Cu Doping‐Induced Transformation from [Ag₆₂S₁₂(SBu^t)₃₂]²⁺ to [Ag_62−xCu_xS₁₂(SBu^t)₃₂]⁴⁺ Nanocluster

Abstract

The change in the valence state of nanocluster can induce remarkable changes in the properties and structure. However, achieving the valence state changes in nanoclusters is still a challenge. In this work, we use Cu 2 + as dopant to "oxidize" [Ag 62 S 12 (SBu t ) 32 ] 2 + (4 free electrons) to obtain the new nanocluster: [Ag 62À x Cu x S 12 (SBu t ) 32 ] 4 + with 2 free electrons. As revealed by its structure, the [Ag 62À x Cu x S 12 (SBu t ) 32 ] 4 + (x = 10~21) has a similar structure to that of [Ag 62 S 12 (SBu t ) 32 ] 2 + precursor and all the Cu atoms occupy the surface site of nanocluster. It's worth noting that with the Cu atoms doping, the [Ag 62À x Cu x S 12 (SBu t ) 32 ] 4 + nanocluster is more stable than [Ag 62 S 12 (SBu t ) 32 ] 2 + at higher temperature and in electrochemical cycle. This result has laid a foundation for the subsequent application and exploration. Overall, this work reveals crystals structure of a new AgÀ Cu nanocluster and offers a new insight into the electron reduction/oxidation of nanocluster.

Doping effect on a two-electron silver nanocluster

“…Such a distribution was also observed in other Cu-doped Ag NCs, such as [Cu x Ag 20− x (dtp) 12 ] (R = i Pr, x = 1–7; R = n Pr, x = 0–5), 19,33 [Ag 29− x Cu x (BDT) 12 ] 3− ( x = 0–13), 37 and [Ag 62− x Cu x S 12 (SBu t ) 32 ] + ( x = 10–21). 32…”

“…In the case of Cu alloying, the Cu atoms tend to position themselves in the shell layer of the core-shell NCs. [30][31][32][33][34][35] Zhu et al reported bimetallic NCs, Au 36−x Cu x (m-MBT) 24 (x = 1-3), 30 Au 38−x Cu x (2,4-DMBT) 24 (x = 0-6, DMBT = 2,4-dimethylbenzenethiolate), 31 and [Ag 62−x Cu x S 12 (SBu t ) 32 ] 4+ (x = 10-21). 32 Liu et al reported bimetallic Cu x Ag 20−x {S 2 P(OR) 2 } 12 (x = 3, 4; R = i Pr, 19 n Pr 33 ).…”

“…[30][31][32][33][34][35] Zhu et al reported bimetallic NCs, Au 36−x Cu x (m-MBT) 24 (x = 1-3), 30 Au 38−x Cu x (2,4-DMBT) 24 (x = 0-6, DMBT = 2,4-dimethylbenzenethiolate), 31 and [Ag 62−x Cu x S 12 (SBu t ) 32 ] 4+ (x = 10-21). 32 Liu et al reported bimetallic Cu x Ag 20−x {S 2 P(OR) 2 } 12 (x = 3, 4; R = i Pr, 19 n Pr 33 ). These studies consistently demonstrated a marked tendency for Cu atoms to favor surface positions, displaying disordered arrangements across multiple sites instead of situating themselves within the core.…”

“…2a) reveals a distribution of [Cu x Ag 11−x (dtp) 8 ] + (x = 0-3) with the Cu 1 Ag 10 (x = 1) species assigned to the most intense band. Such a distribution was also observed in other Cu-doped Ag NCs, such as [Cu x Ag 20−x (dtp) 12 ] (R = i Pr, x = 1-7; R = n Pr, x = 0-5),19,33 [Ag 29−x Cu x (BDT) 12 ] 3− (x = 0-13),37 and [Ag 62−x Cu x S 12 (SBu t ) 32 ] + (x = 10-21) 32. The 31 P{ 1 H} NMR spectrum of Ag 11 (Fig.S2†) shows two chemical shifts at 100.8 and 103.2 ppm, with an integration ratio of approximately 6 : 2, which corresponds to the two coordination environments of the dtp ligands.…”