Spectral and thermal study on the adduct formation between square planar nickel(II) chelates and some bidentate ligands

Abstract

Adducts of Ni(II)-square planar complexes [Ni(β-dik)(Me 4en)] +, with a series of bidentate ligands (L), where β-dik = acetylacetonate (acac) and benzoylacetonate (bzac), Me 4en = N, N, N′, N′-tetramethylethylenediamine and L = Me 4en, 2,2′-bipyridine (bipy), ethylenediamine (en) and oxalate (C 2O 4 2−) have been synthesized and characterized by spectral, thermal and magnetic measurements. Formation constants of the adducts formed from a series of ternary mixed Ni(II) complexes with the general formula [Ni(β-dik)(diam)] + with 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) and pyridine were spectrophotometrically determined. Thermodynamic parameters of the adduct formation between nickel(II) square-planar chelates and pyridine (py), 2,2′-bipyridine (bipy) and acetylacetone (acac) were also spectrophotometrically determined in 1,2-dichloroethane. The thermal stability of the isolated adducts was studied using thermogravimetry and the decomposition schemes of the adducts were given.