Comprehensive study of a novel cobalt(II) complex: Synthesis, X-ray crystal structure, Hirshfeld surface analysis, computational quantum investigations, and molecular docking insights

Abstract

The design of metal complexes that combine structural sophistication with biological relevance has become a cornerstone of modern coordination chemistry. In this study, we present the synthesis and comprehensive characterization of a novel cobalt(II) complex, [Co(phen)₂(η²-bz)]·2bzH·NO₃ (1), featuring a distorted six-coordinate octahedral geometry, stabilized by two 1,10-phenanthroline and one benzoate ligands. The crystal structure was elucidated using single-crystal X-ray diffraction, revealing a robust supramolecular network strengthened by various non-covalent interactions, including CH⋯O, OH⋯O hydrogen bonds, and π–π stacking between aromatic rings. Density functional theory (DFT) calculations, employing the B3LYP/3-21G basis set, provided further insight into the optimized geometry and electronic properties, with a close match to experimental observations. Hirshfeld surface analysis quantified the intermolecular interactions, and molecular electrostatic potential (MEP) maps highlighted the reactive sites of the complex. Additionally, molecular docking studies demonstrated a strong binding affinity between the cobalt complex and Klebsiella pneumoniae receptors (PDB ID: 6RD3), suggesting potential antibacterial properties. This cobalt complex offers new insights into the structure–activity relationships of transition metal complexes and presents promising avenues for the development of novel therapeutic agents targeting multidrug-resistant bacteria. The findings from this study also pave the way for further exploration of cobalt complexes in catalytic and biomedical applications.