Synthesis and photophysical properties of novel thiophenylacrylonitrile derivatives containing a triphenylamine moiety

Article abstract of DOI:10.3184/030823409X12583126129317

(Z)-2-(4-Halogenophenyl)-3-(thiophen-3-yl)acrylonitrile can be prepared by condensation of thiophene-3-carbaldehyde with arylacetonitrile halides in the presence of catalytic amounts of NaOCH₃ at room temperature. Secondary arylamines reacted w

Full text of DOI:10.3184/030823409X12583126129317

JOURNAL OF CHEMICAL RESEARCH 2009
DECEMBER, 729–731
RESEARCH PAPER 729
Synthesis and photophysical properties of novel thiophenylacrylonitrile
derivatives containing a triphenylamine moiety
Haiyan Fang and Mingxin Yu*
Department of Chemistry, Zhejiang University, Hangzhou, 310027, P.R.China
(Z)-2-(4-Halogenophenyl)-3-(thiophen-3-yl)acrylonitrile can be prepared by condensation of thiophene-3-
carbaldehyde with arylacetonitrile halides in the presence of catalytic amounts of NaOCH3 at room temperature.
Secondary arylamines reacted with (Z)-2-(4-halogenophenyl)-3-(thiophen-3-yl)acrylonitriles to afford thiophenyl-
acrylonitrile derivatives containing a triphenylamine moiety on catalysis by Pd(OAc)2/P(o-tolyl)3 at 120°C in toluene.
The UV-Vis absorption and photoluminescent (PL) spectra of the products in CH2Cl2 were investigated.
Keywords: thiophen, acrylonitrile, triphenylamine, aryl halides, Pd-catalysed
Thiophene chemistry1 is well established and thiophene-based
heterocycles are key intermediates and relevant targets in
the fields of synthetic, medicinal and materials chemistry.2,3
Recently, thiophenes and benzothiophenes have emerged
as classes of molecules with synthetic utility4 and a wide
array of biological activities.5-8 The high polarisability of
sulfur atoms in thiophene rings leads to a stabilisation of the
conjugated chain and to excellent charge-transport properties,
which are one of the most crucial assets for applications in
organic and molecular electronics.9-11 At the same time,
triphenylamine derivatives are important materials, widely
used in organic photoconductor, organic light-emitting
compounds,12-15 organic solar cells and other fields due to
their excellent electrochemical stability, electron-donating
ability and optoelectronic properties.16,17 Based on our
studies in the field of triphenylamine18-21 and acrylonitrile
derivatives,22 we became interested in the preparation of
new thiophenylacrylonitrile derivatives containing the
triphenylamine moeity. During the past few decades, Ullmann
coupling23,24 and palladium-catalysed coupling12,13,25 reaction
have been the main synthetic methods for triarylamines.
We now report the synthesis of a series of novel thiophene
derivatives containing the triphenylamine moiety via
palladium-catalysed coupling.
The target compounds were obtained by condensation
reactions and palladium-catalysed coupling reactions. (Z)-
2-(4-Halogenophenyl)-3-(thiophen-3-yl) acrylonitriles were
synthesised according to the method previously reported.26
Thiophenylacrylonitrile derivatives containing the triphenyl-
amine moiety (2a–f) were obtained via C–N bond formation.
The process of synthesis is shown in Scheme 1. Yields of
products are listed in Table 1.
