Organic Ligand Exchange: The Chiral Structure–Property Regulation of Cuprous Halides

The strategy of organic ligand exchange is proposed to tune the optical properties of organic-inorganic hybrid cuprous halides. In this work, the chiral ligand (S)-(-)-2,2'-bis(di-<i>p</i>-tolylphosphino)-1,1'-binaphthyl ((S)-Tol-BINAP) and achiral triphenylphosphine (PPh₃) are introduced into cuprous halides CuX-PPh₃-[(S)-Tol-BINAP] (X = Cl, Br, I) through organic ligand exchange. As a result, the mixed organic ligands can enhance second harmonic generation (SHG) and aggregation-induced emission (AIE) optical properties. Moreover, the title compounds exhibit progressively enlarged SHG effects along with heavier halogen substitution due to their stronger polarizability. In the meantime, the reduced π-π stacking interaction of the organic ligand will improve their photoluminescence quantum yield. The experimental results combined with the theoretical calculation clarify the structure-property relationship well. Furthermore, the title compounds have been developed for the application of latent fingerprint detection.