Construction of functional macromolecules with well-defined structures by indium-catalyzed three-component polycoupling of alkynes, aldehydes, and amines

Article abstract of DOI:10.1021/ma4005346

We present here a new programmable polymerization route for the synthesis of new conjugated polymers via one-pot reaction route. The three-component polycoupling reactions of terephthalaldehyde and dibenzylamine with 4,4′-diethynyl-1,1′-biphenyl, bis(4-ethynylphenyl)dimethylsilane, 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene, N,N-bis(4-ethynylphenyl)aniline, or 2,5-bis(4-ethynylphenyl)-1,1-dimethyl-3,4-diphenylsilole are catalyzed by indium(III) chloride in o-xylene at 140 C, affording soluble polymers with well-defined structures and high molecular weights (M_w up to 51 200) in high yields (up to 96.9%). Model reaction was carried out to elucidate the chemical structures of the polymers. The resulting polymers are processable and enjoy high thermal stability. The polymers carrying tetraphenylethene and silole units are weakly emissive in solutions but become strong emitters when aggregated in poor solvents or fabricated as thin films in the solid state, displaying a phenomenon of aggregation-enhanced emission characteristic. Thin films of the polymers show high refractive indices (n = 1.7529-1.6041) in a wide wavelength region of 400-1600 nm with low optical dispersions (D′ down to 0.005). The polymers are readily metallified by complexation of their triple bonds with cobalt octacarbonyls. Pyrolysis of the resulting organometallic polymers at high temperature under inert atmosphere generates nanostructured ceramics with high magnetic susceptibility (M_s up to 80.7 emu/g) and near-zero coercivity (H_c down to 0.19 kOe).

Full text of DOI:10.1021/ma4005346

Article
pubs.acs.org/Macromolecules
Construction of Functional Macromolecules with Well-Defined
Structures by Indium-Catalyzed Three-Component Polycoupling of
Alkynes, Aldehydes, and Amines
Carrie Y. K. Chan,† Nai-Wen Tseng,† Jacky W. Y. Lam,*,† Jianzhao Liu,† Ryan T. K. Kwok,†
and Ben Zhong Tang*,†,‡,§
†Department of Chemistry, Institute for Advanced Study, Institute of Molecular Functional Materials and Division of Biomedical
Engineering, The Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China
‡Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials
and Devices, South China University of Technology (SCUT), Guangzhou 510640, China
§HKUST-Shenzhen Research Institute, No. 9 Yuexing 1st RD, South Area, Hi-tech Park, Nanshan, Shenzhen 518057, China
S
* Supporting Information
ABSTRACT: We present here a new programmable polymer-
ization route for the synthesis of new conjugated polymers via
one-pot reaction route. The three-component polycoupling
reactions of terephthalaldehyde and dibenzylamine with 4,4′-
diethynyl-1,1′-biphenyl, bis(4-ethynylphenyl)dimethylsilane, 1,2-
bis(4-ethynylphenyl)-1,2-diphenylethene, N,N-bis(4-
ethynylphenyl)aniline, or 2,5-bis(4-ethynylphenyl)-1,1-dimethyl-
3,4-diphenylsilole are catalyzed by indium(III) chloride in o-
xylene at 140 °C, affording soluble polymers with well-defined
structures and high molecular weights (Mw up to 51 200) in high
yields (up to 96.9%). Model reaction was carried out to elucidate the chemical structures of the polymers. The resulting polymers
are processable and enjoy high thermal stability. The polymers carrying tetraphenylethene and silole units are weakly emissive in
solutions but become strong emitters when aggregated in poor solvents or fabricated as thin films in the solid state, displaying a
phenomenon of aggregation-enhanced emission characteristic. Thin films of the polymers show high refractive indices (n =
1.7529−1.6041) in a wide wavelength region of 400−1600 nm with low optical dispersions (D′ down to 0.005). The polymers
are readily metallified by complexation of their triple bonds with cobalt octacarbonyls. Pyrolysis of the resulting organometallic
polymers at high temperature under inert atmosphere generates nanostructured ceramics with high magnetic susceptibility (Ms
up to 80.7 emu/g) and near-zero coercivity (Hc down to 0.19 kOe).
fashion with high atom economy2 and diminution of waste
INTRODUCTION
■
production due to the decrease in the number of synthetic or
Development of new methodologies for the synthesis of
polymers with novel structures and unique properties is a
isolation steps.3 The transition-metal-catalyzed reaction of
alkyne, aldehyde, and amine is one of the representative
fundamental important area in macromolecular science. Natural
examples of the MCRs (Scheme 1). Starting from 2002, Li and
co-workers discovered one-pot three-component coupling of
alkyne, aldehyde, and amine (A3-coupling) using different types
of transition-metal complexes, including Cu−Ru,4 Co,5 and
Cu.6 In 2009, efficient indium-catalyzed A3-coupling via C−H
polymers such as DNA and protein have well-defined primary
structures with ordered sequences of monomer units. In
contrast, most synthetic polymers have random structures and
are accessed via one- or two-component polymerization route.
Some regular polymers have been prepared, but their
preparation is difficult and requires skill-demanding techniques
such as living polymerization. Development of programmable
polymerization reaction is thus of interest because it may
generate biomimic polymers with unique materials properties
and potential practical applications.
Scheme 1. Alkyne-Based Three-Component Coupling
Reaction
Organic chemists have developed various multicomponent
coupling reactions (MCRs) with an aim to access complex
compounds or biological-active intermediates from simple
precursors. These chemical processes involve three or more
reactants for the inherent formation of several covalent bonds
in one operation1 and proceed in chemo- and regioselective
Received: March 13, 2013
Revised: April 12, 2013
© XXXX American Chemical Society
A
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
Scheme 2. Indium-Catalyzed Polycoupling of Diyne, Dialdehyde, and Amine
bond activation was reported by Wang.7 The reaction
underwent smoothly without any cocatalyst or activator and
afforded the corresponding products in nearly quantitative
yields with only water as byproduct.
tech applications and help sharpen the competitive edge of the
technology industries.
EXPERIMENTAL SECTION
■
Despite the advantages of the MCRs, little efforts have been
made to develop these organic reactions into useful tools for
the synthesis of sequentially well-defined polymers. Tomita and
co-workers developed Pd-catalyzed ternary polycondensations
to obtain highly functionalized polymers such as poly(arylene
vinylene)s containing building blocks originated from three
kinds of monomers in high yields.8 In 2008, Endo et al.
