• Correia, Isabel
• Dinda, Rupam
• Sahu, Gurunath
• Sciortino, Giuseppe
• Banerjee, Atanu
• Patra, Sushree Aradhana
• Carvalho, M. Fernanda N. N.
• Pisanu, Federico
• Pessoa, João Costa
• Reuter, Hans
• Garribba, Eugenio

Abstract

<p>A series of mononuclear non-oxido vanadium(IV) complexes, [V^IV(L^1-4)₂] (1-4), featuring tridentate bi-negative ONS chelating S-alkyl/aryl-substituted dithiocarbazate ligands H₂L^1-4, are reported. All the synthesized non-oxido V^IVcompounds are characterized by elemental analysis, spectroscopy (IR, UV-vis, and EPR), ESI-MS, as well as electrochemical techniques (cyclic voltammetry). Single-crystal X-ray diffraction studies of 1-3 reveal that the mononuclear non-oxido V^IVcomplexes show distorted octahedral (1 and 2) or trigonal prismatic (3) arrangement around the non-oxido V^IVcenter. EPR and DFT data indicate the coexistence of mer and fac isomers in solution, and ESI-MS results suggest a partial oxidation of [V^IV(L^1-4)₂] to [V^V(L^1-4)₂]⁺and [V^VO₂(L^1-4)]^-therefore, all these three complexes are plausible active species. Complexes 1-4 interact with bovine serum albumin (BSA) with a moderate binding affinity, and docking calculations reveal non-covalent interactions with different regions of BSA, particularly with Tyr, Lys, Arg, and Thr residues. In vitro cytotoxic activity of all complexes is assayed against the HT-29 (colon cancer) and HeLa (cervical cancer) cells and compared with the NIH-3T3 (mouse embryonic fibroblast) normal cell line by MTT assay and DAPI staining. The results suggest that complexes 1-4 are cytotoxic in nature and induce cell death in the cancer cell lines by apoptosis and that a mixture of V^IV, V^V, and V^VO₂species could be responsible for the biological activity.</p>

Topics

• impedance spectroscopy
• compound
• x-ray diffraction
• density functional theory
• electron spin resonance spectroscopy
• cyclic voltammetry
• vanadium
• elemental analysis
• electrospray ionisation
• electrospray ionisation mass spectrometry