Comparative Density Functional Theory Study on Co (III). Ni (II), Zn (II) Organometallic Complexes and their UV-Vis Absorption Spectra in Dichloromethane Solvent

Abstract

The structural and electronic energy of Co(III), Ni (II) and Zn (II) complexes, based on phenyl pyrazole (ppz) and acetylacetate (acac) ligands have been investigated theoretically in details using DFT/B3LYP method. The most stable structure for three metal ions was predicted to be a distorted octahedral, square-planar and tetrahedral for Co(ppz)₂acc , Ni(ppz)₂ and?? Zn(ppz)₂, respectively and the stability ordering of complexes was found to be Zn(ppz)₂< Ni(ppz)₂< Co(ppz)₂acc. The results show that ppz as the most dominant ligand coordinates to all metal ions forming five member-chelating-ring for stabilization complexes. Time-dependent density functional theory (TD-DFT) method included electrostatic influence of the solvent dichloromethane using IEFPCM has been employed to explore the absorption spectra of the complexes. The effect of solvent could contribute the reduction of maximum absorption wavelengths (l_max) of the complexes when compared with their gas phase.