Investigation of a Cobalt(III) Schiff Base Complex: Synthesis, Crystal Structure, Computational Studies, and Antimicrobial Evaluation

ABSTRACT A cobalt (III) complex, tris(2‐{[(2‐methylpropyl)imino]methyl}phenolato) cobalt(III), was synthesized through template synthesis and characterized by elemental analysis, UV–visible (vis), IR, NMR, mass spectrometry (MS), thermogravimetry (TG), and single‐crystal x‐ray diffraction (SCXRD). The UV–vis spectrum shows absorption bands corresponding to π→π* and n→π* transitions. The IR spectrum confirms the presence of an azomethine group (‐HC═N), which is associated with biological activity. NMR reveals peaks for azomethine (‐HC═N), aromatic, and aliphatic protons and carbon. The MS confirms a molecular weight of 587 g mol −1 . TG analysis indicates a two‐step, rapid decomposition process, leaving a 12% residue at 334 °C. SCXRD uncovers a tetragonal crystal system with an I4 1 /a space group. Density functional theory (DFT) calculations show an energy difference (Δ E ) of 3.18 eV between E LUMO and E HOMO . HSA analysis identified various intermolecular interactions, including H … H (79.1%) and C … H/H … C (17.5%). The complex was tested for antimicrobial activity against bacteria and fungi in vitro, including S. aureus , E . coli , C . albicans , and A . niger . Notable antibacterial effects were observed at minimum inhibitory concentrations (MIC) of 300 to 400 µg mL −1 . The complex also demonstrated anticancer activity against MCF‐7 breast cancer cells, with an IC 50 of 40.5 µg mL −1 .