Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts: Emission Color-Tuning with Counter Anions and Application for Optical Waveguides

Article abstract of DOI:10.1002/smll.201402051

In this paper seven salts of pyridinium-substituted tetraphenylethylene with different anions are reported. They show typical aggregation-induced emission. Crystal structures of three of the salts with (CF₃SO₂)₂N^-

Full text of DOI:10.1002/smll.201402051

Color Tuning
Highly Solid-State Emissive Pyridinium-Substituted
Tetraphenylethylene Salts: Emission Color-Tuning with
Counter Anions and Application for Optical Waveguides
Fang Hu, Guanxin Zhang,* Chi Zhan, Wei Zhang, Yongli Yan, Yongsheng Zhao,
Hongbing Fu, and Deqing Zhang*
I n this paper seven salts of pyridinium-substituted tetraphenylethylene with
different anions are reported. They show typical aggregation-induced emission.
−
−
Crystal structures of three of the salts with (CF3SO2)2N−, CF3SO3 , and SbF6
as the respective counter anions, are determined. The emission behavior of their
amorphous and crystalline solids is investigated. Both amorphous and crystalline
solids, except for the one with I−, are highly emissive. Certain amorphous solids
are red-emissive with almost the same quantum yields and fluorescence life-times.
However, some crystalline solids are found to show different emission colors varying
from green to yellow. Thus, their emission colors can be tuned by the counter anions.
Furthermore, certain crystalline solids are highly emissive compared to the respective
amorphous solids. Such solid-state emission behavior of these pyridinium-substituted
tetraphenylethylene salts is interpreted on the basis of their crystal structures. In
addition, optical waveguiding behavior of fabricated microrods is presented.
interactions leading to formation of detrimental species such
1. Introduction
as excimers and exciplexes.[5] Interestingly, a few organic
Emissive molecules with high quantum yields in the solid fluorophores including siloles[6] and tetraphenylethylenes[7]
states have been intensively explored for applications in show the opposite fluorescent behavior; they are weakly or
organic light emitting diodes (OLEDs),[1] organic light non-emissive in solution, but they become strongly emissive
emitting field transistors,[2] optical waveguides[3] and opti- upon formation of aggregation states and in the solid states.[8]
cally pumped lasers.[4] However, most of luminogens that Such abnormal fluorescent behavior is referred as to aggre-
are highly fluorescent in solutions become weakly or even gation induced (enhanced) emission (AIE), which is ascribed
non-emissive in the aggregation and solid states. Such to the inhibition of internal rotations as well as aggregation
emission quenching is usually attributed to intermolecular induced-planarization and formation of J-aggregates in some
cases.[6–9]
AIE fluorophores have received increasing attentions in
Dr. F. Hu, Dr. G. X. Zhang, Dr. C. Zhan, Dr. W. Zhang,
recent years and sucessfully applied for sensing[10] and bio-
Dr. Y. L. Yan, Prof. Y. S. Zhao, Prof. H. B. Fu,
imaging.[11] They have also utilized as light-emitting materials
in OLEDs[12] and optical waveguides.[13] The results reveal
Prof. D. Q. Zhang
Beijing National Laboratory for Molecular Sciences
CAS Key Laboratory of Organic Solids
Institute of Chemistry
Chinese Academy of Sciences
Beijing 100190, P. R. China
E-mail: gxzhang@iccas.ac.cn; dqzhang@iccas.ac.cn
that these AIE luminogens are not only strongly emissive in
the solid states, but also responsive to external stimuli such
as heating, grinding and chemical vapor.[13a,14] In fact, organic
emissive materials whose emission intensities and colors can
be tuned are highly desirable for the practical applications in
optoelectronic devices.[15]
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Scheme 1. Synthetic route to compounds 1–7. Reagents and conditions: i) 4-pyridinylboronic acid, Pd(PPh3)4, K2CO3, THF/H2O, 75 °C; ii) CH3I,
CH3CN, 80 °C; iii) AgX, CH3OH/H2O, 25 °C.
