A Cu(I)–Thiophene-Based Hydrazone Complex: Structural Elucidation, Photophysical Properties, and Computational Insights

The Cu(I) complex, V was synthesized by the reaction of bis(triphenylphosphine)copper(I) nitrate ([Cu(PPh3)2]NO3) and thiophene based hydrazone, (E)-N'-((E)-3-phenylallylidene)thiophene-2-carbohydrazide; (III) in a mixed solvent of dichloromethane and methanol. The molecular structure of Cu(I) complex was elucidated by single-crystal X-ray diffraction. The Cu(I) adopts a distorted tetrahedral geometry, coordinated by two triphenylphosphine ligands and the N,O-donor sites of the chelating ligand III. The complex crystallizes in a triclinic crystal system with the centrosymmetric P–1 space group. The crystal packing is stabilized by N–H···O and C–H···O strong intermolecular hydrogen bonding and extended supramolecular architectures are observed due to the presence of C–H···π interactions. Theoretical calculations were performed on V to determine its optimized molecular structure and analyze electronic properties. Atoms in Molecules (AIM) analysis and Non-Covalent Interaction (NCI) analysis provide substantial study of hydrogen bonding interactions. Hirshfeld surface analysis reveals the contribution of H···O contacts to the intermolecular interaction landscape. Its photophysical properties were investigated both experimentally and computationally, using UV–Vis absorption spectroscopy and time-dependent density functional theory (TD-DFT) calculations, respectively. The combined crystallographic and computational results provide a detailed description of the structural, supramolecular and electronic characteristics of the V.