[Cu ₁₅ (PPh ₃ ) ₆ (PET) ₁₃ ] ²⁺ : a Copper Nanocluster with Crystallization Enhanced Photoluminescence

Due to their atomically precise structure, photoluminescent copper nanoclusters (Cu NCs) have emerged as promising materials in both fundamental studies and technological applications, such bio-imaging, cell labeling, phototherapy, photo-activated catalysis. In this work, a facile strategy is reported for the synthesis of novel Cu NCs coprotected by thiolate phosphine ligands, formulated [Cu15(PPh3)6(PET)13]2+, which exhibits bright emission near-infrared (NIR) region (?720 nm) crystallization-induced enhancement (CIEE) phenomenon. Single crystal X-ray crystallography shows that NC possesses an extraordinary distorted trigonal antiprismatic Cu6 core a, unique among metal clusters, “tri-blade fan”-like structure. An in-depth structural investigation ligand shell combined with density functional theory calculations reveal extended C?H···? ?-? intermolecular interactions significantly restrict intramolecular rotations vibrations and, thus, are major reason CIEE phenomena. This study provides controllable structurally defined NIR luminescence, enables essential insights into origins optical properties.