A New Copper(I) Complex Based on Imidazole and Triphenylphosphine Ligands: Synthesis, Structure, Third-Order NLO, and Fluorescence Properties

A new candidate [Cu(PPh3)2Him]Br (1, PPh3=triphenylphosphine, Him=1‐H‐imidazole) for nonlinear optical (NLO) materials has been synthesized and characterized crystallographically. The third‐order NLO optical properties were measured by the Z‐scan technique with an 8 ns pulsed laser at 532 nm. Compound 1 exhibits strong NLO absorptive abilities [α2=(61±5)×10−12] and effective self‐focusing performance [n2=(15±3)×10−18 m2·W−1] in 1.01×10−4 mol·dm−3 DMF solution. The compound also exhibits luminescence in DMF solution at room temperature and shows narrow emission with maximum at 382 nm. The electronic structure and photoluminescent process were investigated by means of TD‐DFT calculations. The results suggest that the contribution to the frontier orbitals from the CuBr δ bond plays a crucial role in its linear optical properties, and the origin of luminescence is attributable to the π∗︁→n transitions. Herein, we report the third‐order NLO and fluorescence studies of a new copper(I) complex based on imidazole and triphenylphosphine ligands, together with time‐dependent DFT studies that shed light on the optical behavior.