Surface-enhanced raman scattering of pentamethylene sulfide, 1,4-dithiane, and 1,3,5-trithiane adsorbed on silver

Abstract

Pentamethylene sulfide, 1,4-dithiane, and 1,3,5-trithiane adsorbed on silver sol surfaces were investigated by means of surface-enhanced Raman scattering. The CS bonds in the ring of these compounds did not cleave upon surface adsorption, but retained the chair conformation. The adsorption appeared to occur via the sulfur atom(s) with the ring lying parallel to the surface plane. Shifts of the CH and the CC stretching vibrations could be understood in terms of the hyperconjugation between the nonbonding p-orbital(s) on the sulfur atom(s) and the σ-anti-bonding orbital (s) at the adjacent bond (s).