Alkynyl‐Protected Au₂₃ Nanocluster: A 12‐Electron System

Abstract

A 23-gold-atom nanocluster was prepared by NaBH4-mediated reduction of a solution of PhC≡CAu and Ph3PAuSbF6 in CH2Cl2. The cluster composition was determined to be [Au23(PhC≡C)9(Ph3P)6](2+) and single-crystal X-ray diffraction revealed that the cluster has an unprecedented Au17 kernel protected by three PhC2-Au-C2 (Ph)-Au-C2 Ph motifs and six Ph3P groups. The Au17 core can be viewed as the fusion of two Au10 units sharing a Au3 triangle. Electronic structure analysis from DFT calculations suggests that the stability of this unusual 12-electron cluster is a result of the splitting of the superatomic 1D orbitals under D3h symmetry of the Au17 kernel. The discovery and determination of the structure of the Au23 cluster demonstrates the versatility of the alkynyl ligand in leading to the formation of new cluster compounds.

Polymorphism of Phosphine-Protected Gold Nanoclusters: Synthesis and Characterization of a New 22-Gold-Atom Cluster

“…Hence, the true gold cluster cores are in fact smaller than the AuNC formulas indicate. Similar staples have also been found in the alkynylprotected Au 19 , [ 24 ] Au 23 , [ 25 ] and Au 24 . [ 26 ] On the other hand, phosphine-protected AuNCs tend to have simpler interfaces with well-defi ned cores and ligand layers, [27][28][29][30][31] …”

An Alkynyl‐Stabilized Pt5Ag22 Cluster Featuring a Two‐Dimensional Alkynyl–Platinum “Crucifix Motif”

“…[11] Based on the staple motif hypothesis, av arietyo fA u n (SR) m NCs with known compositions and unknown structures have been predicted. [12][13][14][15][16][17] Moreover,i ns ome particular cases, such as for Au 25 (SR) 18 À , [12] Au 38 (SR) 24 , [13] and Au 24 (SR) 20 , [14] the calculated model was foundt ob eq uite close to the experimentalX -ray structure,i mplying the generality of the staple motif in thiolate-protected gold NCs. Similarly,t he "staplem otif" concept has been applied for deducing and describing novel alkynylprotected coinage NCs as well.…”

Unusual Attractive Au–π Interactions in Small Diacetylene‐Modified Gold Clusters

“…Suchweak interactions are not found in monoacetylene-modified clusters,w hichi ndicates that they are specific for diacetylenic ligands.T he attractive Au-p interactions are likely associated with the low energy of the p*orbital in the diacetylenic moieties,into which the valence electrons of the gold core may be backdonated. [12][13][14][15] Furthermore,W ang et al have recently reported numerous homoleptic and heteroleptic alkynylprotected gold clusters,d emonstrating the formation of various surface Au I -acetylide motifs such as C C À Au À C C and C C À Au À C C À Au À C C. [16][17][18][19][20] These motifs are analogous to the staple units found in thiolate-protected clusters, but their capability to accommodate additional gold atoms through p-coordination should be noted. [1][2][3][4][5][6] Thiolates [1][2][3] and phosphines [6][7][8][9][10] have been frequently used as protecting ligands,w hile alkynyl (acetylide) ligands have recently emerged as unique and suitable ligands that stabilize gold clusters.…”

“…[1][2][3][4][5][6] Thiolates [1][2][3] and phosphines [6][7][8][9][10] have been frequently used as protecting ligands,w hile alkynyl (acetylide) ligands have recently emerged as unique and suitable ligands that stabilize gold clusters. [12][13][14][15] Furthermore,W ang et al have recently reported numerous homoleptic and heteroleptic alkynylprotected gold clusters,d emonstrating the formation of various surface Au I -acetylide motifs such as C C À Au À C C and C C À Au À C C À Au À C C. [16][17][18][19][20] These motifs are analogous to the staple units found in thiolate-protected clusters, but their capability to accommodate additional gold atoms through p-coordination should be noted. We have also introduced alkynyl ligands as coligands into Au 8 and Au 13 clusters and showed the substantial perturbation effects of particular p-electron systems on the electronic properties of the gold clusters.…”