Computational study of the [(CO)2(benzoate)MII/III(terephthalate)]0/1+ complexes with M = V, Cr, Mn, Fe and Co

Computational study at DFT-B3LYP/LANL2DZ level of theory is carried out to evaluate structural, bonding and energetic characteristics of cis/trans isomers of the [(CO)(2)(benzoate)M-II/III(terephthalate))(0/1+) complexes with 3d transition metals M = V, Cr, Mn, Fe and Co. Results of this study show that all cis/trans isomers of these complexes in their two oxidation states are stable with distinctly different structures. As a general trend, for all cis/trans isomers of these complexes, the M-O(benzoate) and M-O(terephthalate) bonds are shorter for the M-III oxidation state of the metal ion compared to those for the corresponding M-II oxidation state. Also, structure of the set of four M-O bonds are almost asymmetric such that the optimized M-II/III-O (terephthalate) bond lengths are slightly longer than the M-II/III-O(benzoate) bond lengths. The coordination M-O bonds structure of the cis/trans isomers of the [(CO)(2)(benzoate)Co-II(terephthalate)] complex have the most asymmetries, and interestingly, its trans isomer is more asymmetric than its cis isomer. The M-III complexes have larger electric dipole moments compared to their corresponding M-II complexes. Furthermore, cis/trans isomerization has no significant effect on the size of electric dipole moment for the M-II complexes.