Structural Engineering of Luminogens with High Emission Efficiency Both in Solution and in the Solid State

Article abstract of DOI:10.1002/anie.201906507

Developing molecules with high emission efficiency both in solution and the solid state is still a great challenge, since most organic luminogens are either aggregation-caused quenching or aggregation-induced emission molecules. This dilemma was overcome by integrating planar and distorted structures with long alkyl side chains to achieve DAπAD type emitters. A linear diphenyl–diacetylene core and the charge transfer effect ensure considerable planarity of these molecules in the excited state, allowing strong emission in dilute solution (quantum yield up to 98.2 %). On the other hand, intermolecular interactions of two distorted cyanostilbene units restrict molecular vibration and rotation, and long alkyl chains reduce the quenching effect of the π–π stacking to the excimer, eventually leading to strong emission in the solid state (quantum yield up to 60.7 %).

Full text of DOI:10.1002/anie.201906507

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Accepted Article
Title: Structural Engineering of Luminogens with High Emission
Efficiency both in Solution and the Solid State
Authors: Yanli Zhao, Hongwei Wu, Zhao Chen, Weijie Chi, Bindra
Anivind Kaur, Long Gu, Cheng Qian, Bing Wu, Bingbing Yue,
Guofeng Liu, Guangbao Yang, and Liangliang Zhu
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201906507
Angew. Chem. 10.1002/ange.201906507
Link to VoR: http://dx.doi.org/10.1002/anie.201906507
http://dx.doi.org/10.1002/ange.201906507

10.1002/anie.201906507
Angewandte Chemie International Edition
COMMUNICATION
Structural Engineering of Luminogens with High Emission
Efficiency both in Solution and the Solid State
Hongwei Wu, Zhao Chen, Weijie Chi, Bindra Anivind Kaur, Long Gu, Cheng Qian, Bing Wu, Bingbing
Yue, Guofeng Liu, Guangbao Yang, Liangliang Zhu* and Yanli Zhao*
Abstract: Developing molecules with high emission efficiency both
in solution and the solid state is still a great challenge, since most
organic luminogens are either aggregation-caused quenching or
aggregation-induced emission molecules. We overcame this
dilemma via integrating planar and distorted structures with long
alkyl side chains to achieve DAπAD type emitters. Linear diphenyl-
diacetylene core and charge transfer effect ensure considerable
planarity of these molecules in excited state, allowing strong
emission in dilute solution (quantum yield up to 98.2 %). On the
other hand, intermolecular interactions of two distorted cyanostilbene
units restrict molecular vibration and rotation, and long alkyl chains
reduce the quenching effect of the π-π stacking to the excimer,
eventually leading to strong emission in the solid state (quantum
yield up to 60.7 %). Thus, multiple bioimaging upon varying the
concentration of the emitters was well established, which may
provide a new vision for applying bright luminescent materials in a
variety of environments.
emission in both dilute solution and aggregated state.17 In these
cases, specific stereogeometry and distinct photophysical
properties between amorphous and aggregated crystalline
states were required. A concise but more precise molecular
design for fabricating such dual-phase (solution and solid state)
highly emissive luminophores is desired.
Organic luminescent materials have been applied in numerous
areas such as bioimaging,1-3 drug release,4,5 sensors,6 light-
emitting diodes,7-10 and memory devices.11 Most of the
luminogens suffer from aggregation-caused quenching (ACQ),
where they can only emit strongly in dilute solution while
showing weak or even no emission in aggregated or solid
state.12 In addition, another type of molecules, namely
aggregation induced emission (AIE) molecules13-15 could exhibit
non-radiative decay via intramolecular rotation in dilute solution
whereas becoming highly emissive in aggregated or solid state.
Nevertheless, obtaining luminophores that can emit strongly
both in dilute solution and the solid state is still a great challenge.
Tang and coworkers applied the conjugation-induced rigidity
effect to obtain three triphenylamine fluorophores showing
strong emission in single molecular and aggregated states.16
Huang et al. developed self-assembled cages containing Pt(II)
centers and tetraphenylethylene ligands to produce strong
Figure 1. Illustration of combined structural engineering (planar core
+
distorted unit + alkyl side chain) for the design of linear DAπAD type emitters.
a) Chemical structures of compounds 1-4. F represents fluorescence. b)
Schematic representation of a planar excited state of compound 1, leading to
strong emission in solution. c) Schematic representation of
a proposed
molecular alignment of compound 1, where the distorted CS unit limits
intramolecular vibration and rotation, and long alkyl chain depresses
unfavorable face-to-face π-π stacking interaction, leading to strong emission
in the solid state. Insets in b,c) show bright photoluminescence of compound 1
in dilute solution and solid powder state, respectively.
