Biological and solid state electrical conductance properties of the complexes of 1-salicyloyl-4-benzoyl-3-thiosemicarbazide with manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II)

This paper describes the solid state electrical conductivity of a new ligand, 1-salicyloyl-4-benzoyl-3-thiosemicarbazide (HL), and its complexes [M(L)(SCN)] [M = Mn(II), Co(II), Cu(II) or Zn(II)], [Ni(L)(SCN)(H2O)] and [M(L)Cl] [M = Mn(II), Co(II), Ni(II), Cu(II) or Zn(II)]. The structure and bonding of the complexes have been investigated on the basis of elemental analyses, magnetic susceptibility, UV-Vis., IR, ESR, FAB-mass and NMR spectral data. The above studies indicate that the cobalt(II), nickel(II) and manganese(II) complexes have a tetrahedral structure, while the copper(II) complex is square-planar. Solution conductivity measurements reveal non-electrolytic behaviour of the complexes. Temperature dependent conductivity of compressed pellets of the complexes in the temperature range 303-383 K exhibited sigma(rt) values in the 10(-11)-10(-7) S cm(-1) range. All of the complexes are semiconductors as their conductivity increases with temperature increase, showing a band gap of 0.21-0.65 eV.