Tetraphenylethylenes with cationic and anionic moie- exist for the conformation of the common luminogen (pyri-
ties were synthesized and investigated mainly for chemo- dinium-substituted tetraphenylethylene) in crystals of 2, 5
sensing[16] and bio-sensing.[17] However, their solid state and 6. For instance, the dihedral angles between rings A and
emissions were rarely examined.[14b,c] In this paper, we report D were found to be 64.30o, 45.41o and 45.11o in 2, 5 and 6,
the solid state emission of pyridinium-substituted tetrap- respectively. Such slight conformation differences can affect
henylethylene salts 1–7 (Scheme 1). The results reveal that the electron conjugation in pyridinium-substituted tetra-
i) these salts are all red-emissive with relatively high quantum phenylethylene of 2, 5 and 6;[13a] as a result, crystals of 1–7
yields (except 1 containing I−) in the amorphous states; are expected to show different absorption and fluorescence
ii) these salts become more emissive in the respective crys- spectra (see below).
talline states; iii) furthermore, the emission colors are varied
Figure S1 and Figure 1 show the respective intermolec-
from green to yellow by just changing the counter anions; ular arrangements and short interatomic contacts between
thus, the emission color of the same luminogen (pyridinium- the pyridinium-substituted tetraphenylethylene cations and
substituted tetraphenylethylene) can be tuned by the counter counter anions within crystals of 2, 5 and 6. There is no inter-
anions. In addition, microrods of 2 and 5 exhibit optical wave- molecular face-to-face arrangements among the nighboring
guiding behavior with relatively low optical loss coefficients.
pyridinium and phenyl rings, thus no intermolecular pi-pi
interactions exist. However, the pyridinium-substituted tet-
raphenylethylene cations and counter anions are interacted
via mutiple short interatomic contacts (see Table S1) within
crystals of 2, 5 and 6 as depicted in Figure 1. It is clear that
intermolecular orientations of the cations and anions are dif-
ferent witin crystals of 2, 5 and 6; moreover, the cations in
2. Results and Discussion
2.1. Synthesis and Crystal Structures
The synthesis of compounds 1–7 is shown in Scheme 1. Suzuki 2, 5 and 6 are surrounded and interacted with the respective
−
−
coupling of compound 8 with 4-pyridinylboronic acid led to 9 anions [(CF3SO2)2N−, CF3SO3 , SbF6 ] in different ways. This
in 62.2% yield, which was transformed into compound 1 after may be regarded as the cations in 2, 5, 6 are influenced by dif-
reaction with iodomethane. Compounds 2–7 were yielded by ferent polar environments.[18]
further reaction of 1 with the respective silver salts in accept-
able yields. The chemical structures of 1–7 were confirmed
by NMR and MS data and their purities were checked with 2.2. Solid-State Emission Behavior
elemental analysis (see Experimental section).
Crystal structures of 2, 5 and 6 were sucessfully deter- The solutions of 1–7 in good solvents such as CH2Cl2 are
mined. Figure 1 shows their molecular structures (ORTEP almost non-emissive (see Figure S2) as reported for other
drawings) and intermoleuclar interactions. Their bonding tetraphenylethylene molecules.[7–14] Also, their solutions
lengths and angles are in normal region. As the carbon show almost the same absorption spectra as depicted in
atoms C1, C2, C3, C15, C21 and C28 in ethylene moieties Figure S3, which is consistent with the fact that 1–7 have
are almost coplanar, they were defined as plane A, and the the common luminogen (pyridinium-substituted tetrapheny-
respective four phenyl rings were defined as plane B, C, D lethylene). The fluorescence of 1–7 can be switched on after
and E as shown in Figure 1. The corresponding dihedral aggregation induced by addition of poor solvent. Figure S2
angles are listed in Table 1. Obviously, subtle differences shows the fluorescence enhancement for solutions of 1–7 in
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Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts
Figure 1. The ORTEP drawings of 2 (a), 5 (c) and 6 (e); the intermolecular interactions within crystals of 2 (b), 5 (d) and 6 (f).
Table 1. The dihedral angles among rings of A, B, C, D and E within
crystals of 2, 5 and 6.
