Theoretical study of the potential-energy surface related to H2N + NS reaction: N2 vs. H2 elimination

Abstract

The potential-energy surface related to the H2N + NS reaction, which involves 13 intermediates and fragment products, as well as 14 transition structures has been fully characterized using both molecular orbital (MP2) and density functional theory (B3LYP) and the 6-311 + +G(d,p) basis set. Improved electronic energies have also been obtained using single-point coupled-cluster CCSD(T) calculations. The system is shown to have three different groups of products: N2H + SH, N2S + H2 and N2 + H2S and a rather complex reaction mechanism. Starting from H2N + NS, several low-lying [H2N2S] isomers participate in the elimination of H2 and N2. The N2 elimination appears to be favoured over other reaction channels in the destruction of NS. The standard enthalpies of formation of the most stable isomers have been estimated, ΔfH298○ in kJ mol-1: H2N-N=S: 250, H2N-S≡N: 262, NH=NH=S: 264, NH=N-SH: 247 and NH=S=NH: 318.