discovered three-component polyaddition through combination
of chemoselective nucleophilic and radical additions.9 The
polymerization results, however, were not satisfactory. The
polydispersity indexes of the polymers were as large as 6.81,
though their molecular weights were around 12 000. In 2012, Li
et al. reported the one-pot synthesis of polyamides with various
functional groups via Passerini reaction of carboxylic acids,
dialdehydes, and diisocyanides.10
Our research group has been working on the construction of
conjugated macromolecules using acetylenic molecules as
building blocks.11 Utilizing monoynes, diynes, and triynes as
monomers, we succeeded in the synthesis of a large variety of
functionalized polyacetylenes,12 polydiynes,13 polyarylenes,14
polytriazoles,15 poly(vinylene sulfide)s,16 poly(silylene
vinylene)s,17 poly(arylene chlorovinylene)s,18 and poly(arylene
ynonylene)s19 with linear and hyperbranched structures and
regio- and stereoregularity by metathesis, cyclotrimerization,
coupling, addition, and “click” polymerizations. We found that
the polymers showed unique electronic, optical, photonic,
mesomorphic, and biological properties, which enabled them to
find an array of high-tech applications. In this work, we explore
the potential of developing the three-component coupling
reaction of alkyne, aldehyde, and amine into versatile alkyne-
based polymerization technique for the synthesis of novel
polymers with structural regularity and advanced functionality
(Scheme 2). Since the new polymers P1a−e/2/3 possess
heteroatoms and unsaturated vinyl and ethynyl units, they are
expected to show high refractive indices. The polymers may
readily form complexes with metallic species, and the resulting
organometallic polymers may serve as processable precursors to
magnetic ceramics upon pyrolysis. It is anticipated that
polymers with advanced materials properties will find high-
Materials and Instrumentation. Tetrahydrofuran (THF) was
distilled from sodium benzophenone ketyl under nitrogen immediately
prior to use. All the chemicals and other reagents were purchased from
Aldrich and used as received without further purification. Monomers
1a−e and 4-ethynylbiphenyl (8) were prepared according to the
literature procedures.20 Weight-average molecular weights (Mw) and
polydispersities (Mw/Mn) of the polymers were estimated by a Waters
gel permeation chromatography (GPC) system equipped with a
Waters 515 HPLC pump, a set of Styragel columns (HT3, HT4, and
HT6; MW range 102−107), a column temperature controller, a Waters
486 wavelength-tunable UV−vis detector, a Waters 2414 differential
refractometer, and a Waters 2475 fluorescence detector. The polymer
solutions were prepared in THF (∼2 mg/mL) and filtered through
0.45 μm PTFE syringe-type filters before being injected into the GPC
system. THF was used as eluent at a flow rate of 1.0 mL/min. The
column temperature was maintained at 40 °C, and the working
wavelength of the UV−vis detector was set at 254 nm. A set of
monodisperse polystyrene standards (Waters) covering MW range of
103−107 were used for MW calibration.
1H and 13C NMR spectra were measured on a Bruker AV 300
spectrometer in deuterated chloroform using tetramethylsilane (TMS;
δ = 0) as internal reference. High-resolution mass spectra (HRMS)
were recorded on a GCT premier CAB048 mass spectrometer
operating in MALDI-TOF mode. IR spectra were recorded on a
PerkinElmer 16 PC FTIR spectrophotometer. UV spectra were
measured on a Milton Ray Spectronic 3000 Array spectrophotometer.
Photoluminescence (PL) spectra were recorded on a PerkinElmer LS
55 spectrofluorometer. Fluorescence quantum yields (ΦF) of thin films
of the polymers were measured on a calibrated integrating sphere.
Thermogravimetric analysis (TGA) was carried on a TA TGA Q5000
under nitrogen at a heating rate of 10 °C/min. Refractive indices (RI
or n) of the polymer films were measured on a prism coupler
(Metricon, model PC-2100) equipped with a He−Ne laser light
source (wavelengths: 403, 473, 632.8, 934, and 1534 nm). The
birefringence (Δn) was calculated as a difference between the nTE (in-
plane) and nTM (out-of-plane) values.
X-ray photoelectron spectroscopy (XPS) experiments were
conducted on a PHI 5600 spectrometer (Physical Electronics), and
the core level spectra were measured using a monochromatic Al Kα X-
ray source (hν = 1386.6 eV). The analyzer was operated at 23.5 eV
pass energy, and the analyzed area was 800 μm in diameter. The
energy-dispersion X-ray (EDX) analyses were performed on a JEOL-
6300 SEM system with quantitative elemental mapping and line scan
B
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
capacities operating at an accelerating voltage of 15 kV. Structures of
the ceramics were investigated on a high-resolution transmission
electron microscopy (HRTEM) JEOL 2010F TEM. The X-ray
diffractograms were obtained on a Philips PW 2830 powder
diffractometer using monochromatized X-ray beam from a nickel-
filtered Cu Kα radiation (λ = 1.5406 Å). Magnetization curves were
recorded on a Lake Shore 7037/9509-P vibrating sample magneto-
meter at room temperature.
Preparation of Nanoaggregates. Stock THF solutions of the
polymers with a concentration of 10−3 M were prepared. Aliquots of
the stock solutions were transferred to 10 mL volumetric flasks. After
appropriate amounts of THF were added, water was added dropwise
under vigorous stirring to furnish 10−5 M solutions with different water
contents (0−95 vol %). The PL measurements of the resulting
solutions were then performed immediately.
Polymer Synthesis. All the polymerization reactions and
manipulations were carried out under nitrogen using the standard
Schlenk technique in a vacuum line system or an inert atmosphere
glovebox (Vacuum Atmosphere), except for the purification of the
polymers, which was done in an open atmosphere. The three-
component polycoupling reactions were catalyzed by indium(III)
chloride in o-xylene. A typical experimental procedure for the
polycoupling of 1a with 2 and 3 is given below as an example.
Into a 20 mL test tube equipped with a magnetic stirrer were placed
1a (0.2 mmol), 2 (0.2 mmol), 3 (0.44 mmol), InCl3 (20 mol %), and 4
Å molecular sieve (∼70 mg) in 2 mL of o-xylene. The reaction mixture
was stirred on an oil bath at 140 °C under nitrogen for 20 h. The
solution was then cooled to room temperature, diluted with 5 mL of
chloroform, and added dropwise to 300 mL of methanol/hexane
mixture (1:5 v/v) through cotton filter under stirring to precipitate the
polymer and meanwhile remove the unreacted monomers and catalytic
species. The polymer was filtered by a Gooch crucible, washed with
methanol and hexane several times, and dried in vacuum overnight at
room temperature to a constant weight.
Characterization Data for P1a/2/3. Yellow solid; yield 96.9%
(Table 4, no. 1). Mw 20 440; Mw/Mn 1.66 (GPC, polystyrene
calibration). IR (KBr), υ (cm−1): 3061, 3028, 2923, 2884, 2832, 2807,
1662, 1603, 1494, 1453. 1H NMR (300 MHz, CDCl3), δ (TMS, ppm):
7.73, 7.43, 7.31, 4.96, 3.81, 3.57. 13C NMR (75 MHz, CDCl3), δ
(TMS, ppm): 140.87, 140.19, 139.12, 133.21, 129.61, 128.99, 127.69,
123.29, 89.04, 86.65, 56.65, 55.39.
P1b/2/3. Yellow solid; yield 94.0% (Table 4, no. 3). Mw 25 940;
Mw/Mn 1.76 (GPC, polystyrene calibration). IR (KBr), υ (cm−1):
3061, 3025, 2953, 2830, 2805, 1664, 1594, 1494, 1453. 1H NMR (300
MHz, CDCl3), δ (TMS, ppm): 8.01, 7.72, 7.57, 7.40, 7.28, 4.93, 3.77,
3.51, 0.61. 13C NMR (75 MHz, CDCl3), δ (TMS, ppm): 140.16,
139.81, 139.16, 139.07, 138.98, 134.83, 131.93, 129.58, 128.97, 128.75,
128.40, 127.69, 124.78, 89.27, 86.42, 56.58, 55.35, −1.82.
139.21, 132.43, 132.34, 130.63, 129.59, 128.96, 128.34, 127.65, 127.24,
120.99, 89.49, 85.58, 56.55, 55.31, −3.04.
Model Reaction. N,N-Dibenzyl-3-(4-biphenylyl)-1-phenylprop-2-
ynylamine (4) was prepared as a model compound by coupling
reaction of 4-ethynylbiphenyl (8), benzaldehyde (9), and dibenzyl-
amine (3). The experimental procedure was similar to that for the
syntheses of P1a/2/3 described above. White solid; yield 58.3%. IR
(KBr), υ (cm−1): 3061, 3027, 2804, 1600, 1489, 1106, 841, 746, 695.
1H NMR (300 MHz, CDCl3), δ (TMS, ppm): 7.76−7.69 (m, 4H),
7.65−7.62 (m, 4H), 7.48−7.44 (m, 6H), 7.39−7.30 (m, 8H), 7.27−
7.24 (m, 2H), 4.96 (s, 1H), 3.83−3.79 (d, 2H), 3.58−3.54 (d, 2H).
