Synthesis, Properties, and Semiconducting Characteristics of BF2 Complexes of β,β-Bisphenanthrene-Fused Azadipyrromethenes

Article abstract of DOI:10.1021/acs.orglett.7b01133

Three novel π-extended BF₂ complexes of β,β-bisphenanthrene-fused azadipyrromethenes containing nine fused rings have been synthesized on the basis of a tandem Suzuki coupling reaction on readily available 2,6-dibromoazaBODIPYs followed by an i

Full text of DOI:10.1021/acs.orglett.7b01133

Letter
pubs.acs.org/OrgLett
Synthesis, Properties, and Semiconducting Characteristics of BF2
Complexes of β,β-Bisphenanthrene-Fused Azadipyrromethenes
Wanle Sheng,† Yu-Qing Zheng,‡ Qinghua Wu,† Yayang Wu,† Changjiang Yu,† Lijuan Jiao,*,†
Erhong Hao,† Jie-Yu Wang,*,‡ and Jian Pei‡
†Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal
University, Wuhu 241000, China
‡Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Peking
100080, China
S
* Supporting Information
ABSTRACT: Three novel π-extended BF2 complexes of β,β-bisphenanthrene-
fused azadipyrromethenes containing nine fused rings have been synthesized
on the basis of a tandem Suzuki coupling reaction on readily available 2,6-
dibromoazaBODIPYs followed by an intramolecular oxidative aromatic
coupling mediated by iron(III) chloride. These resultant BF2 complexes
exhibit strong absorption (extinction coefficients up to 2.4 × 105 M−1 cm−1)
and emission in the near-infrared (NIR) range (790−816 nm) with excellent
photo and thermal stabilities. The hole mobility of the thin-film field-effect
transistors of these dyes fabricated by a solution process reaches up to 0.018
cm2 V−1 s−1.
as π-functional materials.6 In contrast, the synthesis of [α]-fusion
ear-infrared (NIR) dyes with absorption and/or emission
azaBODIPYs containing large aromatic rings and their [β]-fusion
Nlying in the range of 700−2000 nm have found important
analogues (even β,β-bisbenzo-fused azaBODIPYs B, Figure 1)
applications in biomedicine (e.g., as bioimaging and therapeutic
agents) and in material science (as various electronic devices).1
Boron azadipyrromethenes (azaBODIPYs) have received
extensive research interest lately due to their remarkable optical
and electrical properties, especially the good photostability and
the strong tunable absorption at a wavelength above 650 nm.2−4
As demonstrated by α,α-bisbenzo-fused azaBODIPY A (Figure
1) and its pyrazine-fused analogues,5 aromatic ring fusion at the
peripheral positions of the chromophore generally brings the
desired structure rigidity and strong intermolecular π−π
interactions in the solid state, which facilitates their applications
remains a challenge.7
Oxidative ring fusion strategy has recently been used for the
construction of perylene- and porphyrin-fused BODIPYs.8
However, no regioselectivity issue has been involved. Recent
synthetic progress in the preparation of (aza)BODIPYs facilitates
the facile installation of various aromatic moieties, for example,
phenyls onto the 2,6-positions to form 1,2,3,5,6,7-hexaphenyla-
zaBODIPYs 3 (Figure 1). We rationalized that the regioselective
fusion of the 2,3,5,6-tetraphenyl moieties on hexaphenylazaBO-
DIPY 3 via an oxidative ring-fusion reaction9 may straightfor-
wardly generate the desired β,β-bisphenanthrene-fused azaBO-
DIPY chromophore 1 (Scheme 1). Herein, we report the
regioselective straightforward synthesis of a set of β,β-
bisphenanthrene azaBODIPYs 1, their characterizations via X-
ray analysis, optical, stability, and DFT calculations, and the
preliminary investigation of their hole-charge-transport perform-
ance as promising organic field electron transfer (OFET)
materials.
