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

Two new mercury (II) polymeric complexes namely, [Hg2(μ-bbit)Cl4]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 HgCl2 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 HgCl3S (for 1) and HgSe2S2 (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.