\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[greek,english]{babel}



\usepackage{float}








\begin{document}

\title{Emerging Clusteroluminescence from Complexes between Carbonyl-Based
Polymers and Organic Base}



\author[1]{Hongwei Lu}%
\author[2]{Yuan Xie}%
\author[1]{Ziteng Zhang}%
\author[1]{Zhiming Zhang}%
\author[1]{Jing Zhi Sun}%
\author[1]{Haoke Zhang}%
\author[3]{Ben Zhong Tang}%
\affil[1]{Zhejiang University}%
\affil[2]{Shenzhen University}%
\affil[3]{The Chinese University of Hong Kong - Shenzhen}%


\vspace{-1em}



  
  \date{June 14, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
The study of luminescence phenomena in non-conjugated systems, namely
clusteroluminescence, has gained significant attention for the
development of advanced luminescent materials. While conventional
strategies to manipulate the luminescent performances are based on
complicated chemical reactions. In contrast, nature employs complexation
to modulate luminescence, inspiring researchers to adopt an engineering
approach for the construction of efficient clusteroluminogens. In this
work, we explore the complexation-induced clusteroluminescence of
carbonyl-based polymers with nitrogen-containing organic bases,
exemplified by polyamide, polyester, polycarbonate, and
poly(monothiocarbonate). The results demonstrate an increase in the
intrinsic 440 nm emission of carbonyl groups and the emergence of new
emission peaks upon complexation. The study proposes a through-space
n...\selectlanguage{greek}π \selectlanguage{english}complex mechanism, highlighting the potential of complexation as a
strategy for modulating the clusteroluminescent properties of
non-conjugated systems. Further research is necessary to unravel
underlying mechanisms, optimize cluster structures, and explore new
materials for complexation, thereby advancing optoelectronics and
photonics fields and enabling practical applications of
clusteroluminescent materials.%
\end{abstract}%



\sloppy


\textbf{Cite this paper:}\emph{Chin. J. Chem.} \textbf{2023} , \emph{41}
, XXX---XXX. \textbf{DOI: 10.1002/cjoc.202300XXX}

Emerging Clusteroluminescence from Complexes between Carbonyl-Based
Polymers and Organic Base

Hongwei Lu,\textsuperscript{\#,\emph{a,b,c}} Yuan
Xie,\textsuperscript{\#,\emph{d}} Ziteng
Zhang,\emph{\textsuperscript{a,b,c}} Zhiming
Zhang,\emph{\textsuperscript{a,b,c}} Jing Zhi
Sun,\emph{\textsuperscript{a,c}} Haoke
Zhang,*\textsuperscript{,\emph{a,b,c}} and Ben Zhong
Tang*\textsuperscript{,a,\emph{e}}

\textsuperscript{a} MOE Key Laboratory of Macromolecular Synthesis and
Functionalization, Department of Polymer Science and Engineering,
Zhejiang University, Hangzhou 310027, China\textsuperscript{b}
Zhejiang-Israel Joint Laboratory of Self-Assembling Functional
Materials, ZJU-Hangzhou Global Scientific and Technological Innovation
Center, Zhejiang University, Hangzhou 311215, China\textsuperscript{c}
Centre of Healthcare Materials, Shaoxing Institute, Zhejiang University,
Shaoxing 312000, China\textsuperscript{d} Center for AIE Research,
College of Materials Science and Engineering, Shenzhen University,
Shenzhen 518061, China\textsuperscript{e} School of Science and
Engineering, Shenzhen Institute of Aggregate Science and Technology, The
Chinese University of Hong Kong, Shenzhen 518172, China\selectlanguage{english}
\begin{longtable}[]{@{}l@{}}
\toprule
\textbf{Keywords}\tabularnewline
\midrule
\endhead
Clusteroluminescence \textbar{} Complexation \textbar{} Carbonyl-based
polymers \textbar{} Organic bases \textbar{} Through-space \emph{n}...\selectlanguage{greek}π
\selectlanguage{english}complex\tabularnewline
\textbf{Comprehensive Summary}\tabularnewline
The study of luminescence phenomena in non-conjugated systems, namely
clusteroluminescence, has gained significant attention for the
development of advanced luminescent materials. While conventional
strategies to manipulate the luminescent performances are based on
complicated chemical reactions. In contrast, nature employs complexation
to modulate luminescence, inspiring researchers to adopt an engineering
approach for the construction of efficient clusteroluminogens. In this
work, we explore the complexation-induced clusteroluminescence of
carbonyl-based polymers with nitrogen-containing organic bases,
exemplified by polyamide, polyester, polycarbonate, and
poly(monothiocarbonate). The results demonstrate an increase in the
intrinsic 440 nm emission of carbonyl groups and the emergence of new
emission peaks upon complexation. The study proposes a through-space
\emph{n}...\selectlanguage{greek}π \selectlanguage{english}complex mechanism, highlighting the potential of
complexation as a strategy for modulating the clusteroluminescent
properties of non-conjugated systems. Further research is necessary to
unravel underlying mechanisms, optimize cluster structures, and explore
new materials for complexation, thereby advancing optoelectronics and
photonics fields and enabling practical applications of
clusteroluminescent materials.\tabularnewline
\bottomrule
\end{longtable}

