Optical behaviors of conjugated-chain compounds containing benzene and furan units

Article abstract of DOI:10.1016/j.saa.2006.05.035

Thirteen conjugated-chain compounds which contain benzene and furan units were prepared, their optical behaviors, including UV-vis absorption coefficient (ε), absorption wavelengths (λ_a), fluorescence emission wavelengths (λ_e), and q

Full text of DOI:10.1016/j.saa.2006.05.035

Spectrochimica Acta Part A 66 (2007) 1300–1306
Optical behaviors of conjugated-chain compounds
containing benzene and furan units
Wen-Long Pan, Ji-Guo Song, Yong Chen, Yi-Qian Wan, Hua-Can Song∗
School of Chemistry and Chemical Engineering, Sun yat-Sen University, Guangzhou 510275, PR China
Received 18 April 2006; accepted 9 May 2006
Abstract
Thirteen conjugated-chain compounds which contain benzene and furan units were prepared, their optical behaviors, including UV–vis absorp-
tion coefficient (ε), absorption wavelengths (λa), fluorescence emission wavelengths (λe), and quantum yields (Φ) were measured. Meanwhile,
their LUMO and HOMO energy were determined by cyclic voltammetry and their second-order polarizations (βxxx) values were determined by
solvatochromic method, respectively. The results showed that this kind of compounds possess a shorter λa (320–365 nm) and performance a higher
Φ values, especially for 2aa, 2ab, 2ac and 2bb, their Φ values are all more than 90%. These compounds, except 2db, showed a higher βxxx values
in DMSO, especially for 2dc (75.77 × 10−30 m5 C−1) and 2dd (83.32 × 10−30 m5 C−1), than that 10-methyl-acridone (6.578 × 10−30 m5 C−1) or
10-benzylacridone (6.845 × 10−30 m5 C−1) in DMSO did, and second harmonic generation value of 10-methylacridone and 10-benzylacridone in
powder are, respectively, 1.381 and 1.861 times of that value of urea. The βxxx values and Φ values determined for these compounds in this work
were lower than these values which were desired in the original work, this phenomena was explained from their molecular structures. This work
confirmed that as these compounds performance shorter λa and higher Φ values, they could be good blue-color optical materials for some fields,
such as OLED materials, two-photo absorption materials, fluorescent dyes.
© 2006 Elsevier B.V. All rights reserved.
Keywords: Conjugated compound; Trisbustituted-furan; Synthesis; Optical behavior
1. Introduction
on our previous work [25–28], we wish to report herein the
preparation of a series of conjugated-chain compounds which
contain benzene and furan units and their optical behaviors,
including UV–vis absorption coefficient (ε), absorption wave-
lengths (λa), fluorescent emitting wavelengths (λe), quantum
yields (Φ), LUMO energy and HOMO energy and second-order
polarization (βxxx) values. The synthetic method and structures
for these compounds were in the following (Fig. 1).
It has attracted a tremendous amount of recent attention to
synthesize and investigate the optical behaviors of conjugated
organic materials and many remarkable research results were
obtained recently in many fields, such as in organic second-
order nonlinear optical (NLO) materials [1–3], in two-photon
absorption materials [4–6] and in organic light-emitting device
(OLED) [7–11] materials. There are a lot of reports about the
conjugated-chain compounds containing benzene and thiophene
units [12–20] which could show a good photoluminescence
property and it was found several papers about the conjugated-
chain compounds containing benzene and furan units could per-
form a good optical property [8c,21–24]. However, there is very
little of the reports about the fluorescence-emitting behaviors
and second-order polarizations of the conjugated-chain com-
pounds containing benzene and furan units. Therefore, based
2. Results and discussion
2.1. The preparation of samples
According to Refs. [23,25], a series of conjugated-chain
compounds which contain benzene and furan fragments were
prepared in our laboratory, the synthetic method and structures
of trisbustituted-furan derivatives were showed in Fig. 1. In order
to prepare 1-hexynyl (or phenylacetylenyl) aromatic alcohol, 1-
hexynyllithium (or phenylacetylenyllithium) was employed. As
a lower temperature (under −78 ◦C) must be necessary for the
preparation of alkynyllithium by the reaction of butyllithium
∗
Corresponding author. Tel.: +86 20 84110918; fax: +86 20 84112245.
E-mail address: cedc19@zsu.edu.cn (H.-C. Song).
