A Theoretical Study on the Structures and Spectra of Ni(II) Aquo Azides, Thiocyanates and Isothiocyanates

Abstract

A theoretical treatment of the formation and stability of some aquated nickel II azides, thiocyanates and isothiocyanates has been carried out. Ab initio molecular orbital calculations have been carried out using the DZ basis set and 3 F ground state for nickel and using the 3-21 G split valence basis set for H, C, N and O-atoms. For S-atom the 3-21 G basis set was augmented with 3 d -function. Geometry optimization was carried out for each of the studied species; charge distribution and electron overlap population were calculated. The results of this work show that azide ion is a stronger ligand than isothiocyanate ion and the latter is stronger than thiocyanate ion with respect to bonding to nickel ion. The results of calculations indicated that the triplet state was the stable ground state for all the studied species. Calculations using ROHF procedure led to better results than calculations using UHF method.