W. Leigh, K. Zheng, N. Nguyen
Jun 1, 1991
Citations
0
Influential Citations
15
Citations
Journal
Journal of the American Chemical Society
Abstract
Two substituted bicyclic cyclobutene derivatives ― 7-methyl- and 7-(trifluoromethyl)bicyclo[4.2.0]oct-7ene ― have been prepared. Gas- and solution-phase UV absorption and HeI UV photoelectron spectra have been recorded for the two compounds as well as for the parent hydrocarbon bicyclo [4.2.0]oct-7-ene. The gas-phase spectra suggest that the π,R(3s) state is the lowest energy state in bicyclo[4.2.0]octene and the 7-methyl derivative but is raised to higher energies than the π,π* state in the 7-trifluoromethyl derivative. Direct photolysis of the three compounds in hydrocarbon solution with monochromatic far-UV (193 and 214 nm) light leads to competitive ring opening to the corresponding cis,cis- and cis,trans-1,3-cyclooctadiene derivatives, as well as fragmentation to cyclohexene and alkyne in all three cases