2,6-DibromoazaBODIPY 2a was formed in nearly quantitative
yield from the regioselective bromination of readily available
azaBODIPY 4a using a literature procedure (Scheme 1)2b and
was further applied for the Suzuki coupling reaction with 3,5-
dimethoxyphenylboronic acid to smoothly afford the desired
hexaphenylazaBODIPY 3a in 78% isolated yield. Surprisingly,
Figure 1. Chemical structures of [α]- and [β]-fusion azaBODIPYs A
and B and the general concept for the construction of β,β-
bisphenanthrene fused azaBODIPY 1 from hexaphenylazaBODIPY 3
in this work.
Received: April 13, 2017
© XXXX American Chemical Society
A
DOI: 10.1021/acs.orglett.7b01133
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
Letter
excellent isolated yields (93−96%) using the same procedure
described for 1a from readily available azaBODIPY 4b (Scheme
1) and were characterized by NMR and HRMS. As expected, the
installation of dodecyloxy chains at the 1,7-phenyl moieties of the
azaBODIPY chromophore greatly improves the solubility of the
dyes. In great contrast to azaBODIPY 1a, which shows poor
solubility in common organic solvents, both azaBODIPYs 1b and
1c show good solubility in common organic solvents, like
dichloromethane, THF, and toluene.
Scheme 1. Synthesis of azaBODIPYs 1
AzaBODIPYs 3a−c show nearly identical strong absorption
centered at around 683 nm and moderate fluorescence emission
centered at 716 nm, respectively, in toluene (Figure 3 and Table
the subsequent reaction of azaBODIPY 3a with 10 equiv of FeCl3
in CH2Cl2/CH3NO2 at room temperature afforded exclusively
only one product in nearly qualitative yield (96%). The HRMS
(MALDI) analysis clearly shows that four protons have been
eliminated from this reaction. 1H NMR analysis further confirms
that this generated product is a 2-fold-fusion product.
Fortunately, we were able to unambiguously identify the fusion
position via the X-ray analysis result (Figure 2b), which clearly
shows that it is β,β-bisphenanthrene-fused azaBODIPY 1a.
Figure 3. Overlaid normalized absorption (solid lines) and fluorescence
emission (dotted lines) of 3a (black lines) and 1a (red lines) in toluene.
Table 1. Photophysical Properties of 3a,b and 1a−c at Room
Temperature in Toluene
max
max
λabs
λem
ε
Stokes shift
a
dyes
(nm)
(nm)
(M−1 cm−1
)
Φ
(cm−1
)
3a
3b
3c
1a
1b
1c
683
683
684
804
804
790
716
716
718
816
816
807
76200
81800
0.14
0.11
0.03
0.13
0.17
0.05
700
700
700
200
200
300
86500
215900
235100
208100
a
Fluorescence quantum yields were obtained by using 1,7-diphenyl-
3,5-dimethoxyphenylazadipyrromethene (ϕ = 0.36 in chloroform) as
the reference compound for 3a−c, and Indocyanine Green (ICG) (ϕ
= 0.12 in DMSO) for 1a−c. The standard errors are less than 10%.
Figure 2. Top (and side) views of the X-ray crystal structures of (a) 3a
and (b) 1a and (c) the crystal packing structure of 1a. Hydrogen atoms
are omitted for clarity. Key: C, light gray; N, blue; B, dark yellow; F, light
green; O, red.
