Ultraviolet absorption spectra and electronic structure of (alkylthioalkyl)trialkoxysilanes

Abstract

The authors have studied the ultraviolet absorption spectra of solutions of (alkylthioalkyl)-trialkoxysilanes in heptane and acetonitrile in the 4.5-5.3 x 10W m region. The experimental data obtained and the quantum chemical calculations carried out show that the alkyl substitutents at the sulfur atom exert an inductive and steric effect on the sulfide group, while the alkoxyl oxygen atoms experience the substituent effect across space. In molecules of compounds with one methylene group separating the silicon and sulfur atoms, an acceptor effect for the trialkoxysilyl group is apparent, changing the degree of binding for the electronic pairs of the sulfur atom.