1386-1425/$ – see front matter © 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2006.05.035

W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
1301
Table 1
The quantum yield of compounds 2aa–2dd in ethyl acetate
Sample
Φ (%)
2aa
2ab
2ac
2ba
2bb
2bc
2ca
2cb
2cc
2da
2db
2dc
2dd
97
91
101
81
93
78
89
66
71
72
79
70
66
Fig. 1. The synthetic method and structures of trisbustituted-furan deriva-
tives. 1a, R1 = 4-methoxycarbonylphenyl, R2 = n-C4H9; 1b, R1 = 4-biphenyl,
R2 = phenyl; 1c, R1 = 4-methoxyphenyl, R2 = phenyl; 1d, R1 = 2-naphthyl,
R2 = phenyl. 2aa, R3 = 4-phenyl; 2ab, R3 = 4-trifluoromethylphenyl; 2ac,
R3 = 2,4-dimethoxyphenyl; 2ba, R3 = 2,4-dimethoxyphenyl; 2bb, R3 = 4-
fluorophenyl; 2bc, R3 = 4-cyanophenyl; 2ca, R3 = 4-cyanophenyl; 2cb,
R3 = 4-fluorophenyl; 2cc, R3 = 4-hydroxyphenyl; 2da, R3 = 4-fluorophenyl;
2db, R3 = 2,4-dimethoxyphenyl; 2dc, R3 = 4-hydroxyphenyl; 2dd, R3 = 4-
acryloyloxy.
with 1-hexyne (or phenylacetylene), the reaction of alkynyl-
lithium with methylmagnesium iodide at 0–10 ◦C was tried and
a good yield for the reaction was obtained.
previously reported quantum yield values [24], it is confirmed
that the Φ values of compounds could be increased by changing
their structures.
After aromatic aldehyde was added into the mixture of dithi-
aacetal and butyllithium, it is better to keep this resulting mix-
ture for 40 min under −78 ◦C, in order to get a high yield for
trisubstituted-furan compounds. If the reaction time was pro-
longed for 60–80 min, the yield would become lower; if after
the addition of aldehyde the mixture was lad up at the room
temperature and let the temperature of the mixture go up by
itself, the yield became very low and even the desired product
could not be isolated.
In order to get 4-acryloyloxyphenylfuran (2dd) for polymer-
ization, synthetic routes 1–3 for 4-hydroxyphenyl furan (2dc)
were tried, respectively (Fig. 2). By routes 2 and 3 a good result
could be obtained, but a lower yield by route 1 was obtained, as
the yield for demethylation was very low.
By comparison with the structures and Φ values, it is found
generally that those trisubstituted-furan derivatives in which
there is an n-butyl group in three-position possess a stronger
fluorescence emitting ability than that in which there is a phenyl
group in three-position do. This is because that a phenyl group
in three-position of furan-derivative molecules has a stronger
tendency as space factor to twist the plane which furan ring
and the other phenyl ring (or aromatic ring) are in at the same
time, which would destroy the rigid structure in which furan
ring and the other phenyl ring (or aromatic ring) should keep,
compared with an n-butyl group in three-position of the same
furan-derivative molecules.
2.3. LUMO and HOMO
2.2. Quantum yields
According to Ref. [30], the determination for HOMO and
LUMO energy of the samples 2aa–2dd were finished by cyclic
voltammetry (CV) in 0.1 M solution of TBAP in acetonitrile,
platinum electrode and SCE were used as the working elec-
trode and the reference electrode, respectively, the scan rate was
100 mV s−1. The oxidation potential (Epa), reduction potential
(Epc), HOMO energy, LUMO energy and band gaps were shown
in Table 2.
TheΦvaluesforthirteentrisubstituted-furanderivativeswere
determined by comparing method, using coumarin as a standard
sample and its Φ value is 0.99 in ethyl acetate [29]. The results
were listed in Table 1.
It is found from Table 1 that this series of trisubstituted-furan
derivatives possess a strong fluorescence emitting ability, all of
their Φ values are more than 66%, especially for 2aa, 2ab, 2ac,
2bb, their Φ values are all more than 90%, and for 2ba and
2ca, their Φ values are all more than 80%. Compared with the
The redox properties of the furan compounds could be
ascribed to reduction and oxidation occurring on the furan back-
bone. The conjugation degrees of the aromatic ␲-system could
Fig. 2. The synthetic route 1–3 for 4-hydroxyphenyl furan (2dc)

1302
W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
Table 2
The presence of the phenyl group obviously made the elec-
trochemical reduction and oxidation much easier, as reduction
potentials were increased from −2.6 to −2.2 V, and oxidation
potentials were decreased from 1.24 to 0.82 V.
Unfortunately the LUMO energy could not be obtained for
several compounds, since their reduction potentials were out of
the solvent window. The energy level of the HOMO in respect
to vacuum was, therefore, compatible with the excellent hole-
transporting materials such as TPD (5.60 eV) or NPB (5.40 eV).
These furan derivatives are blue light-emitting compounds with
highPLinsolutionandthusshowedagreatpotentialasoptoelec-
tronic materials. Further electrochemical and solid-state studies
were under way and will be reported in due course.
