Insights into the spodium bonding characteristics of a bactericidal Hg(ii) complex

Abstract

In our pursuit to explore the supramolecular properties and biological activities of metal-based complexes, a novel Hg(II) complex 1 having spodium bonds was synthesized in good yields from a o-nitrobenzaldehyde isonicotinoyl hydrazone (HL) ligand in methanol. Hg(II) complex 1 exhibits a 1D chain, constructed exclusively through N3–H3N⋯O3 hydrogen bonding interactions. Furthermore, the 1D chain is strengthened by O⋯π and π⋯π stacking contacts, contributing to the overall stability of the structure. The crystal packing in Hg(II) complex 1 was explicated using supramolecular studies, revealing the existence of two types of intriguing Hg⋯I spodium bonds. Hg⋯I spodium bonds have also been assessed and described by employing density functional theory (DFT) computations. The anisotropic character of the Hg center and its function in controlling the geometry and strength of the spodium bonding contacts in Hg(II) complex 1 are highlighted by the variation in electrostatic potential (ESP) magnitudes. Hirshfeld surface (HS) and two-dimensional fingerprint plot analyses offered a further method for quantifying the Hg⋯I spodium bonding and hydrogen bonding in Hg(II) complex 1. Moreover, the antibacterial properties of Hg(II) complex 1 and the ligand (HL) against Gram-positive bacterial strains (Mammaliicoccus lentus, Staphylococcus cohnii, Corynebacterium stationis, and Bacillus cereus) and Gram-negative bacterial strains (Enterobacter cloacae, Klebsiella pneumoniae, Salmonella enterica, and Shigella sonnei) were assessed.