13C NMR (75 MHz, CDCl3), δ (TMS, ppm): 141.74, 141.11, 140.23,
139.85, 133.07, 129.59, 128.98, 128.81, 128.35, 128.18, 127.79, 127.76,
127.71, 122.84, 89.19, 86.12, 56.80, 55.34. HRMS (MALDI-TOF): m/
z 463.2300 [M+, calcd 463.2303]. Melting point: 125.1 °C.
Metal Complexation. In a typical run for the preparation of
cobalt−polymer complex Co−P1a/2/3, 80 mg of P1a/2/3 was
dissolved under nitrogen in 5 mL of THF in a 30 mL round-bottom
flask. 5 mL of a THF solution of Co2(CO)8 (118.1 mg, 0.34 mmol, or
1.5 mol equiv to the CC units of P1a/2/3) was added. The mixture
was stirred at room temperature for 1 h, after which the THF solvent
was evaporated to about half of its original volume under reduced
pressure. The mixture was then added dropwise into a large amount of
hexane (∼200 mL) through a cotton filter under stirring. The
precipitates were washed with hexane for three times and dried under
vacuum to a constant weight. 140.3 mg of brown solid was obtained.
IR (KBr), υ (cm−1): 2089, 2051, 2025 (CO).
Co−P1b/2/3. It was prepared from 80 mg of P1b/2/3 with
Co2(CO)8 (108.7 mg, 0.32 mmol). Brown solid (126.9 mg). IR (KBr),
υ (cm−1): 2089, 2052, 2026 (CO).
Co−P1c/2/3. It was prepared from 60 mg of P1c/2/3 with
Co2(CO)8 (70.3 mg, 0.20 mmol). Brown solid (96.6 mg). IR (KBr), υ
(cm−1): 2088, 2051, 2025 (CO).
Co−P1d/2/3. It was prepared from 80 mg of P1d/2/3 with
Co2(CO)8 (104.2 mg, 0.30 mmol). Brown solid (147.7 mg). IR (KBr),
υ (cm−1): 2088, 2050, 2023 (CO).
Co−P1e/2/3. It was prepared from 60 mg of P1e/2/3 with
Co2(CO)8 (64.3 mg, 0.19 mmol). Brown solid (97.6 mg). IR (KBr), υ
(cm−1): 2088, 2051, 2025 (CO).
Pyrolytic Ceramization. Ceramics MC1−MC5 were fabricated
from the precursors Co−P1a−e/2/3 by pyrolysis in a Lindberg/Blue
tube furnace with a heating capacity up to 1700 °C. In a typical
ceramization experiment, 100 mg of Co−P1a/2/3 was placed in a
porcelain crucible, which was heated to 1000 °C at a heating rate of 10
°C/min under a steam of nitrogen (0.2 L/min). The sample was
sintered for 1 h at 1000 °C, and black ceramic MC1 was obtained in
45.9% yield (45.9 mg) after cooling.
P1c/2/3. Yellow solid; yield 94.7% (Table 4, no. 4). Mw 30 000;
Mw/Mn 2.38 (GPC, polystyrene calibration). IR (KBr), υ (cm−1):
3059, 3027, 2924, 2883, 2831, 2807, 1663, 1601, 1494, 1443. 1H NMR
(300 MHz, CDCl3), δ (TMS, ppm): 7.75, 7367, 7.37, 7.25, 7.23, 7.20,
7.12, 4.88, 3.75, 3.72, 3.51. 13C NMR (75 MHz, CDCl3), δ (TMS,
ppm): 144.39, 144.30, 144.05, 143.92, 141.56, 140.18, 139.17, 139.09,
132.26, 132.07, 130.26, 129.56, 128.94, 128.72, 128.50, 127.65, 127.48,
122.08, 121.96, 89.31, 86.02, 85.82, 56.54, 55.31.
RESULTS AND DISCUSSION
■
Polymerizatiom Reaction. To explore the one-pot A3-
coupling of diyne, dialdehyde, and secondary amine into a
useful tool for the preparation of sequentially well-defined
polymers, we prepared a group of functional diynes (1a−1e)
according to our previous published papers.20 On the other
hand, terephthalaldehyde 2 and dibenzylamine 3 were
commercially available and purified before use.
To search for optimum conditions for the polymerization, we
first studied the solvent effect on the A3-coupling reaction using
4,4′-diethynyl-1,1′-biphenyl (1a), 2, and 3 as monomers. The
polymerization was carried out in the presence of indium(III)
chloride at high temperature for 20 h under inert atmosphere.
As shown in Table 1, the solvent exerts strong effect on the
reaction. Among the tested solvents, o-xylene was the most
suitable medium for the polycoupling reaction, giving a soluble
polymeric product with the highest molecular weight (Mw = 17
400) in the highest yield (99.3%) (Table 1, no. 6). Satisfactory
results are also obtained in benzene, 1,2-dichloroethane, and
P1d/2/3. Yellow solid; yield 93.0% (Table 4, no. 5). Mw 22 820;
Mw/Mn 2.12 (GPC, polystyrene calibration). IR (KBr), υ (cm−1):
3060, 3027, 2923, 2883, 2831, 2806, 1659, 1594, 1503, 1453, 1318,
1
1273. H NMR (300 MHz, CDCl3), δ (TMS, ppm): 7.72, 7.52, 7.50,
7.41, 7.30, 7.24, 7.20, 7.19, 7.12, 7.11, 4.91, 3.79, 3.76, 3.54, 3.52. 13C
NMR (75 MHz, CDCl3), δ (TMS, ppm): 147.98, 147.53, 140.27,
139.31, 139.22, 133.73, 130.26, 129.60, 129.57, 129.10, 128.95, 128.74,
127.67, 125.96, 124.77, 124.20, 117.94, 89.13, 84.99, 56.60, 55.36.
P1e/2/3. Yellow solid; yield 90.0% (Table 4, no. 7). Mw 51 170;
Mw/Mn 3.33 (GPC, polystyrene calibration). IR (KBr), υ (cm−1):
3059, 3026, 2952, 2832, 2807, 1602, 1494, 1453, 1293, 1248. 1H NMR
(300 MHz, CDCl3), δ (TMS, ppm): 7.96, 7.81, 7.67, 7.39, 7.28, 7.22,
7.07, 6.98, 6.96, 6.86, 4.87, 3.76, 3.72, 3.51, 3.47, 0.55. 13C NMR (75
MHz, CDCl3), δ (TMS, ppm): 155.30, 142.24, 140.60, 140.25, 139.90,
C
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
the concentration effect of 3 on the polymerization was
evaluated. However, neither lower (0.120 M) nor higher (0.173
M) concentration of 3 is good for the polymerization. Instead, a
slightly excess amount of 3 (0.146 M) is enough to give a
soluble polymer with a high molecular weight in a high yield
(96.9%).
Table 1. Solvent Effect on the Polymerization of 1a with 2
and 3
a
b
b
entry
solvent
temp (°C)
yield (%)
Mw
Mw/Mn
1
2
3
4
5
6
7
8
benzene
DCE
80
80
81.5
82.1
trace
0
9500
6200
1.8
1.4
acetonitrile
dioxane
toluene
80
100
120
140
140
140
a
Table 4. Polymerization 1a−e with 2 and 3
80.0
99.3
45.0
28.6
7700
17400
5700
1.6
2.4
1.6
1.4
b
b
o-xylene
o-DCB
entry
monomer
yield (%)
Mw
Mw/Mn
1
2
1a
1b
1b
1c
1d
1e
1e
96.9
71.7
94.0
94.7
93.0
80.7
90.0
19 500
20 400
25 900
30 000
22 800
32 800
51 200
2.5
1.7
1.8
2.4
2.1
2.4
3.3
benzonitrile
4700
a
c
Carried out under nitrogen for 20 h. [1] = [2] = 0.067 M, [3] =
3
0.133 M, [InCl3] = 0.013 M. Abbreviation: DCE = 1,2-dichloroethane,
4
5
6
b
o-DCB = 1,2-dichlorobenzene. Determined by GPC in THF on the
basis of a polystyrene calibration.
c
7
toluene. Polymers with much lower molecular weights,
however, are isolated in lower yields when the polymerizations
were carried out in 1,2-dichlorobenzene and benzonitrile.