\section*{}

{\label{section}}

Background and Originality Content

Fluorescence, after more than a century of development, has become an
indispensable technique in various fields, such as organic
light-emitting diodes (OLEDs), chemical probes, and
bioimaging.\textsuperscript{{[}1-3{]}} Most of the traditional
fluorophores show \selectlanguage{greek}π-\selectlanguage{english}conjugated polycyclic aromatic structures, whose
photophysical performance is regulated by the intramolecular
through-bond conjugation (TBC), for example, increasing the
\selectlanguage{greek}π-\selectlanguage{english}conjugation length or introducing electron-donating/-withdrawing
groups.\textsuperscript{{[}4-5{]}} However, recently, researchers
discovered that some non-conjugated and non-aromatic polymers, such as
polyamidoamine \textsuperscript{{[}6{]}}, maleic anhydride/vinyl acetate
alternating copolymers (PMV),\textsuperscript{{[}7-8{]}} polyethylene
glycol,\textsuperscript{{[}9{]}}polyacrylonitrile,\textsuperscript{{[}10{]}}
and polyesters,\textsuperscript{{[}11-12{]}} were found to exhibit
intrinsic fluorescence at clustering state. The similar phenomenon has
also been observed in natural polymers, including rice, starch,
cellulose,\textsuperscript{{[}13{]}} and
proteins.\textsuperscript{{[}14{]}} These non-conjugated structures do
not fluoresce in isolated state but show anomalous fluorescence upon
aggregation, known as clusteroluminescence
(CL).\textsuperscript{{[}15-21{]}} Luminogens with CL (CLgens) hold
significant technological, theoretical, and practical value. CLgens are
also known for their low toxicity, biocompatibility, and abundant raw
materials.\textsuperscript{{[}22-24{]}} Currently, carbonyl-based
polymers, such as polypeptides and polyesters, constitute an important
class of CLgens and have been widely studied. However, most of these
CLgens predominantly emit blue emission with low
efficiency.\textsuperscript{{[}25{]}} Unlike traditional conjugated
fluorophores based on TBC theory, through-space interactions (TSIs)
among different subunits were revealed to play an important role in
CL.\textsuperscript{{[}26-32{]}} But a systematic photophysical theory
based on TSIs was absent, which makes it a challenge to regulate the CL
performance.

In nature, numerous fluorescent materials are constructed based on
``complexation'', including green fluorescent protein (GFP) and the
bioluminescence exhibited by fireflies.\textsuperscript{{[}33{]}}Besides
the natural materials, recent reports have highlighted the significant
impact of complexation on the photophysical properties of artificial
luminophores, particularly in phosphorescent systems. For example, a few
thousandth doping levels could induce ultralong organic phosphorescence
from fluorescent molecules.\textsuperscript{{[}34{]}}Additionally, one
of the strategies to develop white light-emitting materials is the
complexation among several molecular components with different emission
colors.\textsuperscript{{[}35{]}} Compared with the strategy of
structural modification based on chemical reaction, the complexation is
easier and more efficient in adjusting the luminescent properties.
Therefore, complexation emerges as a novel strategy for the construction
of luminescent materials. Inspired by the complexation phenomenon
observed in natural and artificial luminophores, we are wondering
whether such an engineering strategy could be used to manipulate the CL
performance of carbonyl-based polymers. Actually, in recent studies,
scientists have discovered intriguing complexation phenomena involving
carbonyl-based polymers and organic bases. For example, PMV showed an
intrinsic emission peak around 440 nm, but an extra long-wavelength
emission peak around 600 nm was observed when it was dissolved in
\emph{N} -Methylpyrrolidone (weak organic base
solvent).\textsuperscript{{[}8{]}} This raises the question of whether
complexation is universal in carbonyl-based polymers and organic bases,
especially for the manipulation of CL properties.

In this work, we have systematically investigated the complex formation
between carbonyl-based polymers and organic bases. We investigated the
complexation-induced clusteroluminescence phenomenon in various
carbonyl-based polymers, including polyamide, polyester, polycarbonate,
poly(monothiocarbonate), in conjunction with the electron-rich organic
base, 1,8-diazabicyclo{[}5.4.0{]}undec-7-ene (DBU). Figure 1 illustrates
the fluorescent photos of different polymer-DBU complexes recorded at
different time intervals under 365 nm ultraviolet (UV) excitation. Our
findings demonstrate that upon complexation with DBU, different types of
carbonyl-based polymers exhibit an increase in intrinsic emission
intensity around 440 nm and,\textsuperscript{{[}36-37{]}} importantly,
the emergence of a new long-wavelength CL peak. This article unveils the
potential of carbonyl-based polymer-DBU complexation as a novel strategy
to modulate the clusteroluminescent properties in these systems.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

\textbf{Figure 1.} Left: chemical structures of carbonyl-based polymers
and DBU; right: photos of the complexes between carbonyl-based polymers
and DBU in DMF (PBLG, PES, PMTC, PC) or acetone (PVAc) at different
mixing time taken under 365 nm UV lamp, \emph{c} = 0.1 M, control is the
pure polymer solution without DBU.

