Semiempirical MNDO Study of Phenyl-sydnone and its Protonated Forms

Sa？etak The electronic and geometric structure of the phenylsydnone and its conjugated acids is investigated by the semiempirical MNDO method. A comparison of the interatomic bond distances and bond angles with available experimental data for the parent compound reveals only qualitative accordance. It appears that the MNDO method is unable to reproduce finer details of the molecular geometry of sydnones. The gross changes caused by protonation are described, however, in agreement with chemical intuition .and available experimental data. The variation in geometric parameters is interpreted in terms of rehybridization and :n-electron bond orders. The most stable conjugated acid is that with a proton bonded to the keto-oxygen in accordance with the highest electron density concentration