Synthesis, crystal structure, and photophysical properties of (1E,3E,5E)-1,3,4,6-tetraarylhexa-1,3,5-trienes: A new class of fluorophores exhibiting aggregation-induced emission

Article abstract of DOI:10.1002/asia.200900110

Double Horner-Wadsworth- Emmons reaction of (E)-2,3-diaryl-1,4- bis(diethylphosphonyl)but-2-ene with (p-substituted) benzaldehydes gave (1E,3E,5E)-1,3,4,6-tetraarylhexa-1,3,5-trienes in moderate to good yields. Substitution of electron-withdrawing or -don

Full text of DOI:10.1002/asia.200900110

DOI: 10.1002/asia.200900110
Synthesis, Crystal Structure, and Photophysical Properties of (1E,3E,5E)-
1,3,4,6-Tetraarylhexa-1,3,5-trienes: A New Class of Fluorophores Exhibiting
Aggregation-Induced Emission
Masaki Shimizu,* Hironori Tatsumi, Kenji Mochida, Katsuhiro Shimono, and
Tamejiro Hiyama[a]
Abstract: Double Horner–Wadsworth–
Emmons reaction of (E)-2,3-diaryl-1,4-
bis(diethylphosphonyl)but-2-ene with
(p-substituted) benzaldehydes gave
(1E,3E,5E)-1,3,4,6-tetraarylhexa-1,3,5-
trienes in moderate to good yields.
Substitution of electron-withdrawing or
-donating groups at the para position
of the 1,6-diphenyl groups induced a
slight bathochromic shift of UV spectra
measured in CHCl3 compared with that
of the parent 1,3,4,6-tetraphenylhexa-
1,3,5-triene. Although fluorescence was
not observed with all the trienes in
CHCl3, they markedly emitted visible
light in powder forms with quantum
yields of 0.15–0.44. Introduction of
amino groups at the para position of
the 3,4-diphenyl groups induced a bath-
ochromic shift of emission maxima
with good solid-state quantum yields.
Thus, the tetraarylated triene frame-
work is found to serve as a new class of
fluorophores that exhibit aggregation-
induced emission.
Keywords: aggregation
· chromo-
phores · conjugation · fluorescence ·
materials science
Introduction
very important for the development of emitting materials
employed in such optoelectronic devices.
Since the pioneering report by Tang and co-workers,[1] grow-
ing interest has been paid to p-conjugated compounds,
which exhibit aggregation-induced emission (AIE): an un-
usual phenomena in which nonemissive p-conjugated mole-
cules in solution emit efficiently in the solid state, such as
thin films, nanoparticles, powder, and crystals.[2] Efficient
solid-state emission is essential for optoelectronic devices
such as organic light-emitting diodes,[3] semiconductor
lasers,[4] and solid sensors.[5] Therefore, exploration of novel
AIE-active chromophores and understanding of their char-
acteristics regarding molecular and electronic structures as
well as three-dimensional alignment in the solid state are
In the course of our research on the stereoselective cross-
coupling reaction of gem-diborylated compounds,[6] we ob-
served that (1E,3E,5E)-1,3,4,6-tetraphenylhexa-1,3,5-triene
(1a),[7] one of the products of the coupling reaction, was
blue-fluorescent only in the powder form (Figure 1).[6b]
Figure 1. ACTHNUTRGNE(UNG 1E,3E,5E)-1,3,4,6-Tetraarylhexa-1,3,5-trienes 1.
[a] Prof. Dr. M. Shimizu, H. Tatsumi, K. Mochida, Dr. K. Shimono,
Prof. Dr. T. Hiyama
Department of Material Chemistry
Graduate School of Engineering
Kyoto University
Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)
Fax : (+81)75-383-2445
Thus, 1a was considered to be AIE-active. As (1E,3E,5E)-
1,6-diarylhexa-1,3,5-trienes were reportedly less fluorescent
in the solid state than in solution probably as a result of the
formation of aggregates or an excimer,[8] it should be rea-
sonable to attribute the observed AIE of 1a to the presence
of 3,4-diphenyl groups. Then, we turned our attention to
E-mail: m.shimizu@hs2.ecs.kyoto-u.ac.jp
Homepage: http://npc05.kuic.kyoto-u.ac.jp/e-index.htm
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.200900110.
(1E,3E,5E)-1,3,4,6-tetraarylhexa-1,3,5-trienes 1 as
a
new
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class of AIE-active fluorophores. Reported herein are the
preparation, structures, UV absorption, solid-state fluores-
cence, and theoretical calculations of 1.
Results and Discussion
Preparation of (1E,3E,5E)-1,3,4,6-Tetraarylhexa-1,3,5-
trienes
Preparation of 1a–1 f was effected by diphosphorylation of
(E)-1,4-dibromo-2,3-diphenylbut-2-ene (2)[9] with triethyl-
phosphite followed by two-fold Horner–Wadsworth–
Emmons reaction with p-substituted benzaldehydes
(Scheme 1).[10] Trienes 1 were isolated in moderate to high
yields as a single stereoisomer by silica gel column chroma-
tography followed by recrystallization in all cases.
Scheme 1. Synthesis of (1E,3E,5E)-1,6-diaryl-3,4-diphenylhexa-1,3,5-tri-
enes 1a–1 f. Reagents and conditions: a) PACTHNUTRGENUG(N OEt)3, 1508C; b) for 1a,
Scheme 2. Synthesis of (1E,3E,5E)-3,4-diaryl-1,6-bis(4-trifluoromethyl-
phenyl)hexa-1,3,5-trienes 1g–1j. Reagents and conditions: a) N-bromo-
C6H5CHO, NaH, THF, 508C; for 1b, 4-CF3-C6H4CHO, tBuOK, DMF,
508C; for 1c, 4-Cl-C6H4CHO, NaH, DMF, 508C; for 1d, 4-MeO-
C6H4CHO, NaH, 15-crown-5, DMF, 508C; for 1e, 4-CN-C6H4CHO, NaH,
THF, reflux; for 1 f, 4-C6H5-C6H4CHO, NaH, DMF, 508C.
succinimide, dibenzoyl peroxide, CCl4, reflux; b) P
CF3-C6H4CHO, NaOMe, DMF, 508C; d) for 1g, piperidine, Pd
(5 mol%), NaOtBu (3 equiv), toluene, 1008C; for 1h, diphenylamine, Pd-
(tBu3P)2 (5 mol%), NaOtBu (3 equiv), toluene, 1008C; e) KOH, Pd2dba3
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
(2 mol%), 2-di(tert-butyl)phosphino-2’,4’,6’-triisopropylbiphenyl, hexane/
H2O, 1008C; f) for 1i, MeI, K2CO3, acetone, 608C; for 1j iPrI, K2CO3,
Bu4NI, acetone, 608C.
