J. Pavlik, R. Connors, D. Burns
Aug 1, 1993
Citations
0
Influential Citations
20
Citations
Journal
Journal of the American Chemical Society
Abstract
Photophysical and photochemical properties of 1-phenylpyrazole and 3-,4-, and 5-methyl-1-phenylpyrazoles have been investigated. INDO/S calculations agree with experimental measurements which show that the S 1 and T 1 states of these compounds are π,π * in character. Upon S 0 →S 1 (π,π * ) excitation, these 1-phenylpyrazoles undergo phototransposition via a P 4 permutation pathway. This process is consistent with a mechanism involving initial N-N bond cleavage followed by a 1,2-shift and cyclization to form the 1-phenylimidazole product. The 1,2-shift may occur via an undetected azirine intermediate