CN
N
CH3
2e
S
Pd(OAc)2/L
S
HN
CN
CH3
S
CN
S
CN
R
NH
+
CHO
X
Pd(OAc)2/L
R
N
X
1
1a: X=Cl
1b: X=Br
X=Cl,Br
2
HN
Pd(OAc)2/L
CH2CH3
2a: R=Phenyl
2b: R=m-Tolyl
NC
CH2CH3
2c: R=1-Naphthyl
2d: R=2-Naphthyl
N
S
2f
Scheme 1
* Correspondent. E-mail: mingxinyu@css.zju.edu.cn
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730 JOURNAL OF CHEMICAL RESEARCH 2009
Table
1
Structures, reaction conditions and yields of
2a
2b
2c
2d
2e
2f
thiophenylacrylonitrile derivatives
Product
R
X
Time/h
Yields/%
1.0
0.8
0.6
0.4
0.2
2a
2a
2b
2b
2c
2c
2d
2d
2e
2e
2f
Phenyl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
Br
Cl
16
18
18
19
20
24
18
20
14
17
14
16
66
53
70
65
63
60
75
70
72
68
75
70
Phenyl
m-Tolyl
m-Tolyl
1-Naphthyl
1-Naphthyl
2-Naphthyl
2-Naphthyl
Methyl
Methyl
Ethyl
2f
Ethyl
0
Table
2
Physical properties of thiophenylacrylonitrile
300
400
500
600
700
800
derivatives
Wavelength(nm)
Entry
almaxabs nm
blmaxem nm
.
Fig. 2 PL spectra of compounds 2 in CH2Cl2
2a
2b
2c
2d
2e
2f
298, 395
306, 401
308, 402
297, 391
288, 402
296, 390
522
523
531
517
533
516
Experimental
Aromatic amines, palladium(II) and tri-o-tolylphosphine were
purchased from Aldrich Chemical Co. Sodium tert-butoxide was
purchased from Alfa-Aesar and stored in a Vacuum Atmospheres
glove box under nitrogen. Toluene was distilled under nitrogen
from molten sodium. All other chemicals were used as supplied.
All melting points were determined with a WRS-1A melting point
apparatus and were uncorrected. Proton nuclear magnetic resonance
(1H NMR and 13C NMR) spectra were run on a Bruker AV-400 NMR
spectrometer and chemical shifts expressed as d (ppm) values with
TMS as internal standard. IR spectra were recorded in KBr on a
Nicolet NEXUS 470 FT-IR spectrophotometer. Vibrational transition
frequencies are reported in wave numbers (cm-1). Mass spectra were
obtained on Varian 500-MS. Elemental analyses were determined
with a Perkin–Elmer 240 analyser. UV-Vis spectra were recorded on
a Hitachi U-3300 model while PL spectra were taken using a Hitachi
F-4500 fluorescence spectrophotometer.
aMaximum absorption wavelength in CH2Cl2.
bMaximum emission wavelength in CH2Cl2.
(Z)-2-(4-bromo- and chlorophenyl-3-(thiophen-3-yl)acrylo-
nitriles can react with aromatic amines as in Table 1, the
bromo compounds being more reactive.
We then investigated the photophysical properties of
compounds 2. The UV-Vis (Fig. 1) and PL spectra (Fig. 2)
in dilute dichloromethane solution were recorded. All the
compounds yield green emissions in solution at room
temperature. We have observed from Fig. 1 that the
absorption behaviours are quite similar to each other and
these derivatives reveal a common low-energy broad band at
350–450 nm owing to the π–π* transitions of the compounds.
The absorption bands at 280–350 nm attributed to the
combination of the n–π* transition of triphenylamine moieties
and the π–π* transitions of the thiophene groups.
For the emission spectra in dilute dichloromethane
solutions, as shown in Fig. 2, all of the compounds display
similar behaviour and yield green emission at room
temperature. The emission peaks of compounds are located at
about 515–533nm.
General procedure for the synthesis of (1a, 1b)
A solution of the thiophene-3-carbaldehyde (10 mmol) and aromatic
acetonitrile (10 mmol) in absolute EtOH (30 mL) was treated with
NaOMe (1 mmol) portion wise, stirred at room temperature for 2–3
hours, cooled to 0°C, and filtered. The precipitate was washed with
EtOH.
