 s, followed by the addition of monomer 14 (in 5 mL of
chloroform). After stirring for 10 min, ethyl vinyl ether (1 mL)
was added. After stirring for an additional 10 min, the solution
was concentrated down to 1 mL and added dropwise to 100
mL of cold methanol. The polymer, which precipitated out of
solution, was collected and redissolved in 1 mL of chloroform
and reprecipitated into cold methanol. This purification pro-
cedure was repeated three times. The final product was
collected as a brown solid (15a-c).
Results and Discussion
Synthesis. Scheme 1 outlines the synthesis of mono-
mer 3. The chloromethylhydroxyquinoline salt 2 was
stirred over sodium bicarbonate in the presence of a
large excess of the norbornene methanol to yield the
target monomer 3. Monomer 3 was then polymerized
using the third generation Grubbs ruthenium catalyst.
The homopolymer was isolated and purified, followed
by the addition of freshly prepared ytterbium tris(8-
hydroxyquinoline) (Ybq3).
However, upon purification, we were not able to
redissolve the isolated Ybq3 polymer in any common
solvents. We have reported before that the metalation
(using aluminum and zinc) of polymer-supported quino-
1
Quinoline-co-carbazole Copolymer 15a (1:5). H NMR (300
MHz, CDCl3) δ: 8.79 (1H, broad); 8.51 (1H, broad); 8.14 (10H,
broad); 7.48 (22H, broad); 7.28 (10H, broad); 7.17 (1H, broad);
5.43 (12H, broad); 4.94 (7H, broad); 4.29 (10H, broad); 3.57
(1H, m); 2.2-1.4 (100H, m). 13C NMR (75 MHz, CDCl3) δ:
173.3, 152.5, 147.8, 140.5, 138.8, 133.9, 130.6, 130.4, 130.0,
129.8, 129.6, 128.9, 128.7, 127.7, 126.2, 125.9, 125.3, 123.0,
121.9, 120.6, 119.0, 108.9, 73.8, 68.8, 60.3, 43.1, 34.7, 34.4, 34.1,
33.5, 33.2, 33.0, 32.8, 29.1, 28.9, 27.4, 27.2, 25.7, 25.2, 23.7.
Quinoline-co-carbazole Copolymer 15b (1:10). 1H NMR (300
MHz, CDCl3) δ: 8.78 (1H, broad); 8.49 (1H, broad); 8.14 (20H,

8674 Meyers et al.
Macromolecules, Vol. 38, No. 21, 2005
Scheme 1. Synthesis of Quinoline Monomer 3
Scheme 2. Synthesis of Carbazole Monomer 7
Scheme 3. Copolymerization of 3 with 7
line ligands (these ligands can be viewed as macroli-
gands) can yield to inter- and intramolecular cross-
linking of polymers by incorporating more than one
polymer-supported quinoline unit in a single metal
quinolate complex.32-34 This results in the formation of
a cross-linked three-dimensional polymer network,
thereby lowering the solubility of the functionalized
polymers. In our previous contributions, we have shown
that the incorporation of a nonfunctionalized spacer
molecule (in all cases an alkyl-containing norbornene
monomer) reduces the quinoline density along the
polymer backbone and ultimately the cross-linking
density after metalation. This strategy resulted in the
synthesis of fully soluble polymers in a variety of organic
solvents.32-34 We rationalize that the same cross-linking
phenomenon takes place using Yb metalation and that
this solubility problem can be overcome by simply
diluting the quinoline side chains along the polymer
backbone.
