Synthasis of the 4-N,N-dimethylaminobenzoic acid complexes of Mn(ıı),Co(ıı), Ni(ıı), and Cu(ıı).spectroscopic and thermal characterization

Abstract

4-N,N-dimethylaminobenzoic acid complexes of Mn(II), Co(II), Ni(II) and Cu(II) were synthesised and their structural properties were investigated by employing elemental analysis, magnetic susceptibilitiy, solid state UV-vis, direct injection probe mass, FTIR and thermoanalytic TG-DTG methods. According to the microanalytical results, formula of complexes are $C_{18}H_{32}N_2O_{10}Mn$, $C_{18}H_{24}N_2O_6Co$, $C_{18}H_{34}N_2O_{11}Ni$ and $C_{18}H_{24}N_2O_6Cu$. The complexes of Mn(II) and Ni(II) contain four moles of coordination waters, but Co(II) and Cu(II) complexes have two moles of coordinated water ligands. All of the complexes include two moles 4-N,N-dimethylaminobenzoate ligands, but it was coordinated to metal atom as monodentate in Mn(II) and Ni(II) and bidentate in Co(II) and Cu(II) complexes. It was found that ratio of metal:ligand is 1:2 and the decomposition of each complex starts with dehydration and follows by decomposition of organic part, respectively. The thermal dehydration of the complexes takes place in steps from one to two. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The final decomposition products are found to be the respective metal oxides.