CH2Cl2 after addition of hexane. Addition of hexane into the
CH2Cl2 solutions of 1–7 led to the formation of solid precipi-
tates, which were referred as to 1a, 2a, 3a, 4a, 5a, 6a and 7a,
respectively. As depicted in Figure 2a, no XRD signals were
detected for 1a-7a, indicating that they are amorphous. They
all are red-emissive with almost the same emission spectra as
shown in Figure 3. Their emission quantum yields and life-
times were measured (see Table 2). Except 1a with I− as the
counter anion 2a-7a exhibit rather similar emission behavior;
Compound
Dihedral Angle [o]
AB
AC
AD
AE
2
5
6
69.11
52.78
52.67
55.54
60.25
61.48
64.30
45.41
45.11
54.84
57.99
57.62
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F. Hu et al.
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(a)
(b)
7b
7a
6a
5a
4a
6b
5b
4b
3b
3a
2a
2b
1b
1a
3
6
9
12 15 18 21 24 27 30
3
6
9
12 15 18 21 24 27 30
2θ (deg)
2θ (deg)
Figure 2. The XRD patterns of 1a-7a (left) and 1b-7b (right).
their quantum yields are varied from 0.37 to 0.45 and emis- the cation luminogen due to the dense packing in the crystal-
sion life-times from 2.75 ns to 3.83 ns. The weak fluorescence line state than in the amorphous state. However, 2b-7b are
of 1a can be ascribed to the heavy atom effect of iodide anion more emissive than the respective amorphous solids; as listed
in 1a.[19]
in Table 2, the emission quantum yields of 2b-7b are roughly
Slow evaporation of the solutions of 1–7 in methanol/ two times of those of 2a-7a, respectively. The average emis-
water (1:1, v/v) led to the respective microcrystallines, which sion life-times of 2b-7b become also longer than those of the
were referred as to 1b, 2b, 3b, 4b, 5b, 6b, 7b respectively. The respective amorphous solids 2a-7a. Interestingly, these crys-
crystallinity of 1b, 2b, 3b, 4b, 5b, 6b and 7b was confirmed talline solids 2b-7b are not red-emissive, and their emission
by XRD studies. As examples, Figure 4 shows the XRD pat- colors are varied from yellow to green (see Figure 5). Their
terns of 2b, 5b, 6b, which match well with the respective simu- emission spectra are remarkably blue-shifted compared to the
lated diffraction signals of 2, 5, 6, respectively, based on their corresponding amorphous solids; the emission maxima are
single crystal structural data. Thus, it may be concluded that shifted in the following order: 2b ((CF3SO2)2N−, 528 nm) < 3b
−
−
−
molecular conformations of the cations and the arrangement (ClO4 , 547 nm) < 4b (BF4 , 548 nm) < 5b (CF3SO3 , 557 nm)
−
−
of the cations and anions within 2b, 5b, 6b are the same as < 6b (SbF6 , 564 nm) < 7b (PF6 , 574 nm). To the best of
those of single crystals of 2, 5 and 6 (see above), respectively. our knowledge such anion-dependent emission was rarely
The emission behavior of 1b-7b was investigated. 1b reported for organic salts.
becomes even weakly emissive because I− may be closer to
It is expected that the cations (pyridinium-substituted
tetraphenylethylene) and the respective anions are more
densely arranged in the crystalline states than in the amor-
phous states. As a result, the pyridinium-substituted tetrap-
henylethylene may adopt a more planar conformation in the
amorphous state and become more twisting in the crystalline
state. This may interpret the emission blue-shifts of 2b-7b
compared to 2a-7a. In fact, the absorption tails above 500 nm
of 2a-7a disappear after the transformation into crystalline
states (see Figure S4). Moreover, more short intermolecular
interactions are anticipated for the crystalline states. For
instance, multiple short interatomic contacts are observed
within crystals of 2, 5, and 6 as depicted in Figure 1. Accord-
ingly, molecular conformations of the cations will be more
fixed in the crystalline states than in the amorphous states,
and the internal rotations around sigma bonds within pyri-
dinium-substituted tetraphenylethylene will be inhibited in
the crystalline states. Therefore, it is explainable that 2b-7b
are more emissive than 2a-7a.[8]
The following two structural facts may interpret that
emission colors of 2b-7b are dependent on the respective
counter anions: i) crystal structures of 2, 5, and 6 demon-
strate that the molecular conformation of the cation lumi-
nogen is affected by the intermolecular arrangements that
may be influenced by the respective counter anions with
different geometrical shapes and sizes. As shown in Table 1,
the dihedral angles among phenyl and pyridinium groups
Figure 3. a) Photos of samples 1a-7a under UV light (>365 nm)
illumination; b) the fluorescence spectra of 1a-7a; the excitation
wavelength was 410 nm.
