Ground and excited-state intramolecular interactions in phenol–olefin bichromophoric compounds

Abstract

The intramolecular OH  · · ·  π interactions of the phenolic and olefinic chromophores in o-propenyl and o-butenyl phenols 1a–d in the ground and excited states have been studied by (a) ab initio Hartree–Fock calculations using the 3-21G and 6-31G** basis sets, (b) FTIR spectral measurements in the gas phase, (c) fluorescence emission studies and (d) product studies. Such interactions appear to play a key role in the photochemical behaviour of the four compounds.

References

1. S. Speiser, Chem. Rev., 1996, 96, 1953.
2. V. Balzani and F. Scandola, Supramolecular Photochemistry, Ellis Horwood Limited, Chichester, 1991.
3. W. M. Horspool and P. L. Pauson, J. Chem. Soc., Chem. Commun., 1967, 195.
4. G. Fráter and H. Schmid, Helv. Chim. Acta, 1967, 50, 255.
5. M. A. Miranda and R. Tormos, J. Org. Chem., 1993, 58, 3304.
6. M. C. Jiménez, F. Márquez, M. A. Miranda and R. Tormos, J. Org. Chem., 1994, 59, 197.
7. However, the authors⁴ report on the formation of other unidentified photoproducts.
8. G. Trinquier and J.-P. Malrieu, J. Mol. Struct., 1978, 49, 155.
9. W. J. Hehre, L. Radom, P. V. R. Schleyer and J. A. Pople, Ab initio Molecular Orbital Theory, Wiley, New York, 1986.
10. K. B. Wiberg, Tetrahedron, 1968, 24, 1083.
11. For a related study on 1a in dilute solution, see A. W. Baker and A. T. Shulgin, J. Am. Chem. Soc., 1958, 80, 5358.
12. S. L. Murov, Handbook of Photochemistry, Marcel Dekker, Inc., New York, 1973.
13. D. A. Condirston and J. D. Laposa, Chem. Phys. Lett., 1979, 63, 313.
14. E. E. Schweizer, C. J. Berninger, D. M. Crouse, R. A. Davis and R. S. Logothetis, J. Org. Chem., 1969, 34, 207.
15. F. J. Urban and B. S. Moore, J. Heterocycl. Chem., 1992, 29, 431.
16. However, the previous semiempirical PCILO calculations concluded that the strength of the hydrogen bond depends on the number of methylene units connecting both chromophores.
17. M. J. Frisch, G. W. Trucks, H. B. Schlegel, P. M. W. Gill, B. G. Johnson, M. A. Robb, J. R. Cheeseman, T. Keith, G. A. Petersson, J. A. Montgomery, K. Raghavachari, M. A. Al-Laham, V. G. Zakrzewski, J. V. Ortiz, J. B. Foresman, J. Ciolowski, B. B. Stefanov, A. Nanayakkara, M. Challacombe, C. Y. Peng, P. Y. Ayala, W. Chen, M. W. Wong, J. L. Andres, E. S. Reploge, R. Gomperts, R. L. Martin, D. J. Fox, J. S. Binkley, D. J. Defrees, J. Baker, J. P. Stewart, M. Head-Gordon, C. González and J. A. Pople, Gaussian 94, Revision B.1. Gaussian Inc., Pittsburgh, PA, 1995.
18. H. B. Schegel, J. Comput. Chem., 1982, 3, 214.
19. H. B. Schegel, Geometry Optimization on Potential Energy Surface in Modern Electronic Structure Theory, ed. D. R. Yarkony, vol. I, II; World Scientific Publishing, Singapore, 1994.
20. M. J. S. Dewar, E. G. Zoebisch and E. F. Healy, J. Am. Chem. Soc., 1985, 107, 3902.
21. A. E. Reed, L. A. Curtiss and F. Weinhold, Chem. Rev., 1988, 88, 899.
22. A. E. Reed, R. B. Weinstock and F. Weinhold, J. Chem. Phys., 1985, 83, 735.
23. P. Yates and T. S. Macas, Can. J. Chem., 1988, 66, 1.