DFT study on the reaction of neutral Ti and Ni atoms with CS2

The reaction mechanisms of the ground state (3F) of neutral Ti atom, the lowest triplet (3F) and singlet state (1D) of Ni atom with CS2: M+CS2→MS+CS (M=Ti, Ni) have been investigated by using DFT method B3LYP with DZVP basis set. Two reaction channels have been identified for the reactions of both Ti (3F) and Ni (3F) atoms with CS2, and one channel has been identified for the reaction of Ni (1D) with CS2. These reactions are initiated by different mechanisms, but all the reaction channels involve the insertion of metal atoms into the C-S bond of CS2 yielding insertion intermediates SMCS from C-S bridged intermediates M-(η2-CS)S or cyclic complexes M-(η2-S2)C. The reaction of triplet ground state Ti with CS2 requires no activation energy, whereas the reactions of Ni atom with CS2 proceed with 7, 20 and 17 kcal/mol activation energies for the two triplet and one singlet pathways, respectively. The reaction of Ni with CS2 was shown to occur preferentially on triplet surface and the experimentally observed species, Ni-(η2-CS)S and SNiCS, have been explained according to the mechanisms revealed in this work.