Oligo(p-phenyleneethynylene)-functionalized perylenebisimidetriad: Synthesis, photophysical properties, and self-assembly

Article abstract of DOI:10.1002/cjoc.201200858

The rod-like oligo(p-phenylene ethynylene)-functionalized perylene bisimide triad was synthesized and characterized. Aggregation behavior in solvents of different polarity was investigated by absorption and fluorescent spectroscopy. The results showed tha

Full text of DOI:10.1002/cjoc.201200858

FULL PAPER
DOI: 10.1002/cjoc.201200858
Oligo(p-phenyleneethynylene)-functionalized Perylenebis-
imidetriad: Synthesis, Photophysical Properties, and
Self-assembly
Weiqi Tong,a Wei Wei,b Haibo Chen,c and Hongyu Wang*,a
a Department of Chemistry, Shanghai University, Shanghai 200444, China
b Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu 210003,
China
c Downhole Operation Team, Second Oil Extraction Factory, Zhongyuan Petrol Oil Exploration Bureau, Puyang,
Henan 457001, China
The rod-like oligo(p-phenylene ethynylene)-functionalized perylene bisimide triad was synthesized and
characterized. Aggregation behavior in solvents of different polarity was investigated by absorption and fluorescent
spectroscopy. The results showed that stronger aggregations took place in low-polarity slovent. The experiments
also indicated that the energy and electron transfer might takeplace between the two chromophores during the
photoinduced excitation. Highly ordered two-dimensional assemblies could be observed at solid/liquid interfaces.
Keywords perylenebisimide, donor-acceptor, energy transfer, electron transfer, self-assembly
Introduction
structing D-A architecture with PBIs exhibit the fol-
lowing attributes: (1) The absorption of OPE is a com-
plementation to PBIs, and the absorption of the co-
polymers almost cover the whole visible region. (2) Cy-
lindrical symmetry of the acetylene unit maintains the
π-electron conjugation at any degree of rotation. And
the rigid rod-like character of phenylene-ethynylenes
has ability to communicate charge/excitation energy
over long distances.[11] (3) The solubility of PBIs can be
efficiently increased by introducing OPE unit.
The synthesis and investigation of structurally de-
fined conjugated oligomers as models for the corre-
sponding polymers will lead to more valuable structure
property relationships. In this respect, we report the
synthesis, characterization, and photophysical studies of
a novel D-A-D triad 3 carrying OPE as the electron do-
nor and perylenebisimide as the electron acceptor. The
optical and electrochemical properties of the triad were
carefully investigated using UV-vis absorption and fluo-
rescence spectroscopy. In order to evaluate the influence
on photophysical properties of introduction of OPE unit
to perylenebisimide core, two model compounds
1,4-bis(phenylethynyl)-2,5-bis(hexyloxy)benzene 4 and
N,N'-dicyclohexyl-1,6,7,12-tetrakis(4-tert-butylphenoxy)-
3,4:9,10-perylenedicarboximide 5 were synthesized.
Furthermore, the scanning tunneling microscopy (STM)
was carried out to understand the intermolecular inter-
actions, which are essential for device fabrication.
Inspired by natural photosynthetic reaction centers,
which contain chlorophyll dyes as electron donor and
quinones as electron acceptors, perylenebisimides (PBIs)
have become one of the most popular building blocks to
construct donor-acceptor (D-A) architecture for photo-
physical studies.[1,2] However, perylenebisimide deriva-
tives appear to be more powerful electron acceptor than
quinones, since they can be easily connected to various
scaffolds via the imide nitrogens, and their optical and
redox properties can be easily tuned over a wide range
by molecular structure design, especially by appropriate
choice of the substituents in the “bay” area.[3,4] By using
a variety of binding motifs (e.g. covalent linkages, hy-
drogen bonds, metal ion coordination and π-π stacking),
a large number of functional systems and assemblies
based on PBIs have been developed.[5-7] Particularly,
Wasielewski group and Würthner group have recog-
nized these advantageous features of mono- and bisim-
ide chromophores and exploited them for a broad vari-
ety of photophysical studies on dyad and triad mole-
cules.[8,9]
In our previous work,[10] we reported the alternative
copolymers based on oligo(p-phenyleneethynylene)
(OPE) and PBIs units, which exhibited efficient photo
induced energy and electron transfer from photo excited
OPE unit to PBI. The ideal features of OPE for con-
*
E-mail: wanghy@shu.edu.cn; Tel.: 0086-021-66135108
Received August 23, 2012; accepted November 1, 2012; published online December 11, 2012.
