Synthesis and infrared spectroscopic studyof N,N’-bis(4-methoxybenzylidene)thiourea with its Co(II) and Ni(II) homobinuclear complexes

New homobinuclear complexes of Co(II) and Ni(II) with a Schiff base, N,N’-bis(4-methoxybenzylidene)thiourea derived from [2+1] condensation reaction of 4-methoxybenzaldehyde and thiourea have been synthesized by conventional method. The Schiff base ligand and the complexes were characterized as appropriate by gravimetric determination of chloride content, thermogravimetric estimation of uncoordinated water, melting point, molar conductance measurement and infrared spectroscopy. The ligand was white crystalline solid of sharp melting point (150 oC) whereas the Co(II) and Ni(II) complexes were blue and golden colour with decomposition temperature of 190 oC and 198 oC, allusive of thermostability. Both complexes were hydrated and non-electrolytic in nature with four chloride ions coordinated to the bimetallic ions. The IR study revealed that the ligand is a neutral tridentate diazamonothio moiety coordinated to the Co(II) and Ni(II) ions through its two azomethane nitrogen atoms (C=N) and thione sulphur. The resultant data suggest formation of the homobinuclear complexes as [M2LCl4].nH2O, (where M2+=Co or Ni, L=Schiff base ligand and n=4 for Co and 6 for Ni complex), possessing square planar structure.