Ultraviolet photoelectron spectra of some resorcinols and dithioresorcinols

The photoelectron spectra of resorcinol, dithioresorcinol, 4,6-dichlororesorcinol 1, 4,6-dichlorodithioresorcinol 3 and their methyl derivatives were recorded by using He(I) and HE(II) excitations. The assignment of the photoelectron bands was mainly based on relative band intensity variations and on the results of ab initio STO-3G calculations. The results show clear evidence of the presence of intramolecular OH … Cl hydrogen bonding interactions in 1, while no effects of such a bonding was observed in the corresponding dithiocompound 3. These findings are confirmed by the STO-3G calculations. The photoelectron spectra of both 1,3-dithiomethoxybenzene and 1,3-dithiomethoxy-4,6-dichlorobenzene give evidence of rotational isomerism of the SCH₃ group.