A theoretical study of SN2O2 isomers

Six isomers of SN2O2 have been found to be minima on the potential energy hypersurface calculated by ab initio and density functional theories. Calculations show that two N–N bond isomers, trans- and cis-S(O)NNO, are close in energy and the predicted vibrational frequencies and isotopic shifts of these two isomers reproduce the experimental doublets satisfactorily, which was referred to trans-S(O)NNO previously. The C2v-ONSNO is energetically favored and the vibrational frequencies and isotopic shifts are in excellent agreement with experimental observations.