A DFT study of transition metal complexes with 1,10-phenanthroline, C-C-dimeric 2,2′-bi-1,10-phenanthroline, and its tetraaza chromophore anion

Quantum-chemical calculations of the 1,10-phenanthroline complexes [M(en)(1,10-phen)]2+ (M = Pt, Pd, Ni; en = NH2C2H4NH2) were performed by the DFT B3LYP method in the 6-31G** basis set using the GAMESS-2006 program package. The calculations were also performed for the nickel complexes with 2,2′-bi-1,10-phenanthroline, [Ni(2,2′-bi-1,10-phen)]2+, and with its electron-excessive analog, [Ni(2,2′-bi-1,10-phen)]0, and also for the octahedral complex cation [Ni(2,2′-bi-1,10-phen)Cl(H2O)]+ characterized by single crystal X-ray diffraction. For the Ni(II) complexes, the stabilities of their high-and low-spin isomers were evaluated, and the structural features were revealed. The barriers to mutual transformations of the low-and high-spin Ni(II) complexes are low.