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

Abstract 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 (K2i-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 [Cd2(tn)2(i-mnt)2] (1). The tri-metallic Hg(II) based cocrystallized aggregates of [Hg2(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....S, N - H....N, C - H....S and C - H....N type hydrogen bonds contribute in crystal packing architecture, revealing interesting geometrical patterns and graph-set-motifs. The Hirshfeld surface mapped over dnorm exhibited N....H/H....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 K2i-mnt against Gram-positive (Staphylococcus aureus 9542 and Streptococcus pneumonia 2672) and Gram-negative (Klebsiella pneumonia 7407 and Shigella flexneri 1457) human pathogenic bacterial strains show their promising antimicrobial activities.