isolated yield of 2 is a marked improvement over the 24%
yield obtained in the direct reaction between [60]fullerene and
5,7,12,14-tetraphenylpentacene.24 The low yield of 2 obtained
in the direct reaction between [60]fullerene and 5,7,12,14-
tetraphenylpentacene is attributable to the instability of
the acene and the difficulties associated with its handling.
Preparing and reacting 5,7,12,14-tetraphenylpentacene in situ
via a DDQ deprotection of 6,13-dihydro-5,7,12,14-tetraphe-
nylpentacene is a superior procedure. The use of H-protected
acenes has even more advantages as the length of the acene
increases. Indeed, the instability associated with heptacenes
has complicated the isolation of 6,8,15,17-tetraphenyl-
heptacene. Trisadduct 3 was nonetheless prepared without
complication via the in situ deprotection of 5,7,9,14,16,18-
hexahydro-6,8,15,17-tetraphenylheptacene.22
Nanoscale Exploratory Research grant (ECS-0403954) and the
Center for High-Rate Nanomanufacturing (EEC-0425826).
References
1 See for example: (a) L. Zhou, S. Park, B. Bai, J. Sun, S.-C. Wu,
T. N. Jackson, S. Nelson, D. Freeman and Y. Hong, IEEE
Electron Device Lett., 2005, 26, 640–642; (b) S. A. Odom,
S. R. Parkin and J. E. Anthony, Org. Lett., 2003, 5, 4245–4248.
2 See for example: (a) J. Chen, C. K. Tee, J. Yang, C. Shaw,
M. Shtein, J. Anthony and D. C. Martin, J. Polym. Sci., Part B:
Polym. Phys., 2006, 44, 3631–3641; (b) S. Iba, T. Sekitani, Y. Kato,
T. Someya, H. Kawaguchi, M. Takamiya, T. Sakurai and
S. Takagi, Appl. Phys. Lett., 2005, 87, 023509/1–023509/3; (c)
J. Granstrom and H. E. Katz, J. Mater. Res., 2004, 19, 3540–3546;
(d) K. Ito, T. Suzuki, Y. Sakamoto, D. Kubota, Y. Inoue, F. Sato
and S. Tokito, Angew. Chem., Int. Ed., 2003, 42, 1159–1162.
3 See for example: (a) G. Darlinski, U. Bottger, R. Waser, H. Klauk,
M. Halik, U. Zschieschang, G. Schmid and C. Dehm, J. Appl.
Phys., 2005, 97, 093708/1–093708/4; (b) L. Wang, D. Fine and
A. Dodabalapur, Appl. Phys. Lett., 2004, 85, 6386–6388; (c) S. Jung
and Z. Yao, Appl. Phys. Lett., 2005, 86, 083505/1–083505/3.
4 J. E. Anthony, Chem. Rev., 2006, 106, 5028–5048.
Given our success in preparing H-protected acenes using
HI–AcOH and our general interest in fullerene chemistry,
we attempted an HI–AcOH reduction of a very different
polycyclic aromatic hydrocarbon, namely [60]fullerene.
Because [60]fullerene is not soluble in acetic acid, it was
dissolved in a 10 : 5 : 1 volume mixture of o-dichlorobenzene,
acetic acid and 47% aqueous HI. The resulting two-phase
mixture was heated to boiling under nitrogen in the dark for
five days. Following standard work-up, a green powder was
isolated in 90% yield. 1H and 13C NMR and LDI mass spectral
characterizations revealed it to be C3v C60H18, a known
molecule25 that was recently prepared in high yield using both
a polyamine reduction26 and a high temperature, high pressure
direct hydrogenation.27
5 J. B. Briggs and G. P. Miller, C. R. Chim., 2006, 9, 916–927.
6 (a) C. F. H. Allen and A. Bell, J. Am. Chem. Soc., 1942, 64, 1253;
´
(b) A. Etienne and C. Beauvois, C. R. Hebd. Seances Acad. Sci.,
1954, 239, 64; (c) J. B. Birks, J. H. Appleyard and R. Pope,
Photochem. Photobiol., 1963, 2, 493; (d) E. Clar and I. A.
Macpherson, Tetrahedron, 1962, 18, 1411; (e) E. J. Bowen and
D. W. Tanner, Trans. Faraday Soc., 1955, 51, 475; (f) C. A.
Coulson, L. E. Orgel, W. Taylor and J. Weiss, J. Chem. Soc., 1955,
2961.
7 (a) T. Takahashi, M. Kitamura, B. Shen and K. Nakajima, J. Am.
Chem. Soc., 2000, 122, 12876–12877; (b) R. Schmidt, S. Goettling,
D. Leusser, D. Stalke, A.-M. Krause and F. Wuerthner, J. Mater.
Chem., 2006, 16, 3708–3714.
