The synthesis and structural characterisation of the mercury (II) halide complexes of the phosphorus ylide carbethoxymethylenetriphenylphosphorane

The reaction of the ylide carbethoxymethylenetriphenylphosphorane (EPPY), Ph3PCHCOOEt, with mercury (II) halides has been investigated. The resulting dimeric mercury (II)-ylide complexes are isostructural and of the form [(EPPY)(HgX2)]2 where X is either bromine (1), chlorine (2), or iodine (3). These complexes have been characterised by spectroscopic techniques and X-ray diffraction. The ylide ligands have been shown to be C-coordinated to the mercury (II) atom.