It is essential that the comonomer is moderately
conductive and allows for energy transfer to the lan-
thanide metal center. Both requirements need to be
fulfilled to allow for the potential use of the material in
electronic devices. We rationalized that a carbazole-
based monomer would fulfill these requirements. Poly-
(N-vinylcarbazole) (PVK) has been used previously as
a polymer host for erbium quinolates, with results
suggesting that the PVK not only acts as a hole-
transporting polymer but also allows for energy transfer
into the erbium center.18
The synthesis of carbazole monomer 7 is shown in
Scheme 2. Commercially available carbazole 4 was
functionalized with 1,4-dibromobutane and attached to
bromomethylnorbornene 6 using a Grignard coupling
to yield 7. The copolymerization of 3 and 7 is shown in
Scheme 3. The percentage of 3 in the copolymer was
varied systematically from 5% up to 20%, giving ratios
of 3/7 of 1:5 in 9a, 1:10 in 9b, and 1:20 in 9c. The
resulting purified copolymers were further functional-
ized by reacting them with Ybq3, yielding the Ybq3
copolymer 10 as shown in Scheme 4. The molecular
weights of the copolymers are given in Table 1. Copoly-
mers 9a-c showed glass transition temperatures around
100 °C; however, no glass transition temperatures were
detected upon the formation of the lanthanide complex
on the side chains of the copolymers. All copolymers
decomposed around 260 °C.
The syntheses of the cyclooctene-based quinoline
monomer 12 and carbazole monomer 14 are shown in
Scheme 5. Compound 11 was reacted with 2 in the
presence of sodium bicarbonate to yield monomer 12.
Esterification of compound 11 with 6-bromohexanoic
acid yielded compound 13. Carbazole monomer 14 was
obtained from the reaction of 13 with commercially
available carbazole 4.
The copolymerization of 12 and 14 is shown in
Scheme 6. Ratios of 12 to 14 in copolymers 15a, 15b,
and 15c are 1:5, 1:10, and 1:20, respectively. Reactions
of 15a-c with Ybq3 yielded copolymers 16a-c. Again,

Macromolecules, Vol. 38, No. 21, 2005
Poly(norbornene)s and Poly(cyclooctene)s 8675
Scheme 4. Formation of the Norbornene-Based Ybq3
Copolymers
Scheme 5. Synthesis of Cyclooctene Monomers 12
and 14
All cyclooctene-based copolymers decomposed around
335 °C.
We used elemental analysis methods to determine the
metal contents of polymers 10a,b and 16a,b. We carried
out ICP analyses of all four polymers. In all cases, the
metal contents were only 10-35% of the theoretical
values (for 10a: theoretical value 7.24%, measured
value (ICP) 2.55% (35% of theoretical value) and for
10b: theoretical value 4.29%, measured value (ICP)
0.544% (13% of theoretical value)). These results suggest
that only every third to every tenth quinoline unit along
the polymer backbone is metalated. To verify these
numbers, we also carried out elemental analysis (C, H,
N, and O) of 10a. Since the polymer contains only the
elements C, H, N, and O but for the metal, one can
calculate the metal contents by subtracting the C, H,
N, and O contents from 100%. The remaining contents
must be the metal complex. Using this method, we
measured a metal content of 6.88% (95% of the theoreti-
cal value), suggesting a nearly quantitative metalation
of all quinoline units along the polymer backbone.
While one should expect both methods of metal
contents characterization to agree, we found that both
methods diverse from the theoretical expected metal
contents values. We attribute the error of the two
analytical methods to the small sample sizes and the
low metal percentage of all polymers. Nevertheless, both
methods clearly indicate that metalation of the quino-
line units along the polymer backbone took place and
that the metal contents along the polymers cannot be
characterized conclusively. Our data suggest that the
polymer containing a high density of quinoline units
along the polymer backbone have a higher metal
contents (35-95% depending on the characterization
method) than the polymers with the lower quinoline
density.