Trienes 1g–1j were synthesized starting from an E/Z
(9:91) mixture of 2,3-bis(4-bromophenyl)but-2-ene (4)[11] as
shown in Scheme 2. Thus, dibromination of 4 with N-bromo-
succinimide in the presence of dibenzoyl peroxide in
CCl4,[12] proceeded with isomerization of the olefin geometry
to give an E/Z (80:20) mixture of tetrabromide 5 which was
transformed into 3,4-bis(4-bromophenyl)-1,6-bis(4-trifluoro-
Ph2NH,[14] and hydroxylation with KOH[15] followed by alky-
lation with methyl or isopropyl iodide according to the pro-
tocols developed by Buchwald and co-workers, giving rise to
(1E,3E,5E)-trienes 1g–1j, respectively (Scheme 2).
methylphenyl)hexa-1,3,5-triene (7) as
a
mixture of
(1E,3E,5E)- and (1E,3Z,5E)-isomers (73:27), in a manner
similar to the preparation of 1b.[13] Stereochemically pure
(1E,3E,5E)-7, isolated from the mixture by recrystallization,
was subjected to Pd-catalyzed amination with piperidine or
UV and Fluorescence Spectra
Absorption spectra of 1a–1 f measured in CHCl3 are shown
in Figure 2 and photophysical properties of 1 are summar-
ized in Table 1. All spectra of 1a–1 f showed almost identi-
Abstract in Japanese:
Figure 2. UV absorption spectra of 1a–1 f measured in CHCl3.
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Chem. Asian J. 2009, 4, 1289 – 1297

Synthesis and Properties of a New Class of Fluorophores
Table 1. Photophysical properties of 1.
1i bearing CF3 groups at the molecular termini. The absorp-
tion in CHCl3 and solid-state fluorescence spectra of 1g–1i
are shown in Figures 4 and 5, respectively, together with
those of 1b. Alkoxy-substituted 1i and 1j showed absorp-
Compd
Absorption[a]
Fluorescence[b]
lmax [nm][c]
e [MÀ1 cmÀ1
]
lmax [nm][d]
Ff[e]
1a
1b
1c
1d
1e
1 f
1g
1h
1i
370
375
378
383
393
397
373
312
378
379
63600
52700
72500
63500
51700
52900
37000
50400
47800
41700
459
509
464
497
513
525
551
549
488
491
0.25
0.40
0.30
0.22
0.26
0.33
0.44
0.15
0.43
0.26
1j
[a] Measured in CHCl3. [b] Excitation of 1 in powder form was effected
with UV light (l=365 nm). [c] Wavelength of absorption maxima with
the largest molar extinction coefficient. [d] Wavelength of emission
maxima. [e] Absolute quantum yield determined by a calibrated integrat-
ing sphere system.
Figure 4. UV absorption spectra of 1b and 1g–1j measured in CHCl3.
cal vibrational structures, which were similar to that of
(1E,3E,5E)-1,6-diphenylhexa-1,3,5-triene.[8] The absorption
maxima in CHCl3 slightly red-shifted compared with those
of the corresponding 3,4-unsubstituted counterparts depend-
ing on the p-substituents of the terminal phenyl groups.
Although solutions of 1a–1 f in CHCl3 did not exhibit de-
tectable fluorescence upon irradiation with UV light, solid
1a–1 f emitted blue or green light with solid-state quantum
yields ranging from 0.22 to 0.40 (Figure 3 and Table 1).
Thus, 1a–1 f are AIE-active. No fluorescence of 1a–1 f in
solutions may be ascribed to intramolecular rotation of mul-
Figure 5. Fluorescence spectra of 1b and 1g–1j in powder form.
tion spectra similar to that of 1b, whereas the absorption
edges of the amino derivatives 1g and 1h were significantly
red-shifted relative to those of 1b, 1i, and 1j. Thus, the in-
troduction of amino groups at the para position of the 3,4-
diphenyl groups largely affected the electronic structure to
result in the decrease in the HOMO–LUMO gap (see MO
Calculation section). Emission maxima of 1g and 1h were
bathochromically shifted, whereas those of 1i and 1j were
blue-shifted compared with 1b. The quantum yields of 1g
and 1i were almost the same as that of 1b, but much higher
than those of 1h and 1j, respectively. Therefore, the incor-
poration of piperidyl and methoxy groups can lead to fine
tuning of emission colors, maintaining the good efficiency of
the solid-state emission.
Fluorescence spectra of 1g in a mixed solvent of CH3CN
and water were also measured (Figure 6). A CH3CN solu-
tion of 1g was nonluminescent, whereas the fluorescence in-
tensity remarkably increased when 1g was dissolved in the
mixtures of CH3CN and water. The highest intensity was ob-
served with the water content of 70 vol% and further addi-
tion of water resulted in a decrease in fluorescence intensity.
As water was a poor solvent for 1g, dilution with water
should have induced aggregation of 1g. Thus, aggregation-
induced emission was again confirmed.
Figure 3. Fluorescence spectra of 1a–1 f in powder form.
tiple phenyl groups in solutions, which results in consump-
tion of all the photon energies and deactivation of all the ex-
cited states in solutions. This observation is in marked con-
trast to the fluorescence behavior of (1E,3E,5E)-1,6-bis(p-
substituted phenyl)hexa-1,3,5-trienes that are efficiently
emissive in solution with good to high quantum yields but
nearly nonemissive in microcrystalline state presumably aris-
ing from the close packing of the planar skeletons in the ag-
gregates.[8] Therefore, the 3,4-diphenyl groups whose rota-
tion is limited in the solid state appear to suppress intermo-
lecular interactions in the aggregates, which is responsible
for the quenching of emission (for molecular and crystal
structures of 1a, see below).
Since the solid-state quantum yield of 1b was the highest,
we further investigated the photophysical properties of 1g–
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M. Shimizu et al.
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cell.[17] Thus, the tight packing leading to fluorescence
quenching is well-prevented owing probably to the presence
of the 3,4-diphenyl groups.
MO Calculation
Molecular orbital calculations of 1a, 1b, 1i, and dimethyla-
mino analog 1g’, a model compound of 1g, were carried out
by the DFT method at the B3LYP/6-31G*//B3LYP/6-31G*
level using the Gaussian 03 package.[18] The results are sum-
marized in Table 2 and the HOMO and LUMO drawings
are shown in Figure 9. For 1a and 1b, both the HOMOs and
LUMOs were localized over the Ph-triene-Ph skeleton and
not developed on the 3,4-diphenyl groups. Compared with
1a and 1b, the introduction of trifluoromethyl groups at the
Figure 6. Fluorescence spectra of 1g in a mixture of CH3CN and H2O.
