Binuclear mercury(II) complexes of sulfonium ylides: Synthesis, structural characterization and anti-bacterial activity

Reaction of α-keto stabilized sulfonium ylides (Me)2SCHC(O)C6H4R (R = p-Me (a); p-Cl (b)) with HgX2 (X = Cl, Br and I) in equimolar ratios using methanol as solvent leads to binuclear products of the type [HgX2(ylide)]2 (X = Cl (1), Br (2) and I (3)). Single crystal X-ray diffraction analysis reveals the presence of unexpected asymmetric halide-bridged dinuclear structures for 1a and 2b. Characterization of the compounds by IR, 1H- and 13C NMR spectroscopy confirmed coordination of the ylide to the metal through the carbon atom. In addition, the antibacterial effects of DMSO-solutions of the complexes were investigated by the disc diffusion method against three Gram positive and three negative bacteria. All complexes represent antibacterial activity against these bacteria with high levels of inhibitory potency exhibited against the Gram-positive species.

► The binuclear mercury complexes of sulfonium ylides are structurally characterized for the first time. ► IR, 1H- and 13C NMR spectroscopy demonstrates C-coordination of the ylide to the metal. ► There is an asymmetric halide-bridge structure similar to binuclear phosphonium analogs. ► The HgC bond length in mercury(II) complexes sulfonium ylides is less than phosphonium analogs. ► All complexes display antibacterial activity against the bacteria tested especially on Gram positive ones.