Acetonitrile and 1,4-dioxane are nonsolvents for the polymer-
ization as no or trace amount of polymeric products are
produced in these solvents.
We are then investigated the temperature effect on the
polymerization in o-xylene. At low temperature, no or trace
amount of polymer was obtained (Table 2, no. 2 and 3). At
a
Carried out under nitrogen in o-xylene at 140 °C for 20 h. [1] = [2]
b
= 0.067 M, [3] = 0.146 M, [InCl3] = 0.013 M. Determined by GPC
in THF on the basis of a polystyrene calibration. [1] = [2] = 0.1 M,
[3] = 0.22 M, [InCl3] = 0.02 M.
c
The above investigation allows us to polymerize other
monomer combination under optimum conditions. Table 4
summarizes the polymerization results. All the polymerizations
proceed smoothly, giving polymers in high yields (71.7−94.7%)
with high molecular weights (Mw = 20 400−32 800). The
polymerization of 1b or 1e with 2 and 3 carried out at higher
reactant concentrations gives much better results: polymers
with higher molecular weights up to 51 200 are isolated in
higher yields up to 94.0%.
Synthesis of Model Compound. To confirm the
occurrence of the A3-polycoupling and gain insights into the
chemical structures of the polymers, we performed a model
reaction as shown in Scheme 3. 4-Trimethylsilylbiphenyl (7)
was prepared by lithium-mediated halogen-exchange reaction of
4-bromobiphenyl (5), followed by palladium-catalyzed Sonoga-
shira coupling of 6 with trimethylsilylacetylene. Subsequent
removal of the trimethylsilyl group of 7 in alcoholic K2CO3
solution generated the desirable product 8. Compound 8 was
then reacted with commercially available benzaldehyde (9) and
dibenzylamine (3) in the presence of InCl3 at 140 °C in o-
xylene to afford N,N-dibenzyl-3-(4-biphenylyl)-1-phenylprop-2-
ynylamine (4). The model compound 4 was characterized by
standard spectroscopic techniques from which satisfactory
analysis data corresponding to its expected molecular structure
were obtained (see Experimental Section for details).
Table 2. Temperature Effect on the Polymerization of 1a
a
with 2 and 3
b
b
entry
temp (°C)
yield (%)
Mw
Mw/Mn
1
2
100
120
140
0
65.0
99.3
5100
1.5
2.4
c
3
17400
a
Carried out under nitrogen in o-xylene for 20 h. [1] = [2] = 0.067 M,
b
[3] = 0.133 M, [InCl3] = 0.013 M. Determined by GPC in THF on
the basis of a polystyrene calibration. Data taken from Table 1, no. 6.
c
temperature close to the boiling point of o-xylene, a high
molecular weight polymer was obtained in nearly quantitative
yield. Clearly, the polymerization proceeds only when sufficient
energy is provided.
Control of stereoselectivity in the polymerization process is
very important for the synthesis of polymers with precise
structures. With respect to the catalyst loading, 0.013 M of
InCl3 is found to be optimal. However, no significant
improvement in the polymerization result was observed when
double amount of InCl3 was used for the polycoupling reaction
(Table 3, no. 3). Theoretically, the molar ratio between 1, 2,
and 3 should be in 1:1:2. To see whether it is really the case,
Structural Characterization. The polymeric products
were characterized spectroscopically. The IR spectrum of
P1a/2/3 is given in Figure 1 as an example. The spectra of its
monomers (1a, 2, and 3) and model compound 4 are also
shown in the same figure for the purpose of comparison. The
absorption bands observed at 3237, 1693, and 3326 cm−1 are
associated with the C−H, CO, and N−H stretching
vibrations of 1a, 2, and 3, respectively. The bands, however, are
not observed in the spectrum of P1a/2/3, which is suggestive
of the occurrence of the polymerization.
Table 3. Concentration Effect on the Polymerization of 1a
a
with 2 and 3
b
b
entry
1
[3] (M)
[InCl3] (M)
yield (%)
Mw
Mw/Mn
0.120
0.133
0.133
0.146
0.173
0.013
0.013
0.026
0.013
0.013
98.0
99.3
97.8
96.9
80.2
10100
17400
17400
19500
8400
2.0
2.4
2.2
2.5
1.8
c
2
3
4
5
Figure 2 shows the 1H NMR spectra of P1a/2/3, its
monomers (1a, 2, and 3), and model compound 4. The
spectrum of P1a/2/3 shows no peaks at δ 3.14, 10.14, and 3.74,
which are assigned to the resonances of the acetylene, aldehyde,
and methylene protons of 1a, 2, and 3, respectively. Instead,
three new peaks emerge at δ 4.96, 3.81, and 3.57. By comparing
a
Carried out under nitrogen in o-xylene at 140 °C for 20 h. [1] = [2]
b
= 0.067 M. Determined by GPC in THF on the basis of a polystyrene
calibration. Data taken from Table 1, no. 6.
c
D
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
Scheme 3. Synthetic Route to Model Compound 4
Figure 1. FT-IR spectra of (A) 1a, (B) 2, (C) 3, (D) model
compound 4, and (E) polymer P1a/2/3.
with the model compound, these peaks are associated with the
resonances of the methylene protons connected to the nitrogen
atom. The absorption peaks of P1a/2/3 are much broader than
those of 4, indicative of its polymeric nature.
The 13C NMR spectrum of P1a/2/3 displays no resonance
peak of carbonyl carbon of 2 at δ 192.2. The resonances of the
acetylenic carbon atoms of 1a, however, shift from δ 83.4 and
78.1 to δ 89.0 and 86.6 after the polymerization. New peaks due
to the resonances of the methylene carbons next to the
nitrogen atom of 3 occur at δ 56.6 and 55.4. These results
demonstrate the precise structure of the polymer and are well
1
consistent with the results from IR and H NMR analyses.
Solubility and Thermal Stability. All the polymers
possess good solubility in common organic solvents, such as
dichloromethane, chloroform, tetrahydrofuran, and dioxane.
They also possess good film-forming ability and can be readily
fabricated into tough solid films by spin-coating and static-
casting processes. The thermal properties of the polymers are
evaluated by TGA analysis. As shown in Figure 4, all the
polymers enjoy high thermal stability, exhibiting 5% weight loss
at temperature (Td) from 249 to 281 °C. They also carbonize
in moderate yields up to 50% when they are heated to 800 °C.