HOMO and LUMO (electrochemical data) of compounds 2aa–2dd
Sample
Epa (V)
HOMO (eV)
Epc (V)
LUMO (eV)
Egap (eV)
2aa
2ab
2ac
2ba
2bb
2bc
2ca
2cc
2da
2db
2dc
2dd
0.90
1.03
0.96
0.97
1.14
1.05
0.97
0.92
0.84
0.82
0.87
1.24
5.64
5.77
5.70
5.71
5.88
5.79
5.71
5.66
5.58
5.56
5.61
5.98
−1.75
−1.87
−1.66
2.99
2.87
3.08
2.78
2.83
2.63
−1.84
−1.79
2.90
2.95
2.71
3.03
2.4. Second-order polarizations
According to Eqs. (1)–(5) [25–28] and based on the solva-
tochromic method which was reported in our previous work,
the values of βxxx were determined in five solvents. From CRC
HandbookofChemistryandPhysicsData, 58th, itwasfoundthat
the dielectric constant for these five solvents, DMF, DMSO, 1,2-
dichloro-ethane, ethyl acetate and dichloromethane is, respec-
tively, 37.00, 49.00, 10.45, 6.02 and 9.10. All the data correlated
with this calculation were listed in Tables 3–8.
produce a significant perturbation on the properties of molecular
orbits, which would influence the energy gap.
It is found from Table 2 that in this condition the oxidation
and reduction peaks could be obtained for 2ab, 2ac, 2ba, 2dc
and 2dd, which means that the electrochemistry-behavior was
reversible in this situation for these samples. But the oxidation
and reduction peaks were not obtained for 2aa, 2bb, 2bc, 2ca,
2cc, 2da and 2db, which indicates that the electrochemistry-
behavior was irreversible for these samples. The reason for this
phenomenon was suggested that the ionic species were either
very stable or transformed into the electro-inactive species. It is
likely that the radical anion obtained after the reduction (or oxi-
dation) was protonated in solution (CH3CN), which may contain
a trace amount of water.
1.5h−2μ2eg(μe − μg)ωe2g
βxxx
=
(1)
(2)
(ωe2g − ω2)(ωe2g − 4ω2)
2πωegN0nμ2egM
area =
3(2.303)ε0ch
Table 3
The calculated data of M, B, α, and μe − μg of the samples
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
M
352
402
432
371
351
344
342
364
406
362
416
B
α
3471.4
1.5071
57.738
1883.7
1.5486
32.193
2022.2
1.842
41.108
614.4
1.7184
11.652
2291.8
1.6037
40.561
2985
1.5238
50.198
1302
1.5325
22.020
915.8
1.5398
15.562
677.9
1.6785
12.557
3583.6
1.5721
62.174
2699.7
1.9194
57.186
μe − μg (×10−30 cm)
Table 4
Concentration,λa, ε, λe, H, r1/2, Stokes shift, μeg, ωeg and βxxx in DMSO
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
Concentration (×10−6 mol/L)
λa (nm)
2.890
348
4.400
436
2.488
349
4.744
422
2.315
327
8.165
443
2.695
343
6.826
408
2.849
364
3.019
462
2.907
344
2.821
409
2.924
337
4.480
415
2.747
343
4.623
404
2.463
337
2.923
438
2.762
345
4.706
441
2.404
345
5.366
434
ε (×107 cm2 mol−1
)
λe (nm)
H
0.125
4364.5
5799.9
38.03
28735.6
60.95
0.118
4326.5
4956.6
39.45
28653.3
36.96
0.189
3458.7
8007.7
44.79
30581.0
48.20
0.184
3749.4
4687.3
43.69
29154.5
15.31
0.086
4617.4
5865.3
33.16
27472.5
38.53
0.082
2038.6
4619.9
20.69
29069.8
15.03
0.131
3183.2
5577.2
32.33
29673.6
14.94
0.127
4173.0
4402.0
37.92
29154.5
15.48
0.072
3009.2
6842.5
25.38
29673.6
5.25
0.130
4906.5
6309.8
41.53
28985.5
75.77
0.129
5132.3
5944.0
45.40
28985.5
83.32
r1/2 (cm−1
)
Stokes shift (nm−1
)
μeg (×10−30 cm)
ωeg (cm−1
)
βxxx (×10−30 m5 C−1
)

W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
1303
Table 5
Concentration, λa, ε, λe, H, r1/2, Stokes shift, μeg, ωeg and βxxx in DMF
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
Concentration (×10−6 mol/L)
λa (nm)
2.890
345
4.400
433
2.488
352
4.744
415
2.315
330
8.165
442
2.695
338
6.826
405
2.849
363
3.019
456
2.907
324
2.821
402
2.924
328
4.480
414
2.747
333
4.623
400
2.463
328
2.923
434
2.762
335
4.706
434
2.404
336
5.366
435
ε (×107 cm2 mol−1
)
λe (nm)
H
0.090
4452.1
5890.8
33.10
28985.5
44.70
0.107
3650.9
4353.1
35.25
28409.1
30.31
0.085
