The Structure of a Au7Cu12 Bimetal Nanocluster and Its Strong Emission.

Herein, a Au-Cu bimetal nanocluster (bi-MNC) with strong emission (13.2% quantum yield) was synthesized and structurally determined. Its structure features a sandwich construction: a ring-like Au7Cu6 kernel is caught in the middle of the two "hat-like" (CuSPNC)3 motifs with four Br atoms, resulting in a formula of [Au7Cu12(dppy)6(TBBT)6Br4]3+ (dppy = PPh2Py, TBBT = SPh- t-Bu). Interestingly, structural analysis shows that the bonding (N-Cu and μ3S-Cu3) is the key factor to endow this bi-MNC with strong emission by locking the intramolecular motion of surface structure, and destroying the intramolecular π···π interactions is designed to boost emission (19.2% vs 13.2%). Furthermore, the structure-luminescence relationship is further explored by theoretical calculation. This work will provide new idea and strategy to prepare bi-MNCs with strong emission.