Bimetallic and trimetallic Cd(II) and Hg(II) mixed-ligand complexes with 1, 1-dicyanoethylene-2,2-dithiolate and polyamines: Synthesis, crystal structure, Hirshfeld surface analysis, and antimicrobial study

Two new neutral bimetallic and trimetallic mixed-ligand complexes of Cd(II) and Hg(II) were obtained by using potential flexible molecular building blocks, 1,1-dicyanoethylene-2,2-dithiolate dipotassium salt (K(2)i-mnt) and polyamines. X-ray diffraction analysis revealed that dithiolate (i-mnt(-2)) acts as a bridging unit in the slightly distorted square pyramidal non-polymeric bimetallic cadmium derivative [Cd-2(tn)(2)(i-mnt)(2)] (1). The tri-metallic Hg(II) based cocrystallized aggregates of [Hg-2(tren)(i-mnt)(2)] and [Hg(tren)(i-mnt)] (2), has three different coordination environments around Hg(II) metal centers and one thiolate end of i-mnt(-2) links two Hg atoms in bridging mode. The N-H center dot center dot center dot S, N-H center dot center dot center dot N, C-H center dot center dot center dot S and C-H center dot center dot center dot N type hydrogen bonds contribute in crystal packing architecture, revealing interesting geometrical patterns and graph-set-motifs. The Hirshfeld surface mapped over d(norm) exhibited N center dot center dot center dot H/H center dot center dot center dot N type intermolecular interactions as the principal contributors in crystal packing. The in-vitro antimicrobial study evaluated by disk diffusion and broth dilution method with the compounds 1, 2 and ligand K(2)i-mnt against Gram-positive (Staphylococcus aureus 9542 and Streptococcus pneumonia 2672) and Gramnegative (Klebsiella pneumonia 7407 and Shigella flexneri 1457) human pathogenic bacterial strains show their promising antimicrobial activities.