A Crossed Beam and ab Initio Investigation of the Reaction of Hydrogen Sulfide, H2S(XA1), with Dicarbon Molecules, C2(X1Σg+)

Abstract

The reaction of the dicarbon molecule C2(X1Σg+) with hydrogen sulfide, H2S(X1A1), was investigated under single collision conditions in a crossed beam setup with mass spectrometric detection at an averaged collision energy of 46.0 kJ mol-1. The experiment was supplemented by electronic structure calculations. The reaction dynamics are dictated by a barrierless addition of dicarbon to the sulfur atom to form a bound H2SCC intermediate followed by two successive hydrogen migrations on the singlet surface to give a singlet thiohydroxyacetylene (HCCSH) species. The latter emits atomic hydrogen to yield the HCCS (X2ΠΩ) isomer. Possible alternative pathways, the elimination of atomic and molecular hydrogen from a thioketene (H2CCS) intermediate, to synthesize HCCS and CCS are also discussed.