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Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts
Table 2. The photophysical properties of amorphous solids (1a-7a) and microcrystalline solids (1b-7b).
Compounds
Amorphous solids (1a-7a)
Microcrystalline solids (1b-7b)
Absorption lmax Fluorescence lmax
<τ>a) [ns]
Φfb)
Absorption lmax Fluorescence lmax
<τ>a)
Φfb)
[nm]
406
408
408
399
405
410
408
[nm]
614
617
617
616
617
617
617
[nm]
405
410
408
412
412
410
408
[nm]
[ns]
1
2
3
4
5
6
7
0.99
2.75
3.79
3.83
3.69
3.62
3.68
0.09
0.37
0.41
0.42
0.43
0.37
0.45
–
0.64
4.03
5.18
5.61
5.87
4.84
5.16
0.04
0.77
0.89
0.96
0.65
0.87
0.65
528
547
548
557
564
574
n
i =1ai × τ i
n
∑
a)An apparent decay time constant <τ> was determined by using the following equation:
where τi and ai, respectively, represent the individual exponential
< τ > =
(n = 2 − 3)
i =1ai
∑
decay time constant and the corresponding preexponential factor; b)Φf was measured by calibrated integrating sphere.
within crystals 2, 5 and 6 are subtly different, thus the respec- section) all red-emissive solids were transformed into different
tive cations of 2, 5 and 6 in their crystals adopt different emission colors ranging from green to yellow (see Figure 6a),
conformations. Thus, the pi-conjugation degree among the corresponding well to those of 2b-7b shown in Figure 5. XRD
pyridinium, phenyl and ethylene moieties within the cation studies indicate that the solids after treatment with vapors
luminogen is subtly different; ii) crystal structures also reveal of methanol are crystalline. As an example, Figure 6b shows
that the cation luminogens are interacted with the respective the XRD pattern of the solid sample which was generated
anions in different ways. As a result the cation luminogens by exposing 2a to vapors of methanol; diffraction signals at
are affected by different polar environments.
2.3. Tuning the Emission by Exposure to Solvent Vapors and
Grinding
It is interesting to note that the amorphous states 2a-7a
and the respective crystalline states 2b-7b can be inter-con-
verted by exposing to solvent vapors and grinding. Accord-
ingly, the emission colors of these salts can be tuned by
exposure to solvent vapors and grinding. As mentioned
above the as-prepared amorphous solids are red-emissive.
After exposure to vapors of methanol (see Experimental
Simulated XRD of
6
5
2
XRD pattern of 6b
Simulated XRD of
XRD pattern of 5b
Simulated XRD of
XRD pattern of 2b
10
20
30
2 deg
Figure 5. a) The photos of microcrystalline powders 2b-7b dispersed
in water under UV light (>365 nm) illumination, respectively; b) the
normalized fluorescence spectra of 2b-7b ( λmax = 380 nm) and 2a ( λmax
= 410 nm).
Figure 4. The XRD patterns of 2b, 5b and 6b and simulated XRD patterns
of 2, 5 and 6 delineated on the basis of their crystal structures using the
single crystal software Mercury 1.4.2.
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F. Hu et al.
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Figure 6. a) Photos of the amorphous and crystalline samples of 2–7 after exposure to vapors of solvents and grinding taken under light
(>365 nm) illumination; b) XRD patterns of 2 after exposure to vapors of solvents and grinding; c) fluorescence spectra of 2 after exposure to
vapors of solvents and grinding.
