Theoretical studies on the structure and electronic properties of 3-(4-tolyl)sydnone

Abstract

The structure of 3-(4-tolyl)sydnone has been calculated using the semiempirical MNDO, AM1 and PM3 methods and at the ab initio STO-3G, 3–21 G and 6–31 G** levels and the resulting geometries compared and contrasted with the well resolved crystal structure. While the geometry of the phenyl ring is well reproduced particularly by the ab initio methods, none of the methods give a satisfactory account of the geometry of the sydnone ring. The calculated charge distributions of atoms in the heterocyclic ring vary considerably depending on both the molecular orbital method used and the analysis technique adopted. The calculated dipole moments are generally overestimated with the best results obtained with the MNDO method for the semiempirical procedures and the STO-3G basis set for the ab initio methods.