Synthesis and structural characterization of hetero-binuclear complexes containing a Fe0→Mn+ bond bridged by a non-rigid P,N-phosphine ligand

A new non-rigid phosphine ligand, N-(diphenylphosphinomethyl)morpholine (L), has been synthesized. Its reaction with K[HFe(CO)4] results in the formation of the organometallic tridentate ligand trans-[Fe(CO)3(μ-L)2] which exhibits different coordinate modes in generating hetero-binuclear Fe0→Mn+ complexes (M=Hg(II), Cd(II), Cu(I), Ag(I)). In the copper(I) complex, both tertiary amino groups coordinate to the Cu atom at CuN1=2.059(4) and CuN2=2.055(4) Å. In the cadmium(II) complex, one tertiary N atom coordinates to the Cd atom at CdN1=2.481(3) Å, but only a weak interaction of 2.730 Å exists between the Hg and a N atom in the isomorphous mercury(II) complex.