Geometry optimization and thermodynamic stabilities of Zn-II mixed ligand complexes with salicylaldehyde and substituted salicylaldehydes

PM3 calculations have been carried out on Znin mixed ligand complexes Zn(sal)(5-Clsal), Zn(sal)(5-Brsal), Zn(sal)(5-NO(2)sal), Zn(5-Clsal)(5-Brsal), Zn(5-Clsal)(5-NO(2)sal) and Zn(5-Brsal)(5-NO(2)sal) and the corresponding ligands and their bis-complexes Zn(sal)(2) Zn(5-Clsal)(2), Zn(5-Brsal)(2) and Zn(5-NO(2)sal)(2). Thermodynamic stabilities based on heats of formation, total energies, ionization potentials, atom electron densities and atomic charges have been calculated. Geometry optimization of the complexes has been carried out on the basis of bond lengths and bond angles data. O-Zn-O bond angles are close to 109.5 degrees (100.95 degrees to 116.68 degrees) suggesting distorted tetrahedral geometry for the complexes.