Results and Discussion

As shown in Figure 1, five different kinds of carbonyl-based polymers,
poly(benzyl-L-glutamate) (PBLG),\textsuperscript{{[}36{]}} Polyester
(PES),\textsuperscript{{[}37{]}} poly(monothiocarbonate) (PMTC),
polycarbonate (PC), and polyvinyl acetate (PVAc), were dissolved in
N,N-dimethylformamide (DMF) or acetone, and then DBU was added to the
solution (Figure S1-S6). With the increase in standing time, from 0 h to
7 days, the emission intensity was intensified. To exclude the influence
of solvents and DBU on the enhanced emission, the photoluminescence (PL)
spectra of DBU in DMF and acetone were recorded under different standing
time and excitation wavelength, respectively (Figure S7 and S8). The
results suggested that DBU was almost non-emissive and its PL spectra
were unchanged from 0 h to 7 days. Then, the PL spectra of PBLG in DMF
with concentration (\emph{c} ) of 0.1 M were measured at various
excitation wavelengths ranging from 320 to 500 nm (Figure 2). According
to our previous report, PLGA exhibited two kinds of emission peaks, the
presence of benzene rings in the PBLG side chains resulted in an
emission peak around 300 nm when excited below 320 nm, which can be
attributed to the isolated benzene
ring.\textsuperscript{{[}36{]}}Furthermore, PBLG exhibited a weak blue
emission around 440 nm when the excitation wavelength (\selectlanguage{greek}\emph{λ}
\selectlanguage{english}\textsubscript{ex}) was above 320 nm and the emission intensity reached
the maximum at \selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex}= 360 nm (Figure 2A).
Afterward, same molar concentration of DBU (0.1 M) was added into the
PBLG solution. As shown in Figure 2B, upon the initial addition of DBU
(0 h), no significant redshift in the emission peak was observed.
However, the emission intensity increased by approximately 1.5 times.
Figures 2C-F depict the time-dependent PL spectra of PBLG with equimolar
DBU at different standing time, 1 day, 2 days, 4 days, and 7 days. With
increasing time, a noticeable enhancement in the emission intensity and
a significant redshift in the CL peak was observed. Apparently, a new
peak around 520 nm emerged at\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex} = 460 nm, and
this peak also showed excitation-dependent emission (EDE)
effect,\textsuperscript{{[}26{]}}the maximum emission wavelength
(\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{em}) shifted to 550 nm at \selectlanguage{greek}\emph{λ}
\selectlanguage{english}\textsubscript{ex} = 500 nm, which is unprecedented in unmodified
peptides.

To further investigate the nature of the PBLG-DBU interaction,
the\textsuperscript{1}H NMR spectra of the PBLG-DBU mixture were
measured at the corresponding mixing time (Figure 2H, Figure S9).
Because the signals of PBLG are too complicated to analyze, the proton
signals of DBU were monitored. With the increase in mixing time, the
proton signals in DBU experienced downfield shifts, indicating a change
in the resonance frequency due to electron transfer from the
electron-rich in DBU to PBLG. It is noteworthy that protons 1, 8, and 5
showed a larger downfield shift than the other protons. So, it is
proposed that the complexation of PBLG and DBU should occur between
carbonyl groups of PBLG and the tertiary amine of DBU. Meanwhile, the
absence of new peaks in the NMR spectrum confirms that the interaction
between PBLG and DBU is a complexation process without any chemical
reactions.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}

\textbf{Figure 2.} A-F) PL spectra of 0.1 M PBLG and 0.1 M DBU in DMF at
different excitation wavelengths (\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex}) and
different mixing time; H) \textsuperscript{1}H NMR spectrum of PBLG-DBU
complex (molar ratio 1:1) in CDCl\textsubscript{3} at the different
mixing time.

