Journal of the American Chemical Society
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Accession Codes
lower electronic density at the central phenyl rings than its
electron-donating derivatives. In contrast, TPM-CN and TPM-
NO2, with strong electron-withdrawing groups, exhibited low
electronic density at the central phenyl rings, and the electrons
were pulled to the exterior cyano and nitro groups.
Accordingly, a complete picture of clusteroluminescence of
these different systems was summarized from the perspective
of intramolecular TSC (Figure 9b). In the excited state,
electron-rich TPM derivatives pushed electrons from donors to
the central phenyl rings, to trigger an inward charge transfer
(ICT) process and stabilize the intramolecular TSC. There-
fore, from TPM, then TPM-MO, and finally to TPM-DMA,
the wavelength and efficiency of clusteroluminescence became
longer and higher. In contrast, TPM derivatives with electron-
withdrawing groups attracted electrons from the central phenyl
rings to the exterior acceptors, to produce an outward charge
transfer (OCT) and destabilize the TSC. Finally, TPM-CN
and TPM-NO2 showed inefficient clusteroluminescence,
although the energy levels of their TSC states were lower
than TPM and even their electron-rich cousins.
mentary crystallographic data for this paper. These data can be
contacting The Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
■
Corresponding Authors
Ben Zhong Tang − Department of Chemistry, Hong Kong
Branch of Chinese National Engineering Research Center for
Tissue Restoration and Reconstruction and Institute for
Advanced Study, The Hong Kong University of Science and
Technology, Kowloon, Hong Kong 999077, China; Shenzhen
Institute of Aggregate Science and Technology, School of
Science and Engineering, The Chinese University of Hong
Kong, Shenzhen 518172, China; AIE Institute, Guangzhou
Haoke Zhang − MOE Key Laboratory of Macromolecular
Synthesis and Functionalization, Department of Polymer
Science and Engineering, Zhejiang University, Hangzhou
310027, China; Guangdong Provincial Key Laboratory of
Luminescence from Molecular Aggregates, South China
University of Technology, Guangzhou 510640, China;
CONCLUSION
■
In this work, nonconjugated triphenylmethane and its
derivatives with electron-donating (TPM-DMA and TPM-
MO) and electron-withdrawing (TPM-CN and TPM-NO2)
groups were synthesized, and their photophysical properties
were systematically investigated. Except TPM-NO2, all the
molecules exhibited dual emission in the aggregate state: a
short-wavelength peak from TBC and a long-wavelength
clusteroluminescence stemmed from TSC. Meanwhile, in-
troduction of the electron-donating groups had been found to
red-shift the wavelength and increase the efficiency of the
clusteroluminescence at the same time. Crystal packing and
theoretical calculation suggested that the addition of donors
not only increased the electronic density for TSC but also
stabilized the formed excitons by restricting the intramolecular
motion. However, the introduction of acceptors decreased the
emission efficiency, but still caused a bathochromic shift in
clusteroluminescence. Different from TPM and the electron-
donating counterparts, TPM-CN and TPM-NO2 exhibited
both intra- and intermolecular TSC to result in the reddest
clusteroluminescence of TPM-CN. But the vigorous excited-
state intramolecular motion and unfavorable intermolecular
PET process destabilized the excited excitons to eventually
quench the light emission. This work not only proves the
general mechanism of through-space conjugation for cluster-
oluminescence in nonconjugated luminogens but also provides
a reliable strategy to manipulate its emission efficiency and
color simultaneously. It is anticipated that the development of
TSC theories will establish a significant linkage between
molecular and aggregate photophysics.
Authors
Jianyu Zhang − Department of Chemistry, Hong Kong Branch
of Chinese National Engineering Research Center for Tissue
Restoration and Reconstruction and Institute for Advanced
Study, The Hong Kong University of Science and Technology,
Lianrui Hu − Department of Chemistry, Hong Kong Branch of
Chinese National Engineering Research Center for Tissue
Restoration and Reconstruction and Institute for Advanced
Study, The Hong Kong University of Science and Technology,
Kowloon, Hong Kong 999077, China
Kaihua Zhang − State Key Laboratory of Chemo/Biosensing
and Chemometrics, College of Chemistry and Chemical
Engineering, Hunan University, Changsha 410082, China
Junkai Liu − Department of Chemistry, Hong Kong Branch of
Chinese National Engineering Research Center for Tissue
Restoration and Reconstruction and Institute for Advanced
Study, The Hong Kong University of Science and Technology,
Kowloon, Hong Kong 999077, China
Xingguang Li − Department of Chemistry, Hong Kong Branch
of Chinese National Engineering Research Center for Tissue
Restoration and Reconstruction and Institute for Advanced
Study, The Hong Kong University of Science and Technology,
Kowloon, Hong Kong 999077, China
ASSOCIATED CONTENT
■
Haoran Wang − Department of Chemistry, Hong Kong
Branch of Chinese National Engineering Research Center for
Tissue Restoration and Reconstruction and Institute for
Advanced Study, The Hong Kong University of Science and
Technology, Kowloon, Hong Kong 999077, China
Zhaoyu Wang − Department of Chemistry, Hong Kong
Branch of Chinese National Engineering Research Center for
Tissue Restoration and Reconstruction and Institute for
Advanced Study, The Hong Kong University of Science and
sı
* Supporting Information
The Supporting Information is available free of charge at
Materials and methods, synthetic procedures, character-
ization, crystallographic data (TPM-DMA, TPM-MO,
TPM-CN, and TPM-NO2), and computational details,
including Figures S1−S35 and Tables S1−S14 (PDF)
9572
J. Am. Chem. Soc. 2021, 143, 9565−9574