Synthesis, characterization, and preliminary studies of vanadium(IV) complexes with a Schiff base and thiosemicarbazones as mixed-ligands.

[VO(Sal--tryp)(HO)] (where sal--tryp = -salicylidene--tryptophanate) was used as a precursor to produce the novel complexes, [VO(Sal--tryp)(MeATSC)].1.5CHOH (where MeATSC = 9-Anthraldehyde-N(4)-methylthiosemicarbazone), [VO(Sal--tryp)(-Ethhymethohcarbthio)].HO (where -Ethhymethohcarbthio = ()--ethyl-2-(4-hydroxy-3-methoxybenzylidene)hydrazinecarbothioamide), and [VO(Sal--tryp)(acetylethTSC)].CHOH (where acetylethTSC = ()--ethyl-2-(1-(thiazol-2-yl)ethylidene)hydrazinecarbothioamide), by reaction with the respective thiosemicarbazone. The chemical and structural properties of these ligands and complexes were characterised by elemental analysis, ESI MS, FT-IR, UV-visible, ESR, H and C NMR spectroscopy, and X-ray crystallography. DMSO and DMSO-d solutions of compounds were oxidised in air to produce vanadium(V) species which were verified by ESI MS and V NMR spectroscopy. Anti-cancer properties of compounds were examined with three colon cancer cell lines, HTC-116, Caco-2, and HT-29, and also with non-cancerous colonic myofibroblasts, CCD18-Co. Compounds exhibited less inhibitory effects in the CCD-18Co cells, indicating a possible cytotoxic selectivity towards colon cancer cells. In general, those compounds which exhibited anti-proliferative activity on cancer cells, but did not affect non-cancerous cells, may have a potential in chemotherapy.