Besides polyamide, polyester of PES was also investigated upon
complexation with equimolar DBU through excitation-dependent and
time-dependent PL spectra. As shown in Figure 3A, PES exhibited a quite
weak emission around 440 nm when it was dissolved in DMF with \emph{c}of
0.1 M. When equimolar DBU was added, the emission was intensified,
meanwhile, an obvious EDE effect was observed (Figure 3B). However,
unlike PBLG, the maximum CL wavelength redshifted to 470 nm under 380 nm
excitation at the initial mixing. After standing for 1 day, an extra CL
peak at 510 nm was observed, and its intensity increased with time going
to 2 days. Interestingly, after 1 day, two distinct peaks (\selectlanguage{greek}\emph{λ}
\selectlanguage{english}\textsubscript{em} = 450 nm and 510 nm) are excitation-wavelength
independent (Figure 3C-F). Moreover, with the increase in standing time,
the intensity ratio of 510 nm / 450 nm increased and the
complexation-induced emission became dominant. These results indicated
that the complexation between PES and DBU is stronger than polyamide and
the formed complexes are more stable. Time-dependent\textsuperscript{1}H
NMR spectra revealed downfield chemical shifts of the protons 1,5, and 8
in DBU and upfield chemical shifts of the ester group protons in PES as
the mixing time increased, which further supports the complexation
between PES and DBU (Figure 3H, Figure S10).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image6/image6}

\end{center}
\end{figure}

\textbf{Figure 3.} A-F) PL spectra of 0.1 M PES and 0.1 M DBU in DMF at
different excitation wavelengths (\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex}) and
different mixing time; H) \textsuperscript{1}H NMR spectrum of PES-DBU
complex (molar ratio 1:1) in CDCl\textsubscript{3} at the different
mixing time.

Then the complexation effect on CL was also systematically investigated
in the other three kinds of carbonyl-based polymers, PMTC, PC, and PVAc.
Figure 4 summarized the PL and \textsuperscript{1}H NMR characteristics
of PMTC, PC, and PVAc upon complexation with equimolar DBU. The PL
spectra of the polymer-DBU complexes were recorded at the same
concentration (0.1 M) under different excitation wavelengths and mixing
time. As shown in Figure 4A, PMTC also displayed a weak emission peak
around 440 nm when excited at 400 nm, and no emission peak was observed
at \selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex} = 460 nm. Upon the addition of equimolar
DBU to PMTC, a significant enhancement of fluorescence intensity
occurred and the 440 nm redshifted to 490 nm under the excitation of 400
nm. Meanwhile, a new CL peak appeared around 530 nm at\selectlanguage{greek}\emph{λ}
\selectlanguage{english}\textsubscript{ex} = 460 nm. The change of PL spectra along with the
increase in standing time demonstrates the strong complexation between
PMTC and DBU. Figure 4B showed the PL spectra of PC-DBU complexes. PC
exhibited a typical emission peak related to the carbonyl group around
440 nm when excited at 380 nm, However, an anomalous phenomenon was
observed upon the addition of equimolar DBU to PC. Under 380 nm
excitation, the emission intensity of 440 nm sharply decreased after DBU
addition, and then gradually recovered with time going on, surpassing
the original intensity of PC after 7 days. Furthermore, a new emission
peak was induced near 500 nm upon excitation at 440 nm, and its
intensity kept increasing from 0 h to 7 days. These results indicated
that PC also formed complexes with DBU but not as strong as PMTC.

PVAc is also one kind of polyester, which possesses carbonyl groups in
the side chains. Different from PES, PVAc did not show any emission near
440 nm in acetone with \emph{c} = 0.1 M. Intriguingly, when PVAc was
mixed with equimolar DBU, a broad emission peak appeared in the range of
470-500 nm under 380 nm excitation, and the emission intensity
continuously increased with the increase of mixing time. The emission
intensity at 7 days was approximately four times higher than that at 24
hours (Figure 4C). Additionally, we also tested the PL spectra of PVAc
dissolved in pure DBU, interestingly, a new long-wavelength emission
peak near 550 nm was induced after 7 days of dissolution without the EDE
effect (Figure S11). Meanwhile, the mixture of PVAc and pure DBU
exhibited interesting apparent color change, transitioning from yellow
to orange upon swelling and eventually turning blood red upon complete
dissolution over time. Furthermore, \textsuperscript{1}H NMR spectra of
the PMTC-DBU, PC-DBU, and PVAc-DBU complexes revealed downfield shifts
of multiple protons adjacent to the tertiary amine atom in DBU as the
mixing time increased (Figure 4D-F, Figure S12-14). This observation
further supports the complexation between DBU and these carbonyl-based
polymers, suggesting that both backbone and side-chain carbonyl groups
could form the complexation with the electron-donating amine group. The
strength of the complexation is expected to increase with prolonged
mixing time, as evidenced by the changes observed in photographs taken
under sunlight (Figure S15).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image7/image7}

\end{center}
\end{figure}

\textbf{Figure 4.} A) PL spectra of 0.1 M PMTC and 0.1 M DBU in DMF at
the different mixing time (\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex} = 400 nm and 460
nm); B) PL spectra of 0.1 M PC and 0.1 M DBU in DMF at the different
mixing time \selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex} = 380 nm and 440 nm); C) PL
spectra of 0.1 M PVAc and 0.1 M DBU in acetone at the different mixing
time (\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{ex} = 380 nm); \textsuperscript{1}H NMR
spectrum of (D) PMTC (E) PC (F) PVAc and DBU (molar ratio 1:1) in
CDCl\textsubscript{3} at the different mixing time.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image8/image8}

\end{center}
\end{figure}

\textbf{Figure 5.} Schematic representation of the mechanism of the
through-space \emph{n} ...\selectlanguage{greek}π \selectlanguage{english}complex.