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cjoc.201200858 or from the author.
Chin. J. Chem. 2013, 31, 277—282
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
277

Tong et al.
FULL PAPER
Scheme 1 Synthetic route of the triad 3 and chemical structure of models 4 and 5
O O
OC6H13
O
N
O
O
N
O
Sonogashira
H
I
I
+
C6H13O
O O
1
2
O O
OC6H13
O
N
O
O
N
O
OC6H13
C6H13O
C6H13O
O O
3
O O
OC6H13
O
N
O
O
N
O
C6H13O
O O
4
5
Experimental
and differential thermal analysis DTG-60H at a heating
rate of 10 ℃•min−1 under N2. Differential scanning
calorimetry (DSC) measurements were performed under
a nitrogen atmosphere at heating rates of 10 ℃•min−1,
using NETZSCH DSC 200PC apparatus. UV-vis spec-
tra were recorded on a Shimadzu 3150 PC spectro-
photometer. Fluorescence measurement was carried out
on a Shimadzu RF-5301 PC spectrofluorophotometer
with a xenon lamp as a light source. Cyclic voltammetry
(CV) was performed at a scanning rate of 100 mV•s−1
on an AUTOLAB. PGSTAT30 potentiostat/galvanostat
system (Ecochemie, Netherlands), which was equipped
with a three-electrode cell. The glass carbon electrode
was used as the working electrode and Pt wire was used
Unless otherwise stated, reagents were commercially
obtained and used without further purification. The sol-
vents for cross-coupling reaction were purified accord-
ing to the standard methods. The synthetic procedures
of 1, 2, 4 and 5 have been published previously.[10,12-14]
The NMR spectra were recorded on a Varian Mer-
cury Plus 400 spectrometer with tetramethylsilane as the
internal standard. Matrix-assisted laser desorption ioni-
zation-time-of-flight mass (MALDI-TOF) experiments
were carried out using a Shimadzu AXIMA-CFRTM
plus time-of-flight mass spectrometer (Kratos Analyti-
cal, Manchester, U. K.). Thermogravimetric analysis
(TGA) was performed on a Shimadzu thermogravimetry
278
www.cjc.wiley-vch.de
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 277—282

Oligo(p-phenyleneethynylene)-functionalized Perylenebisimidetriad
as the counter electrode. An Ag/Ag＋ was used as a ref-
erence electrode. 0.1 mol/L tetrabutyl ammonium
hexafluorophosphate (n-Bu4NPF6) was used as a sup-
porting electrolyte. The dichloromethane solution of
oligomer was cast onto the glass carbon disk as a work-
ing electrode and determined in actonitrile. Scanning
tunneling microscope (STM) measurements were per-
formed with a Nanoscope IIIa (Veeco Metrology, USA)
with mechanically formed Pt/Ir (80/20) tips. A droplet
(2 µL) of n-octylbenzenesolution containing 3 at a con-
centration of approximately 10−6 mol/L was dropped on
freshly cleaved highly oriented pyrolytic graphite
(HOPG) (grade ZYB, eeco Metrology, USA) surface
and investigated by STM immediately. All images were
recorded in constant current mode.
The triad 3 has molecular weight of 1937.8 determined
by MALDI-TOF mass, which is consistent with the real
molecular weight. According to thermal gravimetric
analysis (TGA), the triad 3 has fair thermal stability.
The onset of thermal degradation under a nitrogen at-
mosphere was recorded at 353 ℃ (5% weight loss). No
glass transition temperature, Tg, was obtained for the
oligomer by DSC measurement while heating to 250
℃.
Aggregation behavior in solutions
The aggregation behavior of triad 3 was studied in
detail by UV-vis absorption and fluorescence spectros-
copy in polar solvent dichloromethane and nonpolar
solvent hexane (Figures 1－4). The absorption bands of
the PBI chromophore give three characteristic peaks at
longer wavelength from 450 to 600 nm,[15] while the
absorption bands of the OPE chromophore appear at
370 nm.[12] In hexane solution, upon increasing the
concentration (Figure 1), the absorption maxima of PBI
chromophore was red-shifted by about 26 nm. And ag-
gregation-induced broadening was also observed, while
the fine structure remained almost the same. The ab-
sorption spectra of the aggregated triad 3 agreed re-
markably well with the four phenoxy substituents in the
bay positions of perylene derivatives reported by
Würthner.[16] However, the absorption spectra of 3 in
DCM almost unchanged upon increasing the concentra-
tion to 5×10−5 mol/L (Figure 2).