1). In comparison with 3a−c, this ring fusion brings more than
100 nm red-shifts in both the absorption and emission bands, a 2-
fold increase of the extinction coefficients (up to 2.3 × 105 M−1
cm−1), a narrowed absorption band (fwhm decreased from 1364
to 448 cm−1), and a decrease of the Stokes shift (up to 11 nm) in
these [β]-fusion azaBODIPYs 1a−c. This red-shift of the spectra
is in good agreement with the DFT calculations and may be
attributed to the slightly stabilized LUMO and the destabilized
HOMO levels caused by ring fusions (Figure 4). Variation of the
alkoxy substituents at the 1,7-phenyls and the alkyl substituents
at the 2,6-phenyl moieties has negligible influence on the
absorption and emission spectra of these azaBODIPYs 1a−c
(Table 1). The small Stokes shift observed for azaBODIPYs 1a−
c indicates the high rigid symmetrical structure of the
chromophore. Although the fluorescence quantum yields are
moderate for azaBODIPYs 1a (0.13), 1b (0.17), and 1c (0.05) in
X-ray crystals of 3a and azaBODIPY 1a suitable for X-ray
analysis were obtained from the slow diffusion of methanol into
their chloroform solutions. Both dyes show almost planar
azadipyrromethene cores (Figure 2). The central chelated BF2
ring of 3a disordered over two orientations. The small dihedral
angle (0.916°) between the two pyrrole units in azaBODIPY 1a
indicates that this ring fusion causes little structural disruption of
the planar structure of the azadipyrromethene core. The dihedral
angles between the 1,7-phenyl moieties and the azadipyrrome-
thene core are between 54 and 59° for 3a, which were slightly
changed to 44−55° in 1a (Table S1).
To demonstrate the versatility of this highly regioselective [β]-
ring-fusion reaction, azaBODIPYs 1b and 1c were synthesized in
B
DOI: 10.1021/acs.orglett.7b01133
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
Letter
obvious substituent-dependent high-field-effect-mobility (0.018
cm2 V−1 s−1 for 1b and 1.32 × 10−4 cm2 V−1 s−1 for 1c, Figure 5
Figure 4. Frontier molecular orbitals and the energies of 3a (left) and 1a
(right).
Figure 5. Transfer (a) and output (b) characteristics of the thin film
FET device based on 1b.
toluene, it was still impressive when considering the >800 nm
emission wavelength of these dyes.
Electrochemical properties of azaBODIPYs 1a−c were
investigated by cyclic voltammetry (CV) (Figure S9). Each of
these three dyes shows two reversible oxidation and two
reversible reduction waves. AzaBODIPYs 1a and 1b show nearly
identical oxidation and reduction waves to each other, with the
oxidation and reduction waves at 0.87 and −0.38 V, respectively
(vs Fc/Fc+). The oxidation and reduction waves for 1c were
slightly different from 1a and 1b, located at 0.97 and −0.35 V.
The HOMO and LUMO energy levels estimated from the half-
wave value for azaBODIPY 1b are +5.21 and −3.90 eV, and the
values for 1c are +5.31 and −3.93 eV, respectively, which match
well with their optical bands.10 The significantly lowered LUMO
levels of 1b and 1c are comparable to many representative n-type
semiconducting materials (such as perylene bisimides and
fullerenes).11
In addition, in the crystal packing structure (Figure 1c),
azaBODIPY 1a showed a well-ordered (a slipped head-to-tail)
two-dimensional structure due to π−π and dipole−dipole
interactions.12,13 The planes of the two molecules are almost
parallel to each other, with a 3.90 Å mean distance between the
two neighboring cores. Although no azaBODIPY based small
molecules have been used in OFET, we envisioned that this
packing mode may favor the charge transport process in this
organic framework.12a Moreover, to demonstrate the potential
application of these two dyes as semiconducting materials, the
thermal characteristics of these compounds were studied by
thermogravimetric analysis. No obvious weight loss was observed
until 310 °C (Figure S7). Their remarkably high thermostability
indicates their good potential as a novel air-stable semiconductor.
The semiconducting properties for 1b and 1c were
investigated by field-effect transistor (FET) measurements. A
top-gate/bottom-contact (TG/BC) device configuration was
used to fabricate FETs. The semiconducting layer was deposited
by spin-coating the toluene solution (4 mg/mL) of either 1b or
1c on a patterned Au/SiO2/Si substrate at 1500 rpm for 30 s.
After thermal annealing of the film for 5 min at 110 °C, a CYTOP
solution was spin-coated as the dielectric layer, and an aluminum
layer was thermally evaporated as the gate electrode.
