Coordination framework of cadmium(II), harvested from dithiolate-imidazole binary ligand systems: Crystal structure, Hirshfeld surface analysis, antibacterial, and DNA cleavage potential

Abstract

The novel one-dimensional coordination polymer with binuclear building node {[Cd2(i-mnt)2(Im)2]DMF2}n (1) harvested from 1,1-dicyanoethylene-2,2-dithiolate (i-mnt2−) and imidazole (Im) has been systemically designed, synthesized and structurally characterized by elemental analysis, FT-IR and 1H NMR spectroscopy. Single crystal X-ray diffraction analysis revealed that in 1, each Cd(II) is in penta-coordinated environment having slightly distorted square pyramidal geometry (τ5 = 0.24) and have two bridging thiolate ends of i-mnt−2- along with one DMF solvent molecule. The flexible i-mnt2− ligand acts as a tridentate connector by ligating with Cd(II) centers in parallel dimeric units forming a 1D polymeric chain. Hirshfeld surface analyses and two dimensional (2D) finger print plots were employed to decode all types of non-covalent contacts in the crystal frameworks, allowing a systematic evaluation of the crystal structure. From HS analysis, it was observed that N⋯H/H⋯N type interactions (22.1%) have the major contribution compared to overall non-covalent interacrtions. The share of H⋯O/O⋯H interactions of the total surface is only 3.7%, their role is important in the direction and organization of crystal packaging. The in-vitro antimicrobial study of 1 against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (E. coli and P. aeruginosa) human pathogenic bacterial strains show promising antimicrobial activities. Furthermore, DNA cleavage study (E. coli DNA) of 1 using gel electrophoresis method revealed promising DNA cleaver property similar to H2O2 due to the efficient coordination of Cd(II) ion.