Based on our previous studies on the CL properties of carbonyl-based
aliphatic polymers, the 440 nm emission in these CLgens arises from the
(\emph{n} , \selectlanguage{greek}π\selectlanguage{english}*) transition of the carbonyl
groups.\textsuperscript{{[}25, 36-37{]}} The emission intensity of the
440 nm CL is influenced by the electronic structure and conformational
flexibility of the subunits. Generally, a relatively rigid structure
favors the (\emph{n} , \selectlanguage{greek}π\selectlanguage{english}*) transition of carbonyl groups. In terms of
flexibility, PES exhibits the highest flexibility, followed by PMTC, and
finally PBLG and PC, aligning with the observed emission intensities of
440 nm CL. Meanwhile, the flexible backbone of PVAc makes it difficult
to stabilize the (\emph{n} , \selectlanguage{greek}π\selectlanguage{english}*) transition of side-chain carbonyl
groups, preventing effective clusterization between adjacent carbonyl
groups. However, the complexation between carbonyl groups and DBU widely
exists in main-chain and side-chain polymers. Then, we propose the
through-space \emph{n} ...\selectlanguage{greek}π \selectlanguage{english}complex mechanism for the complexation, as
illustrated in Figure 5. Upon the addition of the electron-rich organic
base (DBU) to the carbonyl-based polymers, the electron-withdrawing
carbonyl group can accept electrons from the electron-rich nitrogen in
DBU, leading to the formation of a complex between carbonyl groups and
the Lewis base DBU, thereby modulating the photophysical properties of
the CLgens.

It needs to be emphasized that not only DBU, but other
nitrogen-containing organic bases could also form complexes with
carbonyl groups, for example, triethylamine (TEA). However, according to
our studies, the complexation between TEA and carbonyl groups is
relatively weak, as reflected by the PL changes. Overall, this work
presents an effective approach to induce through-space \emph{n} ...\selectlanguage{greek}π
\selectlanguage{english}complexes by introducing the nitrogen-containing organic base for
clusterization. Further exploration of the through-space \emph{n} ...\selectlanguage{greek}π
\selectlanguage{english}complex theory, such as achieving \emph{n} ...\selectlanguage{greek}π \selectlanguage{english}complexes in a broader
range of carbonyl-containing molecules, especially for small molecules
with distinct structures, is currently underway in our research group,
aiming to establish a more comprehensive theoretical framework.

Conclusions

In conclusion, we have discovered a general complexation phenomenon
between carbonyl-based polymers and the nitrogen-containing organic base
of DBU, which is demonstrated by the PL and \textsuperscript{1}H NMR
characterization. The complexation could not only enhance the intrinsic
440 nm emission of carbonyl groups, arising from its (\emph{n} , \selectlanguage{greek}π\selectlanguage{english}*)
transition, but also induce a new long-wavelength CL corresponding to
the complexes. By understanding the complexation strategies employed in
nature and adopting an engineering approach, researchers can overcome
the challenges to achieve efficient clusteroluminescence. The study of
emerging clusteroluminescence from the complexes between carbonyl-based
polymers and organic bases presents exciting opportunities for advancing
the field of optoelectronics and photonics. Further investigations are
needed to elucidate the underlying mechanisms, optimize the cluster
structures, and explore new materials for complexation. These
advancements will pave the way for the creation of novel luminescent
materials with enhanced performance and expanded applications in various
fields.

Supporting Information

The supporting information for this article is available on the WWW
under https://doi.org/10.1002/cjoc.2023xxxxx.

Acknowledgement

H. Zhang thanks for the financial support from the National Science
Foundation of China (22205197) and the Youth Talent Excellence Program
of ZJU-Hangzhou Global Scientific and Technological Innovation Center.