Interestingly, the OFET devices of these two dyes did not
show the expected n-type transport properties. By contrast, only
p-type transport characteristics were observed for them under
ambient conditions with a > 103 current on/off ratio and an
and Figure S10). The absence of the expected n-type transport
characters in 1b and 1c may be attributed to the concentrated
LUMO distribution, which hampers the intermolecular elec-
tronic overlap.
To understand the substituent-dependent field-effect mobility
of 1b and 1c, atomic force microscopy (AFM) and X-ray
diffraction studies were performed on the thin film (deposited on
Si/SiO2 substrates) of these dyes. Both dyes show similar out-of-
plane distances, which were measured to be 21.06 and 21.63 Å,
respectively. But the thin film of 1b seems to be more in ordered
as indicated by the stranger diffraction signal. The grain size
revealed by AFM indicates that the different p-type transport
properties may associate with the crystallinity of the semi-
conducting layer (Figures S11 and S12). This hole mobility of 1b
is much higher than those of previously reported small molecular
BODIPY dyes14a−d and tetrapyrrole-based dyes14e,f and is even
comparable to those of BODIPY-containing polymers (Figure
S13).15
In summary, we have developed a straightforward approach to
a class of unprecedented β,β-aromatic-ring-fused azaBODIPY
chromophore. The bottom-up selective oxidative ring-fusion
reactions readily provided 1,2,3,5,6,7-hexaphenylazaBODIPY
derivatives. These resultant π-extended systems show highly
spectral selectivity in the NIR region (with narrow absorption
and emission bands), large extinction coefficients, good
thermostability, and interesting semiconducting properties.
The substituent-dependent p-type transport characteristics
under ambient conditions were achieved with the hole mobility
of the thin film devices fabricated by solution process up to 0.018
cm2 V−1 s−1. These results demonstrate the promising
optoelectronic applications of these β,β-bisphenanthrene-fused
azaBODIPYs.
ASSOCIATED CONTENT
* Supporting Information
■
S
Experimental details, tables, additional spectra and CIF files. The
Supporting Information is available free of charge on the ACS
Publications website at DOI: 10.1021/acs.orglett.7b01133.
Experimental details, tables, and additional spectra (PDF)
X-ray data for 1a (CIF)
X-ray data for 3a (CIF)
C
DOI: 10.1021/acs.orglett.7b01133
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
Letter
(6) (a) Gsanger, M.; Bialas, D.; Huang, L.; Stolte, M.; Wurthner, F.
̈
̈
AUTHOR INFORMATION
■
Adv. Mater. 2016, 28, 3615. (b) Stepien, M.; Gonka, E.; Zyla, M.;
Sprutta, N. Chem. Rev. 2017, 117, 3479. (c) Zhylitskaya, H.; Cybinska, J.;
Chmielewski, P.; Lis, T.; Stepien, M. J. Am. Chem. Soc. 2016, 138, 11390.
(7) On the other hand, several β-fused BODIPYs are available:
(a) Hayashi, Y.; Obata, N.; Tamaru, M.; Yamaguchi, S.; Matsuo, Y.;
Saeki, A.; Seki, S.; Kureishi, Y.; Saito, S.; Yamaguchi, S.; Shinokubo, H.
Org. Lett. 2012, 13, 866. (b) Heyer, E.; Retailleau, P.; Ziessel, R. Org. Lett.
2014, 16, 2330. (c) Chua, M. H.; Huang, K.; Xu, J.; Wu, J. Org. Lett.
2015, 17, 4168. (d) Gobo, Y.; Yamamura, M.; Nakamura, T.;
Nabeshima, T. Org. Lett. 2016, 18, 2719. (e) Wakamiya, A.;
Murakami, T.; Yamaguchi, S. Chem. Sci. 2013, 4, 1002. (f) Ni, Y.;
Zeng, W.; Huang, K.; Wu, J. Chem. Commun. 2013, 49, 1217.
Corresponding Authors
*E-mail: jieyuwang@pku.edu.cn.
*E-mail: jiao421@ahnu.edu.cn.
