Transition Metal Complexes as Antibacterial Agents: An Overview

Due to the vacant d-orbitals, variable oxidation states, and coordination geometries of transition metals, they have a tendency to form complexes with variety of ligands. The effectiveness of these transition metal complexes as therapeutic agents has been demonstrated in various domains, such as antibacterial, anti-cancer, anti-fungal, anti-diabetic, and anti-malarial. We have reviewed the antibacterial investigations of several transition metal complexes spanning last few years in this review. Upon reviewing the literature, it has been found that metal complexes work better against bacteria than free ligands do. Almost, all the investigations in literature review have come to the conclusion that the nature of the ligand, the nature of the metal ion, the metal's oxidation state, coordination behavior, symmetry, and the stability of the complexes are the key factors responsible for the increased antibacterial activity of metal complexes. Furthermore, after complexation, the metal complexes exhibit enhanced lipophilicity and increased facile translocation through the cellular membrane. Additionally, in contrast to free ligands, the stability and antibacterial activity of metal complexes increased as a result of chelation.