Photophysical properties, aggregation-induced fluorescence in nanoaggregates and cell imaging of 2,5-bisaryl 1,3,4-oxadiazoles

Article abstract of DOI:10.1039/c4nj02293a

Dye-loaded nanoparticles encapsulating four different aggregation-induced emission (AIE) and intramolecular charge transfer (ICT) active chromophores, which had different numbers of carbazole-containing triphenylamine moieties as donors and one 1,3,4-oxad

Full text of DOI:10.1039/c4nj02293a

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PAPER
Photophysical properties, aggregationꢀinduced
fluorescence in nanoaggregates and cell imaging of
2,5ꢀbisaryl 1,3,4ꢀoxadiazoles
Cite this: DOI: 10.1039/x0xx00000x
Yongchang Jin, Ying Qian*
Dyeꢀloaded nanoparticles encapsulating four different aggregationꢀinduced emission (AIE) and
intramolecular charge transfer (ICT) active chromophores, which had different numbers of
carbazoleꢀcontaining triphenylamine moieties as donors and one 1,3,4ꢀoxadiazole moiety as
acceptor, were reported and investigated. Dyeꢀdoped aminoꢀgroupꢀfunctionalized silica
nanoparticles (SiꢀNPs), with diameter ~30 nm, maintained the AIE characterized phtophysical
properties of the chromophores with high quantum yield up to 0.35 for Oxaꢀ(BCPA)1ꢀdoped Siꢀ
NPs and the fluorescence emission peaks ranged from 476 nm to 513 nm for the four
nanoparticles. Meanwhile, dyeꢀdoped SiꢀNPs had successfully overcome the challenges of poor
biocompatibility of AIE materials and could be well dispersed in water, providing an important
opportunity to further explore their bioapplications by conjugating the NPs with various
biomolecues. The dyeꢀloaded BSAꢀnanoparticles (BSAꢀNPs) were applied to cell imaging and
showed a better uptake by HeLa cells compared to pure dye NPs, which indicating a promising
application for biosensors such as cancer cell detecting.
Received 00th January 2012,
Accepted 00th January 2012
DOI: 10.1039/x0xx00000x
www.rsc.org/
great progress has been made such as using AIE materials to
monitor the process proceeding in drug delivery systems6 or to
Introduction
realize fluorescent cellular tracing7 and even new fluorescence
The advanced development of multifunctional nanoparticles
provides an exciting opportunity for potential bioapplications
8
turnꢀon mechanism was discovered in addition to AIE.
1
2
3
such as cell imaging, biosensors, gene delivery, drug
Combination of the development in AIE materials with the
nanotechnique will absolutely provide a promising potential in
their bioapplications.
4
carriers and thus has attracted great research attention
worldwide in the past few decades. Dyeꢀdopped silica
nanoparticles, especially, are one of the most vigorous research
fields due to several important merits such as almost precisely
controllable size with good monodispersity, simple surface
functionalization to meet the specific application requirements,
excellent compatibility that could encapsulate different
materials in one single particle to realize multifunctional
applications, superior optical properties against photobleaching
and most importantly, great biocompatibility which will make it
possible to explore potential use for dyes with good
photophysical properties but incompatible with biosystem.
Meanwhile, dyes which could be encapsulated inside
nanoparticles should have some advantageous features over
traditional aggregationꢀcaused quenching (ACQ) materials
because they are usually in aggregated state inside
nanoparticles. Aggregationꢀinduced emission (AIE) materials
are one of the choices which are widely investigated due to
their properties as called. After the AIE phenomena was found,5
9
Tian synthesised a 9,10ꢀdistyrylanthraceneꢀdoped folateꢀ
functionalized silica nanoparticles with a high fluorescence
quantum yield up to 0.20 and showing specific targeting ability
to cancer cells over normal cells because the folic acid
decorated on the surface of the nanoparticles showed a high
binding affinity to the folate receptors overexpressed by many
cancer cells. Jung Aa Ko10 reported metal/dyeꢀdoped coreꢀshell
silica nanoparticles with diameter of 60 nm containing metal
salts and dyes inside one nanoparticle, of which the movement
could be easily monitored during the treatment process and thus
to realize multiplex detection such as to monitor DNA cleavage.
Stefania Biffi 11 developed silica nanoparticles encapsulating
two dyes acting as donor–acceptor couple to tune the emission
intensity profile into the NIR spectrum by changing the doping
ratio of the donor–acceptor couple and could be used for both
12
flow cytometry and in vivo imaging. Gao
applied a
fluorescence resonance energy transfer system containing
oligonucleotideꢀmodified fluorescein isothiocyanateꢀdoped
nanoparticles as donors and oligonucleotideꢀmodified gold
nanoparticles as acceptors to detect the DNA hybridization with
School of Chemistry and Chemical Engineering, Southeast University,
Nanjing, 211189, China. E-mail: yingqian@seu.edu.cn
This journal is © The Royal Society of Chemistry 2013
New J. Chem. | 1

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a detection limit of 3 picomole. Dyeꢀdoped nanoparticles have
shown great potential in bioapplications, but dyes which not
only have excellent photophysical properties, but could also be
easily encapsulated inside nanoparticles without any chemical
pretreatment are still highly needed.13
General
N,Nꢀdi(4ꢀiodophenyl) amino benzaldehyde, [[4ꢀ[5ꢀ(4ꢀtertꢀ
butylphenyl)ꢀ1,3,4ꢀoxadiazolꢀ2ꢀyl]phenyl]methyl]
triphenylphosphonium bromide
，
2,5ꢀbis(4ꢀmethylphenyl)ꢀ
In this paper, we have reported four different AIEꢀICT active
chromophores Oxaꢀ(CPA)1, Oxaꢀ(CPA)2, Oxaꢀ(BCPA)1 and
Oxaꢀ(BCPA)2, which are fabricated in a DꢀA or DꢀAꢀD manner
with one or two carbazoleꢀcontaining triphenylamine buildingꢀ
blocks as donors while 1,3,4ꢀoxadiazole as the acceptor.14 Tertꢀ
butyl were introduced to the 3,6ꢀpositions of carbazole in some
cases to improve the solubility of the compounds and enhance
the electronꢀdonation.15 The structures of these compounds are
given in scheme 1. CPA/BCPA represents the two important
intermediates with or without tertꢀbutyl, respectively. Oxaꢀ
(CPA)1 and Oxaꢀ(BCPA)1 are of oneꢀdonorꢀcontaining
structure while Oxaꢀ(CPA)2 and Oxaꢀ(BCPA)2 are of twoꢀ
donorꢀcontaining structure, respectively. Photophysical
properties of the chromophores in different solvents and
aggregated states were investigated. Indeed, both positive
solvatochromism and excellent performance in solid state
characterized by AIE effect were observed. Aminoꢀgroupꢀ
functionalized silica nanoparticles (SiꢀNPs) encapsulating the
aggregated chromophores and dyeꢀloaded BSA nanoparticles
were prepared to explore potential bioapplications.
Photophysical properties of SiꢀNPs are discussed and dyeꢀ
loaded BSA nanoparticles were successfully applied to cell
imaging.
