Molecular Orbital Study on the Polarographic Reduction of Substituted Fulvenes

Abstract

The half wave potentials of 6-phenylfulvene, 6-methyl-6-phenylfulvene, 1-benzylideneindene, 9-benzylidenefluorene, and their derivatives with p-methyl, p-methoxy, and p-N, N-dimethylamino substituents on the phenyl group were studied in relation to the lowest vacant molecular orbital energies which were calculated on the basis of the LCAO-MO methods. The parameters of coulomb and resonance integrals for hetero atoms which were proposed by Streitwieser and Zweig were adopted. The linear relationship between the halfwave potentials and the lowest vacant molecular orbital energies by HMO method gave the correlation coefficient of 0.959. Furthermore, the results using 0.9β and 1.1β as resonance integrals for essential single bonds and essential bouble bonds, respectively, in HMO calculations gave better linear relationship with correlation coefficient of 0.992.