ORCID
Changjiang Yu: 0000-0002-9509-7778
Lijuan Jiao: 0000-0002-3895-9642
Jian Pei: 0000-0002-2222-5361
Notes
The authors declare no competing financial interest.
(8) (a) Jiao, C.; Huang, K.; Wu, J. Org. Lett. 2011, 13, 632. (b) Jiao, C.;
Zhu, L.; Wu, J. Chem. - Eur. J. 2011, 17, 6610. (c) Zeng, L.; Jiao, C.;
Huang, X.; Huang, K.; Chin, W.; Wu, J. Org. Lett. 2011, 13, 6026.
ACKNOWLEDGMENTS
■
(9) (a) Wu, J.; Pisula, W.; Mullen, K. Chem. Rev. 2007, 107, 718.
̈
This work is supported by the National Nature Science
Foundation of China (21372011, 21402001, and 21302009)
and the Nature Science Foundation of Anhui Province
(1508085J07). The numerical calculations in this paper have
been done on the supercomputing system in the Super-
computing Center of USTC.
(b) Grzybowski, M.; Skonieczny, K.; Butenschon, H.; Gryko, D. Angew.
̈
Chem., Int. Ed. 2013, 52, 9900. (c) Narita, A.; Wang, X.; Feng, X.;
́
Mullen, K. Chem. Soc. Rev. 2015, 44, 6616. (d) Nowak-Krol, A.; Gryko,
̈
D. T. Org. Lett. 2013, 15, 5618. (e) Krzeszewski, M.; Gryko, D. T. J. Org.
Chem. 2015, 80, 2893. (f) Chou, C.; Saito, S.; Yamaguchi, S. Org. Lett.
2014, 16, 2868.
(10) Wong, W.-Y.; Wang, X.-Z.; He, Z.; Djurii, A. B.; Yip, C.-T.;
Cheung, K.-Y.; Wang, H.; Mak, C. S. K.; Chan, W.-K. Nat. Mater. 2007,
6, 521.
(11) (a) Ostrick, J. R.; Dodabalapur, A.; Torsi, L.; Lovinger, A. J.;
Kwock, E. W.; Miller, T. M.; Galvin, M.; Berggren, M.; Katz, H. E. J.
Appl. Phys. 1997, 81, 6804. (b) Yamada, K.; Takeya, J.; Takenobu, T.;
Iwasa, Y. Appl. Phys. Lett. 2008, 92, 253311. (c) Itaka, K.; Yamashiro, M.;
Yamaguchi, J.; Haemori, M.; Yaginuma, S.; Matsumoto, Y.; Kondo, M.;
Koinuma, H. Adv. Mater. 2006, 18, 1713.
REFERENCES
■
(1) (a) Yuan, L.; Lin, W.; Zheng, K.; He, L.; Huang, W. Chem. Soc. Rev.
2013, 42, 622. (b) Pansare, V. J.; Hejazi, S.; Faenza, W. J.; Prud’homme,
R. K. Chem. Mater. 2012, 24, 812. (c) Fischer, G. M.; Daltrozzo, E.;
Zumbusch, A. Angew. Chem., Int. Ed. 2011, 50, 1406. (d) Ding, Y.; Tang,
Y.; Zhu, W.; Xie, Y. Chem. Soc. Rev. 2015, 44, 1101. (e) Lei, Z.; Li, X.;
Luo, X.; He, H.; Zheng, J.; Qian, X.; Yang, Y. Angew. Chem., Int. Ed. 2017,
56, 2979.
(2) (a) Loudet, A.; Burgess, K. Chem. Rev. 2007, 107, 4891. (b) Ulrich,
G.; Ziessel, R.; Harriman, A. Angew. Chem., Int. Ed. 2008, 47, 1184.
(c) Boens, N.; Leen, V.; Dehaen, W. Chem. Soc. Rev. 2012, 41, 1130.
(d) Lu, H.; Mack, J.; Yang, Y.; Shen, Z. Chem. Soc. Rev. 2014, 43, 4778.
