P-C versus C-H bond cleavage in coordinated bis(dimethylphosphino)methane: controlled access to either phosphinite or functionalized diphosphine complexes

Treatment of fac-Mn(CNPh)(CO)3(dmpm)]ClO4 (1) with KOH affords neutral phosphinite complex fac-Mn(PMe2O)(CNPh)(CO)3(PMe3)] (2) as a result of P-C bond cleavage on the dmpm ligand, whereas when carrying out the reaction in the presence of iodine the diphosphinoketenimine derivative fac-MnI(CO)3(PMe2)2C=C=NPh]] (4) is obtained after deprotonation and further functionalization of the central carbon atom of the diphosphine.