Mercury(II) complexes of stabilized phosphine–phosphonium ylide derived from bis(diphenylphosphino)methane: Synthesis, spectra and crystal structures

The reaction of a mixed phosphine–phosphonium ylide, PPh2CH2PPh2double bond; length as m-dashC(H)C(O)Ph with mercury(II) halides in methanol under mild conditions yielded the P, C-chelated complexes, [HgX2(PPh2CH2PPh2C(H)C(O)Ph)] where X = Cl (2), Br (3), I (4). Single crystal X-ray diffraction studies reveal the presence of mononuclear complexes containing Hg atom in a distorted tetrahedral environment and long Hg–Cylide bond. The five-membered chelate rings in the two independent molecules present in the asymmetric unit of 4 adopt ‘envelope’ and ‘twist’ conformations. Spectroscopic studies also indicate the weaker Hg–C bonding. Additionally, the molecular structure of the free ylide (1) is also discussed.