Molecular and Crystal
Structures
Table 2. HOMO and LUMO energies of 1a, 1b, 1i, and 1g’.[a]
Single crystals of 1a were ob-
tained by recrystallization from
a hexane solution. X-ray struc-
tural analysis of a single crystal
reveals that the triene crystalli-
zes in the monoclinic space
group P21/c [cell parameters:
a=10.2356(17), b=9.3494(15),
c=11.6070(18), b=91.244(3)]
with Z=2.[16] The triene moiety
Compound
1a
1b
1i
1g’
LUMO [eV]
HOMO [eV]
À1.79
À4.95
3.16
À2.32
À5.37
3.05
À2.21
À5.18
2.97
À2.02
À4.79
2.77
HOMO–LUMO gap [eV] (calculated)
HOMO–LUMO gap [eV] (experimental)[b]
2.89
2.72
2.75
2.50[c]
[a] Calculated at the B3LYP/6–31G*//B3LYP/6–31G* level. [b] Energy gaps were estimated from the absorp-
tion edges of UV/Vis absorption spectra. [c] The value of 1g.
of 1a was found to adapt a completely planar conformation
(Figure 7a), whereas the terminal benzene rings were slight-
Figure 7. Illustration of molecular structure of 1a in the crystal (hydro-
gens are omitted for clarity): a) side view of the molecule; b) view from
long axis of the molecule.
ly distorted with dihedral angles of 158 (Figure 7b). The re-
maining 3,4-diphenyl groups oriented almost perpendicular
(828) to the plane of the triene moiety (Figure 7a). Crystal
packing of 1a, shown in Figure 8, reveals that each molecule
located at the edges of the unit cell was well-separated from
one another, and the triene plane was crossed (not in paral-
lel) with that of the molecule positioned at the center of the
Figure 9. Molecular orbital drawings of the HOMOs and LUMOs of 1a,
1b, 1i, and 1g’.
Figure 8. Packing diagram of 1a (hydrogens are omitted for clarity).
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Synthesis and Properties of a New Class of Fluorophores
through two packed columns of neutral alumina and copper oxide, re-
spectively, under a nitrogen atmosphere before use. All reactions were
carried out under an argon atmosphere. UV absorption spectra were re-
corded with a Shimadzu UV-2100PC spectrometer. Fluorescence spectra
and absolute quantum yields were recorded with a Hamamatsu Photonics
C9920–02 Absolute PL Quantum Yield Measurement System.
terminal phenyl groups lowered both the HOMOs and
LUMOs, and resulted in a decrease in the HOMO–LUMO
gap. Meanwhile, substitution of a methoxy group at the para
position of both 3,4-diphenyl groups of 1b resulted in a
slight extension of the HOMO over the methoxy-substituted
phenyl groups (1i). In case of dimethylamino derivative 1g’,
HOMO was extensively developed over not only the 1,6-di-
phenylhex-1,3,5-triene skeleton but also the stilbene moiety
(Figure 9, left of the bottom), and the energy level was
raised greatly. On the other hand, LUMO of 1g’ was found
to localize over only the long axis of the molecular skeleton
as similar to the other trienes. The longer emission maxima
of 1g and 1h may be ascribed to the amino group-induced
change of the electronic structures. The trend of the
HOMO–LUMO energy gaps is consistent with the absorp-
tion edges in the UV/Visible spectra shown in Figures 2 and
4.
Synthesis
(E)-1,4-Bis(diethylphosphonyl)-2,3-diphenylbut-2-ene (3): An oven-dried
Schlenk tube (20 mL) equipped with a magnetic stirring bar and a rubber
septum was charged with
2 (2.2 g, 6.7 mmol) and triethylphosphite
(4.7 mL, 27 mmol) at room temperature. The mixture was heated at
1508C for 12 h. After cooling to room temperature, the resulting mixture
was dissolved in hexane, cooled at 08C. The precipitates were filtered
through a glass filter and washed with cold hexane. The product was puri-
fied by recrystallization from hexane to give 3 (2.1 g, 65%) as a colorless
solid. Rf =0.24 (ethyl acetate); m.p.: 86.5–87.78C; IR (KBr): n˜ =3518,
3458, 2984, 2907, 1645, 1601, 1493, 1443, 1391, 1367, 1238, 1165, 1097,
1
1028, 966, 891, 779, 708, 660, 554, 521 cmÀ1; H NMR (400 MHz, CDCl3):
d=1.07 (t, J=7.2 Hz, 12H), 2.91 (d, J=18.4 Hz, 4H), 3.62–3.85 (m, 8H),
7.27–7.31 (m, 2H), 7.36–7.44 ppm (m, 8H); 13C NMR (100 MHz, CDCl3):
d=16.3, 34.0 (dd, J=141.1, 6.1 Hz), 61.4, 127.1, 128.1, 129.0, 132.4,
140.4 ppm; MS (FAB): m/z (%): 482 (26) [M+2]+, 481 (100) [M+1]+,
480 (15) M+; MS (FAB-HR): m/z (%) calcd for C24H34O6P2: 480.1831;
found: 480.1821.
Conclusions
In summary, we have demonstrated that (1E,3E,5E)-1,3,4,6-
tetraarylhexa-1,3,5-trienes are a new class of chromophores
that exhibit aggregation-induced emission. The fluorescence
color of the trienes in the solid state can be tuned from blue
to green by substituting functional groups such as alkoxy,
amino, chloro, cyano, phenyl, and trifluoromethyl groups at
the para position of the phenyl groups. Moreover, the intro-
duction of trifluoromethyl groups at the molecular termini
induced good quantum yields of solid-state fluorescence
(Ff =0.40–0.44). Our ongoing research is directed toward
development of highly fluorescent organic solids based on
the molecular design of the present study.
AHCTUNGTRENNUNG
3
0.39 mmol), and THF (4 mL). To the solution was added benzaldehyde
(21 mL, 0.21 mmol) at room temperature. The resulting solution was
stirred at 508C for 69 h before quenching with water (5 mL). The aque-
ous layer was extracted with diethyl ether (5 mLꢁ3). The combined or-
ganic layer was washed with saturated aqueous NaCl (5 mL), dried over
anhydrous MgSO4, and concentrated under reduced pressure with a
rotary evaporator. The crude product was washed with methanol to give
1a (33 mg, 87%) as a pale yellow solid. Rf =0.63 (hexane/ethyl acetate
10:1); m.p.: 173.18C; IR (KBr): n˜ =3030, 1595, 1574, 1489, 1442, 1315,
1146, 1070, 1024, 961, 908, 750, 704, 689, 577, 556, 525 cmÀ1 1H NMR
;
(400 MHz, CDCl3): d=6.07 (d, J=16.0 Hz, 2H), 6.92 (d, J=16.0 Hz,
2H), 7.10–7.53 ppm (m, 20H); 13C NMR (100 MHz, CDCl3): d=126.5,
127.3, 127.4, 128.3, 128.5, 130.4, 130.8, 132.4, 137.6, 138.9, 141.0 ppm; MS
(EI): m/z (%): 386 (7) [M+2]+, 385 (31) [M+1]+, 384 (100) M+; elemen-
tal analysis: calcd (%) for C30H24
H 6.53.