4818.1
7678.6
36.23
30303.0
32.54
0.140
4539.7
4938.3
42.32
29585.8
13.62
0.091
4399.3
5618.4
33.91
27548.2
40.06
0.096
4990.8
5988.6
34.65
30864.2
34.14
0.113
5109.7
6333.2
38.16
30487.8
18.94
0.121
5519.6
5030.0
42.72
30030.0
17.67
0.096
5420.0
7446.3
39.47
30487.8
11.55
0.100
6495.9
6809.3
42.07
29850.7
69.93
0.096
6047.9
6773.4
42.72
29761.9
67.03
r1/2 (cm−1
)
Stokes shift (nm−1
)
μeg (×10−30 cm)
ωeg (cm−1
)
βxxx (×10−30 m5 C−1
)
Table 6
Concentration, λa, ε, λe, H, r1/2, Stokes shift, μeg, ωeg and βxxx in ClCH2CH2Cl
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
Concentration (×10−6 mol/L)
λa (nm)
2.890
349
4.400
423
2.488
351
4.744
408
2.315
327
8.165
435
2.695
341
6.826
405
2.849
365
3.019
446
2.907
320
2.821
395
2.924
324
4.480
401
2.747
341
4.623
403
2.463
325
2.923
431
2.762
341
4.706
422
2.404
342
5.366
414
ε (×107 cm2 mol−1
)
λe (nm)
H
0.081
3830.7
5012.6
29.04
28653.3
35.91
0.052
3656.8
4634.2
24.31
28490.0
14.26
0.058
5852.3
7592.5
32.65
30581.0
25.60
0.092
3841.5
4634.2
31.51
29325.5
7.83
0.076
3914.3
5013.3
29.05
27397.3
29.90
0.061
5779.6
5982.4
29.32
31250.0
23.32
0.059
5310.7
5974.2
27.71
30864.2
9.53
0.088
4450.5
4511.6
32.80
29325.5
11.34
0.0797
6818.8
7567.3
39.93
30769.2
11.45
0.087
5146.6
5671.9
34.97
29325.5
51.21
0.048
4656.8
5128.0
26.57
29239.8
27.48
r1/2 (cm−1
)
Stokes shift (nm−1
)
μeg (×10−30 cm)
ωeg (cm−1
)
βxxx (×10−30 m5 C−1
)
Table 7
Concentration, λa, ε, λe, H, r1/2, Stokes shift, μeg, ωeg and βxxx in EtOAc
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
Concentration (×10−6 mol/L)
λa (nm)
2.890
346
4.400
412
2.488
346
4.744
403
2.315
327
8.165
423
2.695
336
6.826
400
2.849
362
3.019
2.907
318
2.821
394
2.924
323
4.480
399
2.747
336
4.623
396
2.463
326
2.923
414
2.762
339
4.706
415
2.404
331
5.366
412
ε (×107 cm2 mol−1
)
λe (nm)
H
0.070
3759.9
4671.7
27.39
28901.7
30.78
0.129
3953.2
4087.8
40.79
28901.7
38.26
0.052
4305.8
2803.0
27.87
30581.0
18.56
0.115
4229.4
4761.9
37.73
29761.9
10.66
0.061
0.071
5635.7
6065.8
32.05
31446.5
27.43
0.076
5358.4
5897.1
32.45
30959.8
12.99
0.107
4608.9
4509.4
37.62
29761.9
14.15
0.075
2835.8
6520.2
27.32
30674.8
5.42
0.057
5450.5
5445.7
29.95
29498.5
36.79
0.035
5912.2
5939.6
25.93
30211.5
23.44
r1/2 (cm−1
)
3578.6
4935.2
25.46
27624.3
22.22
Stokes shift (nm−1
)
μeg (×10−30 cm)
ωeg (cm−1
)
βxxx (×10−30 m5 c−1
)
Table 8
Concentration, λa, ε, λe, H, r1/2, Stokes shift, μeg, ωeg and βxxx in CH2Cl2
Samples
2aa
2ab
2ba
2bb
2ca
2cb
2cc
2da
2db
2dc
2dd
Concentration (×10−6 mol/L)
λa (nm)
2.890
323
4.400
426
2.488
351
4.744
410
2.315
326
8.165
432
2.695
341
6.826
406
2.849
360
3.019
445
2.907
322
2.821
398
2.924
325
4.480
402
2.747
342
4.623
399
2.463
326
2.923
431
2.762
342
4.706
419
2.404
347
5.366
417
ε (×107 cm2 mol−1
)
λe (nm)
H
0.127
3233.0
4894.6
33.85
30959.8
50.69
0.116
3646.7
4099.8
36.69
28490.0
32.66
0.112
6024.7
7526.7
46.25
30674.8
50.84
0.125
4080.8
4695.0
38.13
29325.5
11.47
0.169
3472.2
5305.9
40.92
27777.7
56.47
0.126
6186.0
5978.6
44.07
31055.9
53.79
0.158
6139.4
5941.0
49.27
30769.2
30.43
0.114
4173.0
4219.9
36.45
29239.8
14.08
0.103
0.088
4889.0
5373.4
34.71
29239.8
51.29
0.108
3811.7
4879.2
36.49
28818.4
54.69
r1/2 (cm−1
)
Stokes shift (nm−1
)
μeg (×10−30 cm)
45.14
30674.8
14.80
ωeg (cm−1
)
βxxx (×10−30 m5 C−1
)

1304
W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
6.909Hr1/2ε0ch
2πωegN0nM
μ2eg
=
=
=
32.11662 × 10−61Hr1/2
(mol C2 m−1
)
nMωeg
3.211662 × 10−58Hr1/2
m
(C2m2)
(3)
Fig. 3. The situation for intra molecular-charge-transfer for acridine derivative
and furan.
nωeg
in furan derivative molecule than that in acridone derivative
molecule, consequently, the βxxx values for furan derivative
molecule should be bigger than that for acridone derivative
molecule.
