Communications
that the s(2) value can be correlated with the degree of
´
Pawlicki, L. Szterenberg, Z. Ciunik, L. Latos-Graz˙ynski, J. Am.
aromaticity in expanded porphyrins within a comparable set
of [4n + 2]/[4n] systems.[11] The maximum s(2) value of 5 was
found to be 8100 GM at 1200 nm, which is comparable to that
of 6 at 173 K (9100 GM) and nearly two times larger than
those of 7a–c (4600–5500 GM).
To gain further insight into the Mꢀbius aromaticity of 5,
we performed theoretical calculations using the Gaussian03
package.[14] These calculations revealed nearly degenerate
HOMOs and LUMOs, which are characteristic of aromatic
expanded porphyrins (Supporting Information).[11] The har-
monic oscillator model of aromaticity (HOMA) value[15] and
the nucleus-independent chemical shift (NICS) value[16] at the
center of macrocycle were calculated to be 0.61 and
À14.9 ppm for 5, whereas those of 6 (optimized Mꢀbius)
and 7a–c were calculated to be 0.85 and À15.1 ppm and 0.39–
0.64 and À11.9–-15.7 ppm, respectively (Supporting Informa-
tion).
[6] a) Y. Tanaka, S. Saito, S. Mori, N. Aratani, H. Shinokubo, N.
Shibata, Y. Higuchi, Z. S. Yoon, K. S. Kim, S. B. Noh, J. K. Park,
Suzuki, Y. Inokuma, H. Shinokubo, K. S. Kim, Z. S. Yoon, J.-Y.
Shin, J. M. Lim, Y. Matsuzaki, O. Matsushita, A. Muranaka, N.
13568; d) K. S. Kim, Z. S. Yoon, A. B. Ricks, J.-Y. Shin, S. Mori,
J. Sankar, S. Saito, Y. M. Jung, M. R. Wasielewski, A. Osuka, D.
Shin, K. S. Kim, J. M. Lin, K. Youfu, S. Saito, D. Kim, A. Osuka,
[7] a) J.-Y. Shin, H. Furuta, K. Yoza, S. Igarashi, A. Osuka, J. Am.
Martins, A. C. Tomꢂ, A. J. D. Silvestre, A. M. S. Silva, V. Fꢂlix,
The degree of aromaticity of 5, as judged from Dd and s(2)
values, is certainly larger than that of 7a–c. This may be
accounted for in terms of smooth connection in constituting
Mꢀbius topology. Actually, the largest tilting angles in the
conjugated circuit (Drm) are 34.48 for 5, 26.58 for 6 (optimized
Mꢀbius), and 39.9–45.88 for 7a–c. If the effect of a rigid
component is too strong, it gives rise to reduced aromatic
character owing to the disturbance of effective p conjugation,
as seen for 7a–c. In this context, the thienyl-fused segment in
5 provides suitable rigidification to sustain the stable Mꢀbius
topology and optimal p-electron conjugation in a [28]hexa-
phyrin macrocycle.
[10] Crystal data for 2: C66H22Cl12F20N6S2 (Mr = 1768), triclinic, space
ꢀ
group P1 (No. 2), a = 10.629(5), b = 11.207(6), c = 14.757(6) ꢃ,
a = 101.541(20),
b = 94.327(18),
g = 93.703(10)8,
V=
1711.6(13) ꢃ3, Z = 1, 1calcd = 1.716 gcmÀ3, T= 123(2) K, R1 =
0.0518 (I > 2s(I)), RW = 0.1452(all data), GOF = 1.103. Crystal
ꢀ
data for 5: C76H45F25N6O6S (Mr = 1645), triclinic, space group P1
(No. 2), a = 12.377(5), b = 16.277(5), c = 21.105(9) ꢃ, a =
108.549(11), b = 91.396(13), g = 102.304(10)8, V= 3919(2) ꢃ3,
Z = 2, 1calcd = 1.394 gcmÀ3, T= 123(2) K, R1 = 0.0847 (I > 2s(I)),
RW = 0.2578(all data), GOF = 0.886. In the crystal structure of 5,
there are disordered solvent molecules, and their contribution to
the scattering values have been removed by using the PLATON
SQUEEZE program.[17] CCDC 729195 (2) and CCDC 729196
(5) contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The
In summary, the unique reactivities of meso-(3-thienyl)-
substituted [26]hexaphyrins have been used to provide a
doubly annulated bis-spiro molecule and stable Mꢀbius
aromatic [28]hexaphyrins. Thiophene-fused [28]hexaphyrin
5 features a molecular twist, a distinct diatropic ring current, a
large HOMA value, a large negative NICS value, and a large
TPA cross-section value even at room temperature, all of
which support Mꢀbius aromaticity of 5.
Received: May 20, 2009
Published online: August 7, 2009
[11] a) J. M. Lim, Z. S. Yoon, J.-Y. Shin, K. S. Kim, M.-C. Yoon, D.
[12] a) T. K. Ahn, J. H. Kwon, D. Y. Kim, D. W. Cho, D. H. Jeong,
S. K. Kim, M. Suzuki, S. Shimizu, A. Osuka, D. Kim, J. Am.
Yoon, M. K. Koh, S. B. Noh, J. L. Sessler, J. T. Lee, D. Seidel, A.
Aguilar, S. Shimizu, M. Suzuki, A. Osuka, D. Kim, J. Am. Chem.
Keywords: aromaticity · electronic structure · hexaphyrins ·
.
Mꢀbius aromaticity · porphyrinoids
[13] M. Sheik-Bahae, A. A. Wei, D. G. Hagan, E. W. van Stryland,
[14] Gaussian03 (RevisionC.02): M. J. Frisch, et al. (see Supporting
Information); Gaussian, Inc.: Wallinford CT, 2004.
Mauksch, V. Gogonea, H. Jiao, P. von R. Schleyer, Angew.
c) J. F. Moll, R. P. Pemberton, M. G. Gutierrez, C. Castro, W. L.
´
[16] Z. Chen, C. S. Wannere, C. Corminboeuf, R. Puchta, P. v. R.
[17] PLATON SQUEEZE program: a) A. L. Spek, PLATON, A
Multipurpose Crystallographic Tool; Utrecht University,
Utrecht, The Netherlands, 2005; b) P. van der Sluis, A. L. Spek,
´
´
[5] a) M. Ste˛pien, L. Latos-Graz˙ynski, N. Sprutta, P. Chwalisz, L.
Szterenberg, Angew. Chem. 2007, 119, 8015; Angew. Chem. Int.
Ed. 2007, 46, 7869; b) E. Pacholska-Dudziak, J. Skonieczny, M.
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2009, 48, 6687 –6690