2θ = 6.1o, 12.1o, 20.8o and 24.4o were detected, corresponding crystalline and amorphous solids can be inter-converted by
well to those of 2b (see Figure 2b). Thus, vapors can induce either exposure to vapors of methanol/CH2Cl2 or grinding.
the re-crystallization of 2a and transformation into 2b. Simi- As a result, the emission colors of these solids with the
larly, it is expected that 3a, 4a, 5a, 6a and 7a can be converted common luminogen (pyridinium-substituted tetraphenyleth-
into 3b, 4b, 5b, 6b and 7b, respectively, after exposure to ylene) can be tuned.
vapors of methanol.
The crystalline samples 2b, 3b and 4b which were formed
by exposure to vapors of methanol became red-emissive 2.4. Optical Waveguiding Behavior
again by further exposure to vapors of CH2Cl2 as shown in
Figure 6a. These solids were found to be amorphous again on Microrods of 2b were successfully yielded by slow evapora-
the basis of XRD data shown in Figure 6b and Figure S5. But, tion of the MeOH/H2O (v/v, 1:1) solution, and microrods of
the crystalline samples of 5b, 6b and 7b could not be trans- 5b were obtained by slow addition of H2O into the MeOH
formed into the respective amorphous solids by treatment solution. Figures 7a and 7b show the PL (photolumines-
with vapors of CH2Cl2. However, all crystalline samples 2b-7b cence) images. Clearly, green and yellow-green emissive spots
which were generated from the respective amorphous solids were detected at the respective two rod-ends of microrods of
after exposure to vapors of methanol could be successfully 2b and 5b, whereas only rather weaker emission came from
converted to the amorphous solids again by just grinding the the rod-bodies. Thus, microrods of 2b and 5b can function as
samples (see Figure 6a). These results demonstrate that these optical waveguides according to previous reports.[3,13]
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Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts
Figure 7. a, b) PL microscopy images of microrods of 2b and 5b deposited on glass wafers; c, d) bright-field images (left) of 2b and 5b and microarea
PL images (right) of 2b and 5b by exciting the respective microrods at six different positions with the focused UV laser (380 nm); e, f) spatially
resolved PL spectra of the emissions that are out-coupled at the tip of the microrods of 2b and 5b; insets show plots of the peak intensity at the
respective maxima vs. the propagation distance for microrods of 2b and 5b.
The respective spatially resolved PL spectra were meas- different positions (labeled as 1′, 2′, 3′, 4′, 5′ and 6′). Obvi-
ured to gain insight into the light waveguiding behaviors ously, the emission intensity at the microrod ends decreases
within microrods of 2b and 5b. As depicted in Figure 7c and upon increasing the propagation distance. As depicted in
7d micro-area PL spectra were collected at the ends of the the inset of Figure 7e, the emission intensity at 530 nm of
respective microrods of 2b and 5b under the excitations at the outcoupled light decreases almost exponentially with
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F. Hu et al.
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the propagation distance. Note that the emission intensities
of the excited points do not change substantially with the
position along the microrods. Thus, the inset of Figure 7e
can also represent the variation of intensity ratio of incident
and outcoupled light vs. the propagation distance. By fit-
ting the data of inset of Figure 7e according to the reported
procedure,[20] the optical loss coefficient at 530 nm for the
microrod of 2b was estimated to be 15.74 dB mm−1. Figure 7f
shows the micro-area PL spectra and the variation of the
emission intensity vs the propagation distance. Similarly, the
optical loss coefficient for the microrod of 5b was estimated
to be 14.32 dB mm−1. Based on the fact that the collected
PL spectra at the ends of microrods of 2b and 5b under the
excitations at different positions are almost the same, self-
absorption may not contribute largely to the optical loss
during the light propagation. Thus, it is assumed that the sub-
strate effect and Rayleigh scattering may induce the optical
loss observed for microrods of 2b and 5b, according to pre-
vious studies.[21]
It is known that optical waveguides of high performance
require emissive molecules with high emission quantum
yields in solid states and tunable emission colors. In this
aspect, molecules with aggregation-induced emission feature
are advantageous in terms of the following considerations: i)
they are highly emissive in the solid states, in particular in the
crystalline states; ii) their emission wavlengths can be easily
tuned by incorproation of appropriate electron donors and
acceptors.