Experimental Section
: C 93.71, H 6.29; found: C 93.72,
General
AHCTUNGTERG(NNUN 1E,3E,5E)-3,4-Diphenyl-1,6-bis[4-(trifluoromethyl)phenyl]hexa-1,3,5-
Melting points were determined using a Yanagimoto Micro Point Appa-
ratus. 1H NMR spectra were measured on Varian Mercury 300
(300 MHz) and 400 (400 MHz) spectrometers. The chemical shifts of
1H NMR are expressed in parts per million downfield relative to the in-
ternal tetramethylsilane (d=0 ppm) or chloroform (d=7.26 ppm). Split-
ting patterns are indicated as s, singlet; d, doublet; t, triplet; q, quartet;
m, multiplet. 13C NMR spectra were measured on Varian Mercury 300
(75 MHz) and 400 (100 MHz) spectrometers with tetramethylsilane (d=
0 ppm) or chloroform (d=77.0 ppm) as an internal standard. 19F NMR
spectra were measured on a Varian Mercury 300 (282 MHz) spectrometer
with CFCl3 as an internal standard (d=0 ppm). Chemical shift values are
given in parts per million downfield relative to the internal standards. In-
frared spectra (IR) were recorded on a Shimadzu FTIR-8400 spectrome-
ter. EI-MS analyses were performed with a JEOL JMS-700 spectrometer
by electron ionization at 70 eV. FAB-MS analyses were performed with a
JEOL-HX110A spectrometer. Elemental analyses were carried out with
a YANAKO MT2 CHN CORDER machine at the Elemental Analysis
Center of Kyoto University. TLC analyses were performed by means of
Merck Kieselgel 60 F254, and column chromatography was carried out
using Merck Kieselgel 60 (230–400 mesh). Gel permeation chromatogra-
phy (GPC) was carried out with a Japan Analytical Industry Co., Ltd,
LC-908 chromatograph using JAIGEL-1H and -2H columns. Reagent-
grade dichloromethane, diethyl ether, and tetrahydrofuran were passed
triene (1b): An oven-dried Schlenk tube (80 mL) equipped with a mag-
netic stirring bar and a rubber septum was charged with 3 (96 mg,
0.20 mmol), tBuOK (88 mg, 0.78 mmol), and DMF (16 mL). To the solu-
tion was added 4-(trifluoromethyl)benzaldehyde (57 mL, 0.42 mmol) at
room temperature. The resulting solution was stirred at 508C for 22 h
before quenching with water (10 mL). The aqueous layer was extracted
with diethyl ether (5 mLꢁ3). The combined organic layer was washed
with saturated aqueous NaCl (10 mL), dried over anhydrous MgSO4, and
concentrated under reduced pressure with a rotary evaporator. The crude
product was purified by column chromatography on silica gel (hexane/
ethyl acetate 5:1) followed by recrystallization from hexane-dichlorome-
thane to give 1b (56 mg, 54%) as a pale yellow solid. Rf =0.61 (hexane/
ethyl acetate 5:1); m.p.: 204.3–204.98C; IR (KBr): n˜ =3051, 2930, 1609,
1491, 1443, 1414, 1327, 1286, 1188, 1161, 1153, 1119, 1067, 1015, 962, 951,
868, 822, 766, 702, 675, 600, 453 cmÀ1 1H NMR (400 MHz, CDCl3): d=
;
6.12 (d, J=16.0 Hz, 2H), 6.98 (d, J=16.0 Hz, 2H), 7.17 (AA’BB’, 4H),
7.36–7.38 (m, 4H), 7.43 (AA’BB’, 4H), 7.46–7.50 (m, 2H), 7.51–7.55 ppm
(m, 4H); 13C NMR (100 MHz, CDCl3): d=124.0 (q, J=269.1 Hz), 125.3
(q, J=3.8 Hz), 126.4, 127.7, 128.3, 128.9 (q, J=32.0 Hz), 130.5, 131.4,
132.3, 138.1, 140.7, 141.7 ppm; 19F NMR (282 MHz, CDCl3): d=
À63.1 ppm; MS (FAB): m/z (%): 522 (9) [M+2]+, 521 (41) [M+1]+, 520
(100) M+; elemental analysis: calcd (%) for C32H22F6: C 73.84, H 4.26;
found: C 73.86, H 4.49.
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M. Shimizu et al.
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A
(1c):
(9.4 mg, 0.39 mmol), and DMF (10 mL). To the solution was added a so-
lution of 4-phenylbenzaldehyde (38 mg, 0.21 mmol) in DMF (2 mL) at
room temperature. The resulting solution was stirred at 508C for 15 h
before quenching with water (10 mL). The aqueous layer was extracted
with diethyl ether (5 mLꢁ3). The combined organic layer was washed
with saturated aqueous NaCl (5 mL), dried over anhydrous MgSO4, and
concentrated under reduced pressure with a rotary evaporator. The crude
product was purified by recrystallization from chloroform to give 1 f
(35 mg, 65%) as a yellow solid. Rf =0.55 (hexane/ethyl acetate 5:1);
m.p.: 229.0–229.28C; IR (KBr): n˜ =3026, 1599, 1487, 1443, 1408, 1317,
1279, 1074, 1024, 1005, 964, 866, 824, 760, 698, 675, 654, 637, 586, 563,
An oven-dried Schlenk tube (20 mL) equipped with a magnetic stirring
bar and a rubber septum was charged with 3 (48 mg, 0.10 mmol), NaH
(9.4 mg, 0.39 mmol), and DMF (7 mL). To the solution was added a solu-
tion of 4-chlorobenzaldehyde (30 mg, 0.21 mmol) in DMF (1 mL) at
room temperature. The resulting solution was stirred at 508C for 45 h
before quenching with water (5 mL). The aqueous layer was extracted
with diethyl ether (5 mLꢁ3). The combined organic layer was washed
with saturated aqueous NaCl (5 mL), dried over anhydrous MgSO4, and
concentrated under reduced pressure with a rotary evaporator. The crude
product was purified by column chromatography on silica gel (hexane/
ethyl acetate 5:1) followed by recrystallization from toluene to give 1c
(26 mg, 48%) as a pale yellow solid. Rf =0.61 (hexane/ethyl acetate 5:1);
m.p.: 208.9–209.28C; IR (KBr): n˜ =3038, 1489, 1443, 1321, 1292, 962, 862,
421 cmÀ1 1H NMR (400 MHz, CDCl3): d=6.12 (d, J=16.0 Hz, 2H), 7.98
;
(d, J=16.0 Hz, 2H), 7.17 (AA’BB’, 4H), 7.29–7.33 (m, 2H), 7.38–7.42
(m, 8H), 7.44 (AA’BB’, 4H), 7.46–7.49 (m, 2H), 7.51–7.55 ppm (m, 8H);
13C NMR (100 MHz, CDCl3): d=126.7, 126.8, 127.0, 127.1, 127.3, 128.2,
128.6, 130.4, 130.7, 131.9, 136.6, 138.8, 139.8, 140.4, 141.0 ppm; MS
(FAB): m/z (%): 537 (8) [M+1]+, 536 (15) M+; HRMS (FAB): m/z (%)
calcd for C42H32: 536.2504; found: 536.2495.
