Coordination Chemistry of Potentially S,N,N_py-Tridentate Thiosemicarbazones with the {Re(CO)₃}⁺ Fragment and Formation of Hemiaminal Derivatives

Abstract

Nine potentially S,N,N py -tridentate thiosemicarbazones (HL) derived from pyridine-2-carbaldehyde or 1-(2pyridyl)ethanone have been prepared and fully characterized. The X-ray crystal structures of six of them and two hydrochlorides were determined and analyzed. The reaction of the [ReX-(CH 3 CN) 2 (CO) 3 ]/[ReX(CO) 5 ] (X = Cl and Br) precursors with these ligands yielded different kinds of compounds: the adducts [ReX(HL)(CO) 3 ], in which the ligands were S,Nbidentate; the trinuclear species [Re 3 Cl 2 (L 23 )(HL 23 )(CO) 9 ]; and the thiosemicarbazonate compounds [Re(L)(CO) 3 ], where the ligand is S,N,N py -tridentate. Besides, the reaction in methanol or ethanol of the thiosemicarbazones derived from aldehydes yielded S,N,N py -tridentate hemiaminal cationic [Re(HL OR )(CO) 3 ]X and neutral [Re(L OMe )(CO) 3 ] complexes after the coordinated ligand underwent addition of the alcohol group to the imine bond. The reactivity of the complex [ReX(HL)(CO) 3 ] in MeOH and NEt 3 led to the formation of dinuclear [Re 2 (L) 2 (CO) 6 ], where the thiosemicarbazonate is again S,N-bidentate. The influence that the substituents on the thiosemicarbazone ligands have on the stability of the complexes and the effect of the reaction medium on the resulting compounds have been analyzed.

Biomolecular Interactions and Anticancer Mechanisms of Ru(II)-Arene Complexes of Cinnamaldehyde-Derived Thiosemicarbazone Ligands: Analysis Combining In Silico and In Vitro Approaches

“…TSCs commonly bind to metal ions in a bidentate (among other) fashion, utilizing nitrogen and sulfur atoms as donor sites and forming stable five-membered chelate rings. This strong coordination enhances the stability of the resulting complexes. , Consequentially, RuTSCs typically exhibit stability across a broad spectrum of conditions, rendering them suitable for diverse chemical processes and reactions. A subset of Ru(II)-arene compounds has exhibited the ability to overcome drug resistance in cancer cells, addressing a severe challenge in cancer therapy .…”