Inspired by these relevant findings where the gap between
ACQ and AIE compounds can be eliminated by structural
engineering, herein, we present a rational strategy to create
luminogens with high emission efficiency both in solution and
the solid state, so as to achieve advanced emissive applications.
Since bright molecules in solution require substantial structural
rigidity to limit intramolecular motions,18 we here employed a
planar diphenyl-diacetylene (DPDA) structure19 as the core to
constitute π-conjugated molecules (Figure 1). As compared to
single and double bond skeletons, the diacetylene group can
greatly limit molecular twisting and improve the regularity of the
molecules by connecting with two benzene rings. On the other
hand, considerable distorted conformation is also needed to
prevent detrimental exciton interactions in the solid state.
Therefore, we introduced donor-acceptor (D-A) type
cyanostilbene (CS) to DPDA to suppress molecular rotation for
improved solid-state emission. Though CS is distorted in the
solid state, it may also become planar in dilute solution due to
the bond length change under the charge transfer (CT) effect.
Meanwhile, we added long alkyl side chains20 to the CS unit
[a]
Dr. H. Wu,[†] Mr. B. Wu, Ms. B. Yue, Prof. Dr. L. Zhu
State Key Laboratory of Molecular Engineering of Polymers
Department of Macromolecular Science
Fudan University, Shanghai 200438, China
E-mail: zhuliangliang@fudan.edu.cn
[b]
Dr. H. Wu, Ms. B. A. Kaur, Dr. L. Gu, Dr. C. Qian, Dr. G. Liu, Dr. G.
Yang, Prof. Y. L. Zhao
Division of Chemistry and Biological Chemistry
School of Physical and Mathematical Sciences
Nanyang Technological University
21 Nanyang Link, Singapore 637371
E-mail: zhaoyanli@ntu.edu.sg
[c]
[d]
[†]
Dr. Z. Chen[†]
School of Computer Science and Technology
Donghua University, Shanghai 201620, China
Dr. W. Chi
Singapore University of Technology and Design
8 Somapah Road, Singapore 487372
These authors contributed equally to this work.
Supporting information for this article is given via a link at the end of
the document.
1
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10.1002/anie.201906507
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COMMUNICATION
with the anticipation of suppressing unfavorable π–π stacking
interactions in the solid state to further enhance the quantum
yield (QY). The alkyl chains would not affect the planarity of the
molecules for showing strong emission in solution state because
of their flexibility. Thus, four compounds 1-4 with the same
DAπAD (Figure 1a) structure but different side alkyl chains were
prepared for the investigations. Their synthesis is detailed in the
Supporting Information.
dominates the emission property. As crystal structures were
difficult to obtain, we employed computational study to explore
the ground and excited state conformation of compounds 1 and
4. Density functional theory (DFT) calculations show that the
HOMO is located on the whole aromatic structures. However,
the LUMO distribution on the methoxybenzene unit becomes
lesser on account of its electron donor property (Figure 3a).
Photoexcitation to the first excited singlet state (S1) mainly
involves the transition from HOMO to LUMO with large oscillator
strength of 3.4292 and 3.2071 for compounds 1 and 4,
respectively. Moreover, compounds 1 (387 nm) and 4 (385 nm)
show similar maximum absorption wavelength, which are in
good agreement with experimental results (Figure 2a). As
compared to the structures in the ground state, molecular
conformation in the excited state tends to be more planar,
evidenced by the rotation of dihedral angle between phenyl and
cyano groups from ~25º to ~4º (Figure 3b). The CT effect
between electron withdrawing cyano group and electron
donating benzene ring could increase the bond length and relax
the distorted conformation in the excited state. Weak emission in
solution might be observed if the molecule does not have such a
structure for the CT effect.22 Since the excited state
conformation largely determines the molecular emission
property, such a planar conformation in the excited state could
effectively diminish the molecular vibration and rotation so as to
improve the efficiency of radiative process. Thus, the bright
emission property of these molecules was unambiguously
observed in dilute solution. In addition, compound 4 showed the
lowest QY, perhaps due to weaker electronic ability of the
phenolic hydroxyl group as compared to the alkoxy one on other
compounds. Strong electron donating ability could promote the
CT effect for molecules with more planar conformation in
solution.