764, 704, 615, 490, 473 cmÀ1; H NMR (400 MHz, CDCl3): d=6.01 (d, J=
16.0 Hz, 2H), 6.86 (d, J=16.0 Hz, 2H), 7.00 (AA’BB’, 2H), 7.14
(AA’BB’, 2H), 7.33–7.36 (m, 4H), 7.43–7.47 (m, 2H), 7.49–7.53 ppm (m,
4H); 13C NMR (100 MHz, CDCl3): d=127.4, 127.5, 128.2, 128.5, 130.56,
130.64, 131.2, 132.8, 135.9, 138.5, 141.1 ppm; MS (FAB): m/z (%): 456
(15) [M+4]+, 455 (26) [M+3]+, 454 (72) [M+2]+, 453 (39) [M+1]+, 452
(100) M+; HRMS: m/z (%) calcd for C30H22Cl2: 452.1099; found:
452.1087.
(E)-1,4-Dibromo-2,3-bis(4-bromophenyl)-but-2-ene (5): An oven-dried
Schlenk tube (250 mL) equipped with a magnetic stirring bar and a
rubber septum was charged with 4 (2.7 g, 7.2 mmol), N-bromosuccinimide
(2.8 g, 16 mmol), benzoyl peroxide (174 mg, 0.72 mmol), and carbon tet-
rachloride (72 mL) at room temperature. The resulting solution was re-
fluxed for 3 h. After cooling to room temperature, the solution was
added with saturated aqueous sodium thiosulfate (100 mL) and dichloro-
methane (50 mL). The aqueous layer was extracted with dichlorome-
thane (5 mLꢁ3). The combined organic layer was washed with saturated
aqueous NaCl (5 mL), dried over anhydrous MgSO4, and concentrated
under reduced pressure with a rotary evaporator. The product was puri-
fied by recrystallization from hexane to give 5 (2.6 g, 68%) as an 80:20
mixture of (E)- and (Z)-isomers as a colorless solid. Mixture: Rf =0.30
(hexane/dichloromethane 10:1); m.p.: 197.7–198.78C; IR (KBr): n˜ =1587,
1487, 1435, 1395, 1209, 1074, 1011, 922, 829, 743, 619, 540 cmÀ1; (E)-
isomer: 1H NMR (400 MHz, CDCl3): d=3.98 (s, 4H), 7.33 (AA’BB’,
4H), 7.60 ppm (AA’BB’, 4H); 13C NMR (100 MHz, CDCl3): d=34.9,
122.5, 129.8, 131.8, 136.5, 138.4 ppm; (Z)-isomer: 1H NMR (400 MHz,
CDCl3): d=4.44 (s, 4H), 6.94 (AA’BB’, 4H), 7.31 ppm (AA’BB’, 4H);
13C NMR (100 MHz, CDCl3): d=31.7, 121.8, 130.6, 131.3, 137.8,
139.1 ppm; MS (EI): m/z (%): 528 (2) [M+8]+, 526 (9) [M+6]+, 524 (12)
[M+4]+, 522 (9) [M+2]+, 443 (7) [MÀ77]+, 366 (41) [MÀ154]+, 364 (87)
[MÀ156]+, 362 (58) [MÀ158]+, 284 (59) [MÀ236]+, 282 (56) [MÀ238]+,
204 (100) [MÀ316]+; elemental analysis: calcd (%) for C16H12Br4:
C 36.68, H 2.31; found: C 36.54, H 2.56.
ACHTUNGTRENNUNG(1E,3E,5E)-1,6-Bis(4-methoxyphenyl)-3,4-diphenylhexa-1,3,5-triene (1d):
An oven-dried Schlenk tube (20 mL) equipped with a magnetic stirring
bar and a rubber septum was charged with 3 (48 mg, 0.10 mmol), NaH
(9.4 mg, 0.39 mmol), 15-crown-5 (44 mg, 0.20 mmol), and DMF (5 mL).
To the solution was added 4-anisaldehyde (25 mL, 0.21 mmol) at room
temperature. The resulting solution was stirred at 508C for 74 h before
quenching with water (5 mL). The aqueous layer was extracted with di-
ethyl ether (5 mLꢁ3). The combined organic layer was washed with satu-
rated aqueous NaCl (5 mL), dried over anhydrous MgSO4, and concen-
trated under reduced pressure with a rotary evaporator. The crude prod-
uct was purified by column chromatography on silica gel (hexane/ethyl
acetate 5:1) followed by recrystallization from ethanol to give 1d (37 mg,
86%) as a pale yellow solid. Rf =0.42 (hexane/ethyl acetate 5:1); m.p.:
189.3–189.88C; IR (KBr): n˜ =2999, 2831, 1603, 1570, 1508, 1458, 1441,
1420, 1302, 1288, 1246, 1173, 1030, 961, 922, 858, 818, 758, 700, 642, 565,
519 cmÀ1 1H NMR (400 MHz, CDCl3): d=3.75 (s, 6H), 5.99 (d, J=
;
15.6 Hz, 2H), 6.70–6.73 (m, 4H), 6.78 (d, J=15.6 Hz, 2H), 7.01–7.04 (m,
4H), 7.35–7.37 (m, 4H), 7.41–7.45 (m, 2H), 7.49–7.52 ppm (m, 4H);
13C NMR (100 MHz, CDCl3): d=55.3, 113.8, 127.0, 127.5, 128.1, 128.4,
130.5, 130.7, 131.3, 139.1, 140.1, 158.8 ppm; MS (FAB): m/z (%): 446 (14)
[M+2]+, 445 (37) [M+1]+; HRMS (FAB): m/z (%) calcd for C32H28O2:
444.2089; found: 444.2080.
