pH-Switchable through-space interaction of organic radicals within a self-assembled coordination cage

Angewandte Chemie - International Edition

Volumn 44, Issue 33, 2005, Pages 5322-5325

  Nakabayashi, Koji ^a   Kawano, Masaki ^a   Fujita, Makoto ^a  

^a UNIVERSITY OF TOKYO   (Japan)

Author keywords

Clathrates; EPR spectroscopy; Host guest systems; Radicals; Self assembly

Indexed keywords

ELECTRON SPIN RESONANCE SPECTROSCOPY; PH EFFECTS; SELF ASSEMBLY;

CLATHRATES; HOST-GUEST SYSTEMS; ORGANIC RADICALS; PROTONATION;

FREE RADICALS;

EID: 24044500317     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200501568     Document Type: Article

References (22)

1. a) W. Fujita, K. Awaga, Science 1999, 286, 261-262;
2. b) M. E. Itkis, X. Chi, A. W. Cordes, R. C. Haddon, Science 2002, 296, 1443-1445.
3. K. Nakabayashi, M. Kawano, M. Yoshizawa, S. Ohkoshi, M. Fujita, J. Am. Chem. Soc. 2004, 126, 16694-16695.
4. The Pt cage is proof against acidic conditions. Self-assembled coordination cage 1 was prepared by a procedure described in the following references: a) M. Yoshizawa, T. Kusukawa, M. Fujita, K. Yamaguchi, J. Am. Chem. Soc. 2000, 122, 6311-6312;
5. b) T. Kusukawa, M. Fujita, J. Am. Chem. Soc. 2002, 124, 13576-13582.
6. Radical 2 was prepared by a procedure described in the following references: a) H. Sakurai, A. Izuoka, T. Sugawara, J. Am. Chem. Soc. 2000, 122, 9723-9734;
7. b) C. Hirel, K. E. Vostrikova, J. Pecaut, V. I. Ovcharenko, P. Rey, Chem. Eur. J. 2001, 7, 2007-2014.
8. For examples of a pH-responsive host-guest system, see: a) M. Haga, M. M. Ali, R. Arakawa, Angew. Chem. 1996, 108, 85-87;
9. Angew. Chem. Int. Ed. Engl. 1996, 35, 76-78;
10. b) D. E. Bergbreiter, J. G. J. Franchina, Chem. Commun. 1997, 1531-1532;
11. c) M.-V. Martínez-Díaz, N. Spencer, J. F. Stoddart, Angew. Chem. 1997, 109, 1991-1994;
12. Angew. Chem. Int. Ed. Engl. 1997, 36, 1904-1907;
13. d) D. Whang, J. Heo, J. H. Park, K. Kim, Angew. Chem. 1998, 110, 83-85;
14. Angew. Chem. Int. Ed. 1998, 37, 78-80;
15. e) F. Ibukuro, T. Kusukawa, M. Fujita, J. Am. Chem. Soc. 1998, 120, 8561-8562.
16. The spin control of through-bond interactions by photoexcitation in the solution and solid states was achieved by the use of diarylethene with two nitronyl nitroxides; K. Matsuda, M. Irie, J. Am. Chem. Soc. 2000, 122, 8309-8310.
17. 2 (see Experimental Section), which suggests the quantitative formation of the 1:2 host-guest complex by this procedure.
18. The spin center was defined as the oxygen atoms of the nitronyl nitroxides.
19. -1, and r = 6.3 Å, the average spin-spin distance between radicals within the cage.
20. Both the acidified and neutral solutions of another stable radical that lacks an amino group gave identical ESR spectra (see Supporting Information).
21. 2 at 293 K.
22. See Supporting Information.