Optical Properties. Figure 5 shows the UV spectra of
P1a−e/2/3 in dilute THF solutions. The absorption spectra
Figure 2. 1H NMR spectra of (A) 1a, (B) 2, (C) 3, (D) model
compound 4, and (E) polymer P1a/2/3 in chloroform-d. The solvent
peaks are marked with asterisks.
vary with the polymer structures and are peaked at 301−377
nm. Among the polymers, the absorption maximum of P1e/2/
3 is located at the longest wavelength, revealing that it
possesses the highest electronic conjugation. The photo-
E
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
3. Their fluorescence quantum yields (ΦF) determined in THF
solutions using 9,10-diphenylanthracene (ΦF = 90% in
cyclohexane) as standard are 7.9 and 10.9%, respectively,
whose values become much lower (ΦF = 3.3 and 5.5%) when
they are fabricated as thin films in the solid state. Such
aggregation-caused quenching (ACQ) effect poses an obstacle
to the development of efficient light emitters utilized as thin
films in real-world applications. We observed an exact opposite
phenomenon of aggregation-induced emission (AIE): a group
of propeller-like luminogenic molecules such as tetraphenyle-
thene (TPE) and hexaphenylsilole are nonemissive in solutions
but emit intensely in the aggregated state.22 The AIE effect
enables the luminogens to serve as excellent light-emitting
materials for organic light-emitting diodes with external
quantum efficiency close to the theoretical limit.22,23 Current
study mainly focuses on small AIE molecules with twisted
structures. To overcome the processing disadvantage of low
molecular weight compound, in this project, we synthesized
TPE and silole-containing diynes (1c and 1e) in order to
prepare new luminescent polymers with high solid-state ΦF
values.
Figure 6 depicts the change in the PL spectra of P1c/2/3 and
P1e/2/3 in THF solutions upon water addition. In diluted
THF solution (10 μM), P1c/2/3 emits a bluish-green light at
503 nm. Gradual addition of water, a nonsolvent for the
polymer, into its THF solution has progressively enhanced its
light emission without any change in the spectral profile,
demonstrating a phenomenon of aggregation-enhanced emis-
sion (AEE). Similar observation was found in P1e/2/3.
However, when more than 80% of water was present in the
THF solution, the suspension became unstable and favored the
formation of aggregates with “larger” sizes. This has lowered the
effective concentration of the solution and hence the PL
intensity. To have a quantitative concept, the ΦF values of P1c/
2/3 and P1e/2/3 in the solution state are measured. The
calculated values (1.5 and 2.9%) are much lower than those in
the solid thin film state (14.3 and 11.6%). Clearly, the polymers
are AEE-active.
Figure 3. 13C NMR spectra of (A) 1a, (B) 2, (C) 3, (D) model
compound 4, and (E) polymer P1a/2/3 in chloroform-d. The solvent
peaks are marked with asterisks.
We have proposed that restriction of intramolecular rotation
(RIR) is the main cause for the AIE effect.22 In the solution
state, the intramolecular rotation is active, which serves as
nonradiative pathways for the excitons to decay. In the
aggregated state, such rotation is restricted, which blocks the
relaxation channels and thus turns on the light emission of the
luminophore. The TPE and silole units in P1c/2/3 and P1e/2/
3 are linked together by covalent bonds, which have partially
restricted their rotation and hence made the polymers
somewhat emissive in THF solution. In THF/water mixture,
the RIR process is further activated, which has further enhanced
the light emission. Demonstratively, the present results provide
good examples on how to build highly emissive polymers with
good spectral stability in the aggregated state.
Light Refraction. Macroscopically processable polymers
with high refractive index (RI or n) are promising candidate
materials for an array of photonic applications, such as lenses,
prisms, waveguides, memories, and holographic image record-
ing systems.24 From the structural point of view, P1a−e/2/3
consist of polarizable aromatic rings, acetylene units, and
heteroatoms and thus may show high light refractivity. Indeed,
P1a−e/2/3 show high RI values of 1.7443−1.6200, 1.6845−
1.6052, 1.7529−1.6178, 1.7202−1.6180, and 1.6979−1.6041,
respectively, in a wide spectral region of 400−1600 nm. All the
polymers exhibit RI values higher than 1.60 from visible to
Figure 4. TGA thermograms of P1a−e/2/3 recorded under nitrogen
at a heating rate of 10 °C/min.
luminescence (PL) spectra of P1a−e/2/3 in dilute THF
solutions are centered at 385−509 nm, whereas those of
amorphous films are observed at the longer wavelengths of
486−590 nm (Table 5).
Conventional luminescent polymers often suffer from strong
interstrand interaction in the aggregated state, which quenches
and red-shifts their light emission.21 In the present work, a
similar phenomenon was also observed in P1a/2/3 and P1d/2/
F
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
Figure 5. (A) UV and (B) PL spectra of P1a−e/2/3 in THF solutions. Solution concentration: 10−5 M; excitation wavelength (nm): 300 (P1a/2/
3), 320 (P1b/2/3), 335 (P1c/2/3), 350 (P1d/2/3), and 380 (P1e/2/3).
As shown in Table 6, the νD and νD′ values of P1/2/3 lie in
the range of 18.4−32.1 and 52.7−208.5, corresponding to D
and D′ values of 0.031−0.054 and 0.005−0.019, respectively.
The low optical aberrations of the polymers coupled with their
high optical transparencies and light refractivities may enable
them to find technological applications as coating materials in
the advanced optical display systems, such as microlens
components for charge-coupled devices and high-performance
CMOS image sensors.24
Table 5. Optical Properties of P1a−e/2/3 in Solution
a
b
c
(Soln), Aggregated (Aggr), and Amorphous (Amor)
States
d
e
λab (nm)
λem (nm)
polymer
Soln
Soln (ΦF,S
)
Aggr
Amor (ΦF,F)
P1a/2/3
P1b/2/3
P1c/2/3
P1d/2/3
P1e/2/3
301
317
333
347
377
449 (7.9)
407 (2.1)
503 (1.5)
486 (3.3)
590 (3.7)
516 (14.3)
550 (5.5)
528 (11.6)
503
512
385, 464 (10.9)
Metal Complexation. Organometallic polymers are hybrid
macromolecules of organic and inorganic species and exhibit
unique magnetic, electronic, catalytic, sensoric, and optical
properties.27 They are also potential candidates as precursors
for the fabrication of nanostructured materials and advanced
ceramics.28 Acetylene triple bond is a versatile ligand and
commonly used in organometallic chemistry.29 Polymers P1a−
e/2/3 contain numerous triple bonds and should be readily
metallified through complexation with organometallic com-
pounds. When mixtures of P1a−e/2/3 and octacarbonyldico-
balt with a [Co2(CO)8]/[CC] ratio of 1.5:1 were stirred in
THF at room temperature, the solution darkened in color
accompanying with gas evolution. The mixture remained
homogeneous until the end of reaction and Co−P1a−e/2/3
were obtained by precipitation of the reaction mixtures into
hexane (Scheme 4). Although the cobalt-containing P1a−e/2/
3 dissolved readily during the complexation reaction, they
became insoluble after purification, probably due to the
formation of supramolecular aggregates during the precipitation
and the drying processes. Comparing the IR spectrum of P1a/
2/3 with that of its organometallic counterpart, new, strong
bands of typical cobalt carbonyl absorption appear at 2089,
2051, and 2025 cm−1, indicative of the integration of the
metallic species into the polymer structure at the molecular
level.
509 (2.9)
a
b
In dilute THF solution (10 μM). In THF/H2O mixture (1:9 by
c
d
e
volume). In solid thin film. Absorption maximum. Emission
maximum with quantum yields (ΦF, %) given in the parentheses.
ΦF,S = fluorescence quantum yield in THF solution determined using
9,10-diphenylanthracene (ΦF = 90% in cyclohexane) as standard; ΦF,F
= fluorescence quantum yield for thin film measured by a calibrated
integrating sphere.
infrared light region, which are much higher than those of the
conventional polymers,25 such as polystyrene (n = 1.602−
1.589), poly(methyl methacrylate) (n = 1.497−1.489), and
polycarbonate (n = 1.593−1.576). Low birefringence (down to
0.008 at a wavelength of 633 nm) is detected. Evidently, these
results highlight the feature of high refractivity of our polymers.
