1
362
N. Vets et al.
LETTER
(10) General Synthesis of 5,7,12,14-Dihydro-5,7,12,14-
At the moment, further investigation of the introduction of
different types of substituents is ongoing and the products
are studied for their electrical properties. We hope to find
a link between the type of substituents and their electrical
and film forming behaviour, and to make a further com-
parison of the properties of 6,13- and 5,7,12,14-substitut-
ed pentacenes as started by Nuckolls and co-workers in a
tetraarylpentacene-5¢,7¢,12¢,14¢-tetrol (3).
n-BuLi (6 equiv) was added to a solution of the(bromo)aryl
(6 equiv) in dry THF at –78 °C under argon atmosphere.
After 10 min pentacene-5,7,12,14-one (1 equiv) was added
and the mixture was allowed to warm up to r.t. and stirred
overnight. The reaction was worked up with 1 M HCl and
extracted with EtOAc. After drying over MgSO and
4
5
very recent study.
evaporation in vacuum, the crude product was purified by
column chromatography on silica gel. The different isomers
were separated.
Example of Characterisation: 5,7,12,14-Dihydro-
5,7,12,14-tetrabenzothienylpentacene-5¢,7¢,12¢,14¢-tetra-
ol (3b).
We can conclude that 5,7,12,14-tetraarylpentacenes are
relatively easy to obtain and are interesting for further in-
vestigation with respect to their potential use in transis-
tors, in particularly 5,7,12,14-tetraarylpentacenes 4c and
Mp 280 °C [cis/cis(trans)/cis-isomer], 170 °C (cis/trans/
4
d. We have observed that the choice of the substituent,
1
trans-isomer), 185 °C [trans/cis(trans)/trans-isomer]. H
which is introduced on the backbone of the pentacene, is
of great importance with respect to the solubility proper-
ties of the resulting pentacene derivative.
NMR (400 MHz, DMSO, 50 °C): d [trans/cis(trans)/trans-
isomer] = 6.7 (s, 4 H), 6.8 (s, 4 H), 7.2 (t, 8 H), 7.3 (m, 4 H),
1
7
.4 (d, 8 H), 7.6 (m, 4 H), 8.0 (s, H). H NMR (400 MHz,
DMSO): d (cis/trans/trans-isomer) = 5.7 (s, 1 H), 5.8 (s, 1
H), 6.7 (d, 2 H), 6.8 (s, 1 H), 6.9–7.2 (m, 8 H), 7.3 (s, 1 H),
Acknowledgment
7
.4 (m, 10 H), 7.5–7.6 (m, 6 H), 7.8 (d, 2 H), 7.9–8.0 (m, 4
1
H), 8.3 (s, 1 H), 8.4 (s, 1 H). H NMR (400 MHz, DMSO):
d [cis/cis(trans)/cis-isomer) = 6.0/6.1 (s, 4 H), 6.7/6.8 (d, 4
H), 6.9 (t, 4 H), 7.0 (t, 4 H), 7.5/7.6 (d, 4 H), 7.6 (m, 4 H), 8.1
We thank P. Heremans for stimulating scientific discussions, K.
Duerinckx for helping with recording the NMR spectra. N.V.
thanks the IWT [Institute for the Promotion of Innovation through
Science and Technology in Flanders (IWT-Vlaanderen)] for a
doctoral fellowship. The University of Leuven and the Ministerie
voor Wetenschapsbeleid are thanked for financial support.
1
3
(
m, 4 H), 8.7/8.8 (s, 2 H). C NMR (400 MHz, DMSO,
5
1
1
0 °C): d [trans/cis(trans)/trans-isomer] = 71.9, 121.3,
21.6, 122.7, 123.2, 123.5, 127.4, 127.8, 128.3, 138.7,
1
3
38.8, 139.1, 139.9, 155.6. C NMR (400 MHz, DMSO):
d (cis/trans/trans-isomer) = 71.0, 71.4, 71.9, 72.7, 121.3,
References and Notes
121.4, 121.6, 121.9, 122.3, 122.4, 123.5, 123.6, 123.7,
1
1
1
1
23.8, 124.2, 125.5, 125.9, 127.6, 127.8, 127.9, 128.7,
37.9, 138.1, 138.8, 138.9, 139.0, 139.2, 139.3, 139.5,
39.6, 140.0, 140.2, 140.8, 141.2, 151.8, 152.0, 156.5,
(1) Vets, N.; Smet, M.; Dehaen, W. Synlett 2005, 217.
