Conformational Analysis of Stilbenes by Photoelectron Spectroscopy

Conformations of (Z)-stilbene, (E)-stilbene, and various methyl-substituted (E)-stilbenes were discussed from the standpoint of photoelectron spectroscopy. Photoelectron spectral data of (Z)-stilbene and (E)-stilbene were found to be perfectly consistent with the results by the gas electron diffraction method concerning the twist angles of the phenyl groups. The twist angles of the phenyl groups in various methyl-substituted (E)-stilbenes were estimated using the photoelectron spectral data by the new method presented recently. These estimated values correspond well to those obtained from the standpoint absorption spectra.