Transition-metal complexes of isatin-beta-thiosemicarbazone. X-ray crystal structure of two nickel complexes

Manganese, iron, cobalt, nickel, copper and zinc complexes of isatin-beta-thiosemicarbazone (H2L) have been synthesized and spectroscopically characterized The X-ray crystal structures of two nickel complexes, namely [Ni(HL)2]. EtOH (1) and [Ni(HL)2]. 2DMF (2), reveal a distorted octahedral coordination with the monodeprotonated ligand that behaves as an O,N,S terdentate. Different packing interactions are determined by the presence of different crystallization solvents, i.e., ethanol in 1 and dimethylformamide (DMF) in 2. 1H and 13C NMR studies of the ligand and zinc complexes in solution were carried out and a complete assignment for the ligand was made by homodecoupling, gradient assisted 2D 1H-13C HMQC and HMBC NMR spectroscopy. Biological studies, carried out in vitro on human leukaemic cell lines U937, have shown that the free ligand and the copper (II) complex are more active in the inhibition of cell proliferation than the nickel complexes. No compound was able to induce apoptosis.

Acenaphthenequinone thiosemicarbazone and its transition metal complexes: synthesis, structure, and biological activity

The reaction of iron, nickel, copper, and zinc chlorides or acetates with acenaphthenequinone thiosemicarbazone, Haqtsc leads to the formation of novel complexes that have been characterized by spectroscopic studies (NMR, IR) and biological properties. The crystal structures of the free ligand Haqtsc 1 and of the compound [Ni(aqtsc)2].DMF 2, have also been determined by X-ray methods from diffractometer data. In 1, the conformation of the two nonequivalent molecules is governed by intramolecular hydrogen bonds, while an intermolecular hydrogen bond is responsible for dimer-like groups formation. In 2, the coordination geometry about nickel is distorted octahedral, and the two ligand molecules are terdentate monodeprotonated. Biological studies have shown that, for the first time at least up the used doses, a free ligand is active both in the inhibition of cell proliferation and in the induced differentiation on Friend erythroleukemia cells (FLC).

Synthesis, structure, and spectroscopic properties of acetato(dimethyl)(pyridine-2-carbaldehydethiosemicarbazonato)tin(IV) acetic acid solvate, [SnMe2(PyTSC)(OAc)].HOAc. Comparison of its biological activity with that of some structurally related diorganotin(IV) bis(thiosemicarbazonates)

The synthesis, X-ray structure, behavior in solution, and biological properties of the complex [SnMe2(PyTSC)(OAc)].HOAc (HPyTSC = pyridine-2-carbaldehydethiosemicarbazone) are reported. The tin atom of this complex is coordinated to an N,N,S-tridentate PyTSC- anion, to a monodentate acetate ion, and to the two methyl groups in an approximately pentagonal bipyramidal environment with a vacant equatorial position. The complex partially evolves in DMSO and in DMSO/CHxCl4-x (X = 1, 2) mixtures, giving HPyTSC and SnMe2(OAc)2. [SnMe2 (PyTSC)(OAc)].HOAc, [SnMe2(DAPTSC)], and [SnPh2(DAPTSC)].2DMF (H2DAPTSC = 2,6-diacetylpyridine bis(thiosemicarbazone)) all suppress proliferation of Friend erythroleukaemia cells (FLC). DMSO-induced differentiation of FLC is slightly suppressed by [SnMe2(DAPTSC)] and is unaffected by [SnPh2(DAPTSC)].2DMF and [SnMe2(PyTSC)(OAc)].HOAc.