Figure 2. Photophysical properties in solution. a) Absorbance spectra of
compounds 1-4 in THF. b) Normalized emission spectra of compound 1 in
different solvents upon 365 nm excitation. c) Photographs of compound 1 in
corresponding solutions under a 365 nm UV light. d) Photoluminescent lifetime
of compound 1 in DMF upon 365 nm excitation measured at 450 and 500 nm
emission. All measurements were performed at room temperature with the
concentration of 10 μM.
Photophysical properties of these compounds were firstly
investigated in different solutions. Compounds 1-4 all show the
maximum absorption peaks at about 390 nm in tetrahydrofuran
(THF, Figure 2a). Meanwhile, they present strong emission in
different solvents (Figures 2b and S1). In particular, the highest
peak around 440 nm and a shoulder peak around 470 nm were
observed in toluene, which might be associated with two
different luminescent moieties (DPDA and CS). They also exhibit
similar emission bands in dichloromethane (DCM) and THF. In
addition, the two peaks could merge into a single band with
longer wavelength in N,N-dimethylformamide (DMF), featuring
the CT effect in these molecules.20,21 For instance, compound 1
exhibits bright emission in different solvents under the UV light
(Figure 2c), and the emission color changes from blue (in THF)
to green (in DMF) with the increase of the solvent polarity
(Figure S2). The CT character could also be proven by the
decreased absorption peak at around 400 nm, due to the
increase of the dipole moment in the CT state upon increasing
the solvent polarity (Figure S1d). The fluorescence lifetime
increases from 1.5 ns (at 450 nm) to 3.0 ns (at 500 nm) due to
the emission redshift (Figure 2d). The fluorescence QY of four
compounds in THF is 98.2%, 74.7 %, 96.3%, and 39.5 %,
respectively.
Figure 3. a) HOMO and LUMO distribution, and photoexcitation properties of
compounds 1 and 4. b) Geometrical conformation of compounds 1 and 4 in
ground and excited states.
For further understanding the intense emission in dilute
solution, we need to know the molecular conformation that
2
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10.1002/anie.201906507
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Figure 4. Photophysical studies in the solid state. a) Emission spectra of compound 1 (100 μM) in THF/H2O with different water fractions under 365 nm excitation.
b) Photographs of compound 1 in THF/H2O with different water fractions under 365 nm UV light. c) TEM images of compound 1 prepared from THF/H2O with 70%
and 90% water. d) Emission spectra of compound 1 in PMMA (0.07 /100 mg) and in the solid powder with inserted photograph. e) Powder XRD pattern of solid
powder 1 with the inset showing corresponding TEM image. f) GiWAXS spectrum of solid state 1 prepared from DCM. g) Powder XRD pattern and non-emissive
photograph of solid powder 4. h) Optimized geometrical conformation of 1-dimer and 4-dimer.
In order to compare the photophysical properties of these
molecules in aggregated state, we investigated their emission
spectra in THF/H2O solution with different water fractions.
Compounds 1-3 show similar emission behavior with gradual
reduction of emission intensity when the water fraction changes
from 0% to 50% (Figures 4a and S3). When the water fraction
reaches 50%, their emission band starts to shift
bathochromically and the reduction of emission intensity
becomes slower. The maximum emission wavelength continues
to shift into the green spectral region upon the water fraction
increase from 70% to 90%, whereas the emission intensity
keeps unchanged. Correspondingly, their solution luminescence
colors are also clearly distinguished under UV light (Figure 4b).