(
2) (a) Katz, H. E.; Bao, Z.; Gilat, S. L. Acc. Chem. Res. 2001,
34, 359. (b) Wolak, M. A.; Jang, B.-B.; Palilis, L. C.; Kafafi,
13
56.9. C NMR (400 MHz, DMSO): d [cis/cis(trans)/cis-
Z. H. J. Phys. Chem. B 2004, 108, 5492.
isomer] = 71.6/71.5, 121.6/121.5, 122.2/122.1, 122.6, 123.5,
(3) Lin, Y. Y.; Gundlach, D. J.; Nelson, S. F.; Jackson, T. N.
IEEE Trans. Electron Devices 1997, 44, 1325.
123.7, 124.2/124.1, 126.0, 127.8/127.7, 138.1/138.0, 139.2/
1
39.1, 140.0/139.9, 140.8/140.6, 152.1/151.8. MS (ESI+)
(
4) (a) Anthony, J. E.; Eaton, D. L.; Parkin, S. R. Org. Lett.
+
[
MH ]: m/z = 857.4 (1 × rearrangement).
2002, 4, 15. (b) Vogel, K. M.; Vogel, D. E.; Terrance, S. P.
(
11) General Synthesis of 5,7,12,14-Tetraarylpentacene (4).
A suspension of tetra-ol 3 (1 equiv), NaI (14 equiv) and
NaH PO (same amount as NaI) in AcOH was heated at
US 0105365, 2003. (c) Meng, H.; Bendikov, M.; Mitchell,
G.; Helgeson, R.; Wudl, F.; Boa, Z.; Siegrist, T.; Kloc, C.;
Chen, C. H. Adv. Mater. (Weinheim, Ger.). 2003, 13, 1090.
2
2
reflux for 3 h. The product 4 was isolated by filtration and
(
2
d) Eaton, D. L.; Parkin, S.; Anthony, J. E. US 6690029,
004.
washed with H O and MeOH. After drying in vacuum,
2
5
,7,12,14-tetraarylpentacene was obtained.
12) Smet, M.; Van Dijk, J.; Dehaen, W. Tetrahedron 1999, 55,
859.
13) Characterisation of 5,7,12,14-Tetrathienylpentacene
4a).
Mp >300 °C. H (400 MHz, CDCl , in concentric tube): d =
(
(
(
5) Miao, Q.; Chi, X.; Xiao, S. X.; Zeis, R.; Lefenfeld, M.;
Siegrist, T.; Steigerwald, M. L.; Nuckolls, C. J. Am. Chem.
Soc. 2006, 128, 1340.
(
(
7
6) (a) Allen, C. F. H.; Bell, A. J. Am. Chem. Soc. 1942, 64,
(
1253. (b) Maulding, D. R.; Roberts, B. G. J. Org. Chem.
1
3
1969, 34, 1734.
6
.7 (d, 4 H), 6.9 (t, 4 H), 7.0 (d, 2 H), 7.9 (m, 4 H), 8.0 (m, 4
7) Baxter, I.; Cameron, D. W.; Titman, R. B. J. Chem. Soc. C
971, 1253.
+
H), 8.9 (s, 2 H). MS (APCI+) [MH ]: m/z = 607.2.
Characterisation of 5,7,12,14-Tetrabenzothienyl-
pentacene (4b).
1
(
(
8) Mills, W. H.; Mills, M. J. Chem. Soc. 1912, 2194.
9) Characterisation of 5,7,12,14-Pentacene-tetra-one.
1
Mp >300 °C. H NMR (400 MHz, CDCl CDCl ): d = 7.3 (m,
1
2
2
Mp >300 °C. H NMR (300 MHz, D SO ): d = 8.1 (m, 4 H),
2
4
8
8
H), 7.35 (s, 4 H), 7.5 (m, 4 H), 7.6 (m, 4 H), 7.7 (m, 4 H),
1
3
8.4 (m, 4 H), 9.2 (s, 2 H). C NMR (300 MHz, D SO in
+
2
4
.0 (m, 4 H), 8.8 (s, 2 H). MS (APCI+) [MH ]: m/z = 806.3.
double tube with DMSO): d = 128.4, 129.0, 131.0, 136.3,
+
137.5, 185.0. MS (CI) [MH ]: m/z = 339.
Synlett 2006, No. 9, 1359–1362 © Thieme Stuttgart · New York