Table 1. Characterization Data for All Monomers and
Polymers
photophysical data
mol wt data
UV/vis
emissiona
Mn
Mw
compd
λmax(nm)
λmax (nm) [1 × 103] [1 × 103] PDI
3
7
316
346, 295
n/a
425
n/a
n/a
10
n/a
n/a
14
n/a
n/a
1.4
1.4
1.4
1.4
1.4
1.4
n/a
n/a
4.3
4.3
4.0
4.2
3.7
3.6
9a
347, 321, 295 511
9b
347, 322, 296 510
3.5
3.5
9.5
3.5
3.5
n/a
n/a
16.5
12.5
15
4.5
4.5
13.5
4.5
4.5
n/a
n/a
71
53.5
61.5
49.5
49.5
53
9c
346, 321, 294 509
10a
10b
10c
12
386, 347, 293 510, 971
384, 344, 295 509, 970
384, 346, 295 510, 971
319
346, 294
n/a
435
14
15a
15b
15c
16a
16b
16c
346, 331, 294 501
346, 331, 297 481
346, 331, 294 496
400, 346, 294 517, 971
402, 346, 297 516, 970
399, 346, 294 518, 975
11.5
13.5
15
a The emission spectrum for all compounds was collected at an
excitation wavelength of 380 nm.
the molecular weights of the copolymers are given in
Table 1. Copolymers 15a-c showed glass transition
temperatures around -15 °C a clear indication of the
significant more flexible polymer backbone, in contrast
to the above-described poly(norbornene)s. Upon forma-
tion of the lanthanide complex, glass transition tem-
peratures of the copolymers increased to around -5 °C.

8676 Meyers et al.
Macromolecules, Vol. 38, No. 21, 2005
Scheme 6. Copolymerization of 12 with 14 and
Formation of the Corresponding Ybq3 Copolymers
Figure 1. UV/vis absorption spectra of 3 (blue), 7 (red), 9a
(green), and 10a (yellow).
Figure 2. Photoluminescence of Ybq3 copolymers: 10a 1:5
(yellow), 10b 1:10 (blue), and 10c 1:20 (green).
the metal to the polymers through side chain quinoline
ligands. This absorption characteristic was used to
excite the copolymers 16a-c for the photoluminescence
study.
Photoluminescence. The solution photolumines-
cence of the Ybq3 copolymers (10a-c, 16a-c) was
measured to determine the effect of the concentration
of Ybq3 in the polymer on the emission properties. While
all metalated copolymers were soluble in chloroform, no
emission was detected in pure chloroform. However,
emission was observed when a mixture of chloroform
and DMSO was used. As previously reported, DMSO
replaces any water molecules coordinated to the lan-
thanide metal.23 The emission of lanthanide-containing
compounds in chloroform is dramatically lower than the
emission of the same compound in DMSO. In solutions
of lanthanide complexes, relatively small energy con-
tents of the long wavelength electronic gap can be
readily dissipated by solvent. If the energy of the gap
between the lowest fluorescence-emitting level and the
nearest nonfluorescence level is dissipated, radiationless
decay occurs. In water, the O-H stretching vibration
is very efficient in dissipating energy. If the O-H
vibration can be replaced by a less energetic vibration,
quenching becomes less efficient. For example, deuter-
ated water is a less efficient quencher due to the lower
energy of the O-D vibration. The same holds true for
the SdO stretching vibrations of DMSO that are less
efficient in quenching the emission than the O-H
stretch of water.23,44-47
Table 1 and Figures 2 and 3 (only infrared region)
show the emission spectra of polymers 10 and 16. In
all cases two emission maxima were observed for the
metalated polymers. One maximum was in the visible
region (green emission around 510-515 nm) that stems
from the emission of the hydroxyquinoline ligand. The
second maxima are in the near-infrared region (around
970 nm) and can be attributed to the ytterbium-
hydroxyquinoline complex. In contrast, the nonmeta-
lated polymers 9 and 15 showed only green emission in
the visible. It is important to note that the polymers
UV/Vis Absorption. The absorption spectra of 3, 7,
9a, and 10a are shown in Figure 1 and are tabulated
in Table 1. The absorption spectrum of the copolymer
9a is a combination of both monomers 3 and 7. The
absorption of the ytterbium-containing copolymer 10a
is almost identical to that of 9a as a result of the
shielding effect of the ligands surrounding the ytter-
bium-metal center. Because of this shielding effect, the
metal center itself cannot be excited directly. Instead,
the quinoline ligands that are coordinated to the metal
center and show absorption maxima around 385 nm and
were excited, and the energy transfer to the lanthanide
metal centers was recorded as photoluminescence spec-
tra. The same behavior was observed for cyclooctene
compounds. Table 1 tabulates the absorption charac-
teristics of 12, 14, 15a-c, and 16a-c. Complexation of
compounds 15a-c with ytterbium produced absorption
bands around 400 nm that indicate the coordination of

Macromolecules, Vol. 38, No. 21, 2005
Poly(norbornene)s and Poly(cyclooctene)s 8677
Conclusions
In this contribution, we have demonstrated the at-
tachment of lanthanide complexes that have been
suggested as important materials for electronic applica-
tions, to poly(norbornene) and poly(cyclooctene) back-
bones. In particular, we have prepared and studied
poly(norbornene) and poly(cyclooctene) copolymers with
pendant carbazole and tris(8-hydroxyquinoline)ytter-
bium complexes. The two polymer backbones investi-
gated have different and distinct physical properties.