To our surprise, the emission intensity of compound 1 in
THF/H2O with 90% water becomes even stronger than that with
70% water. Similarly, compounds 2 and 3 also exhibit relatively
strong emission in THF/H2O with 90% water. In addition, their
absorbance (Figure S4) is blue shifted in THF/H2O with 90%
water as compared to that in THF, suggesting that these
molecules form unique aggregates. As amorphous aggregates
are normally present in high water content solution,15,23,24
transmission electron microscopy (TEM) images show that these
samples prepared from THF/H2O with 70% water give irregular
block aggregates. Interestingly, these aggregates turn regular in
THF/H2O with 90% water (Figure 4c). No major diffraction peaks
observed in powder X-ray diffraction (Figure S5) suggests
amorphous nature of 1 in THF/H2O with 90% water. Its QY in
THF/H2O with 90% water is 40.3 %, indicating that it is very
bright among the related amorphous materials.23 These results
demonstrate that this compound has strong emission both in
dilute solution and amorphous aggregated state, unlike most of
the traditional AIE molecules only showing bright emission from
the crystal state.15,23 Higher emission in solution as compared to
that in amorphous aggregated state may be explained by the
reduced molecular planarity in a loosely stacked state that
cannot well restrict the molecule movement. Compounds 2 and
3 present relatively lower brightness than 1 in THF/H2O with
90% water. For compound 4, the decrease of emission intensity
was observed with the increase of water fraction until complete
quenching (Figure S6), well indicating that long alkyl chains
could prevent unfavorable π-π stacking to maintain the emission
pathway.
To further explore the photophysical properties upon the
formation of the aggregated state, solid powders were prepared
from selected solvent conditions. Solid powers 1-3 could be
straightforwardly obtained from corresponding DCM solutions.
All these powers display remarkably strong green emission with
similar emission maximum around 500 nm (Figures 4d and S7).
The redshifted emission as compared to the monomer one in
THF (Figure 1b) or poly(methyl methacrylate) (PMMA, Figure
4d) is due to the formation of the excimer, proven by the broad
fluorescence band without a vibrational structure in the solid
state and a wavelength shift around 50 nm.25 In addition, the
redshifted UV spectra further confirm the formation of the
3
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10.1002/anie.201906507
Angewandte Chemie International Edition
COMMUNICATION
excimer (Figure S7a). The QY of powder 1 is as high as 60.7%,
followed by moderate QY of 36.3% for 2 and 26.7% for 3.
Compound 4 did not show any solid state emission, supporting
that the alkyl chains have a positive influence on the solid state
emission of this type of compounds.
pattern of 4 are quite strong (Figure 4g), explaining its obvious
emission quenching in the solid state. According to the
optimized dimeric structures (Figure 4h) of 1 and 4 (1-dimer and
4-dimer) by time-dependent DFT calculations, misaligned
stacking was observed between two nearest benzene rings in 1-
dimer, whereas obvious face-to-face π-π stacking was shown in
4-dimer. In addition, 1-dimer presents strong absorption (f =
2.8195), corresponding to a dominant transition from HOMO to
LUMO (Figure S9). However, such phenomenon is replaced by
a main transition contribution from HOMO to LUMO-1 upon the
photoexcitation in 4-dimer. Corresponding oscillator strength of
4-dimer is only 0.0063, originated from dark state of the solid
form on account of strong π-π stacking interaction.
ACQ molecules normally need low concentrations to avoid
aggregation for bioimaging,27 whereas AIE molecules require
high concentrations to form nano-aggregates for bioimaging.28-30
These facts increase the preparation complicacy during the
pretreatment, and would easily cause erroneous signal reading
due to the fluctuation of probe concentration. Herein, we
To better understand the solid state emission mechanism, the
solid state stacking was investigated by powder X-ray diffraction
(XRD). It is known that the π-π stacking can often deteriorate
the emission of molecules in the solid state with the d spacing
around 3.5 Å through easily formed closed excimer or other
species to facilitate non-radiative pathway.20 The powder XRD
pattern of 1 shows a weak peak at 2θ = 25.1° with the d spacing
of 3.5 Å (Figure 4e), indicating that the molecule only has a little
π−π stacking in the solid state that would reduce the non-
radiative decay of the excimer. On the contrary, strong powder
XRD peaks below 10° reflect that the molecule basically adopts
long distance stacking, featuring a crystalline nature in the solid
state, which is also supported by regular block morphology in
TEM image (Figure 4e). Such a crystalline effect would naturally
enhance the emission via the reduction of molecular vibration
and rotation. This is the reason why the emission of powder 1 is
stronger than the emission of its amorphous aggregates. To
further discern the stacking mechanism of powder 1, we applied
grazing incidence wide angle X-ray scattering (GiWAXS, Figure
4f) to characterize the packing orientation and d spacing. The in-
plane (010) diffraction near qz = 1.5 Å−1 corresponding to the π-
π stacking distance of the solid26 is very weak. Meanwhile,
strong intermolecular interactions in qxy direction verify that the
distorted CS structure could restrict the molecular vibration and
rotation, thereby improving the radiation transition process of
excited state electrons.
