Novel Copper‐Thioproline Complex as an Efficient Catalyst for Knoevenagel Condensation in Green Solvent: DFT and Catalytic Activity Study

ABSTRACT In this study, we report the synthesis of copper (II) thioproline complex [ Cu(Thp) 2 ] using optically active ligand L‐thioproline in methanolic solvent via conventional reflux method. The complex was characterized by means of elemental analysis, IR, electronic spectra (DRS UV), EPR, magnetic moment measurements, SEM, and PXRD analysis. The structure and geometry optimization of the Cu‐thioproline complex [ Cu(Thp) 2 ] was performed using DFT calculation confirming the formation of distorted square planar geometry. HOMO and LUMO energy gap were also calculated theoretically and found to be 0.21 eV in alpha spin orbitals and 0.11 eV in beta spin orbitals, respectively. The copper (II) thioproline complex [ Cu(Thp) 2 ] was utilized as a heterogenous catalyst for the Knoevenagel condensation reaction with effective recovery up to fourth catalytic cycle maintaining high activity (above 90% yield) in green solvent ethanol avoiding the use of toxic solvents.