1,3,4ꢀoxadiazole triphenylphosphonium bromide, 3,6ꢀDiꢀtertꢀ
butylꢀ9Hꢀcarbazole were synthesised by our laboratory using
the known literature procedure16 and identified by 1H NMR
and melting point analysis. Solvents were purified and dried
using standard protocols. All other chemical reagents were
obtained commercially and were used as received without
further purification. 3ꢀaminopropyltriethoxysilane (APTES,
Sinopharm Chemical Reagent Co., Ltd, Shanghai, China),
Aerosol OT (AOT, Aladdin Industrial Co., Shanghai, China),
triethoxyvinylsilane (VTES, Aladdin Industrial Co., Shanghai,
China).
1
Chemical structures were confirmed by NMR analysis. H
NMR measurements were determined with a Bruker 500 MHz
spectrometer or Bruker 300 MHz spectrometer, with TMS
(tetramethyl silane) as the internal standard. 13C NMR
measurements were determined with a Bruker 300 MHz
spectrometer.
UVꢀvisible absorption spectra were determined on
Shimadu UVꢀ3600 spectrophotometer. Fluorescence spectra
were measured on an HORIBA FLꢀ4 max spectrometer. The
a
melting points were measured on
a
Microscopic
Melting Point Meter Xꢀ4. The cell imaging equipment used in
our experiment were Upright Fluorescence Microscope (Imager
A1) provide by ZEISS, Germany.
Synthesis
4ꢀN,NꢀBis[4ꢀ(3,ꢀ6ꢀdiꢀtertꢀbutylcarbazolꢀ9ꢀyl)phenyl]ꢀaminoꢀ
benzaldehyde (BCPA). Yellow solid. Yield 80%. m.p. >300
℃.
A mixture of N,Nꢀdi(4ꢀiodophenyl) amino benzaldehyde (5.0
g, 9.5 mmol), 3,6ꢀDiꢀtertꢀbutylꢀ9Hꢀcarbazole (5.8 g, 20.9
mmol), CuI (0.72 g, 3.78 mmol), 1,10ꢀphenanthroline (1.5 g,
8.3 mmol), and K2CO3 (3.5 g, 20.9 mmol) in DMF (50 mL)
was heated to 160
℃ under nitrogen for 24 h. After cooling to
room temperature, the reaction mixture was poured into water
(100 mL). The precipitate was filtered and dried. Further
purification was performed by column chromatography to
afford the pure product. 1H NMR (300 MHz, CDCl3) δ: 9.93 (s,
1H), 8.18 (s, 4H), 7.87 (d, J=8.52 Hz, 2H), 7.63 (d, J=8.49 Hz,
4H), 7.54–7.45 (m, 12H), 7.31(d, J=8.19 Hz, 2H), 1.50 (s, 36H).
4ꢀN,NꢀBis[4ꢀ(carbazolꢀ9ꢀyl)phenyl]ꢀaminoꢀbenzaldehyde
(CPA). Yellow solid. Yield 89%. m.p. 287ꢀ289
℃. The
Scheme 1 Chemical structures of chromophores Oxaꢀ(CPA)n,
Oxaꢀ(BCPA)n (n=1,2) and CPA/BCPA. When n=1, the
chromophores have an asymmetric structure with only one
building block of CPA/BCPA and while n=2, a symmetrical
structure is obtained. CPA/BCPA represents the important
intermediates or building blocks in different cases.
1
synthetic procedure of CPA was similar to that of BCPA. H
NMR (300 MHz, CDCl3) δ: 9.91 (s, 1H), 8.17 (d, J=7.74 Hz,
4H), 7.86 (d, J=8.64 Hz, 2H), 7.62 (d, J=8.67 Hz, 4H), 7.52–
7.42 (m, 12H), 7.33–7.28 (m, 6H).
2ꢀ(4ꢀtertꢀbutylphenyl)ꢀ5ꢀ{4ꢀ[2ꢀ[4ꢀN,Nꢀbisꢀ(4ꢀcarbazolꢀ9ꢀylꢀ
phenyl)ꢀaminoꢀphenyl]vinyl]phenyl}ꢀ1,3,4ꢀoxadizole [Oxaꢀ
Experimental
2 | J. Name., 2012, 00, 1-3
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Chromophore Oxaꢀ(CPA)1. 1H NMR (300 MHz, CDCl3) δ:
8.20ꢀ8.17 (m, 12H), 7.72 (d, J=8.22 Hz, 4H),7.61 (d, J=11.28
(CPA)1]. Yellow solid. Yield 66%. m.p. 293ꢀ295
℃. [[4ꢀ[5ꢀ(4ꢀ
tertꢀbutylphenyl)ꢀ1,3,4ꢀoxadiazolꢀ2ꢀyl]phenyl]methyl]
triphenylphosphonium bromide (1 g, 1.58 mmol) was dissolved Hz, 4H),7.57 (d, J=7.44 Hz, 8H), 7.54ꢀ7.52 (m, 8H),7.48ꢀ7.44
(m, 16H), 7.35 (d, J=8.52 Hz, 4H),7.32 (d, J=14.34 Hz,
2H),7.17 (d, J=16.20 Hz, 2H), 1.52 (s, 72H). 13C NMR (300
MHz, CDCl3) δ: 167.04, 150.07, 148.48, 145.46, 143.54,
141.96, 135.93, 134.39, 132.94, 130.65, 130.34, 129.93, 129.49,
128.92, 127.95, 126.76, 126.20, 125.95, 125.06, 118.88, 111.85,
37.35, 34.65.
in 20 mL THF at 0
2.68 mmol) in 5 mL THF was added under nitrogen. After the
mixture was stirred for h, 4ꢀN,NꢀBis[4ꢀ(carbazolꢀ9ꢀ
yl)phenyl]ꢀaminoꢀbenzaldehyde (1.05 g, 1.74 mmol) in 20 mL
THF was added dropwise to the reaction mixture for 0.5 h.
℃. A solution of sodium hydride (0.06 g,
1
Then the mixture was stirred at 80
℃ for 2 h. After cooling to
room temperature, the reaction was quenched with 100 mL
water. The mixture was filtered and dried. The crude product
was purified by column chromatography on silica gel to afford
the pure product. 1H NMR (500 MHz, CDCl3) δ: 8.18 (d,
J=7.70 Hz, 4H), 8.15 (d, J=7.35 Hz, 2H), 8.09 (d, J=7.00 Hz,
2H),7.69 (d, J=7.25 Hz, 2H), 7.59ꢀ7.56 (m, 4H), 7.55ꢀ7.53 (m,
4H), 7.51 (d, J=8.05 Hz, 4H), 7.47ꢀ7.44 (m, 8H), 7.30ꢀ7.33 (m,
6H), 7.27 (d, J=15.05 Hz, 1H), 7.14 (d, J=15.95 Hz, 1H), 1.39
(s, 9H). 13C NMR (300 MHz, CDCl3) δ: 167.20, 166.90, 157.95,
149.88, 148.89, 143.58, 143.37, 135.32, 134.72, 132.79, 130.75,
130.70, 129.89, 129.48, 129.40, 129.13, 128.67, 128.53, 127.88,
127.07, 125.95, 125.21, 123.75, 122.95, 122.53, 112.39, 37.70,
33.74.