established
a multiple live-cell imaging strategy by using
compound 1 on account of its high brightness no matter in
monomeric, amorphous or crystalline states. For meeting the
practical use, we complexed 1.4 mg, 0.14 mg and 0.014 mg of 1
with amphiphilic triblock copolymer F127 of the same weight (5
mg) to obtain well-dispersed nanoparticles with an average
diameter of around 200 nm in aqueous media (Figure S10). The
viability of HepG2 cells (liver hepatocellular cells) is over 85%
after the incubation with all three types of nanoparticles for 24 h
(Figure S11), indicating that they are low toxic and suitable for
bioimaging. Figure 5 shows confocal images of living HepG2
cells incubated with these nanoparticles for 6 h. The distribution
throughout the cytoplasmic area of cells exhibits that these
nanoparticles are successfully internalized by the cells. Three
types of nanoparticles with different concentrations reveal bright
emission in the green channel, demonstrating that compound 1
could efficiently image cells regardless of its low or high
concentration.
In summary, we have developed
a practical molecular
engineering strategy by combining planar and distorted
structures with long alkyl side chains to obtain DAπAD
molecules with bright emission in dilute solution, amorphous
state and solid crystalline state. The DPDA core and CT effect
from D-A components allow the molecules to possess planar
excited state with high emission in dilute solution. In addition, the
distorted CS structures jointed with long alkyl chains could
restrict molecular rotation and vibration in the solid state,
enabling the strong emission. Weak π-π stacking of the
compounds proven by powder XRD, GiWAXS and
computational simulations is responsible for avoiding the non-
radiative decay of the excimer to present strong emission.
Efficient bioimaging in HepG2 cells has been achieved after the
incubation with different concentrations of the probe. We believe
that this strategy could be valuable for guiding the development
of highly emissive molecules and materials in different situations,
benefiting to their practical applications.
Figure 5. Confocal images of HepG2 cancer cells incubated with 1 (0.014 mg)
/ F127 (5 mg) for 6h: a) bright field, b) with 4’,6-diamidino-2-phenylindole
(DAPI) staining, c) with 1 staining, d) merged image of b) and c). Incubated
with 1 (0.14 mg) / F127 (5 mg) for 6h: e) bright field, f) with DAPI staining, g)
with 1 staining, and h) merged image of f) and g). Incubated with 1 (1.4 mg) /
F127 (5 mg) for 6h: i) bright field, j) with DAPI staining, k) with 1 staining, and
l) merged image of j) and k).
Compound 2 shows moderate intensity of the π-π stacking
signal in the powder XRD pattern (Figure S8), suggesting its
lower effectiveness of preventing the stacking through its linear
side chains as compared with branched alkyl chains from
compound 1. In contrast, these signals in the powder XRD
Acknowledgements
4
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10.1002/anie.201906507
Angewandte Chemie International Edition
COMMUNICATION
[20] L. Zong, Y. Xie, C. Wang, J. R. Li, Q. Li, Z. Li, Chem. Commun.
2016, 52, 11496.
The research is supported by the Singapore Agency for Science,
Technology and Research (A*STAR) AME IRG grant
(A1883c0005), the Singapore National Research Foundation
Investigatorship (NRF-NRFI2018-03), and partially by the
National Key Research and Development Program of China
(2017YFA0207700).
[21] H. G. Lu, Y. Zheng, X. W. Zhao, L. J. Wang, S. Q. Ma, X. Q. Han,
B. Xu, W. J. Tian, H. Gao, Angew. Chem. Int. Ed. 2016, 55, 155.
[22] Z. Zhao, S. Chen, J. W. Lam, P. Lu, Y. Zhong, K. S. Wong, H. S.
Kwok, B. Z. Tang, Chem. Commun. 2010, 46, 2221.
[23] a) D. Ding, K. Li, B. Liu, B. Z. Tang, Acc. Chem. Res. 2013, 46,
2441. b) Z. Zhang, B. Xu, J. Su, L. Shen, Y. Xie, H. Tian, Angew.