Synthesis of the triad 3
Monomer 1 (44.3 mg, 0.11 mmol), 2 (69.4 mg, 0.05
mmol), tetrakis(triphenylphosphine) palladium (4 mg),
and CuI (2 mg) were added to a mixture of THF (5 mL)
and diisopropylamine (5 mL). The mixture was vigor-
ously stirred at 50 ℃ for 48 h under nitrogen. After
cooling to room temperature and removal of the solvent
under reduced pressure, the residue was purified by
column chromatography using a mixture of dichloro-
methane and hexane (V/V＝6∶4) as eluent to afford 3
(78.9 mg, 72%) as dark red powder. 1H NMR (400 MHz,
CDCl3) δ: 8.26 (s, 4H), 7.64 (d, J＝8 Hz, 4H), 7.54－
7.51 (m, 4H), 7.34－7.32 (m, 6H), 7.25－7.23 (m, 12H),
7.02 (d, J＝4.4 Hz, 4H), 6.85 (d, J＝8.4 Hz, 8H), 4.0 (t,
J＝6.4, 8H), 1.82－1.84 (m, 8H), 1.34－1.38 (m, 24H),
1.24 (s, 36H), 0.89－0.90 (m, 12H); 13C NMR (400
MHz, CDCl3) δ: 163.66, 156.36, 153.95, 153.83, 152.97,
147.70, 139.51, 135.12, 133.36, 132.60, 131.80, 128.90,
128.52, 126.94, 124.95, 124.69, 124.29, 123.67, 122.65,
121.03, 120.41, 119.96, 119.58, 117.18, 117.10, 114.41,
113.86, 95.15, 94.33, 87.18, 86.17, 69.86, 69.82, 34.60,
34.07, 32.17, 31.85, 31.66, 30.55, 30.43, 29.94, 25.98,
22.88, 14.30. MASS (MALDI-TOF): 1937.8 (calcd for
C132H130N2O12: 1936.4).
3
3
10-5
10-5
7
5
3
10-6
10-6
10-6
10-6
2
1
0
7
film
10-7
Results and Discussion
350
400
450
500
550
600
650
Wavelength/nm
Characterization
The triad 3 was synthesized by Hagihara-Sonoga-
Figure 1 Concentration-dependent UV-vis absorption spectra
of 3 in hexane (concentration range 7×10−7－3×10−5 mol/L).
Dotted line represents the spectrum of absorption in thin films.
shira cross-coupling reaction in a tetrahydrofuran/
1
diisopropylamine mixture. The results from H NMR,
13C NMR and MALDI-TOF mass analysis confirmed
that the synthesized compounds have the predicted
chemical structures. The NMR spectra and MALDI-
TOF mass spectra of the triad 3 were shown in the sup-
Fluorescence spectroscopy of DCM solutions
showed a significant red shift (about 13 nm) of the
emission maxima upon aggregation, with almost unal-
tered fine structure (Figure 3). An almost linear de-
pendence of the fluorescence intensity on the concentra-
tion was observed until the concentration increased to
10−5 mol/L. The deviation from the linearity at higher
concentrations could be described fully by the applica-
tion of Beer’s law to the excitation light in the sample
(Figure 3, inset). This indicated that the aggregation has
1
porting information (Figures S1－S3). The H NMR
characteristic peaks of the oligomer at δ 8.26 are due to
the resonance of protons on perylene ring, and the triplet
peaks at δ 4.0 are due to the resonance of protons on
methylene adjacent to the oxygen atoms of alkoxy
chains. But the signals of protons of acetylene group at
δ 3.34 in monomer 1 could no longer be detected in 3.
Chin. J. Chem. 2013, 31, 277—282
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
279

Tong et al.
FULL PAPER
a negligible influence on the fluorescence quantum
yield. This result is well agreed with many extended π
systems, including other PBI derivatives.[16] In the low-
polar hexane (Figure 4), when the concentration in-
creased to 5×10−6 mol/L, a new aggregation emission
peak at 621 nm was observed. Increasing concentration
gradually to 3×10−5 mol/L, the aggregation emission
peak red-shifted to 637 nm. While the emission peak at
588 nm gradually decreased and finally disappeared.
