Manganese(I) Catalyzed CO2 Reduction Processes in Homogenous Phase

The catalytic activation of carbon dioxide (CO2) can be a promising tool for the use of this abundant, non-flammable and non-toxic gas as feedstock for C1 chemical synthesis, in particular for bulk products such as formic acid (HCOOH) and methanol (CH3OH). The key for successful, widespread use of CO2 is the design and application of efficient, thermally robust and cheap catalysts. In the last decade, the use of earth-abundant transition metal complexes, in particular those of 3d metals, has shown promising results. In this review article, a comprehensive summary of the main catalytic systems described in the literature for homogeneous Mn(I)-catalyzed CO2 reduction processes (hydrogenation, hydroboration and hydrosilylation) will be described, with particular attention to the effect of stabilizing ligands, reaction conditions and need for additives, together with mechanistic details often obtained by a combination of experimental data and DFT calculations.