Co-crystallization of atomically precise metal nanoparticles driven by magic atomic and electronic shells

Abstract

This paper reports co-crystallization of two atomically precise, different-size ligand-stabilized nanoclusters, a spherical (AuAg)267(SR)80 and a smaller trigonal-prismatic (AuAg)45(SR)27(PPh3)6 in 1:1 ratio, characterized fully by X-ray crystallographic analysis (SR = 2,4-SPhMe2). The larger cluster has a four concentric-shell icosahedral structure of Ag@M12@M42@M92@Ag120(SR)80 (M = Au or Ag) with the inner-core M147 icosahedron observed here for metal nanoparticles. The cluster has an open electron shell of 187 delocalized electrons, fully metallic, plasmonic behavior, and a zero HOMO-LUMO energy gap. The smaller cluster has an 18-electron shell closing, a notable HOMO-LUMO energy gap and a molecule-like optical spectrum. This is the first direct demonstration of the simultaneous presence of competing effects (closing of atom vs. electron shells) in nanocluster synthesis and growth, working together to form a co-crystal of different-sized clusters. This observation suggests a strategy that may be helpful in the design of other nanocluster systems via co-crystallization.

Synthesis, Structure, Properties, and Applications of Bimetallic Nanoparticles of Noble Metals

“…[ 44 ] Besides a number of monometallic clusters, some bimetallic clusters have also been crystallized and structurally characterized. [ 45 ] Such ultrasmall particles have special properties compared to larger ones, in terms of spectroscopic properties (e.g., autofluorescence instead of fluorescent quenching), [ 46 ] biological properties (e.g., a better cell membrane permeability, also into the cell nucleus), [ 47 ] and for heterogeneous catalysis and electrocatalysis. [ 3i,48 ] An interesting synthetic concept is biotemplating by selective peptides to form bimetallic ultrasmall nanoparticles.…”

Au130−xAgx Nanoclusters with Non‐Metallicity: A Drum of Silver‐Rich Sites Enclosed in a Marks‐Decahedral Cage of Gold‐Rich Sites

“…While much work has been done on the smaller sizes of NCs (less than 100 metal atoms), larger‐size NCs (that is, >100 metal atoms) are still rare owing to major difficulties in the synthesis and crystallization . For large bimetallic NCs, the reported structures are alkynyl‐protected Au 80 Ag 30 and Au 57 Ag 53 , as well as thiolate‐protected Au 267− x Ag x . Broadly speaking, it still remains a huge challenge to precisely control the synthesis and map out the dopant distribution in bimetallic nanostructures owing to the complexity …”

“…Similar breakthroughs are expected for nanoalloys considering their outstanding functionality compared to monometallic nanomaterials. To understand the effects of size, structure, and Au/Ag ratios on the transition from quantized to metallic state, experimental approaches should include atomically precise structural analysis and the study on the properties, which has only been partially completed in previous studies …”

An Ultrastable Matryoshka [Hf13] Nanocluster as a Luminescent Sensor for Concentrated Alkali and Acid

“…The synthesis of highly stable polynuclear metal clusters is an important goal owing to their unique structures and versatile applications in optoelectronics, luminescence sensing, solar‐energy harvesting, and other areas . Many impressive metal clusters have been reported, with cores such as [Ti 20 ], [Au 32 ] 8+ , [Fe 42 ], [Cu 53 ], [Ag 374 ], [Gd 140 ], and [Ni 21 Gd 20 ], as well as [As@Ni 12 @As 20 ] 3− and inorganic fullerene‐like molecules .…”