(E)-2,3-Bis(4-bromophenyl)-1,4-bis(diethylphosphonyl)-2-butene (6): An
oven-dried Schlenk tube (20 mL) equipped with a magnetic stirring bar
and a rubber septum was charged with 5 (2.3 g, 4.3 mmol), and triethyl-
phosphite (2.6 mL, 15 mmol) at room temperature. The resulting mixture
was heated at 1208C for 23 h. After cooling to room temperature, the so-
lution was added with hexane. Cooling the solution to 08C gave precipi-
tates, which were filtered and washed with hexane to afford 6 (1.6 g,
58%) as a colorless solid. Rf =0.43 (ethyl acetate); m.p.: 111.3–112.38C;
IR (KBr): n˜ =3447, 2980, 1489, 1391, 1246, 1161, 1063, 1045, 1024, 968,
A
(1e):
An oven-dried Schlenk tube (20 mL) equipped with a magnetic stirring
bar and a rubber septum was charged with 3 (48 mg, 0.10 mmol), NaH
(9.4 mg, 0.39 mmol), and THF (6 mL). To the solution was added a solu-
tion of 4-formylbenzonitrile (28 mg, 0.21 mmol) in DMF (2 mL) at room
temperature. The resulting solution was refluxed for 12 h. The mixture
was quenched with water (5 mL). The aqueous layer was extracted with
diethyl ether (5 mLꢁ3). The combined organic layer was washed with sa-
turated aqueous NaCl (5 mL), dried over anhydrous MgSO4, and concen-
trated under reduced pressure with a rotary evaporator. The crude prod-
uct was washed with methanol and the residue was recrystallized from
benzene to give 1e (26 mg, 59%) as a yellow solid. Rf =0.32 (hexane/
ethyl acetate 5:1); m.p.: 214.4–215.18C; IR (KBr): n˜ =3032, 2222, 1597,
1504, 1493, 1443, 1410, 1329, 1288, 1173, 961, 943, 928, 866, 852, 814, 768,
951, 826, 791, 767, 600, 550, 505 cmÀ1 1H NMR (400 MHz, CDCl3): d=
;
1.12 (t, J=7.2 Hz, 12H), 2.82 (d, J=18.4 Hz, 4H), 3.73–3.88 (m, 8H),
7.30–7.33 (m, 4H), 7.51–7.53 ppm (m, 4H); 13C NMR (100 MHz, CDCl3):
d=16.3 (t, J=3.1 Hz), 34.1 (dd, J=141.8, 6.1 Hz), 61.6 (t, J=3.0 Hz),
121.4, 131.3, 132.0, 139.1 ppm; MS (FAB): m/z (%): 641 (53) [M+5]+,
639 (100) [M+3]+, 637 (52) [M+1]+; HRMS: m/z (%) calcd for
C24H32Br2O6P2: 637.0119; found: 637.0137.
708, 670, 631, 563, 532, 494, 419 cmÀ1 1H NMR (400 MHz, CDCl3): d=
;
6.09 (d, J=16.0 Hz, 2H), 7.00 (d, J=15.6 Hz, 2H), 7.15 (AA’BB’, 4H),
7.34–7.36 (m, 4H), 7.45 (AA’BB’, 4H), 7.49–7.56 ppm (m, 6H); 13C NMR
(100 MHz, CDCl3): d=110.2, 118.9, 126.7, 127.9, 128.38, 128.42, 130.4,
131.4, 132.1, 133.2, 137.7, 141.6, 142.3 ppm; MS (FAB): m/z (%): 436 (26)
[M+2]+, 435 (81) [M+1]+, 434 (100) M+; HRMS (FAB): m/z (%) calcd
for C32H22N2: 434.1783; found: 434.1802.
AHCTUNGTERG(NNUN 1E,3E,5E)-3,4-Bis(4-bromophenyl)-1,6-bis[4-(trifluoromethyl)phenyl]-
hexa-1,3,5-triene (7): An oven-dried Schlenk tube (20 mL) equipped with
a magnetic stirring bar and a rubber septum was charged with 6 (0.64 g,
1.0 mmol), NaOMe (0.12 g, 2.2 mmol), and DMF (10 mL). To the solu-
tion was added 4-trifluoromethylbenzaldehyde (0.30 mL, 2.2 mmol) at
room temperature. The resulting mixture was stirred at 508C for 6 h
before quenching with saturated aqueous NH4Cl (10 mL). The aqueous
layer was extracted with dichloromethane (5 mLꢁ3). The combined or-
ganic layer was washed with saturated aqueous NaCl (5 mL), dried over
ACHTUNGTRENNUNG(1E,3E,5E)-1,6-Bis(4-biphenylyl)-3,4-diphenylhexa-1,3,5-triene (1 f): An
oven-dried Schlenk tube (20 mL) equipped with a magnetic stirring bar
and a rubber septum was charged with 3 (48 mg, 0.10 mmol), NaH
1294
www.chemasianj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 1289 – 1297

Synthesis and Properties of a New Class of Fluorophores
anhydrous MgSO4, and concentrated under reduced pressure with a
rotary evaporator. The crude product was washed with methanol to
afford 7 (0.58 g, 86%) in a 73:27 mixture of (1E,3E,5E)- and (1E,3Z,5E)-
isomers as a yellow solid. Stereochemically pure (1E,3E,5E)-7 was ob-
tained by recrystallization from chloroform. (1E,3E,5E)-isomer: Rf =0.22
(hexane/dichloromethane 10:1); m.p.: 207.5–208.48C; IR (KBr): n˜ =3044,
water (0.22 mL), and dioxane (2 mL) at room temperature. The solution
was heated at 1008C for 20 h before quenching with saturated aqueous
NH4Cl (4 mL). The aqueous layer was extracted with dichloromethane
(5 mLꢁ3). The combined organic layer was washed with saturated aque-
ous NaCl (5 mL), dried over anhydrous MgSO4, and concentrated under
reduced pressure with a rotary evaporator. The crude product was puri-
fied by column chromatography on silica gel (dichloromethane) to give 8
(0.19 g, 95%) as a yellow solid. Rf =0.21 (dichloromethane); m.p.: 224.0–
225.28C; IR (KBr): n˜ =3360, 1611, 1508, 1456, 1327, 1244, 1165, 1111,
1609, 1487, 1325, 1163, 1117, 1067, 1013, 968, 870, 824, 596, 467 cmÀ1
;
1H NMR (400 MHz, CDCl3): d=6.10 (d, J=16.0 Hz, 2H), 6.91 (d, J=
16.0 Hz, 2H), 7.20–7.25 (m, 8H), 7.47 (AA’BB’, 4H), 7.65–7.68 ppm (m,
4H); 13C NMR (100 MHz, CDCl3): d=122.0, 123.9 (q, J=269.9 Hz),
125.4 (q, J=3.8 Hz), 126.6, 129.3 (q, J=32.8 Hz), 131.1, 131.4, 131.7,
132.2, 136.8, 140.3, 140.6 ppm; 19F NMR (282 MHz, CDCl3): d=
À63.1 ppm; MS (FAB): m/z (%): 680 (57) [M+4]+, 678 (100) [M+2]+,
676 (58) M+; elemental analysis: calcd (%) for C32H20Br2F6: C 56.66,
H 2.97; found: C 56.43, H 2.99.