Preparation of dyeꢀencapsulated amineꢀfunctionalized silica
nanoparticles
To a clear solution of surfactant AOT (0.44 g) dissolved in
deionized water (20 mL) was added 0.8 mL cosurfactant 1ꢀ
butanol under sonication at
0
℃
to form oilꢀinꢀwater
microemulsion system. DMF (60 ꢁL) solution containing Oxaꢀ
(CPA)n or Oxaꢀ(BCPA)n (10 mM) was dropped into the
mixture. After sonicating for 3 min, 0.2 mL VTES was added
and the reaction mixture was stirred for 8 h. APTES (20 ꢁL)
was added and the mixture was further stirred at room
temperature for 24 h. After the formation of nanoparticles, the
unreacted starting materials were removed by dialyzing the
solution against deionized water in a 8ꢀ14 KDa cutoff cellulose
membrane for 72 h. The dialyzed solution was then stored at
2,5ꢀdiꢀ{4ꢀ[2ꢀ[4ꢀN,Nꢀbisꢀ(4ꢀcarbazolꢀ9ꢀylꢀphenyl)ꢀaminoꢀ
phenyl]vinyl]phenyl}ꢀ1,3,4ꢀoxadizole [Oxaꢀ(CPA)2]. Yellow
solid. Yield 54%. m.p. 262ꢀ264
℃. The synthetic procedure of
5
℃for later use.
Chromophore Oxaꢀ(CPA)2 was similar to that of Chromophore
Oxaꢀ(CPA)1. 1H NMR (500 MHz, CDCl3) δ: 8.17ꢀ8.14 (m, Preparation of dyeꢀloaded BSA nanoparticles
12H), 7.68 (d, J=8.30 Hz, 4H),7.58 (d, J=8.50 Hz, 4H),7.54 (d,
J=8.65 Hz, 8H),7.50 (d, J=8.15 Hz, 8H),7.46ꢀ7.43 (m, BSA (0.1300 g) was dissolved in deionized water (50 mL) and
16H),7.33ꢀ7.29 (m, 12H),7.27 (d, J=16.30 Hz, 2H),7.14 (d, a solution of THF (80 mL) containing 0.0013 g dye was added
J=16.25 Hz, 2H). 13C NMR (300 MHz, CDCl3) δ: 164.45,
dropwise under sonication. Then 100 ꢁL glutaraldehyde
147.33, 146.31, 140.99, 132.75, 132.10, 130.28, 128.17, 128.12,
127.34, 126.92, 126.51, 125.94, 125.31, 124.47, 123.37, 122.53,
120.37, 119.95, 114.61, 109.80.
solution (25%) was added at room temperature and the mixture
was stirred for 4 h. The THF was removed by rotary
evaporation and stored at 5
℃for later use.
2ꢀ(4ꢀtertꢀbutylphenyl)ꢀ5ꢀ{4ꢀ[2ꢀ[4ꢀN,Nꢀbisꢀ[4ꢀ(3,6ꢀdiꢀtertꢀ
butylcarbazolꢀ9ꢀyl)phenyl]ꢀaminoꢀphenyl]vinyl]phenyl}ꢀ
1,3,4ꢀoxadizole [Oxaꢀ(BCPA)1]. Yellow solid. Yield 50%. m.p.
264ꢀ266℃. The synthetic procedure of Chromophore Oxaꢀ
Cell culture
HeLa cells (human cancer cell lines) were grown in Dulbecco
minimum essential media (DMEM) with 10% fetal bovine
serum (FBS), 1% penicillin, and 1% amphotericin B. Before the
treatment, the cell were plated in 24ꢀwell plates and incubated
for 24 h. Then different nanoparticles were added at a
concentration equal to 1.3
for 4 hours at 37 with 5% CO2. Then the cells were washed
twice with PBS and imaged with a Fluorescence Microscopy.
1
(BCPA)1 was similar to that of Chromophore Oxaꢀ(CPA)1. H
NMR (300 MHz, CDCl3) δ: 8.20 (s, 4H), 8.19 (d, J=9.43 Hz,
2H), 8.14 (d, J=8.37 Hz, 2H), 7.72 (d, J=8.25 Hz, 2H), 7.61ꢀ
7.58 (m, 4H), 7.58ꢀ7.55 (m, 4H), 7.55ꢀ7.53 (m, 4H),7.49ꢀ7.44
(m, 8H), 7.36 (d, J=8.34 Hz, 2H),7.32 (d, J=12.42 Hz, 1H),7.17
(d, J=16.20 Hz, 1H), 1.53 (s, 36H), 1.42 (s, 9H). 13C NMR (300
MHz, CDCl3) δ: 167.19, 166.93, 157.93, 150.05, 148.49,
145.45, 143.44, 141.96, 135.92, 134.42, 132.87, 130.65, 130.34,
129.88, 129.46, 129.41, 128.95, 128.67, 127.93, 126.78, 126.20,
125.95, 125.17, 123.79, 118.88, 111.85, 37.71, 37.36, 34.65,
33.75.
×
10ꢀ6 g/L of pure dyes and incubated
℃
Cytotoxicity of dyeꢀloaded BSAꢀNPs
The cytotoxicity of the BSAꢀNPs against HeLa cells was
assessed by MTT assay using the known literature procedure.17
2,5ꢀdiꢀ{4ꢀ[2ꢀ[4ꢀN,Nꢀbisꢀ[4ꢀ(3,6ꢀdiꢀtertꢀbutylcarbazolꢀ9ꢀ
yl)phenyl]ꢀaminoꢀphenyl]vinyl]phenyl}ꢀ1,3,4ꢀoxadizole
Results and discussion
[Oxaꢀ(BCPA)2]. Yellow solid. Yield 53%. m.p. 291ꢀ293
The synthetic procedure of Oxaꢀ(BCPA)2 was similar to that of
℃.
Synthesis of the chromophores with different number of
building blocks
This journal is © The Royal Society of Chemistry 2012
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a
solid powder
1.0
All the four final compounds, Oxaꢀ(CPA)n, Oxaꢀ(BCPA)n
(n=1,2), were synthesised through two main reactions after
obtaining of the important intermediates, which were N,Nꢀdi(4ꢀ
Oxa-(CPA)
1
0.8
0.6
0.4
0.2
0.0
iodophenyl)
carbazole,
amino
benzaldehyde, 3,6ꢀDiꢀtertꢀbutylꢀ9Hꢀ
Oxa-(CPA)
[[4ꢀ[5ꢀ(4ꢀtertꢀbutylphenyl)ꢀ1,3,4ꢀoxadiazolꢀ2ꢀyl]
2
phenyl]methyl]triphenylphosphonium bromide and 2,5ꢀbis(4ꢀ
methylphenyl)ꢀ1,3,4ꢀoxadiazole triphenylphosphonium
Oxa-(BCPA)
bromide. Ullmann reaction connected the carbazolꢀ9ꢀyl (with or
without tertꢀbutyl substitution at 3,6ꢀpositions) to N,Nꢀdi(4ꢀ
iodophenyl) amino benzaldehyde at the sites of iodine atoms
to generate CPA/BCPA with good yield (>80%). Then
CPA/BCPA reacted with one/twoꢀbranched compounds: [[4ꢀ[5ꢀ
(4ꢀtertꢀbutylphenyl)ꢀ1,3,4ꢀoxadiazolꢀ2ꢀyl]phenyl]methyl]
1
Oxa-(BCPA)
2
triphenylphosphonium bromide or 2,5ꢀbis(4ꢀmethylphenyl)ꢀ
1,3,4ꢀoxadiazole triphenylphosphonium bromide by Wittig
reaction and the final chromophores were obtained with a
middle yield (>50%). All of the final compounds were
450 500 550 600 650 700 750 800 850 900 950
Wavelength / nm
1
confirmed by H NMR and 13C NMR. The synthetic routes of
the chromophores are shown in Scheme 2, taking Oxaꢀ(BCPA)2
as an example and the rest synthetic routes are provided in the
supplementary information.
