Theoretical study of the reaction of Fe+ with CS2 in gas phase

The reaction of Fe+ with CS2, which was selected as a representative system of the reactions of transition metals with CS2, has been investigated using density functional theory at B3LYP/6-311+G(d) level of theory. The geometries, energies and frequencies of reactant, intermediates, transition states and products were explored in detail on both the quartet and sextet potential energy surfaces of [Fe, C, S2]+. Our calculations indicate the reaction proceeds via an insertion–elimination mechanism but not a direct abstract mechanism. All of the observed products in the early experiment has been explained according to the cleavage of different bonds in the insertion intermediate S–Fe+–C–S. The connectivity in [Fe,C,S]+, which cannot be specified by experiment, was revealed as [S–C–Fe]+ in our study. By comparing the Fe++CS2 and V++CS2, we suppose all the reactions of first-row transition metal ions with CS2 could proceed according to the similar insertion–elimination mechanism.