Supramolecular clumps of μ2-1,3-acetate bridges of Cd(II)-Salen complex: Synthesis, spectroscopic characterization, crystal structure, DFT quantization's, and antifungal photodynamic therapy

Abstract

The article divulges the crystal growth, synthesis, and X-ray structure characterization of one centrosymmetric cadmium complex, [Cd{CdL(μ₂-1,3-acetate)}₂] using Salen ligand (SL). The complex is further characterized using spectroscopic and analytical techniques, including DRS, SEM-EDX, PXRD, and ICP-MS. The crystallographic study showed that the complex has a monoclinic space <i>P</i>2₁/<i>c</i>. Addison parameters (Ʈ) show the hexagonal geometry of the central Cd(II) metal ion. Hirshfeld surface and 2-D fingerprint confirm supramolecular contacts despite weak C-H⋯O and C-H···π interactions. Energy frameworks, FMOs, global reactivity parameters, MEP, and energy bandgap explain the complex reactivity outlook. The complex inter- and intramolecular bonding interactions were explored through natural bond orbital (NBO), QTAIM, NCI-RDG, Electron Location Function (ELF), and Localized Orbital Locator (LOL) quantization methods. In addition, the complex and its synthetic components in vitro antibacterial efficacy were investigated using Gram-positive and Gram-negative microbial strains. SAR (<i>structure-activity relationship</i>) correlates with biological potency. Molecular docking assessed antimicrobial potency with proteins <i>S. aureus</i> (PDB ID: 1JIJ), <i>C. albicans</i> (PDB ID: 1M7A), <i>E. coli</i> (PDB ID: 1T9U), <i>P. aeruginosa</i> (PDB ID: 2UV0), and <i>A. Niger</i> (PDB ID: 3K4P). The findings are backed by the Protein-Ligand Interaction Profiler (PLIP). The antifungal potency and cell viability test of <i>C. albicans</i> were conducted using photodynamic therapy (APDT).