Electronic spectral determination of the heterocyclic nitrogen base adducts of nickel(II)-di(2,6-dichlorophenyl)carbazonate

摘要

The ligand di(2,6-dichlorophenyl)carbazone (hereafter named as D2,6DClPC) and its nickel(II) complex have been synthesised and characterised by elemental analyses, magnetic moment and spectral measurements. The adduct formation constants of various heterocyclic nitrogen bases with nickel(II) chelates of D2,6DClPC have been determined in a monophase chloroform by electronic spectral study. Bathochromic and hypsochromic shifts were observed in the optical spectra in the visible range, due to adduct formation. The saturated monodentate bases such as pyrrolidine, piperidine, etc., form pentacoordinate adducts of 1:1 stoichiometry, whereas bidentate and unsaturated monodentate bases form hexacoordinated adducts with 1:1 metal-ligand stoichiometry. The experimental results are discussed in terms of steric properties, basicity and ring structures of the various heterocyclic bases.