Towards ligand simplification in manganese-catalyzed hydrogenation and hydrosilylation processes

• Mn catalysts bearing bidentate ligands may be competitive with pincer systems. • Mn complexes without cooperative ligands can catalyze hydrogenation-type reactions. • Incorporation of N- or C-based donors in bidentate Mn catalysts is often beneficial. • Chemoselectivity in Mn-catalyzed hydrosilylation can be tuned by a tiny ligand choice. • Metal/ligand price balance makes Mn catalysts attractive for sustainable synthesis. Rapidly emerging application of organometallic manganese complexes incorporating less elaborated mono- and bidentate donor ligands in catalytic hydrogenation, transfer hydrogenation, hydrogen-borrowing and hydrosilylation processes is comprehensively reviewed. Special attention is devoted to the influence of the nature of donor moieties (P-, N- and C-donors) on the catalytic activity and/or selectivity, the comparison with structurally related polydentate systems and mechanistic aspects.