Di-μ-oxidovanadium(V) di-nuclear complexes: Synthesis, X-ray, DFT modeling, Hirshfeld surface analysis and antioxidant activity

Advances in Coordination Chemistry of Schiff Base Complexes: A Journey from Nanoarchitectonic Design to Biomedical Applications

Since the discovery of Schiff bases over one and a half centuries ago, there has been tremendous research activity in the design of various Schiff bases and examination of their diverse structures and versatile applications. This family of compounds has continued to captivate many research groups due to the simplicity of their synthesis through the condensation of amines with carbonyl compounds. While conventional synthesis has been the most widely used, green synthetic methodologies have been also explored for this reaction, including sonication, microwave-assisted, natural acid-catalyzed and mechanochemical syntheses as well as utilizing ionic liquid solvents or deep eutectic solvents. Schiff bases have been utilized as excellent ligands for coordination to transition metals and late transition metals (lanthanides and actinides). These Schiff base compounds can be mono-, di-, or polydentate ligands. The aim of this review is to examine the biological applications of Schiff base complexes over the past decade with particular focus on their antimicrobial, antiviral, anticancer, antidiabetic, and anti-inflammatory activity. Schiff base complexes have been found effective in combating bacterial and fungal infections with numerous examples in the literature. The review addressed this area by focusing on the very recent examples while using tables to summarize the vast breadth of research according to the metallic moieties. Viruses have continued to be a target of many researchers in light of their continuous mutations and impact on human health, and therefore some examples of Schiff base complexes with antiviral activity are described. Cancer continues to be among the leading causes of death worldwide. In this article, the use of Schiff base complexes for, and the mechanisms associated with, their anticancer activity are highlighted. The production of reactive oxygen species (ROS) or intercalation with DNA base pairs leading to cell cycle arrest were the main mechanisms described. While there have been some efforts made to use Schiff base complexes as antidiabetic or anti-inflammatory agents, there are limited examples when compared with antimicrobial and anticancer studies. The conclusion of this review highlights the emerging areas of research and future perspectives with an emphasis on the potential uses of Schiff bases in the treatment of infectious and noninfectious diseases.

Oxoperoxovanadium Complexes of Hetero Ligands: X-Ray Crystal Structure, Density Functional Theory, and Investigations on DNA/BSA Interactions, Cytotoxic, and Molecular Docking Studies

Oxoperoxovanadium (V) complexes [VO (O)2 (nf) (bp)] (1) and [VO (O)2 (ox) (bp)] (2) based on 5-nitro-2-furoic acid (nf), oxine (ox) and 2, 2' bipyridine (bp) bidentate ligands have been synthesized and characterized by FT-IR, UV-visible, mass, and NMR spectroscopic techniques. The structure of complex 2 shows distorted pentagonal-bipyramidal geometry, as confirmed by a single-crystal XRD diffraction study. The interactions of complexes with bovine serum albumin (BSA) and calf thymus DNA (CT-DNA) are investigated using UV-visible and fluorescence spectroscopic techniques. It has been observed that CT-DNA interacts with complexes through groove binding mode and the binding constants for complexes 1 and 2 are 8.7 × 103 M-1 and 8.6 × 103 M-1, respectively, and BSA quenching constants for complexes 1 and 2 are 0.0628 × 106 M-1 and 0.0163 × 106 M-1, respectively. The ability of complexes to cleave DNA is investigated using the gel electrophoresis method with pBR322 plasmid DNA. Furthermore, the cytotoxic effect of the complexes is evaluated against the HeLa cell line using an MTT assay. The complexes are subjected to density functional theory calculations to gain insight into their molecular geometries and are in accordance with the results of docking studies. Furthermore, based on molecular docking studies, the intermolecular interactions responsible for the stronger binding affinities between metal complexes and DNA are discussed.