Advances in Imine-Based Ligand Complexes for Catalytic CO2 Reduction: Structural Design, Mechanisms, and Catalytic Applications

Anthropogenic activities have resulted in ever-increasing amounts of CO 2 in the atmosphere, which is the driving cause of global warming and climate change. Although different mitigation processes have been explored by the researchers, catalytic CO 2 reduction and its conversion to chemical species that can be used industrially or for energy production have been explored as one of the most sustainable approaches to mitigate the elevated CO 2 levels. This review outlines the recent advancements in CO 2 reduction employing earth-abundant transition-metal Schiff base-based catalysts. Their ease of synthesis, low cost, structural flexibility, and adjustable electronic and steric properties have established them as useful platforms having a broad range of applications. These Schiff base complexes were found to show high catalytic performance in CO 2 reduction, including electrocatalytic and photocatalytic processes. However, comprehensive discussions on the catalytic efficiency, tuneability, and structural stability of the Schiff base complexes in CO 2 reduction processes are still hard to find. This review focuses on the effect of structural alterations and hybrid designs on product yield, product selectivity, stability, and the catalytic pathways giving special importance on addressing issues such as photosensitizer stability, long-term durability, and effective catalytic intermediate activation- are also included in this review. The review also presents insights on the importance of imine-functionalized hybrid catalysts and also highlights the structure–property–performance relationship, catalyst deactivation processes, and their probable mitigation steps, providing the readers with a detailed account of the challenges and future scope of using these Schiff base complexes in CO 2 reduction processes.