4. Experimental Section
Materials and Characterization Techniques: The reagents and
starting materials were commercially available and used without
any further purification if not specified elsewhere. The water used
was purified by Millipore filtration system. Melting points were
measured with Büchi B540. 1H NMR and 13C NMR spectra were
recorded on Bruker AVANCE III 300 MHz spectrometer and Bruker
AVANCE III 400 MHz spectrometer. MS were recorded with BEFLEX
III spectrometer. Absorption spectra were recorded on UV-VIS-NIR
spectrophotometer (UV-3600, Shimadzu spectrometer). Steady-
state fluorescence spectra were recorded with Hitachi (F-4500)
spectrophotometers at 25 °C. Fluorescence confocal laser scan-
ning images were recorded with Olympus research inverted system
microscope (FV1000-IX81, Tokyo, Japan) equipped with a charge
couple device (CCD, Olympus DP71, Tokyo, Japan) camera; the
excitation source is a Hg lamp equipped with a band-pass filter
(330 ∼ 380 nm). All photographs were recorded on a Canon digital
camera.
Crystal Structure: Crystals of 2, 5 and 6 were grown by slow
evaporation from the methanol/water solution. All single crystals
data were collected on Rigaku Saturn diffractometer with CCD area
detector. All calculations were performed using the SHELXL97
and crystal structure crystallographic software packages. Crys-
tallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication no.
CCDC: 974637, 974638, 974639. X-ray diffraction (XRD) patterns
of 1–7 were carried out in the reflection mode at room temperature
using a 2 kW Rigaku X-ray diffraction system.
Photophysical Studies: Fluorescence quantum yields of 1–7 in
the solids states (amorphous and microcrystalline powders) were
recorded on FLSP 920 fluorescence spectroscopy with a calibrated
integrating sphere system. Fluorescence lifetimes were measured
based on the time-resolved PL experiments which were made
with a regenerative amplified Ti: sapphire laser (Spectra-Physics,
Spitfi re) at 400 nm (150 fs pulse width, second harmonic). The PL
spectra were recorded with a streak camera (C5680, Hamamatsu
Photonics) attached to a polychromator (Chromex, Hamamatsu
Photonics), for which the temporal and spectral resolutions of the
detector are ∼ 10 ps and 2 nm, respectively. All the spectroscopic
measurements were carried out at room temperature.
Optical Waveguide Measurements: To measure the microarea
PL spectra of single microrod, the microrods dispersed on a glass
cover-slip were excited with a UV laser (λ = 380 nm, Beamlok,
Spectraphysics). The excitation laser was filtered with a band-pass
filter (330–380 nm), then focused to excite the microrod with an
objective (50x, N.A. = 0.80).
3. Conclusion
Seven salts of pyridinium-substituted tetraphenyleth-
ylene with different anions were prepared and character-
ized. The solid state emission behavior of seven salts with
the common luminogen (pyridinium-substituted tetrap-
henylethylene) was discussed. All amorphous solids 2a-7a
except the one with I− are red-emissive with almost the
same quantum yields and fluorescence life-times. However,
the crystalline solids 2b-7b except the one with I− show dif-
ferent emission colors varying from green to yellow. Thus,
their emission colors can be tuned by the counter anions.
Furthermore, the crystalline solids 2b-7b are highly emissive
compared to the respective amorphous solids. On the basis
of the crystal structures of 2, 5 and 6 the emission feature
of the crystalline solids 2b-7b may be attributed to the fol-
lowing structural characteristics: i) the cation luminogens
(pyridinium-substituted tetraphenylethylene) adopt slightly
different conformations in the crystals; ii) the cation lumi-
nogens are interacted with the respective anions in different
ways; iii) multiple interatomic contacts among the cation
luminogens and anions will make the conformations of the
cation luminogens more rigid and as a result the internal
rotations will be inhibited. Finally, microrods of 2b and 5b
with green and yellow-green emissions, respectively, exhibit
typical optical waveguide behavior. These results clearly
demonstrate the promising applications of tetraphenyleth-
ylene and its derivatives for highly emissive and color-tun-
able materials.