Chromatic Dispersion. For a material to be useful for
technological applications, its chromatic aberration should be
́
small. The Abbe number (νD) of a material is a measure of the
variation or dispersion in its RI with wavelength and is defined
as νD = (nD − 1)/(nF −nC), where nD, nF, and nC are the RI
values at Fraunhofer D, F, and C lines of 589.3, 486.1, and
656.3 nm, respectively.26 A modified Abbe
́
number (νD′) has
been proposed to evaluate the application potential of an
optical material, using its RI values at the nonabsorbing infrared
wavelengths of 1064, 1319, and 1550 nm. The modified Abbe
number is defined as νD′ = (n1319 − 1)/(n1064 − n1550), where
Pyrolytic Ceramization. The organometallic polymers are
pyrolyzed at 1000 °C for 1 h under nitrogen, which give MC1−
MC5 in satisfactory yields (45.9−51.1%) (Scheme 4). They are
magnetizable and can be readily attracted by a bar magnet,
encouraging us to study their properties.
́
n
1319, n1064, and n1550 are the RI values at 1319, 1064, and 1550
nm, respectively. The optical dispersions D and D′ in the visible
Structure and Composition. The structures of MC1−
MC5 are investigated by TEM. As depicted in Figure 9A,B and
and infrared regions are the reciprocals of νD and νD′ and are
defined as D(′) = 1/νD ′ .
( )
G
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
Figure 6. PL spectra of (A) P1c/2/3 and (C) P1e/2/3 in THF and THF/H2O mixtures with different water fractions. Concentration: 10−5 M;
excitation wavelength (nm): 335 (P1c/2/3) and 380 (P1e/2/3). (B, D) Plot of relative PL intensity (I/I0) versus the composition of the THF/H2O
mixtures of P1c/2/3 and P1e/2/3.
39.06, 82.49, and 49.93%, while opposite result was observed
for the carbon content. This composition gradient from the
bulk to the surface suggests that the ceramization process starts
from the formation of cobalt nanocluster cores, which is then
imbedded into a carbon matrix.
To further investigate the chemical structure of the bulk, we
performed the XRD analysis. Figure 10 exhibits the XRD
patterns of MC1−MC5. The reflection peaks can be identified
according to the databases of JCPDS-International Centre for
Diffraction Data (ICDD) as reflections for the Co metal
(ICDD-data file 15-0806) and Co2Si (ICDD-data file 04-0847).
MC1−MC5 all consist of a majority of Co. Particularly, MC5
also contains a minority of Co2Si nanocrystallites. This peak,
however, is too weak to be observed in MC2 though its
precursor possesses Si atoms. The ED patterns of the Co
nanoparticles show many diffraction spots (Figure 9D and
Figure 7. Wavelength dependence of refraction index of thin films of
P1a−e/2/3.
Figure S2), indicating that the metal clusters are highly
crystalline with well-ordered structures.
Figure S1, all the ceramics consist of irregular nanoparticles
(dark grains) wrapped by carboneous shell (light areas).
Thermolysis of organic materials under nitrogen not only leads
to the formation of carbon but also results in the evolution of
volatile gases, such as methane and hydrogen. We therefore
utilized XPS and EDX to determine the atomic compositions of
the ceramics (Table 7). XPS study reveals the cobalt contents
of 3.61, 4.28, 1.66, 1.56, and 2.26% on the surfaces of MC1−
MC5, respectively. In the bulk, the values rise to 88.96, 37.64,
Magnetization. It now becomes clear that all the ceramic
materials MC1−MC5 contain nanoscopic cobalt species, which
are expected to be magnetically susceptible. Figure 11 shows
the magnetization curves of the ceramics. With an increase in
the magnetic field strength, the magnetization of the ceramics
MC1−MC5 swiftly increases and a saturation magnetization
(Ms) is ultimately reached. It is known that cobalt itself is
H
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
a
Table 6. Refractive Indices and Chromatic Dispersions of P1a−e/2/3
polymer
n633
n1550
Δn633
νD
νD′
D
D′
P1a/2/3
P1b/2/3
P1c/2/3
P1d/2/3
P1e/2/3
1.6603
1.6317
1.6581
1.6791
1.6448
1.6206
1.6050
1.6184
1.6175
1.6048
0.010
0.008
0.008
0.010
0.012
19.8
19.6
18.4
21.8
32.1
58.2
208.5
63.9
0.050
0.051
0.054
0.046
0.031
0.017
0.005
0.016
0.018
0.019
56.7
52.7
a
́
Abbreviation: n = refractive index, Δn = birefringence, νD = Abbe number = (nD − 1)/(nF − nC), where nD, nF, and nC are the RI values at
wavelengths of 589.2, 486.1, and 656.3 nm, respectively, νD′ = modified Abbe number = (n1319 − 1)/(n1064 − n1550), where n1319, n1064, and n1550 are
́
the RI values at 1319, 1064, and 1550 nm, respectively, D(′) = chromatic dispersion = 1/νD ′ .
( )
Scheme 4. Complexation with Cobalt Carbonyls and Ceramization to Magnetic Ceramics
Figure 8. IR spectra of P1a/2/3 (A) before and (B) after
complexation with Co2(CO)8.
ferromagnetic, but its oxides (Co3O4 and CoO) are para-
magnetic at room temperature.30 Among the magnetic
ceramics, MC1 shows the highest Ms value of 80.7 emu/g, in
agreement with its highest content of ferromagnetic Co
nanocrystallites. This value is impressively high when taking
into the account that the Ms value of maghemite (γ-Fe2O3) is
74 emu/g.31 The carboneous shells may have well wrapped the
cobalt nanocrystallites and prevent them from oxidation after
the pyrolysis process. Comparing with MC1, the Ms values of
MC2 (61.3 emu/g) and MC5 (61.2 emu/g) are lower because
of their lower Co content but are still higher than those of MC3
(54.1 emu/g) and MC4 (56.4 emu/g) owing to the presence of
a minority of paramagnetic Co2Si.
The hysteresis loops of our magnetoceramics are small. From
the enlarged H−M plots shown in the inset of Figure 11, the
coercivities (Hc) of MC1−MC5 are found to be 0.19−0.21
kOe. Coupled with their high Ms values, they are anticipated to
find an array of high-technological applications, especially in
magnetic recording systems.
Figure 9. (A−C) TEM images and (D) ED pattern of the magnetic
ceramics MC1.
CONCLUSIONS
■
In this work, we developed a new polymerization route for the
synthesis of new polymers with precise structures. The indium-
catalyzed three-component polycouplings of diynes, dialdehyde,
and secondary amine proceed smoothly in o-xylene at 140 °C
for 20 h, producing polymers P1a−e/2/3 with high molecular
weights in high yields. Rational model reaction was carried out
to help elucidate the polymer structures. All the polymers
possess good solubility and thermal stability. Whereas P1c/2/3
and P1e/2/3 exhibit an unusual AEE characteristics, others are
ACQ emitters. This provides valuable information on how to
build conjugated polymers with high emission efficiency in the
I
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
Table 7. Atomic Compositions of the Magnetic Ceramics Estimated by XPS and EDX Analyses
XPS (atom %)
EDX (atom %)
a
ceramics
yield (%)
C
O
Si
Co
C
O
Si
Co
MC1
MC2
MC3
MC4
MC5
45.9
48.3
51.1
50.6
49.8
88.18
75.13
95.12
94.99
88.72
8.21
16.23
3.22
3.61
4.28
1.66
1.56
2.26
10.51
52.26
59.63
16.85
45.28
0.53
5.88
1.31
0.67
2.21
88.96
37.64
39.06
82.49
49.93
4.37
4.22
3.45
7.05
1.97
2.57
a
Ceramics obtained by pyrolysis of Co−P1a−e/2/3 at 1000 °C for 1 h under nitrogen.
aggregated state. All the polymer films show higher refractive
indices than conventional organic polymers. The polymers can
be utilized as processable precursors to magnetic ceramics. By
complexation with Co2(CO)8 and pyrolysis of the resulting
organometallic polymers at high temperature under inert
atmosphere, nanostructured ceramics MC1−MC5 with high
magnetizability and low hysteresis loss are generated. We hope
that the present results will inspire research enthusiasm for
creation of new, precise polymers with new and/or enhanced
functionalities and properties for high-technological applica-
tions in many areas.