While copolymers of poly(norbornene) have low poly-
dispersity indices and high glass transition tempera-
tures, copolymers of poly(cyclooctene) displayed signifi-
cantly higher polydispersity indices as a result of the
less controlled polymerization and significantly lower
glass transition temperatures. Upon excitation of the
quinoline ligands of the metal complexes, all metalated
copolymers emit light in the infrared region. We have
shown that neither of the two backbones studied
interferes with the emission of the lanthanide complex.
Comonomers containing pendant carbazole groups were
incorporated into the copolymers to potentially increase
charge mobility and to also improve the solubility of the
final polymeric material. Finally, since carbazole is also
a known hole-transport material, it may enhance the
performance of future electronic devices made with our
copolymeric material.
Figure 3. Photoluminescence of Ybq3 copolymers: 16a 1:5
(yellow), 16b 1:10 (blue), and 16c 1:20 (green).
Figure 4. Visible region of the photoluminescence of copoly-
mers 9a (black) (before) and 10a (red) (after metalation with
ytterbium).
were excited at the hydroxyquinoline excitation at 380
nm. As described in the introduction, no direct excita-
tion of the metal center is possible. Therefore, any
observed emission from the metal center must stem
from energy transfer between the ligands and the Yb
metal center. To quantify this energy transfer, we
carried out photoluminescence studies of 9a and 10a
under identical conditions (solvent, concentration, etc.)
and compared the relative intensities of the green
emission maxima at 510 nm (Figure 4). After attach-
ment of the lanthanide, we expected a decrease in the
intensity of the quinoline emission and the observation
of a new emission band in the infrared region due to
energy transfer from the quinoline ligand into the metal
center. Indeed, as outlined in Figure 4, the emission
intensity at 510 nm for the 1:5 Ybq3 copolymer 10a was
∼40% lower in comparison to its nonmetalated 1:5
copolymer analogous 9a. This result suggests that a
significant portion of the energy was transferred to the
lanthanide metal instead of radiatively relaxing back
to the ground state.
Acknowledgment. Financial support has been pro-
vided by the National Science Foundation (ChE-
0239385) and Albemarle Corp. M.W. gratefully acknowl-
edges a 3M Untenured Faculty Award, a DuPont Young
Professor Award, A Camille Dreyfus Teacher/Scholar
Award, an Alfred P Sloan Fellowship, and a Blanchard
Assistant Professorship.
References and Notes
(1) Adachi, C.; Tsutsui, T.; Saito, S. Appl. Phys. Lett. 1990, 56,
799-801.
(2) Antoniadis, H.; Roitman, D.; Miller, J. U.S. Patent 5,719467,
1998.
(3) Baigent, D. R.; Greenham, N. C.; Gruner, J.; Marks, R. N.;
Friend, R. H.; Moratti, S. C.; Holmes, A. B. Synth. Met. 1994,
67, 3-10.
(4) Berggren, M.; Inganas, O.; Gustafsson, G.; Rasmusson, J.;
Andersson, M. R.; Hjertberg, T.; Wennerstrom, O. Nature
(London) 1994, 372, 444-446.
