The influence of co-anions on the structural dimension of mercury (II) coordination polymers: Synthesis, crystal structure, spectroscopy and biological activity investigations

Abstract Two new mercury (II) polymeric complexes namely, [Hg 2 (µ-bbit)Cl 4 ] n ( 1 ) and [Hg(µ-bbit)(SeCN) 2 ] n ( 2 ) [bbit =1,1-(1,4-butanediyl)bis(1,3- dihydro-3-methyl-1H-imidazole- 2-thione] have been successfully synthesized and characterized by the single crystal X-ray diffraction analysis, IR, CHNS, PXRD and TGA. X-ray analysis shows that reaction of the bbit ligand with HgCl 2 leads to the formation of 2D honeycomb coordination polymer of 1 . Polymer 2 with an unpresented 1D wave-like structure was prepared by addition of selenocyanate to the reaction mixture of polymer 1 . In both complexes, the coordination geometry about each mercury atom can best be described as trigonal pyramidal with core structures of HgCl 3 S(for 1 ) and HgSe 2 S 2 (for 2 ) and the bbit ligands adopt a bridging mode through two sulfur atoms between the mercury atoms. The title polymers are further stabilized by the intermolecular hydrogen bonds to form a 3D polymeric network structure. Their antibacterial and DNA cleavage activities were also evaluated. On the base of the obtained results, these compounds have a broad antibacterial activity against both Gram-positive and Gram-negative species, while the Gram-positive species were more effected with these polymers. It may suggest that the functional groups present in the envelope of these bacteria are the main target for S-donor sites in the considered compounds.