Also, the spectrum recorded from thin films closely re-
sembled those obtained from concentrated solutions. At
the concentration higher than 3×10−6 mol/L, the de-
pendence of the fluorescence intensity on the concentra-
tion deviated from the linearity. All those results
showed strong aggregation of the triad 3 takes place in
low-polarity environments.
4
5
3
10-5
10-5
10-5
3
2
1
0
7
5
3
10-6
film
10-6
10-6
10-6
350
400
450
500
550
600
650
Wavelength/nm
Figure 2 Concentration-dependent UV-vis absorption spectra
of 3 in dichloromethane (concentration range 10−6－5×10−5
mol/L). Dotted line represents the spectrum of absorption in thin
films.
Optical properties
In order to avoid intermolecular aggregation, UV-vis
and fluorescence spectra were recorded in high-polarity
dichloromethane at a concentration where no aggrega-
tion takes place (c＝1×10−6 mol/L). The optical pro-
perties of triad are very close to that of the alternative
copolymers reported previously.[10] The absorption
bands of the PBI chromophore give the characteristic π-
π* transitions at 453 nm (S0－S2 electronic transition),
542 and 584 nm (S0－S1 electronic transition),[15] while
the absorption bands of the OPE chromophore appear at
370 nm. The spectrum of the oligomer 3 is almost iden-
tical and close to a linear superposition of the spectra of
4 and 5, except for a 12 nm red shift (Figure 5). This
result demonstrates that there is no ground state elec-
tronic interaction between the two chromophores,[17]
which is mainly due to the nodes in the HOMO and
LUMO at imide nitrogen.[18] The emission spectra of the
oligomer 3 were recorded upon selective excitation of
the two chromophores (Figure 6). When excited at 370
nm, where the OPE chromophore absorbs strongly, the
oligomer displays almost totally quenched OPE fluo-
rescence and a weak emission from the low energy PBI
1200
1.0
0.8
0.6
0.4
0.2
800
0.0
10-4
0
20 40 60 80 100
C/(107 mol/L)
5
5
5
7×10-
5×10-
3×10-
10-
5
400
7×10-
5×10-
3×10-
6
6
6
10-
6
0
550
600
650
700
750
800
Wavelength/nm
Figure 3 Concentration-dependent fluorescence spectra of 3 in
DCM (concentration range 10−6－10−4 mol/L). Inset: dependence
of the fluorescence intensity Ifl on the concentration.
300
1.0
0.10
0.8
0.6
0.4
0.2
4
5
4+5
200
0.0
3
0
20 40 60 80 100
C/(107 mol/L)
3×10-5
10-5
0.05
7×10-6
5×10-6
3×10-6
10-6
100
7×10-7
0.00
0
550
300
400
500
600
600
650
700
750
800
Wavelength/nm
Wavelength/nm
Figure 4 Concentration-dependent fluorescence spectra of 3 in
hexane (concentration range 7×10−7－3×10−5 mol/L). Inset:
dependence of the fluorescence intensity Ifl on the concentration.
Figure 5 Absorption spectra of the triad 3, models 4 and 5 in
DCM (1×10−6 mol/L). The circles represent the spectrum of a
1∶1 molar mixture of 4 and 5.
280
www.cjc.wiley-vch.de
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 277—282

Oligo(p-phenyleneethynylene)-functionalized Perylenebisimidetriad
1000
15
10
5
5 (excitation at 584 nm)
3 (excitation at 367 nm)
3 (excitation at 584 nm)
750
500
250
0
0
-5
-10
-15
400
450
500
550
600
650
700
-2.0 -1.5 -1.0 -0.5 0.0
0.5
1.0
1.5
Potential V (vs. Ag/Ag+)
Wavelength/nm
Figure 6 Fluorescence emission spectra of the triad 3, and 5 in
DCM (1×10−6 mol/L) upon excitation of the OPE chromophore
at 370 nm and excitation of the PBI chromophore at 584 nm,
respectively.
