Theoretical investigations on R(O)nS–NO (n=0,1,2) systems

In the current article we report the ab initio study on the stability of S-Nitrosothiols (MeSNO, ) and their oxidised derivatives (MeS(O)NO, ) and (MeS(O)2NO, ). The bond length, bond order, rotational barrier and bond dissociation energy have been calculated and compared with that of sulfenamide (HS–NH2) and its oxidised derivatives sulfinamide (H(O)S–NH2) and sulfonamide (H(O)2S–NH2). The S–N bond dissociation energy in the oxidised state is very small compared to parent RSNO indicating the weakness of sigma bond. NBO analysis suggests that the negative hyperconjugative interactions are very strong in S-nitrosothiols and their oxidised derivatives, which weaken the sigma bond and facilitate the release of nitric oxide.