Synthesis and Spectroscopic Studies of Schiff Base and Its Divalent and Trivalent Metal Complexes

Abstract

A new macrocyclic ligand is prepared by refluxing isatin and 2,6-diamino-4-chloropyrimidine in methanolic medium with the m.f. C₂₄H₁₂N₈Cl₂. The complexes are synthesized by template condensation of isatin and 2,6-diamino-4-chloropyrimidine in methanolic medium in the presence of divalent nickel, copper, zinc salts and trivalent chromium, iron salts and may be represented by formula: [M(C₂₄H₁₂N₈Cl₂)X₂], [M'(C₂₄H₁₂N₈Cl₂)X]X₂, respectively where M = Ni(II), Cu(II), Zn(II), M' = Cr(III), Fe(III) and X = Cl^–, NO₃^–, CH₃COO^–. The ligand coordinates through all four azomethine nitrogens but heterocyclic nitrogens do not take part in coordination as confirmed by absence of (M-pyrimidine) vibrations. These complexes have been characterized with the help of various physico-chemical techniques like IR, far-IR, NMR, elemental analyses, electronic spectra, conductance and magnetic susceptibilities. The distorted octahedral geometry has been proposed for divalent metal complexes and a five-coordinate distorted square pyramidal geometry for trivalent metal ion complexes.