Reactivity of mercury(II) halides with the unsymmetrical phosphorus ylide Ph₂PCH₂CH₂PPh₂=C(H)C(O)Ph: Crystal structure of {HgI₂ [</i>P</i>Ph₂CH₂CH₂PPh₂=C(H)C(O)Ph]}<i>_n</i>

The unsymmetrical phosphorus ylide, Ph₂PCH₂CH₂PPh₂=C(H)C(O)Ph is shown to react with Hg(II) halides to form polymeric products with the composition {HgX₂ [PPh₂CH₂CH₂PPh₂C(H)C(O)Ph]}<i>_n</i>, where X = Cl (<b>1</b>), Br (<b>2</b>), I (<b>3</b>). The complexes have been characterized by elemental analysis, IR, ¹H, ³¹P NMR spectra as well as by ESI mass spectra. In product <b>1</b> the ylide exhibits a P, C-bridging mode of coordination, while in <b>2</b> and <b>3</b> it shows a monodentate P-coordination with the dangling ylide. The structure of complex <b>3</b> has been characterized crystallographically. The monomeric –Hg–I–Hg– bridging in <b>3</b> leads to a zig-zag polymeric chain in which mercury assumes a distorted tetrahedral geometry.