ASSOCIATED CONTENT
* Supporting Information
■
S
TEM images and ED patterns of the magnetic ceramics. This
material is available free of charge via the Internet at http://
pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail chjacky@ust.hk (J.W.Y.L.) or tangbenz@ust.hk
(B.Z.T.); Ph +852-2358-7375 (8801); Fax +852-2358-1594.
■
Figure 10. XRD diffractograms of the magnetic ceramics MC1−MC5.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work has been partially supported by National Basic
Research Program of China (973 Program; 2013CB834701),
the Research Grants Council of Hong Kong (604711, 602212,
HKUST2/CRF/10 and N_HKUST620/11), and the Univer-
sity Grants Committee of Hong Kong (AoE/P-03/08). B.Z.T.
thanks the support of the Guangdong Innovative Research
Team Program (201101C0105067115).
REFERENCES
■
Figure 11. Plots of magnetization (M) versus applied magnetic field
(H) at 298 K for magnetoceramics MC1−MC5. Inset: enlarged plots
at low magnetic field.
(1) (a)
For multi-component coupling reactions, see: Multi-
component Reactions; Zhu, J., Bienayme, H., Eds.; Wiley: Weinheim,
2005. (b) Ugi, I.; Domling, A.; Werner, B. J. Heterocycl. Chem. 2000,
37, 647−658. (c) Weber, L.; Illgen, K.; Almstetter, M. Synlett 1999,
366−374. (d) Armstrong, R. W.; Combs, A. P.; Tempest, P. A.;
Brown, S. D.; Keating, T. A. Acc. Chem. Res. 1996, 29, 123−131.
(e) Ugi, I.; Steinbrueckner, C. Chem. Ber. 1961, 94, 2802−2814.
(f) Mannich, C.; Kosche, W. Arch. Pharm. 1912, 250, 647−667.
(g) Hantzsch, A. Ber. Dtsch. Chem. Ges. 1890, 23, 1474−1476.
(h) Strecker, A. Ann. Chem. 1850, 75, 27−45.
a
Table 8. Magnetic Properties of the Ceramics
ceramics
Ms (emu/g)
Mr (emu/g)
Hc (kOe)
MC1
MC2
MC3
MC4
MC5
80.7
61.3
54.1
56.4
61.2
8.4
10.4
8.0
0.20
0.19
0.21
0.20
0.20
(2) (a) Bienayme, H.; Hulme, C.; Oddon, G.; Schmitt, P. Chem.
Eur. J. 2000, 6, 3321−3329. (b) Bienayme, H.; Bouzid, K. Angew.
Chem., Int. Ed. 1998, 37, 2234−2237. (c) Trost, B. M. Angew. Chem.,
Int. Ed. 1995, 34, 259−281.
7.6
9.6
a
Determined by vibrating sample magnetometer. Abbreviation: Ms =
saturation magnetization in an external field of ∼10 kOe, Mr =
magnetic remanence at zero external field, and Hc = coercivity at zero
magnetization.
(3) Lalli, C.; Bouma, J. M.; Bonne, D.; Masson, G.; Zhu, J. Chem.
Eur. J. 2011, 17, 880−889.
(4) Li, C.-J.; Wei, C. Chem. Commun. 2002, 268−269.
(5) Chen, W.-W.; Bi, H.-P.; Li, C.-J. Synlett 2010, 3, 475−479.
J
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX

Macromolecules
Article
(6) Dou, X.-Y.; Shuai, Q.; He, L.-N.; Li, C.-J. Adv. Synth. Catal. 2010,
352, 2437−2440.
(7) Zhang, Y.; Li, P.; Wang, M.; Wang, L. J. Org. Chem. 2009, 74,
4364−4367.
Y.; Tang, B. Z. Chem. Commun. 2009, 4332−4353. (f) Luo, J. D.; Xie,
Z. L.; Lam, J. W. Y.; Cheng, L.; Chen, H. Y.; Qiu, C. F.; Kwok, H. S.;
Zhan, X. W.; Liu, Y. Q.; Zhu, D. B.; Tang, B. Z. Chem. Commun. 2001,
1740−1741.
(23) Chen, H. Y.; Lam, W. Y.; Luo, J. D.; Ho, Y. L.; Tang, B. Z.; Zhu,
D. B.; Wong, M.; Kwok, H. S. Appl. Phys. Lett. 2002, 81, 574−576.
(24) Liu, J.; Ueda, M. J. Mater. Chem. 2009, 19, 8907−8919 and
references therein.
(25) (a) Seferis, J. C. Polymer Handbook, 3rd ed.; Brandrup, J.,
Immergut, E. H., Eds.; Wiley: New York, 1989; pp VI/451−VI/461.
(b) Mills, N. J. Concise Encyclopedia of Polymer Science & Engineering;
Kroschwitz, J. I., Ed.; Wiley: New York, 1990; pp 683−687.
(26) Hecht, E. Optics, 4th ed.; Addison Wesley: San Francisco, CA,
2002.
(8) (a) Ishibe, S.; Tomita, I. J. Polym. Sci., Part A: Polym. Chem. 2005,
43, 3403−3410. (b) Choi, C.-K.; Tomita, I.; Endo, T. Macromolecules
2000, 33, 1487−1488. (c) Choi, C.-K.; Tomita, I.; Endo, T. Chem.
Lett. 1999, 1253−1254. (d) Miyaki, N.; Tomita, I.; Endo, T.
Macromolecules 1997, 30, 4504−4506. (e) Miyaki, N.; Tomita, I.;
Endo, T. J. Polym. Sci., Part A: Polym. Chem. 1997, 35, 1211−1218.
(f) Miyaki, N.; Tomita, I.; Endo, T. Macromolecules 1996, 29, 6685−
6690.
(9) Ochiai, B.; Ogihara, T.; Mashiko, M.; Endo, T. J. Am. Chem. Soc.
2009, 131, 1636−1637.
(27) (a) Burchell, T. J.; Puddephatt, R. J. Inorg. Chem. 2005, 44,
3718−3730. (b) Eisler, D. J.; Puddephatt, R. J. Cryst. Growth Des.
2005, 5, 57−59. (c) Mohr, F.; Jennings, M. C.; Puddephatt, R. J.
Angew. Chem., Int. Ed. 2004, 43, 969−971. (d) Burchell, T. J.; Eisler, D.
J.; Jennings, M. C.; Puddephatt, R. J. Chem. Commun. 2003, 2228−
2229. (e) Puddephatt, R. J. Macromol. Symp. 2003, 196, 137−144.
(f) Qin, Z. Q.; Jennings, M. C.; Puddephatt, R. J.; Muir, K. W. Inorg.
Chem. 2002, 41, 5174−5186. (g) Hunks, W. J.; Jennings, M. C.;
Puddephatt, R. J. Inorg. Chem. 2002, 41, 4590−4598. (h) Hunks, W. J.;
Jennings, M. C.; Puddephatt, R. J. Chem. Commun. 2002, 1834−1835.
(i) Brandys, M. C.; Puddephatt, R. J. J. Am. Chem. Soc. 2002, 124,
3946−3950. (j) Qin, Z. Q.; Jennings, M. C.; Puddephatt, R. J. Chem.
Commun. 2002, 4, 354−355.
(28) (a) Bill, J.; Aldinger, F. Adv. Mater. 1995, 7, 775−787.
(b) Interrante, L. V.; Liu, Q.; Rushkin, I.; Shen, Q. J. Organomet. Chem.