Synthesis and Characterization: Compounds 8 and 9 were syn-
thesized according to the reported procedures.[16a]
Compound 1: A mixture of compound 9 (1.60 g, 3.41 mmol)
and iodomethane(1.45 g, 10.23 mmol) in 30 mL of acetoni-
trile was refluxed for 5 hours under argon. After cooling to room
temperature, the solution was poured into water, extracted with
dichloromethane and the organic phase was washed with brine.
The organic layer was dried over anhydrous Na2SO4, filtered and
evaporated. The residue was subjected to column chromatography
with dichloromethane/methanol (v/v, 20/1) as eluent. Compound
1 (1.92 g, 3.14 mmol) was obtained as an orange red solid in
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Highly Solid-State Emissive Pyridinium-Substituted Tetraphenylethylene Salts
1
92.2% yield. M.p. 153.2–154.0 °C; H NMR (400 MHz, DMSO-d6, 2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J = 7.5 Hz, 2H),
δ): 8.94 (d, J = 6.8 Hz, 2H), 8.43 (d, J = 7.0 Hz, 2H), 7.91 (d, J = 6.94 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 6.72 (m, 4H), 4.29
8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J = 6.6 Hz, 2H), 6.94 (d, J = (s, 3H), 3.68 (s, 6H). 13C NMR (75 MHz, DMSO-d6, δ): 158.6, 158.4,
8.6 Hz, 2H), 6.88 (d, J = 8.8 Hz, 2H), 6.72 (m, 4H), 4.29 (s, 3H), 153.9, 148.6, 145.9, 143.8, 142.1, 138.0, 135.7, 132.6, 132.5,
3.68 (s, 6H). 13C NMR (100 MHz, CDCl3, δ): 158.8, 158.6, 155.8, 131.3, 131.2, 128.6, 128.0, 127.1, 124.0, 113.9, 113.7, 100.0,
149.7, 145.5, 143.5, 142.8, 137.5, 135.7, 135.6, 133.0, 132.7, 55.4, 47.4; ESI m/z: 484 [M+]; Anal. calcd for C34H30F6NO2Sb: C
131.4, 130.6, 128.1, 127.3, 126.7, 124.3, 113.5, 113.2, 55.3, 56.69, H 4.20, N 1.94; found: C, 56.87; H, 4.42; N, 2.11.
55.2, 48.6; ESI m/z: 484 [M+]; Anal. calcd for C34H30INO2: C 66.78,
H 4.94, N 2.29; found: C 66.90, H 5.16, N 2.40.
Compound 7: Yield: 96.4%. M.p. 130.4–131.6 °C; 1H NMR
(300 MHz, DMSO-d6, δ) 8.94 (d, J = 6.5 Hz, 2H), 8.43 (d, J = 6.5
Compound 2: Silver bis(trifluoromethanesulfonyl)imide (0.15 g, Hz, 2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J = 7.5 Hz,
0.39 mmol) in 3 mL of deionized water was added to a solution of 2H), 6.94 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 6.72 (t, J =
compound 1 (0.2 g, 0.33 mmol) in methanol and the mixture was 9.4 Hz, 4H), 4.29 (s, 3H), 3.68 (s, 6H). 13C NMR (100 MHz, CDCl3,
stirred for 2 hours at room temperature. The solution was poured δ): 158.8, 158.6, 156.0, 149.7, 144.8, 143.5, 142.7, 137.6,
into water, extracted with dichloromethane and the organic phase 135.7, 135.6, 133.0, 132.7, 131.5, 130.6, 128.1, 127.3, 126.7,
was washed with brine. The organic layer was dried over anhydrous 124.3, 113.5, 113.2, 55.2, 47.7; ESI m/z: 484 [M+]; Anal. calcd for
Na2SO4, filtered and evaporated. Then, compound 2 (0.24 g, 0.31 C34H30F6NO2P: C 64.86, H 4.80, N 2.22; found: C 64.72, H 4.64, N
mmol) was obtained as an orange red solid in 96.2% yield. M.p. 2.30.
