Chemistry of 2,2′-(diamino)azobenzene ligand: a brief review

Abstract In the last few decades, transition metal complexes incorporating various azo ligands have drawn much attention. A different group of researchers designed various multidentate azo ligands and explored the coordinating behavior with transition metals of such azo ligands. Transition metal chelates have a wide range of applications in synthetic chemistry. The ligand backbone containing both azo (–N=N–) and azomethine (–CH=N–) or imine (C=N–) groups have gained remarkable impetus for research in organometallic chemistry. The transition metal chelates incorporating azo-azomethine ligands are plentiful owing to their variant features with multiple coordination sites of the polydentate ligands. The versatile geometry of metal chelates and their potential applications in various fields of life has bestowed a high platform in coordination chemistry. The current review covers the synthetic strategies and coordination behavior of a potential azo ligand named 2,2′-bis(diamino)azobenzene and its related ligands with metal complexes of d-block elements. We have also scrutinized the applications of these ligands in synthetic chemistry and the azo-imine character of ligands in metal complexes.