Photoelectron Spectra and Molecular Properties, LXIII. Ionization Energies of Phenyl Methyl Telluride and Comparison of Effects of Oxygen, Sulphur, Selenium and Tellurium Substituents on the Benzene π System

The photoelectron spectrum of H5C6-Te-CH3 displays in its low energy region overlapping bands of gas-phase conformers. Depending on the dihedral angle between the plane of the phenyl ring and the tellurium lone pair, the π conjugation amounts to only 0.1 eV and 0.3 eV, respectively. These values are compared to the considerably larger ones found for the analogous phenyl derivatives H5C6-X-CH3 with X = O, S and Se

Photoelectron Spectra and Molecular Properties, LXIV. Dimethyldiselenide - an Example for the Interaction between Adjacent Electron Pairs

The well-resolved helium(I) photoelectron spectrum of H3C-Se—Se-CH3 exhibits distinct bands corresponding to 11 of the total 13 valence electron ionizations. The unequivocal assignment is supported by EHMO calculations including spin/orbit coupling. The two selenium lone pair ionizations differ by 0.23 eV; a split observed also for dimethyl disulfide and discussed within a general model for interactions between adjacent lone pairs