1
85.5–87.0 °C; H NMR (300 MHz, DMSO-d6, δ) 8.94 (d, J = 6.5 Hz,
2H), 8.43 (d, J = 6.5 Hz, 2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H),
7.00 (d, J = 7.5 Hz, 2H), 6.94 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz,
2H), 6.72 (m, 4H), 4.29 (s, 3H), 3.68 (s, 6H). 13C NMR (100 MHz,
Supporting Information
CDCl3, δ): 158.8, 158.5, 156.3, 149.8, 144.8, 143.4, 142.8, 137.5,
135.6, 135.5, 133.0, 132.7, 132.6, 131.4, 130.4, 128.1, 127.2,
126.7, 124.4, 121.4, 118.2, 113.4, 113.1, 55.1, 47.6; ESI m/z:
484 [M+]; Anal. calcd for C36H30F6N2O6S2: C 56.54, H 3.95, N 3.66,
S 8.39; found: C 56.55, H 4.21, N 3.48, S 8.30.
Supporting Information is available from the Wiley Online Library
or from the author.
Compounds 3, 4, 5, 6 and 7 were synthesized and purified
similarly as for compound 2 with corresponding silver salts.
Compound 3: Yield: 98.7%. M.p. 136.0–137.5 °C; 1H NMR
(300 MHz, DMSO- d6, δ) 8.94 (d, J = 6.5 Hz, 2H), 8.43 (d, J =
6.5 Hz, 2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J =
7.5 Hz, 2H), 6.94 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 6.72
(m, 4H), 4.29 (s, 3H), 3.68 (s, 6H). 13C NMR (75 MHz, CDCl3, δ):
158.7, 158.5, 155.8, 149.6, 145.1, 143.5, 142.6, 137.5, 135.6,
135.5, 132.9, 132.7, 132.6, 131.4, 130.6, 128.1, 127.3, 126.6,
124.3, 113.4, 113.1, 55.2, 55.1, 47.9; ESI m/z: 484 [M+]; Anal.
calcd for C34H30ClNO6: C 69.92, H 5.18, N 2.40; found: C 69.72, H
2.28, N 5.18.
Compound 4: Yield: 95.7%. M.p. 128.7–129.2 °C; 1H NMR
(300 MHz, DMSO-d6, δ) 8.94 (d, J = 6.5 Hz, 2H), 8.43 (d, J = 6.5 Hz,
2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J = 7.5 Hz, 2H),
6.94 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 6.72 (m, 4H), 4.29
(s, 3H), 3.68 (s, 6H).13C NMR (100 MHz, CDCl3, δ): 158.8, 158.6,
155.8, 145.2, 142.8, 135.7, 133.0, 132.8, 132.7, 131.5, 128.2,
127.3, 126.8, 124.3, 113.5, 113.2, 55.3, 55.2, 47.8. ESI m/z: 484
[M+]; Anal. calcd for C34H30BF4NO2: C 71.47, H 5.29, N 2.45; found:
C 71.02, H 5.15, N 2.37.
Compound 5: Yield: 94.3%. M.p. 110.4–111.6°C; 1H NMR
(300 MHz, DMSO-d6, δ) 8.94 (d, J = 6.5 Hz, 2H), 8.43 (d, J = 6.7 Hz,
2H), 7.90 (d, J = 8.4 Hz, 2H), 7.18 (m, 5H), 7.00 (d, J = 7.1 Hz, 2H),
6.94 (d, J = 8.4 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 6.72 (m, 4H), 4.29
(s, 3H), 3.68 (s, 6H). 13C NMR (75 MHz, CDCl3, δ): 158.7, 158.5,
155.9, 149.7, 145.2, 143.4, 142.7, 137.5, 135.6, 135.5, 133.0,
132.7, 132.6, 131.4, 128.1, 127.2, 126.7, 124.3, 113.4, 113.1,
55.2, 55.1, 47.8; ESI m/z: 484 [M+]; Anal. calcd for C35H30F3NO5
S•0.5CH3OH: C 65.63, H 4.96, N 2.16, S 4.94; found: C 65.43, H
4.91, N 2.27, S 4.91.
Acknowledgements
This work is supported by grants from National Natural Science
Foundation of China, Ministry of Science and Technology of China
and Chinese Academy of Sciences.
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Received: July 12, 2014
Revised: September 10, 2014
Published online:
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© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
small 2014,
DOI: 10.1002/smll.201402051
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