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Abstract

Mn(II) complexes with four semicarbazide and thiosemicarbazide based ligands such as 2-formyl pyridine semicarbazone (L 1 ), 2-formyl pyridine thiosemicarbazone (L 2 ), 5-methyl 2-formyl pyridine semicarbazone (L 3 ) and 5-methyl 2-formyl pyridine thiosemicarbazone (L 4 ) have been synthesized and characterized. All the ligands were characterized by elemental analyses, IR, 1 HNMR and mass spectral studies. The complexes were characterized by using various physicochemical techniques such as elemental analysis, molar conductance, magnetic susceptibility measurements and spectral studies such as IR, UV-visible and EPR. The complexes were found to have general compositionsThe molar conductance data of chloro and nitrato complexes of L 1 , L 2 , L 3 and L 4 suggest nonelectrolytic nature of the complexes. Therefore they may be formulated as [Mn(L) 2 X 2 ].Complexes show magnetic moment corresponding to five unpaired electrons. On the basis of IR electronic and EPR spectral data distorted octahedral geometry of complexes has been suggested. INTRODUCTION:Metal complexes of semicarbazones and thiosemicarbazones were found to show more biological activities as compared to the free semicarbazone and thiosemicarbazone 1 . In addition, the complexes can exhibit bioactivities which are not shown by the free ligands. Owing to the wide range of medicinal properties of semicarbazones and thiosemicarbazones, their metal complexes are emerging as a new class of experimenral studies. A lot of work is going on the synthesis and characterisation of transition metal complexes with semicarbazones and thiosemicarbazones 2 . The transition metal complexes of these ligands were synthesised mainly due to their pharmacological activities.