1067, 968, 837, 419 cmÀ1 1H NMR (400 MHz, CDCl3): d=4.85 (s, 2H),
;
6.16 (d, J=16.0 Hz, 2H), 6.98 (AA’BB’, 4H), 7.02 (d, J=16.0 Hz, 2H),
7.20–7.23 (m, 8H), 7.45 ppm (AA’BB’, 4H); 13C NMR (100 MHz,
CDCl3): d=115.3, 124.0 (q, J=269.2 Hz), 125.3 (q, J=3.9 Hz), 126.4,
128.8 (q, J=32.0 Hz), 130.6, 131.2, 132.0, 132.7, 140.8, 141.4, 154.9 ppm;
19F NMR (282 MHz, CDCl3): d=À63.1 ppm; MS (FAB): m/z (%): 554
(9) [M+2]+, 553 (41) [M+1]+, 552 (100) M+; elemental analysis: calcd
(%) for C32H22F6O2: C 69.56, H 4.01; found: C 69.43, H 3.92.
ACHTUNGTRENNUNG(1E,3E,5E)-3,4-Bis(4-piperidinophenyl)-1,6-bis[4-(trifluoromethyl)phe-
nyl]hexa-1,3,5-triene (1g): An oven-dried Schlenk tube (20 mL) equipped
with a magnetic stirring bar and a rubber septum was charged with 7
(68 mg, 0.10 mmol), piperidine (24 mL, 0.24 mmol), Pd (PtBu3)2 (5 mmol,
3 mg), NaOtBu (29 mg, 0.30 mmol), and toluene (2 mL) at room temper-
ature. The resulting solution was stirred at 1008C for 22 h before quench-
ing with saturated aqueous NH4Cl (2 mL). The aqueous layer was ex-
tracted with dichloromethane (5 mLꢁ3). The combined organic layer
was washed with saturated aqueous NaCl (5 mL), dried over anhydrous
MgSO4, and concentrated under reduced pressure with a rotary evapora-
tor. The crude product was washed with hot ethanol and the residue was
recrystallized from hexane/toluene (1:1) to give 1g (46 mg, 67%) as a
yellow solid. Rf =0.50 (hexane/dichloromethane 1:1); m.p.: 218.0–
219.58C; IR (KBr): n˜ =2938, 1607, 1514, 1452, 1416, 1385, 1323, 1234,
AHCTUNGTERG(NNUN 1E,3E,5E)-3,4-Bis(4-methoxyphenyl)-1,6-bis[4-(trifluoromethyl)phenyl]-
hexa-1,3,5-triene (1i): An oven-dried vial (3 mL) equipped with a mag-
netic stirring bar and a rubber septum was charged with 8 (33 mg,
0.06 mmol), iodomethane (17 mL, 0.18 mmol), K2CO3 (18 mg, 0.13 mmol),
and acetone (1 mL) at room temperature. The resulting solution was
stirred at 608C for 24 h before quenching with saturated aqueous NH4Cl
(1 mL). The aqueous layer was extracted with dichloromethane (3 mLꢁ
3). The combined organic layer was washed with saturated aqueous NaCl
(5 mL), dried over anhydrous MgSO4, and concentrated under reduced
pressure with a rotary evaporator. The crude product was purified by
column chromatography on silica gel (hexane/ethyl acetate 10:1) to give
1i (23 mg, 66%) as a yellow solid. Rf =0.38 (hexane/ethyl acetate 10:1);
m.p.: 198.3–199.48C; IR (KBr): n˜ =1611, 1510, 1329, 1290, 1248, 1177,
1165, 1125, 1067, 968, 872, 826 cmÀ1 1H NMR (400 MHz, CDCl3): d=
;
1163, 1111, 1069, 1032, 1017, 970, 870, 835 cmÀ1 1H NMR (400 MHz,
;
1.66 (m, 4H), 1.80 (m, 8H), 3.30 (t, J=5.4 Hz, 8H), 6.21 (d, J=16.0 Hz,
2H), 7.04 (AA’BB’, 4H), 7.10 (d, J=16.0 Hz, 2H), 7.20–7.24 (m, 8H),
7.43 ppm (AA’BB’, 4H); 13C NMR (100 MHz, CDCl3): d=24.4, 26.1,
50.3, 115.6, 124.1 (q, J=269.2 Hz), 125.2 (d, J=3.8 Hz), 126.4, 128.5 (q,
J=32.1 Hz), 128.8, 130.6, 131.6, 133.4, 141.2, 141.6, 151.2 ppm; 19F NMR
(282 MHz, CDCl3): d=À62.9 ppm; MS (FAB): m/z (%): 688 (23)
[M+2]+, 687 (70) [M+1]+, 686 (100) M+; elemental analysis: calcd (%)
for C42H40F6N2: C 73.45, H 5.87; found: C 73.53, H 5.81.
CDCl3): d=3.94 (s, 6H), 6.16 (d, J=15.6 Hz, 2H), 7.01–7.05 (m, 6H),
7.21 (AA’BB’, 4H), 7.26–7.28 (m, 4H), 7.44 ppm (AA’BB’, 4H);
13C NMR (100 MHz, CDCl3): d=55.4, 113.7, 124.0 (q, J=269.4 Hz),
125.3 (q, J=3.5 Hz), 126.4, 128.7 (q, J=32.3 Hz), 130.4, 131.1, 131.8,
132.9, 140.9 (d, J=1.6 Hz), 141.5, 158.9 ppm; 19F NMR (282 MHz,
CDCl3): d=À63.0 ppm; MS (FAB): m/z (%): 582 (11) [M+2]+, 581 (44)
[M+1]+, 580 (100) M+; elemental analysis: calcd (%) for C34H26F6O2:
C 70.34, H 4.51; found: C 70.04, H 4.59.
