Homogeneous First-row Transition-metal-catalyzed Carbon Dioxide Hydrogenation to Formic Acid/Formate, and Methanol

Depletion of fossil fuel for global energy need emits large amount of greenhouse gas carbon dioxide into the biosphere. Carbon dioxide constitutes a sustainable C1 feedstock and cost-effective raw material for the synthesis of bulk and fine chemicals. The catalytic hydrogenation of CO2 to formic acid, and methanol is an attractive protocol owing to their application in chemical industry and as potential renewable hydrogen storage materials. Catalytic hydrogenation reactions are atom-economical, green and sustainable synthetic routes towards various new environmentally benign transformations. Homogeneous catalytic hydrogenation reactions based on earth-abundant, eco-friendly, first-row base metals for the preparation of an assortment of organic scaffolds is currently of paramount importance in academia and industry. The surge in base metal catalysis is evident from the increase in reports available in the literature in recent years. In this review, we summarize advances on homogeneous first-row transition metal catalysed direct and indirect reduction of carbon dioxide to formic acid/formate and methanol based on the hydrogenation strategy.