Chem. Int. Ed. 2011, 50, 11654. b) Z. An, C. Zheng, Y. Tao, R.
Chen, H. Shi, T. Chen, Z. Wang, H. Li, R. Deng, X. Liu, W. Huang,
Nat. Mater. 2015, 14, 685.
[24] Z. Zhao, B. Chen, J. Geng, Z. Chang, L. Aparicio-Ixta, H. Nie, C. C.
Goh, L. G. Ng, A. Qin, G. Ramos-Ortiz, B. Liu, B. Z. Tang, Part.
Part. Syst. Charact. 2014, 31, 481.
[25] H. Ohkita, S. Ito, M. Yamamoto, Y. Tohda, K. Tani, J. Phys. Chem.
A 2002, 106, 2140.
[26] Q. V. Hoang, C. E. Song, S. J. Moon, S. K. Lee, J. C. Lee, B. J.
Kim, W. S. Shin, Macromolecules 2015, 48, 3918.
[27] G. Battistelli, A. Cantelli, G. Guidetti, J. Manzi, M. Montalti,
Nanobiotechnology 2016, 8, 139.
[28] L. Yan, Y. Zhang, B. Xu, W. Tian, Nanoscale 2016, 8, 2471.
[29] W. C. Wu, C. Y. Chen, Y. Tian, S. H. Jang, Y. Hong, Y. Liu, W. C.
Chen, Adv. Funct. Mater. 2010, 20, 1413.
[30] D. Li, W. Qin, B. Xu, J. Qian, B. Z. Tang, Adv. Mater. 2017, 29,
1703643.
Keywords: bioimaging • luminescence• molecular engineering •
molecular stacking • noncovalent interactions
[1]
a) J. Qian, B. Z. Tang, Chem. 2017, 3, 56. b) C. X. Yin, K. M.
Xiong, F. J. Huo, J. C. Salamanca, R. M. Strongin, Angew. Chem.
Int. Ed. 2017, 56, 13188.
[2]
a) X. Tan, T. Constantin, K. L. Sloane, A. S. Waggoner, M. P.
Bruchez, B. A. Armitage, J. Am. Chem. Soc. 2017, 139, 9001. b) X.
Bai, Y. Huang, M. Lu, D. Yang, Angew. Chem. Int. Ed. 2017, 129,
13053.
[3]
a) L. Zhu, X. Li, Q. Zhang, X. Ma, M. Li, H. Zhang, Z. Luo, H.
Ågren, Y. L. Zhao, J. Am. Chem. Soc. 2013, 135, 5175; b) Y. Zhou,
Y. Zhuang, X. Li, H. Ågren, L. Yu, J. Ding, L. Zhu, Chem. Eur. J.
2017, 23, 7642.
[4]
[5]
a) P. Xing, Y. Zhao, Adv. Mater. 2016, 28, 7304. b) Y. Cheng, Y.
Chang, Y. Feng, H. Jian, Z. Tang, H. Zhang, Angew. Chem. Int. Ed.
2018, 57, 246.
a) X. Chen, W. Zhang, Chem. Soc. Rev. 2017, 46, 734. b) T.
Senthilkumar, L. Zhou, Q. Gu, L. Liu, F. Lv, S. Wang, Angew.
Chem. Int. Ed. 2018, 57, 13114. c) F. Zhang, Q. Ni, O. Jacobson,
S. Cheng, A. Liao, Z. Wang, G. Niu, Angew. Chem. Int. Ed. 2018,
57, 7066.
[6]
[7]
a) Z. Cheng, H. Shi, H. Ma, L. Bian, Q. Wu, L. Gu, S. Cai, X.
Wang, W. Xiong, Z. An, W. Huang, Angew. Chem. Int. Ed. 2018,
57, 678. b) Q. Zhang, D. Li, X. Li, P. White, J. Mecinovic, X. Ma, H.
Ågren, R. Nolte, H. Tian, J. Am. Chem. Soc. 2016, 138, 13541. c)
S. Nishizawa, Y. Kato, N. Teramae, J. Am. Chem. Soc. 1999, 121,
9463.
a) K. T. Ly, R. W. Chen, H. W. Lin, Y. J. Shiau, S. H. Liu, P. T.
Chou, Y. Chi, Nat. Photon. 2017, 11, 63. b) L. S. Cui, H. Nomura,
Y. Geng, J. U. Kim, H. Nakanotani, C. Adachi, Angew. Chem. Int.
Ed. 2017, 56, 1571.
