A Double Open-Shelled Au₄₃ Nanocluster with Increased Catalytic Activity and Stability

Abstract

Atomically precise metal nanoclusters (NCs) are an intriguing class of crystalline solids with unique physicochemical properties derived from tunable structures and compositions. Most atomically precise NCs require closed-shells and coordinatively saturated surface metals in order to be stable. Herein, we report Au43(CC t Bu)20 and Au42Ag1(CC t Bu)20, which feature open electronic and geometric shells, leading to both paramagnetism (23 valence e–) and enhanced catalytic activity from a single coordinatively unsaturated surface metal. The Au-alkynyl surface motifs of these NCs form five helical stripes around the inner Au12 kernel, imparting chirality and high thermal stability. Density functional theory (DFT) calculations suggest that there are minimal energy differences between the open-shelled NCs and hypothetical closed-shell systems and that the open-shelled electronic configuration gives rise to the largest band gap, which is known to promote cluster stability. Furthermore, we highlight how coordinatively unsaturated surface metals create active sites for the catalytic oxidation of benzyl alcohol to benzaldehyde, leading to high selectivity and increased conversion. This work represents the first example of an atomically precise Au NC with a double open-shelled structure and provides a promising platform for investigating the magnetic and catalytic properties of noble metal nanoparticles.

A homologous series of macrocyclic Ni clusters: synthesis, structures, and catalytic properties

“…In some cases, even replacing, adding or removing only one metal atom or ligand will result in an electronic structure variation of the clusters, thereby their properties. 49–51 Interestingly, for this sequence of macrocyclic nickel clusters, Ni n (4MPT) 2 n ( n = 9–12), their electronic structures did not exhibit a significant change with the increasing Ni atom number of rings, which is evidenced by similar experimental absorption spectra and the calculated HOMO–LUMO orbitals as discussed above. We believe that the similar geometries and the same Ni–S coordination of the clusters can satisfactorily explain the similarity of their electronic structures.…”

Atomically precise Au and Ag nanoclusters doped with a single atom as model alloy catalysts

“…93 3 Thermal catalysis 1) for BnOH oxidation (eqn (1)) using tert-butyl hydroperoxide (TBHP) as an oxidant. 61 The conversion decreased from 52% to 18% upon Ag doping. UV-Vis absorption spectroscopy and scanning TEM (STEM) supported the retention of the original cluster during catalysis.…”

“…75 1). 39,40,42,43,[46][47][48][49][50][51][52]54,55,58,[60][61][62][63]93 Galvanic replacement of metal elements driven by a redox reaction is a well-known phenomenon in the bulk surface. It is, for example, used in the synthesis of AuAg 24 (SR) 18 by mixing Ag 25 (SR) 18 and Au(PPh 3 )Cl (entry 9, Table 1), where Ag 0 is oxidized and then dissolved in solution, while Au + is reduced and deposited on the NC (Scheme 2b).…”

%VBur index and steric maps: from predictive catalysis to machine learning

“…With respect to COSMO radii, for Bondi radii no requirement exists for input manipulation to designate the hybridization states of atoms; thus, structures derived from theoretical or experimental methods can be directly employed without modification. Emphasize that ligand is used here because it is the easiest example, and also the pioneer, of using the V concept, but it is really extrapolable to any structure one can imagine, from metallic organic frameworks 147,148 to silicates, 31,149 clusters, 150,151 amino acids or enzymes, 14,152 to give some diametrically opposed examples. And take for instance, the %V Bur index of the ligand can lead to explain how pesticides trap free metals from the soil, 153 or unveil the complexation of trichlorosalicylic acid with metals to enhance the resulting complexes as antibacterial agents.…”