References

\begin{enumerate}
\tightlist
\item
  Han, J. M.; Chen, Y. Y.; Li, N. Q.; Huang, Z. Y.; Yang, C. L.,
  Versatile boron-based thermally activated delayed fluorescence
  materials for organic light-emitting diodes.
  \emph{Aggregate}\textbf{2022,} \emph{3} , e182.
\item
  Zhao, Z.; Zhang, H. K.; Lam, J. W. Y.; Tang, B. Z.,
  Aggregation-Induced Emission: New Vistas at the Aggregate
  Level.\emph{Angew Chem. Int. Ed.} \textbf{2020,} \emph{59} ,
  9888-9907.
\item
  Yu, X.; Zhang, H.; Yu, J., Luminescence anti-counterfeiting: From
  elementary to advanced. \emph{Aggregate} \textbf{2021,} \emph{2} ,
  20-34.
\item
  Bois, J.; Korzdorfer, T., How Bond Length Alternation and Thermal
  Disorder Affect the Optical Excitation Energies of pi-Conjugated
  Chains: A Combined Density Functional Theory and Molecular Dynamics
  Study. \emph{J. Chem. Theory Comput.} \textbf{2016,} \emph{12} ,
  1872-1882.
\item
  Xu, S. D.; Duan, Y. K.; Liu, B., Precise Molecular Design for
  High-Performance Luminogens with Aggregation-Induced
  Emission.\emph{Adv. Mater.} \textbf{2020,} \emph{32} , 1903530.
\item
  Wang, D.; Imae, T., Fluorescence Emission from Dendrimers and Its pH
  Dependence. \emph{J. Am. Chem. Soc.} \textbf{2004,} \emph{126} ,
  13204-13205.
\item
  Xing, C.; Lam, J. W. Y.; Qin, A.; Dong, Y.; Haeussler, M.; Yang, W.;
  Tang, B. Z. Unique photoluminescence from nonconjugated alternating
  copolymer poly{[}(maleic anhydride)-alt-(vinyl
  acetate){]},\emph{Polym. Mater. Sci. Eng.} \textbf{2007} , \emph{96} ,
  418-- 419
\item
  Zhao, E.; Lam, J. W. Y.; Meng, L.; Hong, Y.; Deng, H.; Bai, G.; Huang,
  X.; Hao, J.; Tang, B. Z., Poly{[}(maleic anhydride)-alt-(vinyl
  acetate){]}: A Pure Oxygenic Nonconjugated Macromolecule with Strong
  Light Emission and Solvatochromic Effect.
  \emph{Macromolecules}\textbf{2015,} \emph{48} , 64-71.
\item
  Wang, Y. Z.; Bin, X.; Chen, X. H.; Zheng, S. Y.; Zhang, Y. M.; Yuan,
  W. Z., Emission and Emissive Mechanism of Nonaromatic Oxygen
  Clusters.\emph{Macromol. Rapid Commun.} \textbf{2018,} \emph{39} ,
  1800528.
\item
  Zhou, Q.; Cao, B. Y.; Zhu, C. X.; Xu, S.; Gong, Y. Y.; Yuan, W. Z.;
  Zhang, Y. M., Clustering-Triggered Emission of Nonconjugated
  Polyacrylonitrile. \emph{Small} \textbf{2016,} \emph{12} , 6586-6592.
\item
  Chu, B.; Zhang, H. K.; Chen, K. L.; Liu, B.; Yu, Q. L.; Zhang, C. J.;
  Sun, J. Z.; Yang, Q.; Zhang, X. H.; Tang, B. Z., Aliphatic Polyesters
  with White-Light Clusteroluminescence. \emph{J. Am. Chem.
  Soc.}\textbf{2022,} \emph{144} , 15286-15294.
\item
  Chu, B.; Zhang, H. K.; Hu, L. F.; Liu, B.; Zhang, C. J.; Zhang, X. H.;
  Tang, B. Z., Altering Chain Flexibility of Aliphatic Polyesters for
  Yellow-Green Clusteroluminescence in 38 \% Quantum Yield. \emph{Angew
  Chem. Int. Ed.} \textbf{2022,} \emph{61} , e202114117.
\item
  Gong, Y.; Tan, Y.; Mei, J.; Zhang, Y.; Yuan, W.; Zhang, Y.; Sun, J.;
  Tang, B. Z., Room temperature phosphorescence from natural products:
  Crystallization matters. \emph{Sci. China Chem.}
  \textbf{2013,}\emph{56} , 1178-1182.
\item
  Zhang, Z.; Zhu, L.; Feng, J.; Zhang, H.; Zhang, X.; Sun, J. Z.; Tang,
  B. Z., In situ monitoring of protein aggregation via
  clusteroluminescence. \emph{Mater. Chem. Front.}
  \textbf{2023,}\emph{7} , 713-719.
\item
  Tomalia, D. A.; Klajnert-Maculewicz, B.; Johnson, K. A. M.; Brinkman,
  H. F.; Janaszewska, A.; Hedstrand, D. M., Non-traditional intrinsic
  luminescence: inexplicable blue fluorescence observed for dendrimers,
  macromolecules and small molecular structures lacking
