Synthesis, spectroscopic and structural characterization and antibacterial activity of new dimeric and polymeric mercury(II) complexes of phosphonium ylide

Abstract

The new α-keto stabilized phosphonium ylide (p-tolyl)3C(H)C(O)C6H4-m-Br (Y) was synthesized by addition of tri(p-tolyl)phosphine to 2,3′-dibromoacetophenone, followed by treatment with NaOH 10%. The reaction of this ylide with HgX2 (X=Cl, Br and I) and Hg(NO3)2·H2O in equimolar ratio using dry methanol as solvent led to formation of dimeric complexes of type [(Y)HgX2]2 (X=Cl (1), Br (2), I (3)) and polymeric complex of [(Y)Hg(NO3)2]n (4). Characterization of obtained compounds was performed by elemental analysis and IR, 1H, 31P and 13C NMR spectroscopies. Also, single crystal X-ray diffraction analysis revealed the symmetric halide-bridged dimeric structure of complex 2. Considering these results, we have confirmed that the coordination of ylide to metal center occurred through the ylidic carbon atom. In addition, we report the antibacterial activity of these complexes against both the Gram-positive and Gram-negative bacteria, which in all cases the observed antibacterial activities exceed that of Tobramycin, Tetracycline and Chloramphenicol as standard.