Recent findings in the chemistry of osmium complexes with the POP pincer ligands 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene (xant(PiPr2)2) and 4,6-bis(diisopropylphosphino)dibenzofuran (dbf(PiPr2)2) and their comparison with the ruthenium counterparts are revised. In particular, the ability of polyhydride derivatives to participate in processes of hydrogen generation, to activate C–H bonds, to stabilize the coordination of σ-bonds or to promote organic synthetic reactions, including hydrogen borrowing processes, are highlighted. In addition, it is shown that the linker between the PiPr2 groups determines the flexibility of the diphosphines, allowing them to adapt their coordination mode to the requirements of the sequential processes, changing from κ3-mer to κ3-fac and κ2-PP bidentate according to the electronic and steric requirements of the involved intermediates.

Peer reviewed