  traditional/conventional luminophores. \emph{Prog. Polym.
  Sci.}\textbf{2019,} \emph{90} , 35-117.
\item
  Tang, S. X.; Yang, T. J.; Zhao, Z. H.; Zhu, T. W.; Zhang, Q.; Hou, W.
  B. W.; Yuan, W. Z., Nonconventional luminophores: characteristics,
  advancements and perspectives. \emph{Chem. Soc. Rev.}
  \textbf{2021,}\emph{50} , 12616-12655.
\item
  Liao, P. L.; Huang, J. B.; Yan, Y.; Tang, B. Z.,
  Clusterization-triggered emission (CTE): one for all, all for
  one.\emph{Mater. Chem. Front.} \textbf{2021,} \emph{5} , 6693-6717.
\item
  Wen, Q.; Cai, Q.; Fu, P.; Chang, D.; Xu, X.; Wen, T.-J.; Wu, G.-P.;
  Zhu, W.; Wan, L.-S.; Zhang, C.; Zhang, X.-H.; Jin, Q.; Wu, Z.-L.; Gao,
  C.; Zhang, H.; Huang, N.; Li, C.-Z.; Li, H., Key progresses of MOE key
  laboratory of macromolecular synthesis and functionalization in
  2021.\emph{Chin. Chem. Lett.} \textbf{2023,} \emph{34} , 107592.
\item
  Zhang, H.; Zhao, Z.; McGonigal, P. R.; Ye, R.; Liu, S.; Lam, J. W. Y.;
  Kwok, R. T. K.; Yuan, W. Z.; Xie, J.; Rogach, A. L.; Tang, B. Z.,
  Clusterization-triggered emission: Uncommon luminescence from common
  materials. \emph{Mater. Today} \textbf{2020,} \emph{32} , 275-292.
\item
  Liu, B.; Chu, B.; Zhu, L.; Zhang, H.; Yuan, W.-Z.; Zhao, Z.; Wan,
  W.-M.; Zhang, X.-H., Clusteroluminescence: A gauge of molecular
  interaction. \emph{Chin. Chem. Lett.} \textbf{2023,} \emph{34} ,
  107909.
\item
  He, B.; Zhang, J.; Zhang, J.; Zhang, H.; Wu, X.; Chen, X.; Kei, K. H.
  S.; Qin, A.; Sung, H. H. Y.; Lam, J. W. Y.; Tang, B. Z.,
  Clusteroluminescence from Cluster Excitons in Small Heterocyclics Free
  of Aromatic Rings. \emph{Adv. Sci.} \textbf{2021,} \emph{8} , 2004299.
\item
  Deng, J. W.; Jia, H. Y.; Xie, W. D.; Wu, H. R.; Li, J. Y.; Wang, H.
  L., Nontraditional Organic/Polymeric Luminogens with Red-Shifted
  Fluorescence Emissions. \emph{Macromol. Chem. Phy.}
  \textbf{2022,}\emph{223} , 2100425.
\item
  Feng, Y.; Yan, H.; Ding, F.; Bai, T.; Nie, Y.; Zhao, Y.; Feng, W.;
  Tang, B. Z., Multiring-induced multicolour emission: hyperbranched
  polysiloxane with silicon bridge for data encryption. \emph{Mater.
  Chem. Front.} \textbf{2020,} \emph{4} , 1375-1382.
\item
  Ye, R.; Liu, Y.; Zhang, H.; Su, H.; Zhang, Y.; Xu, L.; Hu, R.; Kwok,
  R. T. K.; Wong, K. S.; Lam, J. W. Y.; Goddard, W. A.; Tang, B. Z.,
  Non-conventional fluorescent biogenic and synthetic polymers without
  aromatic rings. \emph{Poly. Chem.} \textbf{2017,} \emph{8} ,
  1722-1727.
\item
  Zhang, Z.; Zhang, Z.; Zhang, H.; Sun, J. Z.; Tang, B. Z., The
  mysterious blue emission around 440 nm in carbonyl-based aliphatic
  clusteroluminogens. \emph{J. Poly. Sci.} \textbf{2022,} \emph{60} ,
  2127-2135.
\item
  Zhang, H.; Tang, B. Z., Through-Space Interactions in
  Clusteroluminescence. \emph{JACS Au} \textbf{2021,} \emph{1} ,
  1805-1814.
\item
  Zhang, H.; Zheng, X.; Xie, N.; He, Z.; Liu, J.; Leung, N. L. C.; Niu,
  Y.; Huang, X.; Wong, K. S.; Kwok, R. T. K.; Sung, H. H. Y.; Williams,
  I. D.; Qin, A.; Lam, J. W. Y.; Tang, B. Z., Why Do Simple Molecules
  with ``Isolated'' Phenyl Rings Emit Visible Light? \emph{J. Am. Chem.
  Soc.} \textbf{2017,} \emph{139} , 16264-16272.
\item
  Zhang, J.; Hu, L.; Zhang, K.; Liu, J.; Li, X.; Wang, H.; Wang, Z.;
  Sung, H. H. Y.; Williams, I. D.; Zeng, Z.; Lam, J. W. Y.; Zhang, H.;
  Tang, B. Z., How to Manipulate Through-Space Conjugation and
  Clusteroluminescence of Simple AIEgens with Isolated Phenyl
  Rings.\emph{J. Am. Chem. Soc.} \textbf{2021,} \emph{143} , 9565-9574.
\item
  Liu, J. K.; Zhang, H. K.; Hu, L. R.; Wang, J.; Lam, J. W. Y.;