(Z)-2-(4-chlorophenyl)-3-(thiophen-3-yl)acrylonitrile (1a): Yellow
solid. Yield: 91%. M.p. 92–94°C. FTIR (KBr pellet, cm-1): 3092,
2209, 1601, 1491, 1417, 1341, 1097, 825, 775. 1H NMR (400 MHz,
CDCl3) dH: 7.66 (d, J = 1.8 Hz, 1H), 7.63 (s, 1 H), 7.57 (d, J = 8.0 Hz,
2 H), 7.56 (d, J = 6.0 Hz,1 H), 7.15 (dd, J = 4.0 Hz, J = 4.8 Hz,
1 H). 13C NMR (400 MHz, CDCl3) dc: 135.6, 135.4, 132.9, 132.1,
128.9, 127.1, 127.1, 126.58, 123.0, 118.2, 108.3. Anal. Calcd for
C13H8ClNS: C, 63.54; H, 3.28; Cl, 14.43; N, 5.70; S, 13.05. Found:
C, 63.50; H, 3.25; N, 5.69%.
(Z)-2-(4-bromophenyl)-3-(thiophen-3-yl)acrylonitrile (1b): Yellow
solid. Yield: 90%. M.p. 88–90°C FTIR (KBr pellet, cm-1): 3097,
2207, 1602, 1488, 1415, 1336, 1076, 823, 779. 1H NMR (400 MHz,
CDCl3) dH: 7.97 (d, J = 2.0 Hz, 1 H), 7.78 (d, J = 5.2 Hz, 1 H), 7.56
(d, J = 8.4 Hz, 2 H), 7.53 (s, 1 H), 7.51(d, J = 9.0 Hz, 2H) 7.40 (dd,
J = 2.8 Hz, J = 2.8 Hz,1 H). 13C NMR (400 MHz, CDCl3) dc:135.8,
135.6, 133.1, 132.2, 129.9, 127.2, 127.2, 126.8, 123.1, 118.0, 108.7.
Anal. Calcd for C13H8BrNS: C, 53.81; H, 2.78; Br, 27.54; N, 4.83; S,
11.05. Found: C, 53.74; H, 2.70; N,4.76%.
2a
2.0
2b
2c
2d
2e
1.5
2f
1.0
General procedure for the synthesis of thiophenylacrylonitrile
derivatives (2a–f)
To a 25 mL sidearm flask under vacuum was added (Z)-2-(4-
halogenophenyl)-3-(thiophen-3-yl) acrylonitrile (1.20 mmol), the
aromatic amine (1.00 mmol), Pd(OAc)2(0.06 mmol, Pd/Br = 5%),
P(o-tolyl)3(0.18 mmol), and sodium tert-butoxide (1.50 mmol). To the
flask was injected via a syringe toluene (10 mL). The reaction mixture
was heated and stirred at 120°C under nitrogen for an appropriate
time until the reaction was completed. The reaction mixture was
then cooled to room temperature, filtered through a mixture of celite
and silica gel pad and washed with dichloromethane. The filtrate
was washed with water and then dried by MgSO4. Concentration of
the filtrate on a rotary evaporator followed by washing of the solid
0.5
0.0
300
350
400
450
500
Wavelength(nm)
Fig.1 UV-Vis spectra of compounds 2 in CH2Cl2.
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JOURNAL OF CHEMICAL RESEARCH 2009 731
material with ethanol afforded the desired crude product. The crude
product was purified by column chromatography on silica gel using
ethyl acetate/cyclohexane (1/10 mixture) as eluents.
(Z)-2-(4-(ethyl(phenyl)amino)phenyl)-3-(thiophen-3-yl)
acrylonitrile (2f): Yellow solid. M.p. 84–86°C. FTIR (KBr pellet,
cm-1): 3039, 2973, 2929, 2212, 1610, 1514, 1376, 1266, 1199, 1129,
822, 781, 699. 1H NMR (400 MHz,CDCl3) dH: 7.87 (d, J = 2.0 Hz,
1 H), 7.76 (d, J = 5.2 Hz, 1 H), 7.49 (s, 1 H),7.40 (s, 1H), 7.39–7.37
(m, 4 H), 7.19–7.17 (m, 3 H), 6.87 (d, J = 8.2 Hz, 2 H), 3.85–3.80
(m, 2 H), 1.26 (t, 3 H). 13C NMR (400 MHz, CDCl3) dc: 148.8, 147.2,
139.4, 133.0, 129.5, 129.1, 128.5, 127.3, 126.5, 125.8, 124.9, 123.6,
122.5, 122.3, 109.6, 48.0, 29.70. MS m/z: 331(M + 1). Calcd for
C21H18N2S: C, 76.33; H, 5.49; N, 8.48; S, 9.70. Found: C, 76.33; H,
5.50; N, 8.45%.
