concentrated solution of 5 (CHCl3/MeOH (2 : 3)) yielded extremely small,
deep-red, needle-shaped crystals. Crystallographic data for 5 were collected
using the synchrotron radiation source at Station 9.8, Daresbury SRS, UK,
on a Bruker SMART CCD diffractometer. The structures of 1, 2 and 5
were solved by direct methods using the program programs SIR92.11 The
refinements (on F) and graphical calculations were performed using the
CRYSTALS12 program suite. Crystal data. 1?MeOH?CH2Cl2:
C70H80Cl2IN4OZn, M = 1256.62, Z = 2, triclinic, space group P-1, a =
10.9085(2), b = 15.7116(3), c = 20.0954(4) s, a = 101.3092(7), b =
90.3507(8), c = 91.7091(12)u, U = 3375.52(11) s3, T = 180(2) K,
m = 0.943 mm21. Of 138647 reflections measured, 49864 were independent
(Rint = 0.08). Final R = 0.0949 (9164 reflections with I > 3s(I)) and wR =
0.0816. 2: C24H39B3O6, M = 456.00, Z = 4, orthorhombic, space group
P212121, a = 10.3474(2), b = 12.5764(2), c = 20.7829(3) s, a = 90, b = 90, c =
90u, U = 2704.54(8) s3, T = 180(2) K, m = 0.076 mm21. Of 23365
reflections measured, 3111 were independent (Rint = 0.05). Final R = 0.0389
(1832 reflections with I > 3s(I)) and wR = 0.0457. 5?MeOH?2H2O:
C218H234N12O3Zn3, M = 3218.48, Z = 4, monoclinic, space group P21/c, a =
45.66(5), b = 14.605(15), c = 30.04(3) s, b = 90.50(10)u, U = 20032(36) s3,
T = 150 (2) K, m = 0.409 mm21, synchrotron radiation l = 0.68920 s. Of
63297 reflections measured, 12041 were independent (Rint = 0.05). Final R =
0.0790 (5680 reflections with I > 3s(I)) and wR = 0.0874. CCDC 288530–
288532. For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b515902d
Fig. 3 Three energy-minimized gas phase conformations of the large
porphyrin trimer 5 (PM3 level, Spartan’04).10 (Key: Grey = carbon, blue =
nitrogen, purple = zinc).
1 T. S. Balaban, Acc. Chem. Res., 2005, 38, 612; R. Takahashi and
Y. Kobuke, J. Org. Chem., 2005, 70, 2745; C. Ikeda, A. Satake and
Y. Kobuke, Org. Lett., 2003, 5, 4935.
2 J. Wojaczynski and L. Latos-Grazynski, Coord. Chem. Rev., 2000, 204,
113; T. Imamura and K. Fukushima, Coord. Chem. Rev., 2000, 198,
133; J. K. M. Sanders, in The Porphyrin Handbook, ed. K. M. Kadish,
K. M. Smith and R. Guilard, Academic Press, New York, 2000, vol. 3,
pp. 347.
3 Z. Liu, I. Schmidt, P. Thamyongkit, R. S. Loewe, D. Syomin, J. R. Diers,
Q. Zhao, V. Misra, J. S. Lindsey and D. F. Bocian, Chem. Mater., 2005,
17, 3728; D. Kim and A. Osuka, Acc. Chem. Res., 2004, 37, 735; T. E.
O. Screen, J. R. G. Thorne, R. G. Denning, D. G. Bucknall and
H. L. Anderson, J. Am. Chem. Soc., 2002, 124, 9712; D. Holten,
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Rev., 2001, 101, 2751.
5 Z. Clyde-Watson, N. Bampos and J. K. M. Sanders, New J. Chem.,
1998, 22, 1135; A. Vidal-Ferran, Z. Clyde-Watson, N. Bampos and J. K.
M. Sanders, J. Org. Chem., 1997, 62, 240; H. L. Anderson, C. J. Walter,
A. Vidal-Ferran, R. A. Hay, P. A. Lowden and J. K. M. Sanders,
J. Chem. Soc., Perkin Trans. 1, 1995, 2275; L. G. Mackay,
H. L. Anderson and J. K. M. Sanders, J. Chem. Soc., Perkin Trans.
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J. Chem. Soc., Perkin Trans. 1, 1995, 2247.
precursor 1, the MeOH-coordinated Zn(1) atom is situated 0.27 s
above the best N4 plane.