(e) Ni, Y.; Wu, J. Org. Biomol. Chem. 2014, 12, 3774. (f) Zhao, J.; Xu, K.;
Yang, W.; Wang, Z.; Zhong, F. Chem. Soc. Rev. 2015, 44, 8904.
(3) (a) Killoran, J.; Allen, L.; Gallagher, J. F.; Gallagher, W. M.; O’Shea,
D. F. Chem. Commun. 2002, 1862. (b) McDonnell, S. O.; Hall, M. J.;
Allen, L. T.; Byrne, A.; Gallagher, W. M.; O’Shea, D. F. J. Am. Chem. Soc.
2005, 127, 16360. (c) McDonnell, S. O.; O’Shea, D. F. Org. Lett. 2006, 8,
3493. (d) Wu, D.; O’Shea, D. F. Org. Lett. 2013, 15, 3392. (e) Loudet,
A.; Bandichhor, R.; Burgess, K.; Palma, A.; McDonnell, S. O.; Hall, M. J.;
O’Shea, D. F. Org. Lett. 2008, 10, 4771. (f) Ge, Y.; O’Shea, D. F. Chem.
Soc. Rev. 2016, 45, 3846.
(4) (a) Coskun, A.; Yilmaz, M. D.; Akkaya, E. U. Org. Lett. 2007, 9, 607.
(b) Bellier, Q.; Pegaz, S.; Aronica, C.; Guennic, B. L.; Andraud, C.;
Maury, O. Org. Lett. 2011, 13, 22. (c) Gresser, G.; Hartmann, H. M.;
Wrackmeyer, K. L.; Riede, M. Tetrahedron 2011, 67, 7148. (d) Bellier,
Q.; Dalier, F.; Jeanneau, E.; Maury, O.; Andraud, C. New J. Chem. 2012,
36, 768. (e) Bhuniya, S.; Lee, H.; Jeon, H. M.; Han, J. H.; Lee, J. H.; Park,
N.; Maiti, S.; Kang, C.; Kim, J. S. Chem. Commun. 2013, 49, 7141.
(f) Jiao, L.; Wu, Y.; Wang, S.; Hu, X.; Zhang, P.; Yu, C.; Cong, K.; Meng,
Q.; Hao, E.; Vicente, M. G. H. J. Org. Chem. 2014, 79, 1830. (g) Guo, S.;
Ma, L.; Zhao, J.; Kucukoz, B.; Karatay, A.; Hayvali, M.; Yaglioglu, H. G.;
Elmali, A. Chem. Sci. 2014, 5, 489. (h) Ziegler, C. J.; Chanawanno, K.;
Hasheminsasab, A.; Zatsikha, Y. V.; Maligaspe, E.; Nemykin, V. N. Inorg.
Chem. 2014, 53, 4751. (i) Jiang, X.; Xi, D.; Sun, C.; Guan, J.; He, M.;
Xiao, L. Tetrahedron Lett. 2015, 56, 4868.
(5) (a) Donyagina, V. F.; Shimizu, S.; Kobayashi, N.; Lukyanets, E. A.
Tetrahedron Lett. 2008, 49, 6152. (b) Lu, H.; Shimizu, S.; Mack, J.; Shen,
Z.; Kobayashi, N. Chem. - Asian J. 2011, 6, 1026. (c) Liu, H.; Mack, J.;
Guo, Q.; Lu, H.; Kobayashi, N.; Shen, Z. Chem. Commun. 2011, 47,
12092. (d) Gresser, G.; Hummert, M.; Hartmann, H.; Leo, K.; Riede, M.
Chem. - Eur. J. 2011, 17, 2939. (e) Zheng, W.; Wang, B.; Li, C.; Zhang, J.;
Wan, C.; Huang, J.; Liu, J.; Shen, Z.; You, X. Angew. Chem., Int. Ed. 2015,
54, 9070. (f) Majumdar, P.; Mack, J.; Nyokong, T. RSC Adv. 2015, 5,
78253.
