Ligational behavior of thiosemicarbazide and thiosemicarbazone(VI): Some trivalent metal complexes of innocent ligands

Abstract

New complexes of Cr(III), Mn(III), Fe(III) and Co(III) with Schiff's bases of substituted thiosemicarbazide have been prepared and characterized by. chemical analyses, IR, electronic spectral and magnetic measurements. The tridentate NSO Schiff's base, 1-salicyl-4-benzylamidothiosemicarbazone (HSBTS) forms octahedral complexes of the type [M(SBTS) 2] +, whereas, the bidentate NS Schiff's base, 1-phenyl-4-benzylamidothiosemicarbazone (PBTS) yields the complexes of the type [M(PBTS) 2X 2] + except Co(III)-PBTS complex, [Co(PBTS) 2(H 2O) 2] 3+, conforming to the pseudooctahedral symmetry (where, M = Cr, Mn, Fe, Co and X = Cl or OH). The various ligand field parameters, wherever possible, have been evaluated. The lowering of symmetry may be the possible reason for the small reduction in the values of magnetic moments for tetragonally distorted complexes.