Fig. 1 The normalized fluorescence spectra of the 2,5ꢀbisarylꢀ
1,3,4ꢀoxadiazoles in solid state excited at 400 nm (a) and the
inset presented the fluorescence pictures of solid powder
excited at 365 nm; the CIE chromaticity coordinate of the four
chromophores(b).
All the two groups of compounds are soluble in common
organic solvents such as CH2Cl2, THF and DMF. Fig. 2 (a, b)
shows the absorption and emission spectra of them in THF
solution. Two major absorption bands located at 300ꢀ350 and
350ꢀ475 nm are observed. The former is ascribed to localized
πꢀπ* transition of aromatic moieties in the molecular while the
latter is of ICT character.18 In changing from CPA, Oxaꢀ(CPA)1
to Oxaꢀ(CPA)2 (Group 1, Fig. 2a), the maximum absorption
peaks within 300ꢀ350 nm almost remain unchanged but an
obvious bathochromic shift from 365 nm, 396 nm to 407 nm is
spotted for the ICT band within 350ꢀ475 nm. The ratio of molar
extinction coefficient εmax [Oxaꢀ(CPA)2]:εmax [Oxaꢀ(CPA)1]
calculated from the ICT band is 10.1:1.0. Excited at the
absorption maximum, CPA, Oxaꢀ(CPA)1 and Oxaꢀ(CPA)2 have
single emission peaks locating at 498 nm, 504 nm and 508 nm,
respectively, and the fluorescence intensity is increased from
CPA, Oxaꢀ(CPA)1 to Oxaꢀ(CPA)2 by a ratio of 1.0:4.1:7.8. The
same trend is spotted in group 2 (Fig. 2b), with bathochromic
Scheme 2 Synthetic routes of target chromophores Oxaꢀ
(BCPA)2
Photophysical properties of 2,5ꢀbisarylꢀ1,3,4ꢀoxadiazoles
The CPA/BCPA and four 2,5ꢀbisarylꢀ1,3,4ꢀoxadiazoles can
be devided into two groups by structures without (group 1:
CPA, Oxaꢀ(CPA)1 and Oxaꢀ(CPA)2) or with (group 2: BCPA,
Oxaꢀ(BCPA)1 and Oxaꢀ(BCPA)2) tertꢀbutyls on the 3,6ꢀ
positions of carbazoles. The normalized fluorescence spectra
of the four 2,5ꢀbisarylꢀ1,3,4ꢀoxadiazoles in solid state was
shown in Fig. 1a. The maximum emission peaks of the four
chromophores were from 494 nm to 523 nm
（Table1）.
Obvious bathochromic shift was observed when the oneꢀ
donorꢀcontaining compounds changed into twoꢀdonorꢀ
containing compounds, for example, 494 nm for Oxaꢀ(CPA)1
and 523 nm for Oxaꢀ(CPA)2. The fluorescence pictures of
solid powder excited at 365 nm are also presented in the inset.
The CIE chromaticity coordinate of the four chromophores
was depicted in Fig. 1b. The CIE chromaticity coordinate
values of Oxaꢀ(CPA)1, Oxaꢀ(CPA)2, Oxaꢀ(BCPA)1 and Oxaꢀ
(BCPA)2 were calculated to be (0.21, 0.49), (0.32, 0.62), (0.18,
0.51) and (0.25, 0.61), respectively. An obvious change from
green to yellowish green is observed when the oneꢀdonorꢀ
containing compounds changed into twoꢀdonorꢀcontaining
compounds.
shifts in fluorescence spectra (
≈10 nm) compared to group 1,
which is resulted from the electronꢀdonating ability of tertꢀbutyl.
The data is provided in Table 1. It is obvious that the additional
carbazoleꢀcontaining triphenylamine chromophore moiety has
largely affected the optical property of the 2,5ꢀbisarylꢀ1,3,4ꢀ
oxadiazoles, showing increased molar extinction coefficient
and fluorescence intensity.
4 | J. Name., 2012, 00, 1-3
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8.8x106
2.0x105
Fig. 3 The emission (a) spectra of Oxaꢀ(CPA)1 in different
solvents at the concentration of 10ꢀ5 M and the linear plots of
the Lippert’s equation (b), Bakshiev’s equation (c) and
Kawski–Chamma–Viallet’s equation (d) for Oxaꢀ(CPA)1 and
Oxaꢀ(CPA)2, the calculation processes and definition of the
functions are performed according to the literature.15
a
CPA
Oxa-(CPA)
1
2
Oxa-(CPA)
6.6x106
4.4x106
1.5x105
1.0x105
5.0x104
-5
10
M
Three equations, Lippert’s equation, Bakshiev’s equation,
Kawski–Chamma–Viallet’s equation are often used to estimate
the dipole moment change of the molecular when excited.20 The
linear plots of the three equations are given in Fig. 3 (b, c, d),
from good to excellent R2 value can be observed and the
detailed information is listed in Table 1. From the calculation
results, large dipole moment difference ꢂꢁ ranging from 9.38 D
to 13.25 D are obtained, indicating a strong ICT effect occurs
during the excitation and emission process and the excited state
of the molecule possess an increased dipole moment compared
than that of the ground state (Table 1). The electron distribution
in the molecular were simulated and the results are provide in
Fig. 4a, the electron densities are largely located on the donor
in HOMO while in LUMO the electron densities mostly located
on the acceptor through the πꢀbridge. From comparing the
electron distribution condition in the HOMO and LUMO levels,
an obvious ICT process is observed from the electronꢀrich
region (donor) to the electronꢀpoor region (acceptor) as
depicted in Fig. 4b.
2.2x106
0.0
0.0
750
350
400 450 500 550
600 650 700
BCPA
Wavelength / nm
6.8x106
5.1x106
3.4x106
1.2x105
b
Oxa-(BCPA)
Oxa-(BCPA)
-5
1
2
8.7x104
5.8x104
10
M
2.9x104
0.0
1.7x106
a
0.0
750
350
400
450
500
550
600
650
700
Wavelength / nm
Fig. 2 Absorption and emission spectra of CPA, Oxaꢀ(CPA)1,
Oxaꢀ(CPA)2 (a) and BCPA, Oxaꢀ(BCPA)1, Oxaꢀ(BCPA)2 (b) in
THF with a concentration of 10ꢀ5 M.
