Electronic Structure and Photophysical Properties of Planar Conjugated Hydrocarbons with a 4n-Membered Ring
The electronic absorption spectra of compounds 3 to 8 exhibit systematic features which differ radically from the well known pattern of benzenoid hydrocarbons. The observed regularities are discussed on the basis of a simple LCAO-scheme including first-order configuration interaction. The resulting assignments have been corroborated by polarization measurements for to 5 to 7. Triplet state absorption spectra and energies of 6 to 8 were determined by flash photolysis and energy transfer experiments. The observed trend in fluorescence and triplet yields provides an illustrative example for the photophysical consequences of an avoided surface crossing.
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- N.S. Hush & J.R. Rowlands, Mol. Phys. 6, 317 (1963) F. Peradejordi, R. Domingo & J.I. Fernández-Alonso, Int. J. Quantum Chem. 3, 683 (1969); P. Francois, J. Chim. Phys. Fr. 67, 1063 (1970).Google Scholar
- E. Ciar, Aromatische Kohlenwasserstoffe, Springer-Verlag (1952).Google Scholar
- R. Wolovsky & F. Sondheimer, J. Amer. Chem. Soc. 87, 5720 (1965), “isomer B” corresponds to 4; see also UV-Atlas of Organic Compounds, Vol. V, Butterworths & Verlag Chemie (1971).Google Scholar
- O.M. Behr, G. Eglinton, A.R. Galbraith & R.A. Raphael, J. Chem. Soc. 1960, 3614.Google Scholar
- C.A. Coulson & G.S. Rushbrooke, Proc. Cambridge Phil. Soc. 36, 193 (1940) see e.g. L. Salem, Molecular Orbital Theory of Conjugated Systems, Benjamin (1966).Google Scholar
- E. Rommel & J. Wirz, Helv. Chim. Acta, in preparation.Google Scholar
- J. Michl, E.W. Thulstrup & J.H. Eggers, Ber. Bunsenges. 78, 575 (1974).Google Scholar
- J.D. Campbell, G. Eglinton, W. Henderson & R.A. Raphael, Chem. Commun. 1966, 87.Google Scholar
- R.J. Buenker & S.D. Peyerimhoff, J. Chem. Phys. 413, 354 (1968); G. Binsch, Jerusalem Symposia on Quantum Chemistry and Biochemistry, Vol. Ill, 25 (1971).Google Scholar