Homogeneous Iron Catalysts in the Reaction of Epoxides with Carbon Dioxide

Among the attempts to consolidate the so-called circular economy, the conversion of carbon dioxide (CO2) into added-value products has gained more and more attention during the last three decades. One of the feasible applications of CO2 as a C-1 building block is its incorporation into cyclic organic carbonates (COCs) and aliphatic polycarbonates (APCs) by reaction with epoxides. A plethora of homogeneous catalytic systems has been reported to promote this reaction, based mainly on magnesium, aluminium, cobalt, chromium and zinc complexes. Despite the abundance and low toxicity of iron, only few examples of catalysts based on this metal had been reported until fifteen years ago, and relevant advances were made only during the last decade. This review seeks to cover this progress and to give a renewed impulse for further research into iron utilisation in this kind of catalysis.