In-situ Salen-type ligand formation-driven of a heterometallic Cu(II)-Hg(II) complex: Synthetic update, crystallographic features, DFT calculations, and unveil antimicrobial profiles

Abstract

This article vividly describes the synthesis and structural characterization of one 6-Bromo-2-hydroxy-3-methoxybenzaldehyde ligand involving heteronuclear complex, [Cu(L)Hg(Cl)2]. X-ray single-crystal determined the complex crystal structure and characterized it by various physical methods, including elemental, FT-IR, Raman, PXRD, UV–vis, NMR, and SEM-EDX techniques. X-ray diffraction analysis reveals that the compound adopts a monoclinic space group Cc during crystallization. The crystal structure exhibits unique supramolecular interactions, like intermolecular C-H∙∙∙π H-bonding and X-bonding (X = Halogen) between Br(1) and Br(2) atoms. Hirshfeld surfaces (HS) and 2-D fingerprint plots confirm significant H…Cl (21.9 %) contacts. Further, dispersion energy dominates due to Br atoms' higher electron/electron cloud. The complex underwent DFT calculations based on the Gaussian software package at B3LYP, HF, and M062x levels, utilizing the lanl2dz, sdd, and def2tzvp basis sets. The HOMO-LUMO, ESP, Global reactivity, Interaction energy and energy frameworks, and Fukui function investigated the complex properties in a multidimensional spectrum. The complex showed promising NLO activity, which has broad technological applications. Fukui function calculation identifies regions prone to nucleophilic (Nu-) and electrophilic (E+) attacks. The complex and synthetic components were examined for antimicrobial function against Gram+ve and Gram-ve bacterial and fungal strains. Molecular docking (MD) and Protein-Ligand Interaction Profilers (PLIP) further support the antimicrobial findings.