Synthetic and theoretical study on novel N-ylidic complexes of mercury as new antibacterial agents

The novel structure of Hg(II) complexes including the pyridinium ylide C₅H₅NCHC(O)C₆H₄-m-Br (Y) were synthesized and reported in this study. In the first step, the pyridinium salt C₅H₅NCH₂C(O)C₆H₄-m-Br (S) was produced by reacting 2,3'-dibromoactophenone and pyridine. then, treatment of S with K₂CO₃ gave the related pyridinium ylide Y. Finally, the reaction of Y with HgX₂ and Hg(NO₃)₂·H₂O leads to the formation of novel binuclear [HgY₂][HgX₄] (X=Cl (1); X=Br (2); X=I (3)) and polymeric [HgY(NO₃)₂]_n (4) complexes. The structure of complex 2 was also determined by X-ray diffraction analysis. The obtained analyses proved the coordination through the ylidic carbon to metallic center. Additionally, Natural Bond Orbital (NBO), Energy Decomposition Analysis (EDA), and EDA-NOCV studies are also used to investigate the nature of metal-ligand bonding in the complexes. Finally, the antibacterial activity of 1-4 was also examined against Gram positive and negative represented significant levels of inhibitory potency respected to used standards.