2(μe − μg)2
,
Va − Vf = A + B(BK),
B =
hcα3
ꢀ
ꢁ
D − 1
n2 − 1
ˆ
¡A
BK =
−
In original, it was hoped that the βxxx values for these furan
derivativemolecules, especiallyfor2ac, 2bb, 2bc, 2ca, 2cb, 2da,
would be bigger than these βxxx values which were obtained in
this work. Because of the presence of substituent in 3-position
of furan, the planes which two substituents in 2-, 5-position of
furan were on and the furan ring plane were twisted out, which
made the intramolecular-charge-transfer only occur between
furan ring and one aromatic ring, the intramolecular-charge-
tansfer length would become shorter, thus, the βxxx values for
these compounds synthesized in this work became less than that
for the desired compound.
2D + 1 2n2 − 1
ꢀ
ꢁ
ꢀ
ꢁ
2
1 − (n2 − 1)
1 − (D − 1)
2D + 1
ˆ
×
¡A
(4)
(5)
2n2 + 1
1.5(6.6262 × 10−34
)
−2 J−2 S−2μ2eg(μe − μg)λ2e
βxxx
=
=
c(1 − ω2/ωe2)(1 − 4ω2/ωe2)
−2
3.8012(9−1 × 10−9 C2 m−1
)
μ2 (μe − μg)λ2e
eg
(1 − λ2e/λ2a)(1 − 4λe2/λ2a)
3. Experimental
It is all known that urea in solid state possesses a high sec-
ond harmonic generation (SHG) value and could be used as
double-frequency laser materials in the early days. We reported
previously [25] for 10-methylacridone and 10-benzylacridone,
the SHG values in powder was, respectively, 1.381 and
1.861 times of that value of urea, which was determined
by Kurtz’s method, therefore, in powder state, both com-
pounds of 10-methylacridone and 10-benzylacridone possess
a higher SHG value than urea does. For 10-methylacridone
and 10-benzylacridone [25], the βxxx values in DMSO was,
respectively, (6.578 and 6.845) × 10−30 m5 C−1 determined
by solvatochromic method. It could be found from Table 4
that these thirteen trisubstituted-furan compounds, except 2db,
all showed a higher βxxx value in DMSO, especially for
2dc (75.77 × 10−30 m5 C−1) and 2dd (83.32 × 10−30 m5 C−1),
than that 10-methylacridone (6.578 × 10−30 m5 C−1) or 10-
benzylacridone (6.845 × 10−30 m5 C−1) [25] in DMSO did.
According to the theory of organic nonlinear optical mate-
rials, the more the degree of intramolecular charge transfer,
the higher the βxxx value of this material, and the degree
of intramolecular charge transfer depend on two factors:
electronegativity-difference between electrowithdrawing group
and electrodonating group and the length between electrowith-
drawing group and electrodonating group. The difference of βxxx
value between acridone derivative and furan derivative could
be suggested that as the electronegativity-difference between
electrowithdrawing group and electrodonating group in acridone
derivative molecule and in furan derivative molecule are nearly
same, however, the length between electrowithdrawing group
and electrodonating group in acridone derivative molecule are
shorter than that in furan derivative molecule (Fig. 3), therefore,
the degree of intramolecular charge transfer could be bigger
3.1. Instruments and reagents
All melting point were determined on a 4× melting point
microscope. 1H, 13C and 19F NMR spectra were run on a
Bruker AVANCE-300 NMR spectrometer. Ultraviolet spectra
were recorded on a Shimadzu UV-1601 spectraphotometer. Flu-
orescence spectra were taken with a Shimadzu RF-5301PC
spectro-fluorophotometer. Element analysis was taken with an
Elementar Vario EL. Mass spectra were taken with a Shimadzu
LCMS-2010A. n-Butyllithium (Alfa-Aesor), trifluoroaceticacid
(Fluka), 4-fluorobenzaldehyde, 2,4-dimethoxybenzaldehyde, 4-
hydroxybenzaldehyde, 4-trifluoromethylbenzaldehyde were of
analytical grade and used without further purification. All the
solvents were dried using standard methods before use.
3.2. The preparation of samples
Intermediate compounds 1a–d and terminal compounds
2aa–2dd were prepared, respectively, as Refs. [23,24].
3.2.1. Methyl 4-(2-(hex-1-ynyl)-1,3-dithiolan-2-yl)benzoate
(1a) [24]
1
Yield: 67%, H NMR (CdCl3), δ, 0.91 (t, J = 7.5 Hz, 3H),
1.43 (tq, J1 = J2 = 7.4 Hz, 2H), 1.55 (tt, J1 = 7.5 Hz, J2 = 7.1 Hz,
2H), 2.34 (t, J = 7.1 Hz, 2H), 3.50 (m, 4H), 3.90 (s, 3H), 7.98 (s,
4H). ESI-MS for C17H21O2S2 (M + H+), 321.2.
