Same Magic Number but Different Arrangement: Alkynyl‐Protected Au₂₅ with D₃ Symmetry

Abstract

Two homoleptic alkynyl‐protected gold clusters with compositions of Na[Au25(C≡CAr)18] and (Ph4P)[Au25(C≡CAr)18] (Na⋅1 and Ph4P⋅1, Ar=3,5‐bis(trifluoromethyl)phenyl) were synthesized via a direct reduction method. 1 is a magic cluster analogous to [Au25(SR)18]− in terms of electron counts and metal‐to‐ligand ratio. Single‐crystal structure analysis reveals that 1 has an identical Au13 kernel to [Au25(SR)18]−, but adopts a distinctly different arrangement of the six peripheral dimer staple motifs. The steric hindrance of alkynyl ligands is responsible for the D3 arrangement of Au25. The introduction of alkynyl also significantly changes the optical absorption features of the nanocluster as supported by DFT calculations. This magic cluster confirms that there is a similar but quite different parallel alkynyl‐protected metal cluster universe in comparison to the thiolated one.

Insight into the Geometric and Electronic Structures of Gold/Silver Superatomic Clusters Based on Icosahedron M13 Units and Their Alloys

“…In this review, we focus on gold/silver metal superatomic clusters based on the assembly of M 13 units, which have become a new class of nanomaterial and shown intriguing properties . Benefiting from single‐crystal X‐ray crystallography, the well‐determined structures have explicitly revealed the surface structure, the type of bonding, and the assembly method for nanoclusters consisting of M 13 units . We take some superatomic clusters as examples to present the geometric and electronic structures of superatomic clusters of gold/silver and clusters of their alloys based on M 13 units, such as [Au 13 Cl 2 (PR 3 ) 10 ] 3+ , Au 25 (SR) 18 − , Ag 25 (SR) 18 − Au 38 (SR) 24 and [Au 2 Ag 42 (SAdm) 27 ] + (SAdm=adamantanethiol .…”

“…Benefiting from single-crystal X-ray crystallography,t he well-determined structuresh ave explicitly revealed the surface structure, the typeo fbonding, and the assembly methodf or nanoclustersc onsisting of M 13 units. [21,[48][49][50] We take somes uperatomicc lusters as examples to present the geometrica nd electronic structureso fs uperatomic clusters of gold/silver and clusters of their alloys based on M 13 27 ] + (SAdm = adamantanethiol. [23, 24, 26-28, 43, 46] The insights gained will help to understand the metal superatomic cluster and provide ab asis for specific applications through the regulation of assembly.…”

Formation of an Alkynyl‐Protected Ag112 Silver Nanocluster as Promoted by Chloride Released In Situ from CH2Cl2

“…Cluster Ag 112 has a broad multiband optical absorption between 300 and 800 nm (one prominent peak at 482 nm and four bands at 389, 424, 580, and 710 nm; Figure d). According to previous studies, the low‐energy absorption peaks (580 and 710 nm) can mainly be attributed to charge transfer within the metal kernel, and the high‐energy absorption peaks (389, 482, and 424 nm) arise from the mixing of metal‐to‐metal and metal‐to‐ligand charge‐transfer processes (MMCT and MLCT) . The number of free electrons for Ag 112 was calculated to be 58e (112−6−51+3), which indicates shell closing in a spherical structure.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] In addition to the extensive use of thiolate and phosphine ligands for the synthesis of metal nanoclusters, [13][14][15][16][17][18][19][20][21][22][23] alkynyl ligands have been attracting great recent attention. [24][25][26][27][28][29][30][31][32][33] A series of all alkynyl-protected gold nanoclusters, such as Au 44 (C CR) 28 , Au 36 (C CR) 24 , Au 144 (C CR) 60 , and [Au 25 (C CR) 18 ] À , have been reported. However, all alkynyl-protected Ag nanoclusters have been much less studied, because of the poor stability of silver nanoclusters, and only two structurally determined examples are known.…”

“…According to previous studies, the low-energy absorption peaks (580 and 710 nm) can mainly be attributed to charge transfer within the metal kernel, and the high-energy absorption peaks (389, 482, and 424 nm) arise from the mixing of metal-tometal and metal-to-ligand charge-transfer processes (MMCT and MLCT). [31,44] The number of free electrons for Ag 112 was calculated to be 58e (112À6À51 + 3), which indicates shell closing in a spherical structure. Gold or bimetallic nanoclusters (Au 102 , [15] Au 103 , [45] Au 80 Ag 30 , [38] and Au 57 Ag 53 [37] ) have been reported to be 58 e systems, but no other silver clusters with 58 e are known.…”