A theoritical study on the mechanism of interconversion of 2-amino-5-mercapto-1,3,4-thiadiazole isomers

The optimized geometries, infrared spectra, electron structure and bonding behavior of the isomers and transition states of 2-amino-5-mercapto-1, 3, 4-thiadiazole are studied by density functional theory(DFT) and second-order Moller-Plesset perturbation theory at B3LYP/6-311G(d, p)and MP2/6-31G(d) levels. The mechanisms of interconversion of 2-amino-5-mercapto-1, 3, 4-thiadiazole(AMT) isomers are studied, and a mechanism of cyclic interconversion of AMT isomers areversible arrowbreversible arrowcreversible arrowdreversible arrowa is proposed. The atom charges, bond order and hybrids orbitals of the AMT isomers are discussed using the natural bond orbital(NBO) analysis.