3.2.2. 2-(2-Phenylethynyl)-2-(4-biphenyl)-1,3-dithiolane
(1b)
Yield: 79%, mp 102–104 ◦C. 1H NMR (CdCl3), δ, 3.76 (m,
4H), 7.33 (m, 4H), 7.43 (m, 2H), 7.50 (m, 2H), 7.59 (m, 4H), 8.07

W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
1305
(d, J = 10.5 Hz, 2H). 13C NMR (CdCl3), δ, 43.0, 62.7, 87.4, 91.4,
122.9, 127.1, 127.2, 127.6, 128.2, 128.3, 128.4, 128.5, 128.9,
131.7, 137.8, 140.5, 141.3. ESI-MS for C23H19S2 (M + H+),
359.1.
52.5, 55.9, 99.3, 105.1, 110.8, 113.7, 123.5, 125.5, 128.2, 130.5,
132.1, 135.7, 148.0, 151.6, 158.7, 161.7, 167.4.
3.2.8. 2-(2,4-dimethoxyphenyl)-3-phenyl-5-
(4-biphenyl)furan (2ba)
Yield: 35%, mp 50–52 ◦C. 1H NMR (CdCl3), δ, 3.52 (s, 3H),
3.90 (s, 3H), 6.55 (s, 1H), 6.65 (d, J = 8.6 Hz, 1H), 7.06 (s, 1H),
7.44 (m, 10H), 7.71 (d, J = 8.1 Hz, 4H), 7.88 (d, J = 8.3 Hz, 2H).
13C NMR (CdCl3), δ, 55.8, 56.1, 99.7, 105.3, 108.2, 114.3,
124.4, 124.8, 125.4, 127.5, 127.8, 127.9, 128.0, 128.1, 128.7,
129.3, 129.4, 130.5, 132.4, 135.4, 140.4, 141.3, 146.8, 153.2,
153.5, 158.8, 162.1, 162.2. ESI-MS for C30H25O3 (M + H+),
433.2.
3.2.3. 2-(2-Phenylethynyl)-2-(4-methoxyphenyl)-
1,3-dithiolane (1c)
1
Yield: 78%, mp 92–94 ◦C. H NMR (CdCl3), δ, 3.75 (m,
4H), 3.82 (s, 3H), 6.90 (d, J = 6.8 Hz, 2H), 7.34 (m, 3H), 7.51
(m, 2H), 7.95 (d, J = 6.6 Hz, 2H). 13C NMR (CdCl3), δ, 41.8,
55.9, 62.6, 87.2, 91.9, 114.0, 123.3, 128.8, 128.9, 129.5, 130.7,
132.1, 160.1. ESI-MS for C18H17OS2 (M + H+), 313.0.
3.2.4. 2-(Naphthalen-3-yl)-2-(2-phenylethynyl)-
1,3-dithiolane (1d)
3.2.9. 2-(4-fluorophenyl)-3-phenyl-5-(4-biphenyl)furan
(2bb)
Yield: 80%, mp 118–119 ◦C. 1H NMR (CdCl3), δ, 3.80 (m,
4H), 7.35 (m, 3H), 7.49 (m, 2H), 7.56 (m, 2H), 7.86 (m, 3H), 8.05
(d, J = 10.0 Hz, 3H), 8.47 (s, 1H). 13C NMR (CdCl3), δ, 41.7,
62.6, 87.2, 91.1, 122.7, 125.6, 126.3, 126.5, 127.4, 128.1, 128.2,
128.3, 128.4, 131.6, 132.6, 133.0, 136.0. ESI-MS for C21H16S2
(M + H+), 332.1.
1
Yield: 38%, mp 176–178 ◦C. H NMR (CdCl3), δ, 6.88 (s,
1H), 7.06 (t, J = 8.7 Hz, 2H), 7.42 (m, 4H), 7.49 (m, 4H), 7.66
(m, 6H), 8.25 (d, J = 8.6 Hz, 2H). 13C NMR (CdCl3), δ, 110.0,
115.8, 116.1, 124.6, 127.4, 127.9, 128.4, 128.5, 129.1, 129.3,
129.8, 134.5, 140.7, 141.0, 147.6, 152.8. 19F NMR (CdCl3), δ,
−113.99 (m). ESI-MS for C28H20FO (M + H+) 391.2.