(12) (a) Wang, C.; Dong, H.; Hu, W.; Liu, Y.; Zhu, D. Chem. Rev. 2012,
112, 2208. (b) Takacs, C. J.; Sun, Y.; Welch, G. C.; Perez, A.; Liu, X.;
Wen, W.; Bazan, G. C.; Heeger, A. J. J. Am. Chem. Soc. 2012, 134, 16597.
(c) Huang, L.; Stolte, M.; Burckstummer, H.; Wurthner, F. Adv. Mater.
̈
̈
̈
2012, 24, 5750. (d) Wang, X.; Lin, H.; Lei, T.; Yang, D.; Zhuang, F.;
Wang, J.; Pei, J. Angew. Chem., Int. Ed. 2013, 52, 3117. (e) Lv, A.; Stolte,
M.; Wurthner, F. Angew. Chem., Int. Ed. 2015, 54, 10512.
̈
(13) (a) Kumar, S.; Ho, M.; Tao, Y. Org. Lett. 2016, 18, 4876.
(b) Nakano, M.; Sawamoto, M.; Yuki, M.; Takimiya, K. Org. Lett. 2016,
18, 3770. (c) Ie, Y.; Uchida, A.; Kawaguchi, N.; Nitani, M.; Tada, H.;
Kakiuchi, F.; Aso, Y. Org. Lett. 2016, 18, 4320. (d) Rao, M. R.; Black, H.
T.; Perepichka, D. F. Org. Lett. 2015, 17, 4224. (e) Miyamoto, F.;
Nakatsuka, S.; Yamada, K.; Nakayama, K.; Hatakeyama, T. Org. Lett.
2015, 17, 6158. (f) Chen, W.; Tian, K.; Song, X.; Zhang, Z.; Ye, K.; Yu,
G.; Wang, Y. Org. Lett. 2015, 17, 6146. (g) Ye, Q.; Chang, J.; Shi, X.; Dai,
G.; Zhang, W.; Huang, K.-W.; Chi, C. Org. Lett. 2014, 16, 3966.
́ ̂
(14) (a) Bura, T.; Leclerc, N.; Fall, S.; Leveque, P.; Heiser, T.;
Retailleau, P.; Rihn, S.; Mirloup, A.; Ziessel, R. J. Am. Chem. Soc. 2012,
134, 17404. (b) Poe, A.; Della Pelle, A. M.; Subrahmanyam, A. V.;
White, W.; Wantz, G.; Thayumanavan, S. Chem. Commun. 2014, 50,
2913. (c) Singh, S.; Venugopalan, V.; Krishnamoorthy, K. Phys. Chem.
Chem. Phys. 2014, 16, 13376. (d) Liu, W.; Tang, A.; Chen, J.; Wu, Y.;
Zhan, C.; Yao, J. ACS Appl. Mater. Interfaces 2014, 6, 22496. (e) Gao, D.;
Zhang, X.; Kong, X.; Chen, Y.; Jiang, J. ACS Appl. Mater. Interfaces 2015,
7, 2486. (f) Lu, G.; Kong, X.; Ma, P.; Wang, K.; Chen, Y.; Jiang, J. ACS
Appl. Mater. Interfaces 2016, 8, 6174.
(15) (a) Popere, B. C.; Pelle, A. M. D.; Thayumanavan, S.
Macromolecules 2011, 44, 4767. (b) Usta, H.; Yilmaz, M. D.; Avestro,
A.; Boudinet, D.; Denti, M.; Zhao, W.; Stoddart, J. F.; Facchetti, A. Adv.
Mater. 2013, 25, 4327. (c) Yoshii, R.; Yamane, H.; Nagai, A.; Tanaka, K.;
Taka, H.; Kita, H.; Chujo, Y. Macromolecules 2014, 47, 2316.
(d) Debnath, S.; Singh, S.; Bedi, A.; Krishnamoorthy, K.; Zade, S. S. J.
Phys. Chem. C 2015, 119, 15859.
D
DOI: 10.1021/acs.orglett.7b01133
Org. Lett. XXXX, XXX, XXX−XXX