The solvatochromism behaviour of the 2,5ꢀbisarylꢀ1,3,4ꢀ
oxadiazoles was investigated. As seen in Fig. 3, taking Oxaꢀ
(CPA)1 as an example, the emission spectra of the chromophore
undergo changes induced by the solvents owing varying
HOMO
-8.00 eV
LUMO
-1.25 eV
b
polarities. In stark contrast to
a
slightly positive
solvatochromism effect in the absorption properties,
a
remarkable change in the emission maximums (Fig. 3a) ranging
from 497 nm (CCl3) to 546 nm (DMF) indicates that ICT
transitions are facilitated in more polar solvents such as DMF
and ICT process probably occurs in the excited state of the
molecule. Meanwhile, a decreasing in fluorescence intensity is
also observed in highly polar solvents , with a ratio of
3.8(CCl3):1(DMF) for example, due to the fast interconversion
from the high emissive local excited (LE) state to the low
Fig. 4 Frontier molecular orbitals of Oxaꢀ(BCPA)1 (a) and
model picture of ICT process from the electronꢀrich region
(donor) to the electronꢀpoor region(acceptor) (b).
emissive ICT state reported by many groups.19
7000
a
b
Acetone
DMF
DCM
THF
Table 1 Photophysical properties of the four chromophores
Oxaꢀ(CPA)n and Oxaꢀ(BCPA)n (n=1,2)
Oxa-(CPA)
1
6000
5000
4000
2
Oxa-(CPA)
2
R
=0.96
Stoke
’
s
ꢁꢂ
λem λabs
εmax
λem
(nm) (nm) (Mꢀ1cmꢀ1) (nm)
shifts (D)
EA
2
=0.95
R
(cmꢀ1)
(
Solid) (THF
)
(
THF
)
(THF)
CF
(
THF)
0.16
0.20
0.24
0.28
450
500
550
600
650
700
750
F
(ε,n)
494
523
498
515
396
407
398
410
504 5547
9.38
Oxaꢀ(CPA)1
Oxaꢀ(CPA)2
Oxaꢀ(BCPA)1
Oxaꢀ(BCPA)2
Wavelength / nm
1
1.98×104
2.00×105
4.87×104
1.14×105
46000
7000
6000
5000
4000
508 4885 11.73
517 5696 11.10
518 5032 13.25
d
c
45000
44000
43000
42000
Oxa-(CPA)
1
Oxa-(CPA)
1
2
R
=0.86
2
Oxa-(CPA)
Oxa-(CPA)
2
R
=0.95
2
*
λabs UV absorption maximum; λem fluorescence emission
2
2
=0.98
R
=0.95
R
maximum; εmax maximum molar extinction coefficient; ꢂꢁ =ꢁeꢀ
ꢁg, ꢁe dipole moment of excited state, ꢁg dipole moment of
ground state.
0.9
1.0
1.1
1.2
(ε,
1.3
1.4
1.5
0.4
0.5
0.6
(ε,
0.7
0.8
F
n
)
F
n
)
2
3
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DOI: 10.1039/C4NJ02293A
1.2
1.0
0.8
0.6
0.4
0.2
c
φ
f=0.55
φ
f=0.28
From the discussion above, the two groups of chromophores
φ
f=0.24
indicated structureꢀrelated emission in solid states, showing an
obvious change from green to yellowish green when the oneꢀ
donorꢀcontaining compounds changed into twoꢀdonorꢀ
containing compounds. Solvatochromism effect, a sign of ICT,
was also observed due to the DꢀA configuration of the
chromophores. Thus it is necessary to further investigate the
photophysical properties of the chromophores in different
aggregated states to explore the potential bioapplications.
Nanoparticle formation
and AIE
solvent polarity
quenching (ICT)
0
10
20
30
40
50
60
70
80
90
Water fraction (VOl%)
Fig. 5 Absorption (a) and fluorescence spectra (b) of 10ꢀ5
M
Oxaꢀ(CPA)1 in the mixed solvent of water and THF system
with different water fractions and corresponding changes in PL
peak intensities(I/I0, I0= PL intensity in pure THF solution) (c).
Aggregationꢀinduced fluorescence in nanoꢀ
aggregates and cell imaging
All the chromophores are insoluble in water and the
dispersion system of nanoꢀaggregates was obtained by gradual
addition of water into THF with different ratios. As seen in Fig.
5a, when the water fraction ƒW < 60% for Oxaꢀ(CPA)1, the
absorption peaks almost remain unchanged. However, with
more water added, remarkable changes were observed which
can be attributed to the aggregation of the chromophore
molecules. In spite of this, the water/THF system remain
homogenous without obvious precipitates, indicating that
aggregates are probably at nanoscale sizes which can also be
proved by the levelꢀoff tail stretched into the longer wavelength
region in absorption spectra. 21 The emission spectra were
presented in Fig. 5 (b, c). The Vꢀprofiled fluorescence intensity
plots (Fig. 5c) obviously indicated a synergic effect of two
different mechanisms, ICT and AIE effect. When the water
fraction increased from 0 to 50%, the emission peaks
bathochromic shifted from 501 nm to 533 nm and the
fluorescence intensity decreased dramatically from quantum
yield (Φf) up to 0.55 in THF and to a very low value at the
water fraction of 50%. This can be attributed to an enhanced
extent of ICT process when the more polar solvent water was
added. In a less polar system (THF), the emission mostly comes
from local excited (LE) state which is high in fluorescence
intensity and short in emission peak, while with the polarity of
the system increasing, ICT process is facilitated and LE state is
substituted by ICT state and bathochromicꢀshifted emission
accompanied by decreasing in emission intensity occurs.22 But
with the more water added (ƒW > 50%), the solubility of the
mixture solvent decreased and nanoꢀaggregates started to form,
ICT was eliminated and AIE effect became a dominated
factor.23 Thus a blueꢀshifted wavelength (from 533 nm to 504
nm) and increased fluorescence intensity (Φf =0.28, ƒW = 80%)
were observed due to a decreasing in the polarity of local
environment and the restricted intramolecular torsion in
aggregated state. The detailed quantum yield in mixed solvent
of water and THF system are presented in Table 2. Fig. 6 shows
the fluorescence pictures of Oxaꢀ(BCPA)1 (a) and Oxaꢀ
(BCPA)2 (b) in mixed solvent of water and THF system with
different water fractions at concentrations of 10ꢀ5 M excited at
365 nm.
Fig. 6 The fluorescence pictures of Oxaꢀ(BCPA)1 (a) and Oxaꢀ
(BCPA)2 (b) in mixed solvent of water and THF system with
different water fractions at concentrations of 10ꢀ5 M excited at
365 nm.
From the discussion above, it can be concluded that all the
four chromophores are AIEꢀICT active with good
photophysical properties in aggregated state with quantum yield
even up to 53% for Oxaꢀ(BCPA)1 in mixed solvent of water
and THF system with water fraction of 90%. Thus it is
necessary to further explored for potential bioapplications.
The main obstacle is that they are incompatible to aqueous
biological systems because of poor solubility in water,24 which
is a common problem that largely limits their bioapplications.
To overcome these limitations, we have synthesised two kinds
of nanoparticles with different structural features aiming at
various functions such as cell imaging, biosensor, gene delivery
and drug carriers. Aminoꢀgroupꢀfunctionalized SiꢀNPs were
synthesized as the first step towards the promising applications
in cell imaging or bioprobes because that amino groups can be
easily modified in the next step by biomolecules which would
be able to, for instance, target specifically the cancer cells or
detect DNA hybridization.25
The model structure of the SiꢀNPs is presented in Fig. 7(left).
It is consisted by two parts: (1) the core made of aggregatied
chromophore molecules and (2) the silica shell whose internal
surface was modified by vinyl that would create a nonꢀpolar
environment for organic chromophores while the outside
surface was decarated with amino groups which would provide
bonding sites for biomolecules. TEM image of the dyeꢀdoped
SiꢀNPs is shown in Fig.6(right). The average particle size of the
SiꢀNPs indicated by the TEM image is 30 nm.