(Z)-2-(4-(diphenylamino)phenyl)-3-(thiophen-3-yl)acrylonitrile
(2a): Yellow solid. M.p. 82–84°C. FTIR (KBr pellet, cm-1): 3035,
2213, 1590, 1490, 1332, 1284, 1076, 828, 755, 697. 1H NMR
(400 MHz, CDCl3) dH: 7.91 (d, J = 2.4 Hz, 1 H), 7.77 (d, J = 4.8 Hz,
1 H), 7.58–7.54 (m, 1 H), 7.51 (d, J = 8.8 Hz, 2 H), 7.44 (s, 1 H),
7.41–7.40 (m, 1 H), 7.31–7.29 (m, 4 H), 7.15 (d, J = 8.0 Hz, 4 H),
7.11–7.08 (m, 3 H). 13C NMR (400 MHz, CDCl3) dc: 141.4, 137.3,
134.5, 134.1, 132.3, 132.2, 130.4, 129.8, 129.8, 129.4, 127.3, 127.1,
125.4, 123.7, 107.1. MS m/z: 379(M + 1). Anal. Calcd for C25H18N2S:
C, 79.33; H, 4.79; N, 7.40; S, 8.47. Found: C, 79.16; H, 4.72; N, 7.44%.
(Z)-2-[4-(phenyl-m-tolyl-amino)phenyl]-3-(thiophen-3-yl)
acrylonitrile (2b): Yellow solid. M.p. 92–96°C. FTIR (KBr pellet,
cm-1): 3033, 2913, 2856, 2204,1592, 1508, 1318, 1279, 1190, 833,
782. 1H NMR (400 MHz, CDCl3) dH: 7.91 (d, J = 2.4 Hz, 1 H), 7.79
(d, J = 5.2 Hz, 1 H), 7.52 (d, J = 8.4 Hz, 2 H), 7.45 (s, 1 H), 7.40–7.39
(m, 1 H), 7.34–7.30 (m, 2 H), 7.21 (d, J = 8.0 Hz, 1 H), 7.16 (d,
J = 7.6 Hz, 2 H), 7.10 (d, J = 8.8 Hz, 3 H), 7.00 (s, 1 H), 6.96 (dd,
J = 7.2 Hz, J = 7.2 Hz, 2 H), 2.30 (s, 3 H). 13C NMR (400 MHz, CDCl3)
dc: 142.3, 139.2, 138.3, 137.3, 136.3, 134.4, 133.8, 132.2, 131.3, 130.0,
130.0, 129.9, 129.8, 129.3, 128.8, 128.2, 127.7, 127.4, 125.3, 124.9,
109.2, 28.3. MS m/z: 393(M + 1). Calcd for C26H20N2S: C, 79.56; H,
5.14; N, 7.14; S, 8.17. Found: C, 79.40; H, 5.28; N, 7.19%.
