Metal complexes of pyrimidine derived ligands—II: Cobalt(II) complexes of 2-hydrazino-4,6-dimethyl pyrimidine

Abstract

Bis- and tris-Co(II) complexes of 2-hydrazino-4,6-dimethyl pyrimidine (L) are reported: they are of the type CoL 2X 2· nH 2O and CoL 3X 2· nH 2O (X = Cl, Br, I, NO 3, ClO 3, BF 4, SCN and n = 0, 1 or 2). Structural characterisation of the complex species is made from electronic and vibrational spectra, magnetic susceptibility measurements in the solid state and conductivity measurements in solution. The magnetic and electronic spectral data together with the ligand-field parameters suggest a pseudo-octahedral environment for all the Co(II) complexes. An interesting colour change from pink to green on heating CoL 2X 2· nH 2O (X = Cl, Br, NO 3)_has been attributed to a stereochemical change from octahedral to tetrahedral as indicated by physico-chemical measurements. IR spectra indicate tentatively the mode of linkage of the ligand molecules and the anion (X) to the metal ion in the solid state.