Figure 7 Cyclic voltammograms of the triad 3 recorded from a
thin film deposited on an electrod in an electrolyte solution of
Bu4NPF6 (0.1 mol/L) in CH3CN at a scan rate of 100 mV/s.
at −1.14 eV. This oxidation and reduction potential is
very close to the PBI monomer 5 (Eox＝0.78 V and Ered
＝－1.06 V),[10] which means the oxidation and reduc-
tion mainly take place in the PBI unit.
unit at 610 nm is observed. This indicates that there ex-
ist the energy and/or electron transfer between two
chromophores. When excited at 584 nm, the PBI emis-
sion is also strongly quenched in comparison with the
fluorescence spectrum of model 5. Because the singlet
excited state of the PBI unit lies below that of the OPE
unit according to UV-vis absorption spectra, excitation
of the PBI unit, only electron transfer occurs from the
PBI unit to charge-separated state, resulting in quench-
ing the PBI fluorescence.
Self-assembly at the solid-liquid interface
In recent years, the self-assembly of complex multi-
component molecules with tailored functionalities into
highly ordered nanostructures attracts more attentions in
the context of nanomaterials and nanotechnology.[19] In
particular, nanopatterning has become one of the major
topics in these fields.[20] The STM is a powerful tool to
investigate two-dimensional organization of functional-
ized organic molecules at a solid-liquid interface, which
provides access to molecular and supramolecular struc-
ture and dynamics on the single-molecule level.[21] For
example, DeFeyter and De Schryver have reported
two-dimensional self-assembly of D-A triads based on
perylenebisimides and oligo(p-phenylenevinylene)s
(OPV4-PDI-OPV4)[22] at solid-liquid interface. The two-
dimensional self-assembly of 3 was presented. Figure 8
displays STM images of highly ordered monolayers of 3
at the solid-liquid interface on highly oriented pyrolytic
Electrochemical properties
We carried out cyclic voltammogram to investigate
the redox properties of the triad 3 (Figure 7). As we
know, perylenebisimides are fairly electron-deficient
dyes, which are easy to reduce and rather difficult to
oxidize.[18] With phenoxy electrondonor substituents,
the triad 3 exhibits reversible reduction and irreversible
oxidation waves. The anodic scan showed that the onset
of oxidation occurred at 0.84 eV. When scanning catho-
dically, 3 exhibited the onset potentials of reduction
Figure 8 (a) Large-scale STM image (76.5 nm×76.5 nm) of 3. The imaging conditions are I＝188.0 pA and V＝−906.2 mV. (b) A
high-resolution STM image (15.2 nm×15.2 nm) of 3. The imaging conditions are I＝156.6 pA and V＝−941.3 mV. (c) Structural model
for 3.
Chin. J. Chem. 2013, 31, 277—282
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
281

Tong et al.
FULL PAPER
[4] Xiao, S. Q.; El-Khouly, M. E.; Li, Y. L.; Gan, Z. H.; Liu, H. B.; Ji-
ang, L.; Araki, Y.; Ito, Q.; Zhu, D. B. J. Phys. Chem. B 2005, 109,
3658.
[5] Qiu, W. F.; Chen, S. Y.; Sun, X. B.; Liu, Y. Q.; Zhu, D. B. Org. Lett.
2006, 8, 867.
[6] Li, Y. J.; Wang, N.; Gan, H. Y.; Liu, H. B.; Li, H.; Li, Y. L.; He, X.
R.; Huang, C. S.; Cui, S.; Wang, S.; Zhu, D. B. J. Org. Chem. 2005,
70, 9686.
[7] Liu, Y.; Li, Y. J.; Jiang, L.; Gan, H. Y.; Liu, H. B.; Li, Y. L.;
Zhuang, J. P.; Lu, F. S.; Zhu, D. B. J. Org. Chem. 2004, 69, 9049.
[8] For selected examples, (a) Sinks, L. E.; Rybtchinski, B.; Iimura, M.;
Jones, B. A.; Goshe, A. J.; Zuo, X. B.; Tiede, D. M.; Li, X. Y.;
Wasielewski, M. R. Chem. Mater. 2005, 17, 6295; (b) Kelley, R. F.;
Shin, W. S.; Rybtchinski, B.; Sinks, L. E.; Wasielewski, M. R. J. Am.
Chem. Soc. 2007, 129, 3173.
[9] For selected examples, (a) Kaiser, T. E.; Stepanenko, V.; Würthner,
F. J. Am. Chem. Soc. 2009, 131, 6719; (b) Fischer, M. K. R.; Kaiser,
T. E.; Würthner, F.; Bäuerle, P. J. Mater. Chem. 2009, 19, 1129.
[10] Wang, H. Y.; Pu, K. Y.; Huang, S.; Liu, F.; Peng, B.; Wei, W. React.
Funct. Polym. 2009, 69, 117.