(Z)-2-[4-(naphthalen-1-yl-phenylamino)phenyl)-3-(thiophen-
3-yl] acrylonitrile (2c): Yellow solid. M.p. 74–76°C. FTIR(KBr
pellet, cm-1):3035, 2216, 1592, 1506, 1316, 1269, 1190, 908, 837, 778,
754, 696, 755, 696. 1H NMR (400 MHz, CDCl3) dH: 7.92(d, J = 3.6 Hz,
1 H), 7.89 (d, J = 3.6 Hz, 1 H), 7.87 (d, J = 2.0 Hz, 1 H), 7.82 (d,
J = 8.0 Hz, 1 H), 7.74 (d, J = 5.2 Hz, 1 H), 7.50 (d, J = 8.0 Hz, 1 H),
7.49(s, 1 H), 7.45 (d, J = 8.4 Hz, 2 H), 7.39–7.35 (m, 4 H), 7.24 (d,
J = 8.0 Hz, 2 H), 7.14 (d, J = 7.6 Hz, 2 H), 7.04 (d, J = 7.6 Hz, 1 H),
6.98 (d, J = 8.4 Hz, 2 H). 13C NMR (400 MHz, CDCl3) dc:151.3,
150.5, 149.9, 148.3, 145.3, 139.3, 135.9, 133.2, 132.8, 132.1, 131.1,
130.64, 130.1, 129.4, 128. 8, 128.0, 127.3, 127.0, 126.4, 126.3, 125.7,
124.6, 123.6, 119.0, 108.6. MS m/z: 429(M + 1). Calcd for C29H20N2S:
C, 81.28; H,4.70; N, 6.54; S, 7.48. Found: C, 81.37; H, 4.59; N, 6.65%.
(Z)-2-[4-(naphthalen-2-yl-phenylamino)phenyl]-3-(thiophen-3-yl)
Acrylonitrile (2d): Yellow solid. M.p. 143–145°C. FTIR (KBr pellet,
cm-1): 3036, 2213, 1593, 1506, 1294, 1236, 1190, 908, 838, 750, 732,
659. 1H NMR (400 MHz, CDCl3) dH: 7.91 (d, J = 2.0 Hz, 1 H), 7.80
(d, J = 8.8 Hz, 2 H), 7.76 (d, J = 3.2 Hz, 1 H), 7.63 (d, J = 7.6 Hz,
1 H), 7.53 (d, J = 8.8 Hz, 3 H), 7.45 (s, 1 H), 7.44–7.39 (m, 3 H),
7.32–7.30 (m, 3 H), 7.19 (d, J = 8.0 Hz, 2 H), 7.16 (s, 1 H), 7.14–
7.11 (m, 2 H). 13C NMR (400 MHz, CDCl3) dc: 150.4, 149.3, 148.2,
147.3, 144.7, 138.5, 132.1, 131.2, 130.6, 129.7, 129.0, 127.9, 127.6,
127.1, 127.00, 126.6, 126.2, 125.7, 125.0, 124.2, 123.8, 123.1, 122.1,
118.8, 107.2. MS m/z: 429(M + 1). Calcd for C29H20N2S: C, 81.28;
H, 4.70; N, 6.54; S, 7.48. Found: C, 81.24; H, 4.71; N, 6.45%.
(Z)-2-[4-(methylphenylamino)phenyl]-3-(thiophen-3-yl) acrylo-
nitrile (2e): Yellow solid. M.p. 82–84°C.FTIR (KBr pellet, cm-1):
3039, 2973, 2929, 2212, 1590, 1515, 1348, 1255, 1194, 1122, 821,
750, 700. 1H NMR (400 MHz, CDCl3) dH: 7.85 (d, J = 2.8 Hz,
1 H), 7.75 (d, J = 4.0 Hz, 1 H), 7.52 (d, J = 8.8 Hz, 2 H), 7.39–7.36
(m, 4 H), 7.18 (d, J = 8.0 Hz, 2 H), 7.14 (dd, J = 7.2 Hz, J = 7.2 Hz,
1 H), 6.92 (d, J = 8.8 Hz, 2 H), 3.36 (s, 3 H). 13C NMR (400 MHz,
CDCl3) dc: 148.6, 147.1, 139.4, 133.2, 129.7, 129.3, 128.6, 127.0,
126.4, 125.2, 124.3, 123.3, 122.1, 122.0, 109.1, 46.88. MS m/z:
317(M + 1). Calcd for C20H16N2S: C, 75.92; H, 5.10; N, 8.85; S,
10.13. Found: C, 75.83; H, 5.19; N, 8.80%.
The project is sponsored by the Natural Science Foundation
for the Education Ministry of Zhejiang Province.
