Alkynyl-Protected Ag12Cu4 Cluster with Aggregation-Induced Emission Enhancement

Photoluminescence (PL) of atomically precise metal clusters is attractive for various applications, including light emission, chemical sensing, and bioimaging. Herein, we report the synthesis and total structure of an alkynyl-protected bimetallic AgCu cluster, Ag 12 Cu 4 (C≡CR) 14 (PPh 3 ) 4 ( Ag 12 Cu 4: HC≡CR = 3,5-bis(trifluoromethyl)phenylacetylene; PPh 3 = triphenylphosphine), which exhibits crystallization-induced emission enhancement and aggregation-induced emission enhancement phenomena. As revealed by the single crystal X-ray diffraction data, the Ag 12 Cu 4 cluster comprises an octahedron Ag 6 core, which is stabilized by two large Ag 3 Cu 2 (C≡CR) 7 (PPh 3 ) 2 metal–ligand motifs. The free valence electron count suggests that Ag 12 Cu 4 is a two-electron superatom. Interestingly, the weak PL of Ag 12 Cu 4 solution at ≈730 nm (near-infrared region) is found to be significantly …