Effect of Copper Doping on Electronic Structure, Geometric Structure, and Stability of Thiolate-Protected Au₂₅ Nanoclusters

Abstract

Several recent studies have attempted to impart [Au 25 (SR) 18 ] − with new properties by doping with foreign atoms. In this study, we studied the effect of copper doping on the electronic structure, geometric structure, and stability of [Au 25 (SR) 18 ] − with the aim of investigating the effect of foreign atom doping of [Au 25 (SR) 18 ] − . Cu n Au 25−n (SC 2 H 4 Ph) 18 was synthesized by reducing complexes formed by the reaction between metal salts (copper and gold salts) and PhC 2 H 4 SH with NaBH 4 . Mass analysis revealed that the products contained Cu n Au 25−n (SC 2 H 4 Ph) 18 (n = 1−5) in high purity. Experimental and theoretical analysis of the synthesized clusters revealed that copper doping alters the optical properties and redox potentials of the cluster, greatly distorts its geometric structure, and reduces the cluster stability in solution. These findings are expected to be useful for developing design guidelines for functionalizing [Au 25 (SR) 18 ] − through doping with foreign atoms.

Toward the Creation of Functionalized Metal Nanoclusters and Highly Active Photocatalytic Materials Using Thiolate-Protected Magic Gold Clusters

“…Interestingly, a maximum of only five atoms could be doped in Au 25 (SR) 18 (R = C 2 H 4 Ph or C 8 H 17 ) (Figure 2c), regardless of the experimental conditions, 87 even though Cu belongs to the same group as Au. In addition, Au 25¹n Cu n (SR) 18 (n = 15) decomposed readily in solution, in contrast with Au 24 Pd-(SC 12 H 25 ) 18 and Au 25¹n Ag n (SR) 18 (n = 113).…”

“…The resulting mixture was dried, followed by separation of only Au 25¹n Cu n (SR) 18 using size-related differences in the cluster solubilities (acetonitrile and acetone were used as solvents for the extraction of Au 25¹n Cu n -(SC 2 H 4 Ph) 18 and Au 25¹n Cu n (SC 8 H 17 ) 18 , respectively). 87 Figure 2a shows the matrixassisted laser desorption/ionization (MALDI) mass spectrum of Au 24 85 In contrast, the Au 25 (SR) 18 cluster has been reported to form the negative ion [Au 25 (SR) 18 ] ¹ . 53,56,57 High-resolution separation of these two species by HPLC using a reverse-phase column was successful because of the different charge states of the two clusters.…”

Noble metal alloy clusters in the gas phase derived from protein templates: unusual recognition of palladium by gold

“…Copper is also known to form alloy with gold and recently Negishi's group could dope a maximum of five copper atoms in the Au 25 (SR) 18 system. 54 In the gas phase, however, a drastic change was found in the overall spectrum upon Cu addition. As Cu is having a high affinity towards sulphur, it occupies Au binding sites in Lyz.…”

Active metal (cadmium) doping enhanced the stability of inert metal (gold) nanocluster under O2 atmosphere and the catalysis activity of benzyl alcohol oxidation

“…By doping these small homogold nanoclusters with even single atom, many new physical and chemical properties are expressed [6][7][8][9][10]. In the past few years, significant advances have been made in the synthesis and property studies of these doping nanoclusters [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Among homogold nanoclusters, Au 25 (SR) 18 nanocluster has been well studied due to its stable structure among three different charges (−1/0/+1) [22][23][24][25][26], which led to the exploration of a wide range of catalytic pathways facilitated by Au 25 for organic reactions, such as oxidation [27][28][29], hydrogenation [30][31][32], electronic transfer reactions [26,33], and electrocatalysis [34,35].…”

“…Among homogold nanoclusters, Au 25 (SR) 18 nanocluster has been well studied due to its stable structure among three different charges (−1/0/+1) [22][23][24][25][26], which led to the exploration of a wide range of catalytic pathways facilitated by Au 25 for organic reactions, such as oxidation [27][28][29], hydrogenation [30][31][32], electronic transfer reactions [26,33], and electrocatalysis [34,35]. Recent research implies that doping foreign atoms into this 25 noble metal system can largely affect the stability and the catalytic activity compared to the homogold counterpart [7][8][9][10][17][18][19]. Compared with these inert metal doped (M-Au) 25 (M=Pt/Pd/Cu/Ag) nanoclusters, the research on highly active metal (such as Cd) being used to dope into the nanocluster was rarely studied.…”