Semi-empirical calculations (PM3) have also been performed to
further explore the highly flexible nature of the zinc porphyrin
trimeric systems.10 Fig. 3 shows three gas-phase PM3 optimised
geometries of three thermodynamically-stable conformers of 5
found in the gas phase: bowl-shaped 5a, propeller-shaped 5c, and
5b with a conformation resembling the crystal structure. The
relative differences in the heats of formation of 5a, 5b and 5c are
less than 20 kJ mol21. Negligible differences are observed between
the bowl-shaped and propeller-shaped conformers of 4.
Preliminary results suggest that trimer 5 has the ability to bind
1
to C60 molecules in solution; the H NMR spectrum (500 MHz,
CDCl3/CS2 (9 : 1), 25 uC) of a 1 : 1 mixture of 5 and C60 showing
several significant shifts. Details will be reported elsewhere.
In summary, we provide practical routes to a new family of
tripodal porphyrin arrays. Extensive studies of the new systems
become possible as a result of their large-scale preparation. The
electron rich p surfaces of porphyrins in conjunction with their
axial binding abilities mean that a variety of encapsulation
processes are possible with the porphyrin trimers. More impor-
tantly, the rotationally flexible nature of the systems will enable the
selection of a wider range of guest molecules.
6 C.-C. Mak, N. Bampos, S. L. Darling, M. Montalti, L. Prodi and J. K.
M. Sanders, J. Org. Chem., 2001, 66, 4476; C.-C. Mak, D. Pomeranc,
M. Montalti, L. Prodi and J. K. M. Sanders, Chem. Commun., 1999,
1083.
7 G. C. Fu and A. F. Littke, Angew. Chem., Int. Ed., 2002, 41, 4176.
8 A. B. Morgan, J. L. Jurs and J. M. Tour, J. Appl. Polym. Sci., 2000, 76,
1257.
9 Z. Clyde-Watson, A. Vidal-Ferran, L. J. Twyman, C. J. Walter, D. W.
J. McCallien, S. Fanni, N. Bampos, R. S. Wylie and J. K. M. Sanders,
New J. Chem., 1998, 22, 493; M. Nakash, Z. Clyde-Watson, N. Feeder,
J. E. Davies, S. J. Teat and J. K. M. Sanders, J. Am. Chem. Soc., 2000,
122, 5286; M. Marty, Z. Clyde-Watson, L. J. Twyman, M. Nakash and
J. K. M. Sanders, Chem. Commun., 1998, 2265; L. G. Mackay,
R. S. Wylie and J. K. M. Sanders, J. Am. Chem. Soc., 1994, 116, 3141.
10 Spartan’04, Wavefunction Inc., Irvine, CA, USA.
We thank Drs. Paolo Pengo, Greg Davidson and Chris S. K.
Mak for valuable discussions, Professor Paul Raithby and Dr.
Simon Teat (SRS Daresbury) for crystallographic support, the
EPSRC for financial support and the Royal Society for a
University Research Fellowship (S. I. P.).
11 A. Altomare, G. Carascano, C. Giacovazzo and A. Guagliardi, J. Appl.
Crystallogr., 1993, 26, 343.
Notes and references
12 D. J. Watkin, C. K. Prout, J. R. Carruthers and P. W. Betteridge,
CRYSTALS, issue 11, Chemical Crystallography Laboratory, Oxford
UK, 2001; P. W. Betteridge, J. R. Carruthers, R. I. Cooper, K. Prout
and D. J. Watkin, J. Appl. Crystallogr., 2003, 36, 1487.
§ X-ray quality crystals of 1 were obtained from a CH2Cl2 solution layered
with MeOH, and for 2, were grown by slow evaporation of an MeOH
solution. Data for 1 and 2 were collected at 180 K on a Nonius Kappa
CCD with graphite monochromated Mo-Ka radiation (l = 0.71073 s). A
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