1996, 521, 1−10. (c) Corriu, R. J. P. Angew. Chem., Int. Ed. 2000, 39,
1376−1398. (d) Manners, I. Science 2001, 294, 1664−1666.
(29) (a) Babudri, F.; Farinola, G. M.; Naso, F. J. Mater. Chem. 2004,
14, 11−34. (b) Chan, W. Y.; Berenbaum, A.; Clendenning, S. B.;
Lough, A. J.; Manners, I. Organometallics 2003, 22, 3796−3808.
(c) Long, N. J.; Williams, C. K. Angew. Chem., Int. Ed. 2003, 42, 2586−
2617. (d) Bunz, U. H. F. J. Organomet. Chem. 2003, 683, 269−287.
(30) (a) O’Handley, R. C. Modern Magnetic Materials: Principles and
Applications; Wiley: New York, 2000. (b) Goldmann, A. Handbook of
Ferromagnetic Materials; Kluwer: Boston, MA, 1999. (c) Evetts, J. E.
Concise Encyclopedia of Magnetic & Superconducting Materials;
Pergamon: New York, 1992.
(10) (a) Wang, Y.-Z.; Deng, X.-X; Li, L.; Li, Z.-L.; Du, F.-S.; Li, Z.-C.
Polym. Chem. 2013, 4, 444−448. (b) Li, L.; Kan, X.-W.; Deng, X.-X.;
Song, C.-C.; Du, F.-S.; Li, Z.-C. J. Polym. Sci., Part A: Polym. Chem.
2013, 51, 865−873.
(11) (a) Liu, J.; Lam, J. W. Y.; Tang, B. Z. Chem. Rev. 2009, 109,
5799−5867. (b) Haußler, M.; Tang, B. Z. Adv. Polym. Sci. 2007, 209,
̈
1−58.
(12) (a) Lam, J. W. Y.; Tang, B. Z. Acc. Chem. Res. 2005, 38, 745−
754. (b) Li, Z.; Dong, Y.; Qin, A.; Lam, J. W. Y.; Dong, Y.; Yuan, W.;
Sun, J.; Hua, J.; Wong, K. S.; Tang, B. Z. Macromolecules 2006, 39,
467−469. (c) Li, Z.; Dong, Y.; Haussler, M.; Lam, J. W. Y.; Dong, Y.;
̈
Wu, L.; Wong, K. S.; Tang, B. Z. J. Phys. Chem. B 2006, 110, 2302−
2309. (d) Zeng, Q.; Lam, J. W. Y.; Jim, C. K. W.; Qin, A.; Qin, J.; Li,
Z.; Tang, B. Z. J. Polym. Sci., Part A: Polym. Chem. 2008, 46, 8070−
8080.
(13) (a) Haußler, M.; Lam, J. W. Y.; Qin, A.; Tse, K. K. C.; Li, M. K.
̈
S.; Liu, J.; Jim, C. K. W.; Gao, P.; Tang, B. Z. Chem. Commun. 2007,
2584−2586. (b) Haußler, M.; Zheng, R.; Lam, J. W. Y.; Tong, H.;
̈
Dong, H.; Tang, B. Z. J. Phys. Chem. B 2004, 108, 10645−10650.
(14) (a) Liu, J.; Zhong, Y.; Lam, J. W. Y.; Lu, P.; Hong, Y.; Yu, Y.;
Yue, Y.; Faisal, M.; Sung, H. H. Y.; Williams, I. D.; Wong, K. S.; Tang,
B. Z. Macromolecules 2010, 43, 4921−4936. (b) Jim, C. K. W.; Qin, A.;
Lam, J. W. Y.; Haußler, M.; Liu, J.; Yuen, M. M. F.; Kim, J. K.; Ng, K.
̈
M.; Tang, B. Z. Macromolecules 2009, 42, 4099−4109.
(15) (a) Qin, A.; Lam, J. W. Y.; Tang, B. Z. Chem. Soc. Rev. 2010, 39,
2522−2544. (b) Qin, A.; Lam, J. W. Y.; Tang, B. Z. Macromolecules
2010, 43, 8693−8702.
(31) (a) Tang, B. Z.; Geng, Y.; Lam, J. W. Y.; Li, B.; Jing, X.; Wang,
X.; Wang, F.; Pakhomov, A. B.; Zhang, X. X. Chem. Mater. 1999, 11,
1581−1589. (b) Tang, B. Z. CHEMTECH 1999, 29 (11), 7−12.
(c) Tang, B. Z.; Geng, Y.; Sun, Q.; Zhang, X.; Jing, X. Pure Appl. Chem.
2000, 72, 157−162.
(16) (a) Jim, C. K. W.; Qin, A.; Lam, J. W. Y.; Faisal, M.; Yu, Y.;
Tang, B. Z. Adv. Funct. Mater. 2010, 20, 1319−1328. (b) Liu, J.; Lam,
J. W. Y.; Jim, C. K. W.; Ng, J. C. Y.; Shi, J.; Su, H.; Yeung, K. F.; Hong,
Y.; Faisal, M.; Yu, Y.; Wong, K. S.; Tang, B. Z. Macromolecules 2011,
44, 68−79.
(17) Lu, P.; Lam, J. W. Y.; Liu, J.; Jim, C. K. W.; Yuan, W.; Chan, C.
Y. K.; Xie, N.; Hu, Q.; Cheuk, K. K. L.; Tang, B. Z. Macromolecules
2011, 44, 5977−5986.
(18) Liu, J.; Deng, C.; Tseng, N.-W.; Chan, C. Y. K.; Yue, Y.; Ng, J.
C. Y.; Lam, J. W. Y.; Wang, J.; Hong, Y.; Sung, H. H. Y.; Williams, I.
D.; Tang, B. Z. Chem. Sci. 2011, 2, 1850−1859.
(19) Li, Z.; Qin, A.; Lam, J. W. Y.; Dong, Y.; Dong, Y.; Ye, C.;
Williams, I. D.; Tang, B. Z. Macromolecules 2006, 39, 1436−1442.
(20) (a) Liu, J.; Zheng, R.; Tang, Y.; Haussler, M.; Lam, J. W. Y; Qin,
A.; Ye, M.; Hong, Y.; Gao, P.; Tang, B. Z. Macromolecules 2007, 40,
7473−7486. (b) Peng, H.; Cheng, L.; Luo, J.; Xu, K.; Sun, Q.; Dong,
Y.; Salhi, F.; Lee, P. P. S.; Chen, J.; Tang, B. Z. Macromolecules 2002,
35, 5349−5351.
(21) Birks, J. B. Photophysics of Aromatic Molecules; Wiley: London,
1970.
(22) (a) Hong, Y.; Lam, J. W. Y.; Tang, B. Z. Chem. Soc. Rev. 2011,
40, 5361−5388. (b) Liu, Y.; Tang, Y.; Barashkov, N. N.; Irgibaeva, I.
S.; Lam, J. W. Y.; Hu, R.; Yu, Y.; Tang, B. Z. J. Am. Chem. Soc. 2010,
132, 13951−13953. (c) Yuan, W. Z.; Lu, P.; Chen, S.; Lam, J. W. Y.;
Wang, Z.; Liu, Y.; Kowk, H. S.; Ma, Y.; Tang, B. Z. Adv. Mater. 2010,
22, 2159−2163. (d) Zhao, Z.; Wang, Z.; Lu, P.; Chan, C. Y. K.; Liu,
D.; Lam, J. W. Y.; Sung, H. H. Y.; Williams, I. D.; Ma, Y.; Tang, B. Z.
Angew. Chem., Int. Ed. 2009, 48, 7608−7611. (e) Hong, Y.; Lam, J. W.
K
dx.doi.org/10.1021/ma4005346 | Macromolecules XXXX, XXX, XXX−XXX