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.