Synthesis, Characterization and DFT calculations of Novel Mononuclear Nickel (II), Cobalt (II) and Iron (II) Complexes derived from 2-(1H-benzimidazol-2-yl)- phenol Ligand

In this study, the new mononuclear complexes, K₂ [Ni (L)₂ Cl₂]. 2H₂O (C1), K₂ [Co (L)₂ Cl₂]. H₂O (C2) and K₂ [Fe (L)₂ Cl₂]. 4H₂O (C3), was L is the 2-(2-hydroxyaryl)-1H-benzimidazole, have been synthesized and characterized. The structures of these compounds were confirmed on the basis of FT-IR, UV-Vis, ¹H-, ³C-NMR, TGA, DTA, DTG measurements, conductivity, ICP and elemental analyses (C, H and N). The purity of the compounds was ascertained by melting point (m.p.) and TLC. According to the analysis used, in all of the complexes, the ligand coordinated as bidentate, via one imine nitrogen atom and phenolate oxygen atom. The coordination for all of the complexes is completed with two chloride ions adopting a six-coordinated octahedral geometry. The geometry optimization and vibrational frequency calculations of the compounds were carried out in Gaussian 09 program using B3LYP/TZVP level of theory. Based on the combined experimental and theoretical studies, all complexes showed six-coordinated octahedral structures.