[11] Yoosaf, K.; James, P. V.; Ramesh, A. R.; Suresh, C. H.; Thomas, K.
G. J. Phys. Chem. C 2007, 111, 14933.
[12] Li, H.; Powell, D. R.; Hayashi, R. K.; West, R. Macromolecules
1998, 31, 52.
[13] James, P. V.; Sudeep, P. K.; Suresh, C. H.; Thomas, K. G. J. Phys.
Chem. A 2006, 110, 4329.
[14] Sudeep, P. K.; James, P. V.; Thomas, K. G.; Kamat, P. V. J. Phys.
Chem. A 2006, 110, 5642.
[15] Ford, W. E.; Kamat, P. V. J. Phys. Chem. 1987, 91, 6373.
[16] Würthner, F.; Thalacker, C.; Diele, S.; Tschierske, C. Chem. Eur. J.
2001, 7, 2245.
[17] Neuteboom, E. E.; Meskers, S. C. J.; van Hal, P. A.; van Duren, J. K.
J.; Meijer, E. W.; Janssen, R. A. J.; Dupin, H.; Pourtois, G.; Cornil,
J.; Lazzaroni, R.; Brédas, J. L.; Beljonne, D. J. Am. Chem. Soc. 2003,
125, 8625.
graphite (HOPG) under ambient conditions. Figure 8a
shows the large uniform and well-ordered assembly. It
is noticed that herringbone-shaped patterns are full of
the whole viewed area. The details of the adlayer can be
seen in a high-resolution STM image in Figure 8b. The
adjacent molecules in the same rows are parallel to each
other with a uniform bent direction. It is clear that the
bright rods consist of three parts: the central part is at-
tributed to the location of the PBI core part and the out-
ermost parts correspond to the OPE moieties. A pro-
posed model for the molecular arrangement could be
shown in Figure 7c according to the STM image. The
unit cell of the two dimensional (2D) assembly is su-
perimposed on the molecular model with parameters a
＝2.0±0.1 nm, b＝5.1±0.2 nm, α＝70°±2°.
Conclusions
In conclusion, we have synthesized a new OPE-PBI-
OPE triad using the Sonogashira cross-coupling reaction.
The aggregation behavior has been investigated by
UV-vis absorption and fluorescent spectroscopy in
hexane and dichloromethane. The stronger aggregation
takes place in low-polarity hexane, when concentration
reaches 3×10−6 mol/L. Excitation of the OPE unit in
the triad results in photoinduced energy and electron
transfers. Excitation of the PBI unit in the triad can only
result in photoinduced electron transfer. Highly ordered
two-dimensional assemblies can be obtained at solid/
liquid interfaces.
[18] Würthner, F. Chem. Commun. 2004, 1564.
[19] Kimura, M.; NariKawa, H.; Ohta, K.; Hanabusa, K.; Shirai, H.;
Kobayashi, N. Chem. Mater. 2002, 14, 2711.
References
[1] Liu, H. B.; Li, Y. L.; Xiao, S. Q.; Gan, H. Y.; Jiu, T. G.; Li, H. M.;
Jiang, L.; Zhu, D. B.; Yu, D. P.; Xiang, B.; Chen, Y. F. J. Am. Chem.
Soc. 2003, 125, 10794.
[20] Tominaga, M.; Suzuki, K.; Kawano, M.; Kusukawa, T.; Ozeki, T.;
Sakamoto, S.; Yamaguchi, K.; Fujita, M. Angew. Chem., Int. Ed.
2004, 43, 5621.
[2] Liu, H. B.; Xu, J. L.; Li, Y. J.; Li, Y. L. Accounts Chem. Res. 2010,
43, 1496.
[3] Wang, C. Y.; Tang, W.; Zhong, H. B.; Zhang, X. C.; Shen, Y. J.
Chin. J. Chem. 2009, 27, 2020.
[21] Feyter, S. D.; Schryver, F. C. D. J. Phys. Chem. B 2005, 109, 4290.
[22] Miura, A.; Chen, Z. J.; Uji-i, H.; De Feyter, S.; Zdanowska, M.;
Jonkheijm, P.; Schenning, A. P. H. J.; Meijer, E. W.; Würthner, F.;
De Schryver, F. C. J. Am. Chem. Soc. 2003, 125, 14968.
(Zhao, X.)
282
www.cjc.wiley-vch.de
© 2013 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2013, 31, 277—282