Synthesis,spectral, thermal,solid state d.c. electrical conductivity and biological studies of lanthanum(III) and thorium(IV) complexes with thiocarbohydrazone

The La(III) and Th(IV) complexes have been synthesized by reacting La(III) and Th(IV) nitrate with the Schiff base derived from thiocarbohydrazide and thiophene-2-aldehyde. These complexes are soluble only to a larger extent in DMF and DMSO. The observed molar conductance values indicate that they are non-electrolytes. The elemental analyses of the complexes and confined to the stoichiometry of the type La.L.(NO₃)₃H₂O and Th.L.(NO₃)₄. Further, the complexes have been characterized by the spectral and thermogravimetric data. The solid state d.c. electrical conductivity of the La(III) and Th(IV) complexes has been investigated from room temperature to 205 °C; which indicates the electrical conductivity increases with increase in temperature. Hence, La(III) and Th(IV) complexes were considered as semiconductors. Fluorescence spectra of the Schiff base and its Th(IV) complex were investigated in various solvents; the Schiff base and its metal complexes were evaluated for their antimicrobial activity.