Biological activity of complexes derived from thiophene-2-carbaldehyde thiosemicarbazone.: Crystal structure of [Ni(C6H6N3S2)2]

The crystal structure of [Ni(L-III)(2)] (1), where HLIII = thiophene-2-carbaldehyde thiosemicarbazone, consists of monomeric entities where the nickel(II) ions exhibit distorted square planar geometry. The two bidentate thiosemicarbazone ligands are centrosymmetric. (CS)-S-... van der Waals' links and nonbonded intramolecular interactions are present in the structure. The biological activity of 1 is compared to that of the free ligand, and the cobalt (III) (2) and copper(H) (3) derivatives. The observed order of cytotoxicity against melanoma B16F10 and Friend erythroleukemia. cells is: 1 less than or equal to ligand <2 <3. A structure-activity correlation using Extended-Huckel MO calculations is described. (C) 2001 Elsevier Science BY All rights reserved.