Study of DNA Interaction and Cytotoxicity Activity of Oxidovanadium(V) Complexes with ONO Donor Schiff Base Ligands

Syntheses, Structures, and Electrochemical Properties of Metallacyclic Oxidovanadium(V) Complexes with Asymmetric Multidentate Linking Ligands

Trinuclear metallacyclic oxidovanadium(V) complexes, [{VO(L3+2R)}3] (1-3) with asymmetric multidentate linking ligands (H3L3+2R: R = H, Me, Br), were synthesized. The molecular structure of 1 is characterized as a tripod structure, with each V(V) ion coordinated by ONO-atoms from a tridentate Schiff base site and ON-atoms from a bidentate benzoxazole site of two respective H3L3+2H ligands. The intramolecular V⋯V distances range from 8.0683 to 8.1791 Å. Complex 4 is a mononuclear dioxidovanadium(V) complex, (Et3NH)[VO2(HL3+2H)]. Cyclic voltammograms of 1-3 in DMF revealed redox couples attributed to three single-electron transfer processes.

Hydrolytically Stable TiIV-Hydrazone-Based Metallodrugs: Protein Interaction and Anticancer Potential

In this work, three titanium(IV) [TiIV(L1-3)2] (1-3) complexes have been reported using three different tridentate dibasic ONO donor hydrazone ligands, pyridine-4-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)-hydrazide (H2L1), furan-2-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)-hydrazide (H2L2), and thiophene-2-carboxylic acid (3-ethoxy-2-hydroxybenzylidene)-hydrazide (H2L3) tethered with heterocyclic moieties. Elemental analysis, FT-IR, UV-vis, NMR, HR-ESI-MS, and single-crystal X-ray analysis have been used to characterize H2L1-3 and 1-3. In solid structures of 1-3, two ligand molecules with N2O4 donor sets give distorted octahedral geometries to the metal center. The aqueous stability of 1-3 was investigated and well correlated to their perceived pharmacological results. During the investigation, all three complexes were found to be hydrolytically stable in a 90% DMSO-d6/10% D2O (v/v) medium up to 48 h. Furthermore, the interaction of 1-3 with bovine serum albumin (BSA) was tested using fluorescence and absorption techniques. The complexes showed static quenching with a biomolecular quenching constant of Kq ∼ 1013 proposing a high affinity of complexes for BSA. Finally, the anticancer potential of 1-3 was tested against HeLa, A549, and NIH-3T3 cell lines. Among all, 1 with an IC50 value of 11.6 ± 1.1 μM against HeLa cells was found to be the most cytotoxic in the series. Furthermore, it has been found that the compounds induce an apoptotic mode of cell death, which is confirmed by the live cell confocal microscopy and flow cytometry techniques.

A Series of Non-Oxido VIV Complexes of Dibasic ONS Donor Ligands: Solution Stability, Chemical Transformations, Protein Interactions, and Antiproliferative Activity

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^IV compounds 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^IV complexes show distorted octahedral (1 and 2) or trigonal prismatic (3) arrangement around the non-oxido V^IV center. 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^VO₂ species could be responsible for the biological activity.

A Vanadium(V) complexes derived from pyridoxal/salicylaldehyde. Interaction with CT-DNA/HSA, and molecular docking assessments

With the increasing development of metallopharmaceuticals, coordination compounds become viable alternatives for therapeutic uses. Despite the importance of platinum derivatives in this area, first-row transition metals complexes are welcome due to their characteristics. Vanadium is a promising metal in this context, as it has a range of compounds with different biological applications, including anticancer therapeutic effects. In this effort, the study of interactions between coordination compounds with deoxyribonucleic acid and with human serum albumin is fundamental. In this way, ten iminic ligands were synthesized by condensing p-substituted aromatic benzohydrazides (OH, CH₃, H, NO₂, and NH₂) with salicylaldehyde (L1As-L5As) or pyridoxal hydrochloride (L1P-L5P). These ligands have characteristics that allow the tridentate coordination of vanadium cations, leading to the formation of ten vanadium(V) complexes (C1As-C5As and C1P-C5P) with different structural features, all characterized by single-crystal X-ray diffraction, UV-Vis and infrared spectroscopies, and cyclic voltammetry. In addition, the complexes were tested for their interactions with calf thymus deoxyribonucleic acid and human serum albumin by spectroscopic assays and molecular docking calculations. These new results can contribute to further research and provide different ways to design new vanadium complexes with biological applications.

New Trends on Vanadium Chemistry, Biochemistry, and Medicinal Chemistry

Vanadium was discovered twice [...]

Synthesis, characterization and application of oxovanadium(iv) complexes with [NNO] donor ligands: X-ray structures of their corresponding dioxovanadium(v) complexes

Two oxovanadium(iv) complexes ligated by [NNO] donor ligands have been synthesized and characterized by ESI-HRMS, elemental (CHN) analysis and spectroscopic (UV-Vis, IR and EPR) techniques. Block shaped brown crystals from the methanolic solutions of these oxovanadium(iv) complexes were obtained during the crystallization process. Crystallographic structures of the resulting crystals revealed that the original oxovanadium(iv) complexes have been transformed into new dioxovanadium(v) complexes with concomitant oxidation of VIV to VV. The original oxovanadium(iv) complexes have been identified to be an efficient catalyst for the CO2 cycloaddition reaction with epoxides resulting up to 100% cyclic carbonate products. The geometries of oxovanadium(iv) complexes are optimized by the density functional theory (DFT) calculations at the uB3LYP/6-31G**/LANL2DZ level of theory. The geometry and structural parameters of optimized structures of oxovanadium(iv) complexes are in excellent agreement with the parameters of X-ray structures of their dioxovanadium(v) counterparts. Further, TD-DFT and Spin Density Plots for the oxovanadium(iv) complexes are performed in order to get more insights about their electronic absorption and EPR spectroscopies, respectively.