0.30
a
b
Water Fraction
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
0.25
0.20
0.15
0.10
0.05
0.00
90%
80%
70%
Nanoparticles formation and AIE
Solvents Polarity Effects
60%
50%
40%
30%
20%
10%
THF
450
500
550
600
650
700
750
300
350
400
450
500
550
600
Wavelength / nm
Wavelength / nm
6 | J. Name., 2012, 00, 1-3
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Paper
DOI: 10.1039/C4NJ02293A
7.2x106
0.60
0.45
0.30
0.15
Oxa-(BCPA) -loaded
b
2
Si-NPs
5.4x106
-6
C≈10
M
φ
=0.23
f
3.6x106
1.8x106
Fig. 7 Model structure (left) and TEM picture (right) of Oxaꢀ
(BCPA)2 doped and aminoꢀgroupꢀfunctionalized nanoparticles
with average diameter of 30 nm.
0.0
750
0.00
350
400
450
500
550
600
650
700
The absorbance and fluorescence spectra of the dyeꢀdoped
SiꢀNPs were investigated to assess the photophysical properties
of the chromophores when encapsulated in nanoparticles. All
the four SiꢀNPs can be well dispersed in water while the good
inherent photophysical properties of the pure dyes were
maintained as presented in Fig. 8 and Table 2. The absorption
peaks of dyeꢀdoped SiꢀNPs were at 411, 414, 419, 420 nm
while the emission peaks were at 500, 507, 476, 513 nm,
showing a Stoke’s shifts of 89, 93, 57, 93 nm respectively for
Oxaꢀ(CPA)1, Oxaꢀ(CPA)2, Oxaꢀ(BCPA)1 and Oxaꢀ(BCPA)2.
Taking Oxaꢀ(BCPA)2 as an example to compare the emission
behavior of the chromophores in different states, the emission
peaks of which located at 518 nm in pure THF, 542 nm in
mixed solvent of water and THF system with water fraction of
20%, 518 nm when the water fraction is 50%, 509 nm when the
water fraction is 90% and 513 nm if Oxaꢀ(BCPA)2 was
encapsulated in SiꢀNPs dispersed in water. It was obvious that
the emission peaks of dyes encapsulated inside the silica shell
were similar to that of which was in low polar solvent THF or
aggregated particles dispersed in higher water fraction and
different from in mixꢀsolvents with lower water fractions such
as 20%. Meanwhile, the quantum yield of Oxaꢀ(BCPA)1 is up
to 35% and Oxaꢀ(BCPA)2 is up to 23%, respectively. Thus it
could be concluded that the excellent photophysical properties
of the chromophores in solid states were maintained in the Siꢀ
NPs while the potential bioapplications based on the SiꢀNPs
could be further explored.26
Wavelength / nm
Fig. 8 Absorption and fluorescence spectra of SiO2ꢀNPs of
Oxaꢀ(BCPA)1 (a) and Oxaꢀ(BCPA)2 (b) in water(10ꢀ6 M); the
insets are fluorescence pictures of NPs in water excited at 365
nm.
Table 2 Photophysical properties of the four chromophores
Oxaꢀ(CPA)n and Oxaꢀ(BCPA)n (n=1,2) in different
aggregated states
SiꢀNPsa
ƒW=80%
ƒW=90%
λabs λem
(nm) (nm)
/ Φf
λabs λem
(nm) (nm)
/ Φf
λabs λem
(nm) (nm)
/ Φf
411 500
/0.13
421 508
/0.28
428 509
/0.08
405
430
412
439
501
/0.24
506
Oxaꢀ(CPA)1
Oxaꢀ(CPA)2
Oxaꢀ(BCPA)1
Oxaꢀ(BCPA)2
414 507
/0.07
/0.07
417 515
/ꢀꢀ
510
/0.53
419 476
/0.35
434 515
/ꢀꢀ
509
/0.24
420 513
/0.23
a
*
ƒW water fraction of THF and water system; SiꢀNPs
dispersed in water;λabs UV absorption maximum; λem
fluorescence emission maximum; Φf fluorescence quantum
yield
a
Oxa-(BCPA) -loaded
1
Si-NPs
8.0x106
6.0x106
4.0x106
0.32
0.24
0.16
0.08
0.00
Cell imaging
Dyeꢀloaded BSAꢀNPs17 were synthesized and investigated
and the preparation process was presented in Fig. 9. With the
THF solution of chromophores gradually added into the
aqueous solution of BSA, the dye molecules aggregated
because of its poor solubility in water and the aggregated
molecules entangled with BSA chain. When the addition
process finished, the mixture would be a mixed solvent of water
and THF system of 38% (V/V) water fraction. Then
glutaraldehyde (GA) was added to knit together the BSA matrix.
After the reaction finished, the THF was removed and the
mixture returned into aqueous system but BSA matrix would
not be dissolved back into water because of the GAꢀknitted
structure.
-6
C≈10
M
φ
=0.35
f
2.0x106
0.0
350
400
450
500
550
600
650
700
750
Wavelength / nm
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J. Name., 2012, 00, 1-3 | 7

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DOI: 10.1039/C4NJ02293A
Fig. 9 The preparation process and model structure of dyeꢀ ability in water for all the chromophores were observed. Dyeꢀ
loaded BSA nanoparticles.
loaded BSAꢀNPs were also successfully applied to cell imaging.
TEM image of the dyeꢀloaded BSAꢀNPs are shown in Fig.
10. It indicates that the dyeꢀloaded BSAꢀNPs have a spherical
shape and a smooth surface.
Conclusions
With combination of carbazoleꢀcontaining triphenylamine
with 1,3,4ꢀoxadiazole by conjugated πꢀbridge, two groups of
aggregationꢀinduced emission and intramolecular charge
transfer active chromophores were synthesized. Strong
structureꢀrelated emissions of the chromophores in solid states
with peaks ranging from 494 nm to 523 nm were observed,
showing an obvious change from green to yellowish green
when the oneꢀdonorꢀcontaining compounds changed into twoꢀ
donorꢀcontaining compounds. Remarkable solvatochromism
effect was found and the emission peaks for Oxaꢀ(CPA)1
ranged from 498 nm in chloroform to 545 nm in DMF for
instance.
Fig. 10 TEM pictures of Oxaꢀ(BCPA)2.
Aggregationꢀinduced emission and intramolecular charge
transfer effect was also found in mixed solvent of water and
THF system. Obvious bathochromic shifts was observed with
the increase of the water fraction and the quantum yield in THF
was up to 0.54 for Oxaꢀ(BCPA)1, for instance, while in mixed
solvent of water and THF system with water fraction of 90%,
the quantum yield was 0.53.
Similar to the dyeꢀdoped SiꢀNPs, the chromophore molecules
in the dyeꢀloaded BSAꢀNPs were in aggregated states and thus
the photophysical properties were kept due to AIE effect. BSA
matrix was introduced to improve the bioꢀcompatibility of the
nanoparticles and to enhance the permeability and retention
effect of the chromophores.