Received 5 July 2009; accepted 1 November 2009
Paper 09/0667 doi: 10.3184/030823409X12583126129317
Published online: 8 December 2009
References
1
2
M. Amaresh, C.Q. Ma and B. Peter, Chem. Rev., 2009, 109, 1141.
B. Frølund, L.S. Jensen, S.I. Storustovu, T.B. Stensbøl, B. Ebert and
J. Kehler, J. Med. Chem., 2007, 50, 1988.
3
4
5
E.M. Krovat, K.H. Frühwirth and T.J. Langer, Chem. Inf. Model., 2005,
45, 146.
L.A. Carpino, A.A. Abdel-Maksoud, D. Ionescu, E.M.E. Mansour and
M.A. Zewail, J. Org. Chem., 2007, 72, 1729.
H. Yoshimura, M. Nagai, S. Hibi, K. Kikuchi, S. Abe, T. Hida, S. Higashi,
I. Hishinum and T. Yamanaka, J. Med. Chem., 1995, 38, 3163.
J. Lee, USP, 2006, 135, 488.
H. Zhu, M. Huang, F. Yang, Y. Chen, Z.H. Miao, X.H. Qian, Y.F. Xu,
Y.X. Qin, H.B. Luo, X. Shen, M.Y. Geng, Y.J. Cai and J. Ding, Mol.
Cancer. Therap., 2007, 6, 484.
6
7
8
9
Y. Xu, B. Qu, X. Qian and Y. Li, Bioorg. Med. Chem. Lett., 2005, 15, 1139.
M.L. Tang, O. Toshihiro and Z.N. Bao, J. Am. Chem. Soc., 2006, 128,
16002.
10 A. Tania, C. Adam, J.C. Simon and K.C. Anna, Macromolecules, 2009,
42, 2505.
11 C. Anthony and T.P. Mary, Inorg. Chem., 2008, 47, 10980–10990.
12 T. Yamamoto, M. Nishiyama and Y. Koie, Tetrahedron Lett., 1998,
39, 2367.
13 S. Thayumanavan, S. Barlow and S.R. Marder, Chem. Mater., 1997,
9, 3231.
14 M.I. Ranasinghe, O.P. Varnavski, J. Pawlas, S.I. Hauck, J. Louie,
J.F. Hartwig and T. Goodson, J. Am. Chem. Soc., 2002, 124, 6520.
15 C. Chen, Y.F. Li and L.M. Yang, J. Mol. Catal. A: Chem., 2007, 269, 158.
16 Y. Shirota, J. Mater. Chem., 2005, 15, 75.
17 M. Thelakkat, Macromol. Mater. Eng., 2002, 287, 442.
18 M.X. Yu, J.P. Duan, C.H. Lin, C.H. Cheng and Y.T. Tao, Chem. Mater.,
2002, 14, 3958.
19 M.X. Yu, W.J. Wen and C.H. Chen, Chin. J. Org. Chem., 2006, 26, 1239.
20 M.X. Yu, L.C. Chang, C.H. Lin, J.P. Duan, F.I. Wu and I.C. Chen,
Adv. Funct. Mater., 2007, 17, 369.
21 M.X. Yu, J.H. Kang and C.H. Chen, Chin. J. Org. Chem., 2008, 8, 1393.
22 Y.F. Yue, H.Y. Fang, M.J. Wang, Z.Y. Wang and M.X. Yu, J. Chem. Res.,
2009, 6, 377.
23 H.B. Goodbrand and N.X. Hu, J. Org. Chem., 1999, 64, 670.
24 Y. Yasuhiro, N.S. Osaka-fu and S.K. Kazuyos, E.P. 1018505/2000.
25 N. Kataoka, Q. Shelby, J.P. Stambuli and J.F. Hartwig, J. Org. Chem.,
2002, 67, 5553.
26 W. Vaccaro, C. Amore, J. Berger, R. Burrier, J. Clader and H. Davis,
J. Med. Chem., 1996, 39, 877.
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