Recent developments in homogeneous catalysis for the functionalisation of CO₂

This chapter discusses recent developments on the conversion of CO₂ into compounds such as formates and methanol, in addition to looking at utilising CO₂ for N-methylation transformations and within cascade-type reactions. These synthetic routes share a common pathway, connected by the hydrogenation of CO₂. The rational design of the catalyst and choice of ligands are emphasised. The effects of specifically designed ligands, which impart rigidity, stability, solubility, and which also confer other steric and electronic properties on to the metal, are analysed. Several new methodologies and separation techniques for the commercial production of value-added chemicals, especially ones based on the use of amines and biphasic solvent mediums, are outlined. The role of additives such as Lewis acid co-catalysts, the choice of base, the effect of the partial pressures of H₂ and CO₂ and the active form of the catalyst are highlighted whilst discussing the mechanism of those transformations. In parallel, catalysts based on first-row transition metals are emphasised, in places, due to their relevance towards a sustainable future.