This work was supported by the National Science Foundation
NSF-STC/MDITR), PRF (41492-AC3), AFOSR, and the
(
University of Washington. We are grateful to Dr Bart Kahr for
X-ray crystallographic analysis and for the use of a U-Pole
spectrophotometer.
b
Dinesh G. Patel, Jason B. Benedict, Roni A. Kopelman and
b
b
a
Natia L. Frank*
Department of Chemistry, PO Box 3065, University of Victoria,
Victoria, BC, V8W 3V6, Canada. E-mail: nlfrank@uvic.ca;
a
Fax: (+1) 250-721-7149; Tel: (+1) 250-721-7154
Department of Chemistry, Box 351700, University of Washington,
Seattle, WA, 98195-1700, USA
b
Notes and references
1
R. C. Bertelson, in Photochromism, ed. G. H. Brown, Wiley-
Interscience, New York, 1971.
2
3
G. H. Brown, in Photochromism, Wiley-Interscience, New York, 1971.
H. D u¨ rr and H. Bouas-Laurent, in Photochromism: Molecules and
Systems, Elsevier, New York, 1990.
4
5
6
A. S. Dvornikov, Y. C. Liang, C. S. Cruse and P. M. Rentzepis, J. Phys.
Chem. B, 2004, 108, 8652.
E. Murguly, T. B. Norsten and N. R. Branda, Angew. Chem., Int. Ed.,
Fig. 4 Fourier electron density difference map showing the electron
density of an irradiated (UV light) single crystal of 1a minus the electron
density of a non-irradiated single crystal of 1a as viewed down the a-axis.
2001, 40, 1752.
S. B e´ nard, A. L e´ austic, E. Rivi e´ re, P. Yu and R. Cl e´ ment, Chem.
Mater., 2001, 13, 3709.
7
8
M. Irie, S. Kobatake and M. Horichi, Science, 2001, 291, 1769.
J. R. Scheffer and P. R. Pokkuluri, in Unimolecular Photoreactions of
Organic Crystals, ed. V. Ramamurthy, Wiley-VCH, New York, 1990.
S. Yamamoto, K. Matsuda and M. Irie, Angew. Chem., Int. Ed., 2003,
42, 1636.
experiments on irradiated crystals of 1a support the latter
interpretation. The high optical density of the photocolored form
9
(e y 30,000) may in fact preclude high conversion efficiency after
initial irradiation, suggesting the need for two-photon conversion
10 G. Berkovic, V. Krongauz and V. Weiss, Chem. Rev., 2000, 100, 1741.
1 A. K. Chibisov and H. Gorner, J. Phys. Chem. A, 1999, 102, 5211.
1
experiments.
1
2 N. Y. C. Chu, in 4n + 2 Systems: Spirooxazines, ed. H. B.-L. Durr,
As topochemical reactions are diffusionless, sufficient space in
the ‘‘reaction cavity’’ and sufficient flexibility in the overall crystal
packing are required for spatial reorganization to occur. It is
possible that in this case, the azahomoadamantyl group provides
sufficient free space in the crystal lattice to allow single crystalline
phase photoisomerization. Consistent with this is the observation
that steady state visible irradiation of single crystals of indolyl
analog, spiro[indoline-isoquinolinoxazine], does not lead to
photocoloration. Both spirooxazines, however, undergo photo-
isomerization in the microcrystalline state and in KBr pellets with
comparable rates, suggesting that microcrystalline state photo-
isomerization does not necessarily correlate with single crystalline
behavior.
Elsevier, Amsterdam, 1990.
13 M. Suzuki, T. Asahi, K. Takahashi and H. Masuhara, Chem. Phys.
Lett., 2003, 368, 384.
14 N. Tamai and H. Miyasaka, Chem. Rev., 2000, 100, 1875.
15 K. Chamontin, V. Lokshin, A. Samat, R. Guglielmetti, R. Dubest and
J. Aubard, Dyes Pigments, 1999, 43, 119.
16 A. V. Metelitsa, J. C. Micheau, N. A. Voloshin, E. N. Voloshina and
V. I. Minkin, J. Phys. Chem. A, 2001, 105, 8417.
17 S. Maeda, in Spirooxazines, ed. J. C. Crano and R. Gugliemetti, Plenum
Press, New York, 1999.
8 G. Favaro, V. Malatesta, U. Mazzucato, G. Ottavi and A. Roamni,
1
J. Photochem. Photobiol. A, 1995, 87, 235.
19 A. Kellmann, F. Tfibel and R. Guglielmetti, J. Photochem. Photobiol. A,
1
995, 91, 131.
0 S. B e´ nard and Y. Pei, Adv. Mater., 2000, 12, 48.
1 Y. R. Yi and I. J. Lee, J. Photochem. Photobiol. A, 2002, 151, 89.
22 S. B e´ nard and Y. Pei, Chem. Commun., 2000, 65.
23 C21 O M 5 333.42, a 5 6.6340(2), b 5 15.3270(4), c 5
6.2050 (6) A, U 5 1619.82(9) A , space group P2
2
2
In conclusion, we have synthesized an azahomoadamantyl
spirooxazine that undergoes photochemically reversible and
thermally irreversible coloration in the single crystalline phase.
While investigations of thermal and light-induced isomerization
processes for 1 reveal behavior typical of spirooxazines in solution,
the thermal reversion in the single crystal is extraordinarily slow,
consistent with generation of a PMC form in a constrained
environment. Reversible photocoloration in the single crystalline
phase was observed only from the closed SO form of 1, and not
from single crystals of other spirooxazines. Future studies will
involve structural analysis of the photocolored form generated in
the single crystalline phase through two-photon processes and
X-ray crystallography.
23 3
H N
3
˚
˚
1
1
/c (No. 14), Z 5 4,
˚
Wavelength 5 0.71073 A, 4354 relections measured, 2381 unique
(Rint 5 0.0259) which were used in all calculations. The final wR(F ) was
2
b417026a/ for crystallographic data in CIF or other electronic format.
4 W. Clegg, N. C. Norman, T. Flood, L. Sallans, W. S. Kwak,
2
P. L. Kwiatkowski and J. G. Lasch, Acta Crystallogr., Sect. C, 1991, 47,
817.
25 R. Millini, G. del Piero, P. Allegrini, L. Crisci and V. Malatesta, Acta
Crystallogr., Sect. C, 1991, 47, 2567.
26 J.-P. Reboul, A. Samat, P. Lareginie, V. Lokshin and R. Guglielmetti,
Acta Crystallogr., Sect. C, 1995, 51, 1614.
7 M. Suzuki, T. Asahi and H. Masuhara, Phys. Chem. Chem. Phys., 2002,
4, 185.
2
2
210 | Chem. Commun., 2005, 2208–2210
This journal is ß The Royal Society of Chemistry 2005