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-p-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.