The dyeꢀloaded BSAꢀNPs were incubated with HeLa cells
Based on the excellent performances of the chromophores in
aggregated states, dyeꢀloaded nanoparticles were prepared and
tested. The dyeꢀdoped silica nanoparticles indicated that besides
the greatly enhanced bioꢀcompatibility, the inherent advantages
of the pure dyes were also maintained and the quantum yield of
Oxaꢀ(BCPA)1ꢀdoped silica nanoparticles was even up to 35%.
Most importantly, it provided a promising approach in
exploring applications in bioprobes by decorating the surface of
the silica nanoparticles with different functional components.
The dyeꢀloaded BSAꢀnanoparticles were applied to cell
imaging and showed a better uptake by HeLa cells compared to
pure dye nanoparticles, which indicating dyeꢀloaded BSAꢀ
nanoparticles could be significant biosensors in cancer cell
detecting. The detailed bioapplications of these materials are
underway.
for 4 hours at 37
℃ and fixed for cell imaging and the result
was presented in Fig. 11. From the imaging bright green
fluorescence emitted from the chromophores could be clearly
seen, which covered the cells very well. Compared with bare
chromophore NPs, which were failed to be uptaken by HeLa
cells in the same incubation conditions, dyeꢀloaded BSAꢀNPs
showed an excellent intracellular uptake and
a
high
fluorescence contrast, which suggested dyeꢀloaded BSAꢀNPs
could be potential cancer cell biosensors with good
biocompatibility and photostability. The cytotoxicity of the
dyeꢀloaded BSAꢀNPs against HeLa cells was investigated using
a MTT cellꢀviability assay according to the known literature
procedure.17 High cell viabilities of more than 92% were
observed, indicating low cytotoxicity of the dyeꢀloaded BSAꢀ
NPs (Fig. S2).
Acknowledgements
We thank the financial support from the National Natural
Science Foundation of China (Grant numbers: 60678042 and
61178057). We thank Prof. S. Q. Liu, Dr H. N. Li, D. H. Chen,
Y. M. Zhang for their kind help with the cell culture and MTT
assay.
Notes and references
1 (a) Xiaoyong Zhang, Xiqi Zhang, Shiqi Wang, Meiying Liu, Yun Zhang,
Lei Tao and Yen Wei, ACS Appl. Mater. Interfaces, 2013, 5, 1943; (b)
Xueling Zhao, Zongyan Chen, Hongli Zhao, Denghao Zhang,a Liang Tao
and Minbo Lan, RSC Adv., 2014, 4, 62153; (c) Xiaoyong Zhang, Xiqi Zhang,
Bin Yang, Liangji Liu, Junfeng Hui, Meiying Liu, Yiwang Chen and Yen
Wei, RSC Adv., 2014, 4, 10060; (d) Henan Li, Yawen Mu, Jusheng Lu, Wei
Wei, Yakun Wan and Songqin Liu, Anal. Chem. 2014, 86, 3602; (e) Marine
Perrier, Magali GaryꢀBobo, Lenaı¨c Lartigue, David Brevet, Alain More`re,
Marcel Garcia, Philippe Maillard, J Nanopart Res, 2013, 15, 1602; (f) Babao
Lin, Xiuzhong Yao, Yihua Zhu, Jianhua Shen, Xiaoling Yang and
Fig. 11 Fluorescence imaging pictures of HeLa cells treated
with dyeꢀloaded BSA nanoparticles containing Oxaꢀ(BCPA)1
and Oxaꢀ(BCPA)2.
In this part, based on the excellent AIE properties and high
quantum yield of the chromophores, the photophysical
properties of dyeꢀdoped SiꢀNPs were investigated and high
quantum up to 35% for Oxaꢀ(BCPA)1 and good dispersing
Chunzhong Li, Chiara Agnoletto, Giorgio Zauli and Paola Secchiero, RSC
Adv., 2014, 4, 20641; (g) Hongxing Xia, Xiaoquan Yang, Jitao Song, Jun
8 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 2012

Page 9 of 10
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View Article Online
NJC
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DOI: 10.1039/C4NJ02293A
Chen, Mingzhen Zhang, Dongmei Yan, Lin Zhang, Mengyao Qin, Lingyu
10 Jung Aa Ko and H. B. Lim, J. Anal. At. Spectrom., 2013, 28, 630
Bai, Yuanꢀdi Zhao and Zhiya Ma, J. Mater. Chem. B, 2014, 2, 1945
11 Stefania Biffi, Luca Petrizza, Enrico Rampazzo, Rebecca Voltan,
Massimo Sgarzi, Chiara Garrovo, Luca Prodi, Laura Andolfi, RSC Adv., 2014,
4, 18278
2 (a) Xiaoting Yu, Xu Jia, Xiaolong Yang, Weisheng Liu and Wenwu Qin,
RSC Adv., 2014, 4, 23571; (b) Kasoju Aruna, T. Mohammad Munawar,
M.V.Prashanthi,M.Lakshmi Narsu, International Journal of Advanced
Research, 2013, 1, 1; (c) Raffaele Riccò, Anna Meneghello, Francesco
Enrichi, Biosensors and Bioelectronics, 2011, 26, 2761; (d) Eue Soon Jang,
Seung Yong Lee, EuiꢀJoon Cha, InꢀCheol Sun, Ick Chan Kwon, Dukjoon
Kim, Young II Kim, Kwangmeyung Kim and CheolꢀHee Ahn, Pharm Res,
2014, 31, 3371; (e) B Korzeniowska, R Nooney, D Wencel and C McDonagh,
Nanotechnology, 2013, 24, 442002(20pp); (f) Vinoth Kumar Rajendran,
Padmavathy Bakthavathsalam, Baquir Mohammed Jaffar Ali, Microchim
Acta, 2014, 181, 1815
12 Feng Gao, Peng Cui, Xiaoxiao Chen, Qingqing Ye, Maoguo Li and Lun
Wang, Analyst, 2011, 136, 3973
13 Yun Xia, Min Li, Tao Peng, Weijie Zhang, Jun Xiong, Qinggang Hu,
Zifang Song and Qichang Zheng, Int. J. Mol. Sci., 2013, 14, 1080
14 (a) Binbin Wang and Ying Qian, New J. Chem.,2013, 37, 1402; (b) Ying
Qian, Zhifeng Lu, Changgui Lu, Zhiming Chen, Yiping Cui, Dyes and
Pigments, 2007, 75, 641; (c) Binbin Wang and Ying Qian, Chin. J. Org.
Chem. 2014, 34, 210; (d) Xiaoqin Zhu and Ying Qian, Chinese Journal of
Organic Chemistry, 2009, 29, 1975; (e) Hua Yang and Ying Qian, Chin. J.