(5) Burroughes, J. H.; Bradley, D. D. C.; Brown, A. R.; Marks,
R. N.; MacKay, K.; Friend, R. H.; Burn, P. L.; Holmes, A. B.
Nature (London) 1990, 347, 539-541.
(6) Cacialli, F.; Friend, R. H.; Moratti, S. C.; Holmes, A. B. Synth.
Met. 1994, 67, 157-160.
As shown in Figures 2 and 3, as the chromophore
density in the polymer decreases, the emission intensity
also decreases. The integrated emission signal of the
1:20 copolymer was approximately half of that of the
1:10 copolymer, which was half of that of the 1:5
copolymer, indicating a linear relationship between the
concentration of lanthanide-quinolate in the copolymer
and the emission intensity. Note that the curves shown
in Figures 2 and 3 are corrected for concentration.
However, when measuring the photoluminescence of a
nonsupported Ybq3 molecule (not shown for clarity), the
emission intensity was significantly lower than the
emission of the 1:20 Ybq3 copolymer. This indicates that
not only does the polymer backbone not interfere with
the emission properties of the lanthanide quinolate, but
the polymer backbone actually prevents self-quenching
of the Ybq3 chromophore, a reported occurrence for
lanthanide-based materials.30
(7) Chen, C. H.; Shi, J. Coord. Chem. Rev. 1998, 171, 161-174.
(8) Friend, R. H.; Gymer, R. W.; Holmes, A. B.; Burroughes, J.
H.; Marks, R. N.; Taliani, C.; Bradley, D. D. C.; Santos, D.
A. D.; Bre´das, J. L.; Lo¨gdlund, M.; Salaneck, W. R. Nature
(London) 1999, 397, 121-128.
(9) Greiner, A. Polym. Adv. Technol. 1998, 9, 371-389.
(10) Howard, W. E.; Prache, O. F. IBM J. Res. Dev. 2001, 45, 115-
127.
(11) Kido, J.; Kimura, M.; Nagai, K. Science 1995, 267, 1332-
1334.
(12) Sheats, J. R.; Antoniadis, H.; Hueschen, M.; Leonard, W.;
Miller, J.; Moon, R.; Roitman, D.; Stocking, A. Science 1996,
273, 884-888.
(13) Tang, C. W.; VanSlyke, S. A. Appl. Phys. Lett. 1987, 51, 913-
915.
(14) Khreis, O. M.; Curry, R. J.; Somerton, M.; Gillin, W. P. J.
Appl. Phys. 2000, 88, 777-780.
(15) Gillin, W. P.; Curry, R. J. Appl. Phys. Lett. 1999, 74, 798-
799.
(16) Curry, R. J.; Gillin, W. P. Appl. Phys. Lett. 1999, 75, 1380-
1381.

8678 Meyers et al.
Macromolecules, Vol. 38, No. 21, 2005
(17) Hong, Z. R.; Liang, C. J.; Li, R. G.; Zhao, D.; Fan, D.; Li, W.
L. Thin Solid Films 2001, 391, 122-125.
(31) Iwamuro, M.; Adachi, T.; Wada, Y.; Kitamura, T.; Nakashima,
N.; Yanagida, S. Bull. Chem. Soc. Jpn. 2000, 73, 1359-1363.
(32) Meyers, A.; Weck, M. Macromolecules 2003, 36, 1766-1768.
(33) Meyers, A.; Weck, M. Chem. Mater. 2004, 16, 1183-1188.
(34) Meyers, A.; South, C.; Weck, M. Chem. Commun. 2004, 1176-
1177.
(18) Sun, R. G.; Wang, Y. Z.; Zheng, Q. B.; Zhang, H. J.; Epstein,
A. J. J. Appl. Phys. 2000, 87, 7589-7591.
(19) Kawamura, Y.; Wada, Y.; Yanagida, S. Jpn. J. Appl. Phys.
2001, 40, 350-356.