[8]
[9]
G. J. Li, T. Fleetham, J. Li, Adv. Mater. 2014, 26, 2931.
Z. Q. Xie, B. Yang, F. Li, G. Cheng, L. L. Liu, G. D. Yang, H. Xu, L.
Ye, M. Hanif, S. Y. Liu, D. G. Ma, Y. G. Ma, J. Am. Chem. Soc.
2005, 127, 14152.
[10] a) B. Geffroy, P. Le Roy, C. Prat, Polym. Int. 2006, 55, 572; b) H.
Wu, W. Chi, G. Baryshnikov, B. Wu, Y. Gong, D. Zheng, X. Li, Y.
Zhao, X. Liu, H. Agren, L. Zhu, Angew. Chem. Int. Ed. 2019, 58,
4328.
[11] Y. Liu, Z. Zhou, L. Qu, B. Zou, Z. Chen, Y. Zhang, J. Xu, Mater.
Chem. Front. 2017, 1, 326.
[12] M. Belletête, J. Bouchard, M. Leclerc, G. Durocher,
Macromolecules 2005, 38, 880.
[13] J. Luo, Z. Xie, L. Cheng, H. Chen, C. Qiu, H. S. Kwok, X. Zhan, Y.
Liu, D. B. Zhu, B. Z. Tang, Chem. Commun. 2001, 37, 1740.
[14] a) B. K. An, D. S. Lee, J. S. Lee, Y. S. Park, H. S. Song, S. Y. Park,
J. Am. Chem. Soc. 2004, 126, 10232. b) H. Wu, Y. Zhou, L. Yin, C.
Hang, X. Li, H. Ågren, L. Zhu, J. Am. Chem. Soc. 2017, 139, 785-
791.
[15] a) H. Wei, Z. Zhao, C. Wei, G. Yu, Z. Liu, B. Zhang, Z. Bian, C.
Huang, Adv. Funct. Mater. 2016, 26, 2085. b) S. A. Fateminia, Z.
Wang, C. C. Goh, P. N. Manghnani, W. Wu, D. Mao, B. Liu, Adv.
Mater. 2017, 29, 1604100.
[16] G. Chen, W. Li, T. Zhou, Q. Peng, D. Zhai, H. Li, W. Z. Yuan, Y. M.
Zhang, B. Z Tang, Adv. Mater. 2015, 27, 4496.
[17] X. Yan, T. Cook, P. Wang, F. Huang, P. J. Stang, Nat. Chem.
2015, 7, 342.
[18] a) Z. Zhang, C. L. Chen, Y. A. Chen, Y. C. Wei, J. Su, H. Tian, P.
T. Chou. Angew. Chem. Int. Ed. 2018, 130, 10028. b) S. Zhang, A.
Qin, J. Sun, B. Tang, Prog. Chem. 2011, 23, 623. c) W. Chen, C. L.
Chen, Z. Zhang, Y. A. Chen, W. C. Chao, J. Su, H. Tian, P. T.
Chou. J. Am. Chem. Soc. 2017, 139, 1636.
[19] a) L. Zhu, H. Tran, F. L. Beyer, S. D. Walck, X. Li, H. Ågren, L. M.
Campos, J. Am. Chem. Soc. 2014, 136, 13381. b) L. Zhu, M. T.
Trinh, L. Yin, Z. Zhang. Chem. Sci. 2016, 7, 2058.
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10.1002/anie.201906507
Angewandte Chemie International Edition
COMMUNICATION
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COMMUNICATION
The integration of planar and
distorted structures with long alkyl
side chains to obtain molecules with
high emission efficiency both in
solution and the solid state is
demonstrated. Efficient intracellular
bioimaging using the molecules with
Hongwei Wu, Zhao Chen, Weijie Chi,
Bindra Anivind Kaur, Long Gu, Cheng
Qian, Bing Wu, Bingbing Yue,
Guofeng
Liu,
Guangbao
Yang
Liangliang Zhu,* Yanli Zhao*
Page No. – Page No.
different
concentrations
Structural
Engineering
of
demonstrates the possibility of
applying the highly emissive
systems.
Luminogens with High Emission
Efficiency both in Solution and the
Solid State
6
This article is protected by copyright. All rights reserved.