Structural, theoretical and multinuclear NMR study of mercury(II) complexes with a new ambidentate phosphorus ylide

The reaction of the new ambidentate ylide, Ph3PCHCOCH2COOC2H5 (EAPPY), with HgX2 (X = Cl, Br and I) in equimolar ratios using methanol as the solvent leads to binuclear complexes of the type [EAPPY·HgX2]2 (X = Cl (1), Br (2) and I (3)). Single crystal X-ray analysis reveals the presence of a centrosymmetric dimeric structure containing the ylide and HgX2 (X = Br or I). The IR and NMR data of the product [(EAPPY)·HgCl2]2 (1), formed by the reaction of mercury(II) chloride with the same ylide, are similar to those of 2 and 3. Analytical data indicate a 1:1 stoichiometry between the ylide and Hg(II) halide in each of the three products. Theoretical studies indicate that the nature of the R group in ylides of the type Ph3PCHCOR has a weak effect on the Hg–C(ylide) bond length in binuclear Hg2L2I4 complexes.

The reaction of the new ambidentate ylide EAPPY with Hg(II) halides leads to binuclear complexes. The NMR data and the X-ray crystal structures of complexes 2 and 3 demonstrate C-coordination of the ylide to the metal. A theoretical study on the binuclear Hg2L2I4 complexes, in which the ligand L is a series of ylides of the type Ph3PCHCOR, at the B3LYP level of theory using three different basis sets including pseudo-potentials is reported.Figure optionsDownload as PowerPoint slideHighlights
► Synthesis and characterization of some binuclear Hg(II) complexes of the new phosphorus ylide.
► The single crystal X-ray analysis reveals a centrosymmetric dimeric structure for the complexes.
► The solid state and gas phase structures of several binuclear Hg–ylide complexes are compared.
► The nature of the R group in the ylides of the type Ph3PCHCOR has a weak effect on the Hg–C(ylide) bond length.
► The Hg–C(ylide) distance increases with decreasing hardness of the coordinated halide ion.