3.2.5. Methyl 4-(4-butyl-5-(4-fluorophenyl)furan-
2-yl)benzoate (2aa)
3.2.10. 2-(4-Cyanophenyl)-3-phenyl-5-(4-biphenyl)furan
(2bc)
Yield: 45%, mp 82–83 ◦C. 1H NMR (CdCl3), δ, 0.98
(t, J = 7.4 Hz, 3H), 1.47 (tq, J1 = J2 = 7.4 Hz, 2H), 1.68 (tt,
J1 = 7.4 Hz, J2 = 8.0 Hz, 2H), 2.69 (t, J = 8.0 Hz, 2H), 3.95 (s,
3H), 6.81 (s, 1H), 7.19 (t, J = 8.7 Hz, 2H), 7.68 (m, J = 6.8 Hz,
2H), 7.77 (d, J = 8.5 Hz, 2H), 8.07 (d, J = 8.5 Hz, 2H), 13C NMR
(CdCl3), δ, 14.4, 23.0, 26.1, 32.5, 52.5, 111.8, 116.0, 116.3,
123.6, 124.4, 128.0, 128.7, 130.6, 135.1, 148.8, 151.2, 160.8,
164.0, 167.3. 19F NMR (CdCl3), δ, −114.45 (m). ESI-MS for
C22H22FO3 (M + H+) 353.2. Anal. calcd. for C22H21FO3: C,
74.98; H, 6.01. Found: C, 75.18; H, 6.12.
Yield: 26%. 1H NMR (CdCl3), δ, 6.88 (s, 1H), 7.50 (m, 10H),
7.42 (d, J = 8.5 Hz, 2H), 7.69 (m, 8H), 7.85 (m, 2H). 13C NMR
(CdCl3), δ, 110.7, 110.9, 119.6, 125.1, 126.3, 127.5, 127.8,
128.1, 128.5, 129.0, 129.4, 132.9, 134.2, 135.6, 141.0, 141.5,
146.3, 154.3.
3.2.11. 2-(4-Cyanophenyl)-5-(4-methoxyphenyl)-3-
phenylfuran (2ca)
1
Yield: 24%, mp 137–139 ◦C. H NMR (CdCl3), δ, 3.89 (s,
3H), 6.71 (s, 3H), 7.00 (d, J = 8.8 Hz, 2H), 7.46 (m, 6H), 7.56 (d,
J = 8.6 Hz, 2H), 7.68 (d, J = 8.7 Hz, 2H), 7.73 (d, J = 8.9 Hz, 2H).
13C NMR (CdCl3), δ, 55.8, 109.2, 110.2, 114.8, 115.9, 119.5,
122.9, 123.3, 125.9, 128.4, 129.1, 129.4, 130.3, 132.7, 134.2,
135.6, 145.4, 154.5, 160.2. ESI-MS for C24H18NO2 (M + H+)
352.2.
3.2.6. Methyl 4-(4-butyl-5-(4-trifluoromethylphenyl)furan-
2-yl)benzoate (2ab)
Yield: 47%, mp 99–100 ◦C. 1H NMR (CdCl3), δ, 1.00
(t, J = 7.2 Hz, 3H), 1.50 (tq, J1 = J2 = 7.3 Hz, 2H), 1.72 (tt,
J1 = 7.2 Hz, J2 = 8.0 Hz, 2H), 2.76 (t, J = 8.0 Hz, 2H), 3.96 (s,
3H), 6.83 (s, 1H), 7.71 (d, J = 8.5 Hz, 2H), 7.79 (d, J = 8.3 Hz,
2H), 7.83 (d, J = 8.5 Hz, 2H), 8.09 (d, J = 8.3 Hz, 2H). 13C NMR
(CdCl3), δ, 14.4, 23.0, 26.3, 32.4, 52.6, 67.6, 112.0, 123.9,
3.2.12. 2-(4-Fluorophenyl)-5-(4-methoxyphenyl)-3-
phenylfuran (2cb)
1
Yield: 67%, mp 90–92 ◦C. H NMR (CdCl3), δ, 3.88 (s,
125.9, 126.0, 128.9, 130.6, 134.7, 135.0, 148.0, 152.1, 167.2. 19
F
3H), 6.70 (s, 1H), 7.00 (m, 4H), 7.45 (m, 5H), 7.58 (dd,
J1 = 8.9 Hz, J2 = 5.4 Hz, 2H), 7.71 (d, J = 8.8 Hz, 2H). 13C NMR
(CdCl3), δ, 55.8, 108.3, 114.8, 115.7, 116.0, 122.9, 123.9, 124.6,
125.7, 127.8, 128.0, 128.2, 128.3, 129.1, 129.2, 134.7, 146.8,
153.1, 159.7. 19F NMR (CdCl3), δ, −114.464 (m). ESI-MS
for C23H18FO2 (M + H+) 345.1. Anal. calcd for C23H17FO2:
C, 80.22; H, 4.98. Found: C, 80.01; H, 5.12.
NMR (CdCl3), δ, −62.94 (s). ESI-MS for C23H22F3O3 (M + H+)
403.0. Anal. calcd. for C23H21F3O3, C, 68.65; H, 5.26. Found:
C, 68.35; H, 5.51.