Org. Chem., 2013, 33, 184; (f) Ying Qian, Xinming Lv, Zhiqing Zhou and
Yiping Cui, Chemical Journal of Chinese Universites, 2011, 32, 2441; (g)
Kaiming Hu and Ying Qian, Actachimicasinica, 2010, 68, 1; (h) Ying Qian,
Manli Luo, Dyes and Pigments, 2014, 101, 240
3 (a) Jianliang Shen, Hancheon Kim, Hua Su, Feng Wang, Joy Wolfram,
Dickson Kirui, Junhua Mai, Chaofeng Mu, Liangnian Ji, Zongwan Mao,
Haifa Shen, Theranostics, 2014, 4, 487; (b) Dechao Niu, Zuojin Liu,
Yongsheng Li, Xiaofeng Luo, Junyong Zhang, Jianping Gong and Jianlin Shi,
Adv. Mater. 2014, 26, 4947; (c) Sandy B Hartono, Meihua Yu, Wenyi Gu, Jie
Yang, Ekaterina Strounina, Xiaolin Wang, Shizhang Qiao and Chengzhong
Yu, Nanotechnology, 2014, 25, 055701 (12pp); (d) Fengpeng Chang, Linyun
Kuang, ChiaꢀAn Huang, Wannneng Jane, Yann Hung, Yueꢀie C. Hsing and
Chungyuan Mou, J. Mater. Chem. B, 2013, 1, 5279; (e) Xing Ma, Yun Zhao,
Kee Woei Ng and Yanli Zhao, Chem. Eur. J., 2013, 19, 15593; (f) Jiantao
Lin, Chao Wang, Yi Zhao and Guanhai Wang, Materials Research Express,
2014, 1, 0354031
15 Wei Huang, Fansheng Tang, Bo Li, Jianhua Sua and He Tian, J. Mater.
Chem. C, 2014, 2, 1141
16 (a) Tinghua Xu, Ran Lu, Xingliang Liu, Xiangqian Zheng, Xianping Qiu,
and Yingying Zhao, Org. Lett., 2007, 9, 5; (b) Jiuyan Li, Ting Zhang,
Yunjing Liang and Ruixia Yang, Adv. Funct. Mater. 2013, 23, 619
4 (a) S. Karthik, Avijit Jana, Biswajit Saha, B. Krishna Kalyani, Sudip
Kumar Ghosh, Yanli Zhao and N. D. Pradeep Singh, J. Mater. Chem. B,
2014, 2, 7971; (b) Christophe Thron, Audrey Gallud, Carole Carcel, Magali
GaryꢀBobo, Marie Maynadier, Marcel Garcia, Jie Lu, Fuyuhiko Tamanoi,
Jeffrey I. Zink and Michel Wong Chi Man, Chem. Eur. J., 2014, 20, 9372; (c)
Rajendra K. Singh, TaeꢀHyun Kim, Kapil D. Patel, JungꢀJu Kim and Haeꢀ
Won Kim, J. Mater. Chem. B, 2014, 2, 2039; (d) Rijun Gui, Yanfeng Wang,
Jie Sun, Colloids and Surfaces B: Biointerfaces, 2014, 116, 518; (e) Bei Liu,
Chunxia Li, Dongmei Yang, Zhiyao Hou, Ping’an Ma, Ziyong Cheng,
Hongzhou Lian,Shanshan Huang and Jun Lin, Eur. J. Inorg. Chem., 2014,
1906; (f) Robert Roggers, Shrey Kanvinde, Suthida Boonsith and David
Oupický, AAPS PharmSciTech, 2014, 15, 5; (g) Peng Zhang, Tianyi Wang,
Huanming Xiong, Jilie Kong, Talanta, 2014, 127, 43
17 Wei Qin, Dan Ding, Jianzhao Liu, Wang Zhang Yuan, Yong Hu, Bin Liu
and Ben Zhong Tang, Adv. Funct. Mater. 2012, 22, 771
18 Tainan Duan, Ke Fan, Cheng Zhong, Wuwei Gao, Xingguo Chen,
Tianyou Peng, Jingui Qin, Journal of Photochemistry and Photobiology A:
Chemistry, 2014, 278, 39
19 (a) Zhangyuan Wang, Yongyang Gong, Shuming Chen, et al, Chem.
Mater. 2012, 24, 1518; (b) Yilin Li, Zhipeng Li, Yang Wang, Energy
Environ. Sci., 2013, 6, 2907; (c) Ziqi Yana, Zhiyong Yang, Hai Wang,
Spectrochimica Acta Part A, 2011, 78, 1640; (d) Bingrong Gao, Haitu Wang,
Yawei Hao, J. Phys. Chem. B, 2010, 114, 128
20 (a) J.S. Kadadevarmath, G.H. Malimath, N.R. Patil, Can. J. Phys., 2013,
91, 1107; (b) S. A. ElꢀDaly, A. M. Asiri , K. A. Alamry, J Fluoresc, 2014, 24,
1307
5 Jingdong Luo, Zhiliang Xie, Jacky W. Y. Lam, Lin Cheng, Haiying Chen,
Chengfeng Qiu, Hoi Sing Kwok, Xiaowei Zhan, Yunqi Liu, Daoben Zhu and
Ben Zhong Tang, Chem. Commun., 2001, 1740
21 (a) B.Z. Tang, Y. Geng, Lam JWY, B. Li, X. Jing, X. Wang, F. Wang,
Pakhomov AB, X. Zhang, Chem Mater, 1999, 11, 1581; (b) Yuting Gao, Hao
Zhang, Tao Jiang, Ji Yang, Bo Li, Zhen Li, Sci China Chem, 2013, 56, 1204
6 (a) Youyong Yuan, Ryan T. K. Kwok, Benzhong Tang and Bin Liu, J. Am.
Chem. Soc., 2014, 136, 2546; (b) Xiangdong Xue, Yuanyuan Zhao, Luru Dai,
Xu Zhang, Xiaohong Hao, Chunqiu Zhang, Shuaidong Huo, Juan Liu,
Chang Liu, Anil Kumar, Weiqiang Chen, Guozhang Zou and Xingjie Liang,
Adv. Mater., 2014, 26, 712
22 Peiyang Gu, Caijian Lu, Zhijun Hu, J. Mater. Chem. C, 2013, 1, 2599
23 Guofeng Zhang, Matthew P. Aldred, Chem. Commun., 2012, 48, 7711
24 Chenfei Guan and Ying Qian, Chin. J. Org. Chem., 2014, 34, 537
7 Zhengke Wang, Sijie Chen, Jacky W. Y. Lam, Wei Qin, Ryan T. K. Kwok,
Ni Xie, Qiaoling Hu and Ben Zhong Tang, J. Am. Chem. Soc., 2013, 135,
8238
25 (a) Zhou Jiang, Tingting Yang, Minyan Liu, Yanli Hu and Jian Wang,
Biosensors and Bioelectronics, 2014, 53, 340; (b) Sehoon Kim, Tymish Y.
Ohulchanskyy, Dhruba Bharali, Yihui Chen, Ravindra K. Pandey and Paras
N. Prasad, J. Phys. Chem. C, 2009, 113, 12641; (c) Zhivko Zhelev, Hideki
Ohba and Rumiana Bakalova, J. AM. CHEM. SOC. 2006, 128, 6324
8 Jie Zhao, Dong Yang, Yanxia Zhao, XiaoꢀJuan Yang, YaoꢀYu Wang and
Biao Wu, Angew. Chem. Int. Ed., 2014, 53, 6632
9 Zilong Wang, Bin Xu, Lei Zhang, Jibo Zhang, Tenghe Ma, Jiabao Zhang,
Xueqi Fu and Wenjing Tian, Nanoscale, 2013, 5, 2065
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26 (a) Jun Qian, Xin Li, Ming Wei, Xiangwei Gao, Zhengping Xu and
Sailing He, Optics Express, 2008, 16, 19568; (b) Xuhua Wang, Sheng Yao,
HyoꢀYang Ahn, Yuanwei Zhang, Mykhailo V. Bondar, Joseph A. Torres and
Kevin D. Belfield, Biomedical Optics Express, 2010, 1, 453
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