Ab initio SCF-MO study of quinones of pyridine

Ab initio calculations at HF/6-31G∗∗ and B3LYP/6-31G∗∗ levels of theory for geometry optimization, MP2/6-31G∗∗//HF/6-31G∗∗ and MP2/6-31G∗∗//B3LYP/6-31G∗∗ for single point total energy calculations are reported for six quinones of pyridine and three benzoquinones. Among pyridoquinones, the 2,5-isomer is calculated to be the most stable geometry; the 2,3- and 3,4-isomers are 18.26 and 43.21 kJ mol−1 less stable, respectively.