ACHTUNGTRENNUNG(1E,3E,5E)-3,4-Bis[4-(N,N-diphenylamino)phenyl]-1,6-bis[4-(trifluorome-
thyl)phenyl]hexa-1,3,5-triene (1h): An oven-dried Schlenk tube (20 mL)
AHCTUNGTRENGN(UN 1E,3E,5E)-3,4-Bis[4-(isopropoxy)phenyl]-1,6-bis[4-(trifluoromethyl)phe-
nyl]hexa-1,3,5-triene (1j): An oven-dried vial (3 mL) equipped with a
magnetic stirring bar and a rubber septum was charged with 8 (17 mg,
0.030 mmol), 2-iodopropane (9 mL, 0.09 mmol), K2CO3 (19 mg,
0.14 mmol), Bu4NI (1.0 mg, 3 mmol), and acetone (1 mL) at room temper-
ature. The resulting solution was stirred at 608C for 42 h before quench-
ing with saturated aqueous NH4Cl (1 mL). The aqueous layer was ex-
tracted with dichloromethane (3 mLꢁ3). The combined organic layer
was washed with saturated aqueous NaCl (5 mL), dried over anhydrous
MgSO4, and concentrated under reduced pressure with a rotary evapora-
tor. The crude product was purified by column chromatography on silica
gel (hexane/ethyl acetate 10:1) followed by recrystallization from hexane
to give 1j (5.0 mg, 26%) as a yellow solid. Rf =0.60 (hexane/ethyl acetate
5:1); m.p.: 197.4–199.28C; IR (KBr): n˜ =1607, 1508, 1327, 1240, 1165,
equipped with a magnetic stirring bar and a rubber septum was charged
with
7 (68 mg, 0.10 mmol), diphenylamine (37 mg, 0.22 mmol), Pd
(PtBu3)2 (3 mg, 5 mmol), NaOtBu (29 mg, 0.30 mmol), and toluene
(1.4 mL) at room temperature. The resulting solution was stirred at
1008C for 21 h before quenching with saturated aqueous NH4Cl (2 mL).
The aqueous layer was extracted with dichloromethane (5 mLꢁ3). The
combined organic layer was washed with saturated aqueous NaCl
(5 mL), dried over anhydrous MgSO4, and concentrated under reduced
pressure with a rotary evaporator. The crude product was passed through
a short pad of florisil (eluent: dichloromethane) and the organic solvent
was removed under reduced pressure. The residue was purified by GPC
(eluent: chloroform) followed by recrystallization from hexane-toluene
(1:1) to give 1h (46 mg, 54%) as a yellow solid. Rf =0.23 (hexane/di-
chloromethane 5:1); m.p.: 198.8–199.88C; IR (KBr): n˜ =3038, 1609, 1591,
1123, 968, 953, 829 cmÀ1 1H NMR (400 MHz, CDCl3): d=1.45 (d, J=
;
6.0 Hz, 12H), 4.63–4.72 (m, 2H), 6.18 (d, J=15.6 Hz, 2H), 7.00–7.07 (m,
6H), 7.21–7.25 (m, 8H), 7.44 ppm (AA’BB’, 4H); 13C NMR (100 MHz,
CDCl3): d=22.3, 70.0, 115.5, 124.0 (q, J=269.9 Hz), 125.3 (q, J=3.8 Hz),
126.4, 128.7 (q, J=32.0 Hz), 130.2, 131.0, 131.9, 132.9, 141.0, 141.5,
157.2 ppm; 19F NMR (282 MHz, CDCl3): d=À63.0 ppm; MS (FAB): m/z
(%): 638 (12) [M+2]+, 637 (51) [M+1]+, 636 (100) M+; elemental analy-
sis: calcd (%) for C38H34F6O2: C 71.69, H 5.38; found: C 70.97, H 5.51.
1508, 1491, 1323, 1283, 1165, 1111, 1065, 826, 758, 700 cmÀ1 1H NMR
;
(400 MHz, CDCl3): d=6.30 (d, J=16.0 Hz, 2H), 7.07–7.12 (m, 6H),
7.20–7.25 (m, 16H), 7.27–7.34 (m, 12H), 7.50 ppm (AA’BB’, 4H);
13C NMR (100 MHz, CDCl3): d=122.6, 123.2, 125.4 (q, J=269.6 Hz),
124.6, 125.3 (q, J=3.8 Hz), 126.4, 128.8 (q, J=32.4 Hz), 129.3, 131.0,
131.5, 131.8, 132.8, 141.0, 141.5, 147.2, 147.4 ppm; 19F NMR (282 MHz,
CDCl3): d=À63.0 ppm; MS (FAB): m/z (%): 856 (39) [M+2]+, 855 (88)
[M+1]+, 854 (100) M+; elemental analysis: calcd (%) for C56H40F6N2:
C 78.67, H 4.72; found: C 78.59, H 4.88.
ACHTUNGTRENNUNG(1E,3E,5E)-3,4-Bis(4-hydroxyphenyl)-1,6-bis[4-(trifluoromethyl)phenyl]-
Acknowledgements
hexa-1,3,5-triene (8): An oven-dried Schlenk tube (20 mL) equipped with
a magnetic stirring bar and a rubber septum was charged with 7 (0.25 g,
0.37 mmol), KOH (0.13 g, 2.2 mmol), Pd
diACHTUNGTRENNUNG(t-butyl)phosphino-2’,4’,6’-triisopropylbiphenyl (16 mg, 0.040 mmol),
(dba)3 (17 mg, 0.020 mmol), 2-
This work was supported by Grants-in-Aid for Creative Scientific Re-
search, No. 16GS0209, from the Ministry of Education, Culture, Sports,
Chem. Asian J. 2009, 4, 1289 – 1297
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1295

M. Shimizu et al.
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b
=91.244(3)8, V=1110.5(3) ꢆ3, Z=2, 1calcd=1.150 gcmÀ3
,
m-
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www.chemasianj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2009, 4, 1289 – 1297

Synthesis and Properties of a New Class of Fluorophores
Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W.
Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J.
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slowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaro-
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Chen, M. W. Wong, C. Gonzalez, and J. A. Pople, Gaussian, Inc.,
Wallingford CT, 2004. GaussView, Version 4.1, Roy Dennington II,
Todd Keith and John Millam, Semichem, Inc., Shawnee Mission,
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À1157.625112 (1a), À1831.702172 (1b), À2060.748487 (1i), and
À2099.638803 (1g’).
Received: March 20, 2009
Published online: June 17, 2009
Chem. Asian J. 2009, 4, 1289 – 1297
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1297