8 A. R. Reddy and M. Bendikov, Chem. Commun., 2006, 1179–1181.
9 M. M. Payne, S. R. Parkin and J. E. Anthony, J. Am. Chem. Soc.,
2005, 127, 8028–8029.
Conclusions and future direction
10 G. P. Miller, J. Mack and J. Briggs, Fullerenes—Volume 11,
Proceedings of the International Symposium on Fullerenes,
Nanotubes, and Carbon Nanoclusters, ed. P. V Kamat, D. M.
Guldi and K. M. Kadish, The Electrochemical Society,
Pennington, NJ, 2001, pp. 202–206.
11 G. P. Miller, J. Mack and J. Briggs, Org. Lett., 2000, 2, 3983–3986.
12 (a) S.-H. Chien, M.-F. Cheng, K.-C. Lau and W.-K. Li, J. Phys.
Chem. A, 2005, 109, 7509–7518; (b) A. R. Reddy, G. Fridman-
Marueli and M. Bendikov, J. Org. Chem., 2007, 72, 51–61.
13 P. T. Herwig and K. Mullen, Adv. Mater., 1999, 11, 480–483.
14 (a) H. Yamada, Y. Yamashita, M. Kikuchi, H. Watanabe,
T. Okujima, H. Uno, T. Ogawa, K. Ohara and N. Ono, Chem.–
Eur. J., 2005, 11, 6212–6220; (b) H. Uno, Y. Yamashita,
M. Kikuchi, H. Watanabe, H. Yamada, T. Okujima, T. Ogawa
and N. Ono, Tetrahedron Lett., 2005, 46, 1981–1983.
We have performed the first systematic study concerning the
hydrogenation of acenes and acene quinones. In all cases,
mixtures of HI and acetic acid were utilized as reductant.
Hydrogenations of unsubstituted pentacenes and smaller
acenes proceed in regioselective fashion. Phenyl substituted
acenes and acene quinones have also been examined for
systems up to and including seven contiguous rings (i.e.,
heptacene backbone). In these cases, the reductions are highly
regioselective and the corresponding H-protected acenes
are stable species that show vastly improved solubility.
H-Protected acenes may be deprotected using common
dehydrogenation reagents such as DDQ. In this manner, three
[60]fullerene-acene adducts have been prepared, including
15 R. Mondal, B. K. Shah and D. C. Neckers, J. Am. Chem. Soc.,
2006, 128, 9612–9613.
16 P. F. Fu and R. G. Harvey, Chem. Rev., 1978, 78, 317–361.
17 (a) M. Konieczny and R. G. Harvey, J. Org. Chem., 1979, 44,
4813–4816; (b) R. G. Harvey, C. Leyba, M. Konieczny, P. P. Fu
and K. B. Sukumaran, J. Org. Chem., 1978, 43, 3423–3425.
18 (a) G. Portella, J. Poater, J. M. Bofill, P. Alemany and M. Sola,
J. Org. Chem., 2005, 70, 2509–2521; (b) A. K. Phukan, R. P. Kalagi,
S. R. Gadre and E. D. Jemmis, Inorg. Chem., 2004, 43, 5824–5832;
(c) M.-F. Cheng and W.-K. Li, Chem. Phys. Lett., 2003, 368,
630–638; (d) P. v. R. Schleyer, M. Manoharan, H. Jiao and
F. Stahl, Org. Lett., 2001, 3, 3643–3646; (e) D. Biermann and
W. Schmidt, J. Am. Chem. Soc., 1980, 102, 3163–3173.
19 R. Mondal, B. K. Shah and D. C. Neckers, J. Org. Chem., 2006,
71, 4085–4091.
a
cis,cis-tris[60]fullerene adduct of 6,8,15,17-tetraphenyl-
heptacene, 3, via in situ [60]fullerene trapping of the reactive
acenes. Finally, a modified HI–AcOH reduction was success-
fully utilized to convert [60]fullerene into C3v symmetric
C60H18 in excellent yield. It is anticipated that H-protection
will provide access to suitably substituted larger acenes like
phenylated nonacenes and undecacenes. These systems should
possess extraordinary physical and chemical properties and we
are currently working to prepare them.
20 M. Bendikov, K. N. Houk, H. M. Duong, K. Starkey, E. A. Carter
and F. Wudl, J. Am. Chem. Soc., 2004, 126, 7416–7417.
21 (a) H. Angliker, E. Rommel and J. Wirz, Chem. Phys. Lett., 1982,
87, 208–212; (b) J. L. Bredas, R. R. Chance, R.H. Baughman and
R. Silbey, J. Chem. Phys., 1982, 76, 3673–3678; (c) K. Tanaka,
Acknowledgements
The authors gratefully acknowledge partial support of this
work by the National Science Foundation through both a
2640 | J. Mater. Chem., 2007, 17, 2636–2641
This journal is ß The Royal Society of Chemistry 2007