Alkynyl-Protected Ag₁₂Cu₄ Cluster with Aggregation-Induced Emission Enhancement

Abstract

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, Ag12Cu4(CCR)14(PPh3)4 (Ag12Cu4 : HCCR = 3,5-bis(trifluoromethyl)phenylacetylene; PPh3 = triphenylphosphine), which exhibits crystallization-induced emission enhancement and aggregation-induced emission enhancement phenomena. As revealed by the single crystal X-ray diffraction data, the Ag12Cu4 cluster comprises an octahedron Ag6 core, which is stabilized by two large Ag3Cu2(CCR)7(PPh3)2 metal–ligand motifs. The free valence electron count suggests that Ag12Cu4 is a two-electron superatom. Interestingly, the weak PL of Ag12Cu4 solution at ≈730 nm (near-infrared region) is found to be significantly enhanced in the solid state (15 and 8 fold respectively, for the crystalline and aggregated forms). A detailed structural analysis of the Ag12Cu4 cluster reveals the presence of abundant intercluster C–H···F interactions, which significantly restrict the intramolecular rotations and vibrations, leading to strong PL enhancement in the solid state. This work will trigger the studies of other alloy metal nanoclusters with promising photophysical properties for optoelectronic and other applications.

Au10Ag17(TPP)10(SR)6Cl5nanocluster: structure, transformation and the origin of its photoluminescence

“…Atomically precise metal nanoclusters are of tremendous interest as nanomaterials due to their unique physical and chemical properties, [1][2][3][4][5][6][7][8][9][10][11][12][13] including luminescence, chirality, catalysis, and electrochemistry [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] -all of which can be tuned according to structure-property relationships. 18,33,34 The luminescence of noble metal nanoclusters is of particular interest due to their good photostability and low biological toxicity, and increasing the luminescence intensity of such nanoclusters is an important area of research.…”

Superatom Pruning by Diphosphine Ligands as a Chemical Scissor

“…In this work, we report a facile way to reach NC pruning from an 8-electron heptacapped centered icosahedral Ag 20 NC to a 2-electron octahedral Ag 6 NC. It is noteworthy that most of the known Ag 6 octahedral clusters are composed of solely Ag­(I), i.e., they are 0-electron species. , Although 2-electron [Ag 6 ] 4+ cores have also been reported, they constitute kernels embedded in larger metal cages. − To our knowledge, there is only one exception of a 2-electron octahedral hexanuclear silver species that was recently reported by Liu et al, which is protected by trithiane and alkynyl ligands . In any case, reports on small superatomic silver clusters remain scarce .…”

Alkynyl‐Protected Bimetallic Nanoclusters with a Hybrid Mackay Icosahedral Ag42Cu12Cl Kernel and an Octahedral Ag22Cu12 Kernel

“…Although thiolate‐protected Ag−Cu nanoclusters such as Ag 17 Cu 12 (SSR) 12 (PPh 3 ) 4 , [Ag 20 Cu 12 (SR) 14 (Dppm) 6 Br 8 ] 2+ , [Ag 28 Cu 12 SR 24 ] 4− , [Ag 61 Cu 30 SR 38 S 3 ] + and [Ag 77 Cu 22 (SR) 48 ] 2+ have been reported, [31–38] examples of alkynyl‐protected Ag−Cu bimetallic clusters have been limited [39–45] . Herein, we report a direct reduction strategy for the preparation of alkynyl‐protected Ag−Cu nanoclusters.…”

“…Although [31][32][33][34][35][36][37][38] examples of alkynyl-protected AgÀ Cu bimetallic clusters have been limited. [39][40][41][42][43][44][45] Herein, we report a direct reduction strategy for the preparation of alkynylprotected AgÀ Cu nanoclusters. Two AgÀ Cu alloy nanoclusters were successfully synthesized, (Ph 4 P) 1a and 1b).…”