(20) Slooff, L. H.; Polman, A.; Cacialli, F.; Friend, R. H.; Hebbink,
G. A.; van Veggel, F. C. J. M.; Reinhoudt, D. N. Appl. Phys.
Lett. 2001, 78, 2122-2124.
(21) Harrison, B. S.; Foley, T. J.; Knefely, A. S.; Mwaura, J. K.;
Cunningham, G. B.; Kang, T.-S.; Bouguettaya, M.; Boncella,
J. M.; Reynolds, J. R.; Schanze, K. S. Chem. Mater. 2004,
16, 2938-2947.
(22) Vicinelli, V.; Ceroni, P.; Maestri, M.; Balzani, V.; Gorka, M.;
Vo¨gtle, F. J. Am. Chem. Soc. 2002, 124, 6461-6468.
(23) van Deun, R.; Fias, P.; Nockemann, P.; Schepers, A.; Parac-
Vogt, T. N.; van Hecke, K.; van Meervelt, L.; Binnemans, K.
Inorg. Chem. 2004, 43, 8461-8469.
(24) Baigent, D. R.; Hamer, P. J.; Friend, R. H.; Moratti, S. C.;
Holmes, A. B. Synth. Met. 1995, 71, 2175-2176.
(25) Suzuki, H.; Hattori, Y.; Iizuka, T.; Yuzawa, K.; Matsumoto,
N. Thin Solid Films 2003, 438-439, 288-293.
(26) Desurvire, E. Phys. Today 1994, 47, 20-27.
(27) Rizzo, F.; Papagni, A.; Meinardi, F.; Tubino, R.; Ottonelli, M.;
Musso, G. F.; Dellepiane, G. Synth. Met. 2004, 147, 143-
147.
(35) Schwab, P.; France, M. B.; Ziller, J. W.; Grubbs, R. H. Angew.
Chem., Int. Ed. Engl. 1995, 34, 2039-2041.
(36) Bielawski, C. W.; Grubbs, R. H. Angew. Chem., Int. Ed. 2000,
39, 2903-2906.
(37) Sanford, M. S.; Ulman, M.; Grubbs, R. H. J. Am. Chem. Soc.
2001, 123, 749-750.
(38) Love, J. A.; Morgan, J. P.; Trnka, T. M.; Grubbs, R. H. Angew.
Chem., Int. Ed. 2002, 41, 4035-4037.
(39) Trnka, T. M.; Grubbs, R. H. Acc. Chem. Res. 2001, 34, 18-
29.
(40) Handbook of Metathesis; Wiley VCH: Weinheim, 2003; Vol.
3.
(41) Burckhalter, J. H.; Leib, R. I. J. Org. Chem. 1961, 26, 4078-
4083.
(42) Stubbs, L. P.; Weck, M. Chem.sEur. J. 2003, 9, 992-999.
(43) Hillmyer, M. A.; Laredo, W. R.; Grubbs, R. H. Macromolecules
1995, 28, 6311-6316.
(44) Hasegawa, Y.; Kimura, Y.; Murakoshi, K.; Wada, Y.; Kim,
J.-H.; Nakashima, N.; Yamanaka, T.; Yanagida, S. J. Phys.
Chem. 1996, 100, 10201-10205.
(28) Pitois, C.; Vestberg, R.; Rodlert, M.; Malmstro¨m, E.; Hult,
A.; Lindgren, M. Opt. Mater. 2002, 21, 499-506.
(29) Curry, R. J.; Gillin, W. P. Synth. Met. 2000, 111-112, 35-
38.
(30) Curry, R. J.; Gillin, W. P. Curr. Opin. Solid State Mater. Sci.
2001, 5, 481-486.
(45) Stein, G.; Wu¨rzberg, E. J. Chem. Phys. 1975, 62, 208-213.
(46) Kawa, M.; Takahagi, T. Chem. Mater. 2004, 16, 2282-2286.
(47) Hasegawa, Y.; Yamamuro, M.; Wada, Y.; Kanehisa, N.; Kai,
Y.; Yanagida, S. J. Phys. Chem. A 2003, 107, 1697-1702.
MA050923K