  Blancafort, L.; Tang, B. Z., Through-Space Interaction of
  Tetraphenylethylene: What, Where, and How. \emph{J. Am. Chem.
  Soc.}\textbf{2022,} \emph{144} , 7901-7910.
\item
  Zhang, J. Y.; Alam, P.; Zhang, S. W.; Shen, H. C.; Hu, L. R.; Sung, H.
  H. Y.; Williams, I. D.; Sun, J. W.; Lam, J. W. Y.; Zhang, H. K.; Tang,
  B. Z., Secondary through-space interactions facilitated
  single-molecule white-light emission from
  clusteroluminogens.\emph{Nat. Commun.} \textbf{2022,} \emph{13} ,
  3492.
\item
  Sturala, J.; Etherington, M. K.; Bismillah, A. N.; Higginbotham, H.
  F.; Trewby, W.; Aguilar, J. A.; Bromley, E. H. C.; Avestro, A.-J.;
  Monkman, A. P.; McGonigal, P. R., Excited-State Aromatic Interactions
  in the Aggregation-Induced Emission of Molecular Rotors. \emph{J. Am.
  Chem. Soc.} \textbf{2017,} \emph{139} , 17882-17889.
\item
  Jing, Y. N.; Li, S. S.; Su, M. Q.; Bao, H. L.; Wan, W. M., Barbier
  Hyperbranching Polymerization-Induced Emission toward Facile
  Fabrication of White Light-Emitting Diode and Light-Harvesting
  Film.\emph{J. Am. Chem. Soc.} \textbf{2019,} \emph{141} , 16839-16848.
\item
  Zhang, H.; Zhao, Z.; Turley, A. T.; Wang, L.; McGonigal, P. R.; Tu,
  Y.; Li, Y.; Wang, Z.; Kwok, R. T. K.; Lam, J. W. Y.; Tang, B. Z.,
  Aggregate Science: From Structures to Properties. \emph{Adv.
  Mater.}\textbf{2020,} \emph{32} , 2001457.
\item
  Chen, C. J.; Chi, Z. G.; Chong, K. C.; Batsanov, A. S.; Yang, Z.; Mao,
  Z.; Yang, Z. Y.; Liu, B., Carbazole isomers induce ultralong organic
  phosphorescence. \emph{Nat. Mater.} \textbf{2021,} \emph{20} ,
  175-180.
\item
  Zhang, J. Y.; Zhao, X. Q.; Shen, H. C.; Lam, J. W. Y.; Zhang, H. K.;
  Tang, B. Z., White-light emission from organic aggregates: a
  review.\emph{Adv. Photonics} \textbf{2022,} \emph{4} , 014001
\item
  Zhang, Z.; Yan, W.; Dang, D.; Zhang, H.; Sun, J. Z.; Tang, B. Z., The
  role of amide (\emph{n} ,\selectlanguage{greek}π\selectlanguage{english}*) transitions in polypeptide
  clusteroluminescence. \emph{Cell Rep. Phys. Sci.} \textbf{2022}
  ,\emph{3} , 100716.
\item
  Zhang, Z. T.; Xiong, Z. P.; Chu, B.; Zhang, Z. M.; Xie, Y.; Wang, L.;
  Sun, J. Z.; Zhang, H. K.; Zhang, X. H.; Tang, B. Z., Manipulation of
  clusteroluminescence in carbonyl-based aliphatic
  polymers.\emph{Aggregate} \textbf{2022,} \emph{3} , e278.
\end{enumerate}\selectlanguage{english}
\begin{longtable}[]{@{}l@{}}
\toprule
Manuscript received: XXXX, 2023 Manuscript revised: XXXX, 2023
Manuscript accepted: XXXX, 2023 Accepted manuscript online: XXXX, 2023
Version of record online: XXXX, 2023\tabularnewline
\bottomrule
\end{longtable}

\textbf{Entry for the Table of Contents}\selectlanguage{english}
\begin{longtable}[]{@{}l@{}}
\toprule
\textbf{Emerging Clusteroluminescence from Complexes between
Carbonyl-Based Polymers and Organic Base} Hongwei
Lu,\textsuperscript{\#} Yuan Xie,\textsuperscript{\#} Ziteng Zhang,
Zhiming Zhang, Jing Zhi Sun, Haoke Zhang,* and Ben Zhong Tang*
\emph{Chin. J. Chem.} \textbf{2023}, \emph{41}, XXX---XXX. \textbf{DOI:
10.1002/cjoc.202300XXX}\tabularnewline
A general complexation phenomenon between carbonyl-based polymers and
the nitrogen-containing organic base of DBU was discovered, which is
demonstrated by photoluminescence. The complexation could not only
enhance the intrinsic emission of carbonyl groups but also induce a new
long-wavelength clusteroluminescence corresponding to the through-space
\emph{n}...\selectlanguage{greek}π \selectlanguage{english}complex.\tabularnewline
\bottomrule
\end{longtable}

\selectlanguage{english}
\FloatBarrier
\end{document}

