A Comprehensive Review on Anthranilic acid-derived Schiff bases and their Metal Chelates: Structures and Applications

The worthwhile contributions made to the literature by researchers on the ligation behaviour of Schiff bases derived from anthranilic acid and their applications is hitherto not togetherized. This review covers a comprehensive bibliographic perusal of anthranilic acid-derived Schiff bases and their chelates reported circa over the last three decades (۱۹۹۰ - ۲۰۲۲) with a view to furnishing information that will help researchers in the design of new Schiff bases as potential candidates in different applications. A scrupulous survey of the literature suggests that anthranilic acid-derived Schiff bases preferentially ligate metal ions through azomethine nitrogen (-N=CH-) and the hydroxyl oxygen (OH) of the carboxyl group after deprotonation rather than chelating via the carbonyl oxygen (C=O). However, a pocket of the literature reported the coordination sites as the iminic nitrogen (-N=CH-) and carbonyl oxygen (C=O) of the carboxylic group. While most first row transition metals complexes of diverse geometries with the Schiff bases' denticity ranging from N,O-bidentate, O,N,O-tridentate and N۲O۲-tetradentate amongst others have been documented, only few heavier transition metals are reported. Furthermore, these Schiff bases find promising applications in medicinal, pharmaceutical, catalytic, and analytical chemistry, especially in the seperation, identification, and detection of several metal ions and anions. In addition to these, they are used as corrosion inhibitors, as odorants, etc. Notably, the chelates more often exhibited more potency as antibacterial, antifungal, anticancer, antidiabetic, antioxidant, antioxidant, antiulcer and molluscicidal agents than the free Schiff base ligands. This review exhaustively did synthesized most significant works on the subject.