3.2.7. Methyl 4-(4-butyl-5-(2,4-dimethoxylhenyl)furan-
2-yl)benzoate (2ac)
1
Yield: 53%, viscose liquid. H NMR (CdCl3), δ, 0.92 (t,
J = 7.4 Hz, 3H), 1.37 (tq, J1 = 7.4 Hz, J2 = 7.6 Hz, 2H), 1.59 (tt,
J1 = 7.6 Hz, J2 = 8.1 Hz, 2H), 2.45 (t, J = 8.0 Hz, 2H), 3.85 (s,
3H), 3.88 (s, 3H), 3.93 (s, 3H), 6.60 (m, J = 8.3 Hz, 2H), 6.83
(s, 1H), 7.39 (t, J = 8.3 Hz, 2H), 7.74 (m, J = 8.5 Hz, 2H), 8.05
(d, J = 8.6 Hz, 2H). 13C NMR (CdCl3), δ, 14.4, 23.0, 25.7, 32.7,
3.2.13. 2-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-
3-phenylfuran (2cc)
1
Yield: 51%, mp 170–173 ◦C. H NMR (CdCl3), δ, 6.73 (s,
1H), 6.88 (d, J = 8.8 Hz, 2H), 7.01 (d, J = 8.9 Hz, 2H), 7.41 (m,
3H), 7.52 (m, 3H), 7.74 (d, J = 8.9 Hz, 2H). 13C NMR (CdCl3),

1306
W.-L. Pan et al. / Spectrochimica Acta Part A 66 (2007) 1300–1306
δ, 55.8, 108.3, 114.6, 115.8, 125.6, 127.5, 128.2, 129.0, 134.7,
146.8, 153.1, 159.7. ESI-MS for C23H19O3 (M + H+), 343.1.
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3.2.14. 2-(4-Fluorophenyl)-5-(naphthalen-2-yl)-
3-phenylfuran (2da)
1
Yield: 33%, mp 130–132 ◦C. H NMR (CdCl3), δ, 6.96 (s,
1H), 7.06 (t, J = 8.8 Hz, 2H), 7.46 (m, 7H), 7.77 (m, 2H), 8.07
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122.6, 124.8, 126.5, 127.0, 127.8, 127.9, 128.2, 128.3, 128.5,
128.6, 128.9, 129.1, 129.2, 133.3, 134.0, 134.5, 147.8, 153.1,
161.0, 164.3. ESI-MS for C26H18FO (M + H+), 364.9.
3.2.15. 2-(2,4-Dimethoxyphenyl)-5-(naphthalen-2-yl)-
3-phenylfuran (2db)
Yield: 28%, mp 47–49 ◦C. 1H NMR (CdCl3), δ, 3.50 (s, 3H),
3.90 (s, 3H), 6.52 (s, 1H), 6.62 (d, J = 8.6 Hz, 1H), 7.10 (s, 1H),
7.32 (m, 6H), 7.40 (m, 3H), 7.87 (m, 4H), 8.23 (s, 1H). 13C
NMR (CdCl3), δ, 55.6, 55.9, 99.5, 105.3, 108.4, 114.1, 122.4,
122.8, 125.3, 126.2, 126.8, 127.6, 128.2, 128.6, 128.7, 128.8,
132.3, 133.1, 134.1, 135.2, 146.8, 153.3, 158.7, 162.0. ESI-MS
for C28H23O3 (M + H+), 407.2.
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3.2.16. 2-(4-Hydroxyphenyl)-5-(naphthalen-2-yl)-
3-phenylfuran (2dc)
1
Yield: 40%, mp 141–143 ◦C. H NMR (CdCl3), δ, 6.84 (d,
J = 8.8 Hz, 2H), 6.95 (s, 1H), 7.41 (m, 3H), 7.53 (m, 6H), 7.86
(m, 4H), 8.25 (s, 1H). 13C NMR (CdCl3), δ, 110.3, 115.9, 122.4,
122.7, 123.7, 124.6, 126.3, 127.0, 127.6, 128.3, 128.4, 128.5,
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3.2.17. 4-(5-(naphthalen-2-yl)-3-phenylfuran-2-yl)phenyl
acrylate (2dd)
1
Yield: 69%, mp 121–123 ◦C. H NMR (CdCl3), δ, 6.09 (d,
J = 10.4 Hz, 1H), 6.40 (dd, J1 = 10.4 Hz, J2 = 10.6 Hz, 1H), 6.66
(d, J = 10.7 Hz, 1H), 6.99 (s, 1H), 7.18 (d, J = 8.6 Hz, 2H), 7.47
(m, 7H), 7.74 (d, J = 8.7 Hz, 2H), 7.91 (m, 4H), 8.29 (s, 1H).
13C NMR (CdCl3), δ, 110.6, 122.1, 122.6, 125.3, 126.5, 127.0,
127.7, 127.9, 128.2, 128.3, 128.7, 128.9, 129.2, 129.3, 133.2,
133.3, 134.0, 147.9, 150.3, 153.2, 164.9. ESI-MS for C29H21O3
(M + H+), 417.2. Anal. calcd. for C29H20O3: C, 83.63; H, 4.84.
Found: C, 83.33; H, 5.01.
Acknowledgements
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Am. Chem. Soc. 122 (2000) 4992.
This project is supported by Scientific and Technical Project
foundation of Guangdong Province (2003C103006) and HCS
thanks Professor T.-Y. Luh (Taiwan University, Taiwan) for his
help on author’s research work.
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