A computational exploration of some transnitrosation and thiolation reactions involving CH3SNO, CH3ONO and CH3NHNO.

Nitric oxide (NO) is a biologically active species and its carrier molecules RXNO (X = S, O, NH) have drawn significant attention recently. In the present work, the CBS-QB3 level of theory was used to study the transnitrosation and thiolation reaction between MeXNO (X = S, O, and NH) molecules and three reactive forms of the methanethiol: the neutral molecule, MeSH, the anion, MeS-, and the radical, MeS . The transnitrosation and thiolation reactions between MeXNO and MeSH have the highest barriers, both with and without a molecule of water assisting. Reactions with MeS- proceed with much lower barriers, while reactions with radical MeS have the lowest barriers. Comparing the reactions of MeXNO (X = S, O, NH), both transnitrosation and thiolation are more favorable for X = S than X = O or NH.