Naslov
Oxovanadium(V) complexes with thiosemicarbazone ligands: formation of thiadiazole and thiazoline derivatives by vanadium induced cyclization

Autori
Rubčić, Mirta ; Cindrić, Marina ; Đilović, Ivica ; Tomišić, Vladislav ; Novak, Predrag ; Hrenar, Tomica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
Gordon Research Conference on Inorganic Reaction Mechanisms

Mjesto i datum
Ventura (CA), Sjedinjene Američke Države, 17.02.2007. - 23.02.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
thiosemicarbazones ; vanadium(V) complexes ; cyclization ; IR spectroscopy ; X-ray diffraction ; UV/VIS spectroscopy ; DFT calculations

Sažetak
Thiosemicarbazones are a class of small molecules that have been evaluated over the last 50 years as antiviral and anticancer therapeutics. Various metal complexes of thiosemicarbazones have been recently studied because in many cases biological activity of such ligands is related to their chelating properties, since they can be in vivo coordinated to metal ions. On the other hand, chemistry of vanadium is currently a subject of extensive research partly because of its increasingly recognized biochemical importance. Based on these considerations, we were interested in investigating the reactions of simple vanadium species with pharmacologically interesting ligands such as thiosemicarbazones. We have investigated the reactions of oxovanadium(IV) acetylacetonate and salicylaldehyde-4-phenylthiosemicarbazone (H2L1), 4-methoxysalicylaldehyde-4-phenylthiosemicarbazone (H2L2) and 3-methoxy-4-phenylthiosemicarbazone (H2L3) in series of different alcohols, methanol, ethanol and n-propanol, respectively. All reactions were carried under aerial conditions. Reactions afforded three different kinds of compounds , mononuclear oxovanadium(V) complexes [VO(L)(OR')] (R': Me, Et, n-Pr), thiazoline products of intermolecular cyclization of thiosemicarbazone ligands and acetylacetone as well as dinuclear oxovanadium(V) complexes in which the ligand has undergone intramolecular cyclization to generate thiadiazole ring. Amount of the particular kind of product is mainly dependent on duration of the reaction, choice of alcohol as well as the nature of ligand, more precisely substituent R on aldehyde ring. Structure of products was determined by single crystal X-ray diffraction methods. All compounds were characterised by means of IR spectroscopy and when possible by means of X-ray powder diffraction methods, thermogravimetric methods, UV/VIS and NMR spectroscopy.Furthermore, in aim of understanding and clearyfieng reaction mechanism DFT calculations were also performed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA