Recent advances in the synthetic chemistry of atomically precise metal nanoclusters (NCs) have significantly broadened the accessible sizes and structures. Such particles are well defined and have intriguing properties, thus, they are attractive for catalysis. Especially, those NCs with identical size but different core (or surface) structure provide unique opportunities that allow the specific role of the core and the surface to be mapped out without complication by the size effect. Herein, we summarize recent work with isomeric Aun NCs protected by ligands and isostructural NCs but with different surface ligands. The highlighted work includes catalysis by spherical and rod‐shaped Au25 (with different ligands), quasi‐isomeric Au28(SR)20 with different R groups, structural isomers of Au38(SR)24 (with identical R) and Au38S2(SR)20 with body‐centred cubic (bcc) structure, and isostructural [Au38L20(PPh3)4]2+ (different L). These isomeric and/or isostructural NCs have provided valuable insights into the respective roles of the kernel, surface staples, and the type of ligands on catalysis. Future studies will lead to fundamental advances and development of tailor‐made catalysts.
Herein, we report the synthesis and atomic structure of the cluster-assembled [Au60Se2(Ph3P)10(SeR)15](+) material. Five icosahedral Au13 building blocks from a closed gold ring with Au-Se-Au linkages. Interestingly, two Se atoms (without the phenyl tail) locate in the center of the cluster, stabilized by the Se-(Au)5 interactions. The ring-like nanocluster is unprecedented in previous experimental and theoretical studies of gold nanocluster structures. In addition, our optical and electrochemical studies show that the electronic properties of the icosahedral Au13 units still remain unchanged in the penta-twinned Au60 nanocluster, and this new material might be a promising in optical limiting material. This work offers a basis for deep understanding on controlling the cluster-assembled materials for tailoring their functionalities.
A structure evolution map of face-centered
cubic (fcc)-structured
thiolate-ligand protected gold nanoclusters is outlined on the basis
of total structure determination of a new 6e Au21(SR)15 (R = tert-butyl, t-Bu)
cluster. The structural evolution map described some basic structural
evolution patterns such as a triangle-Au3 and tetrahedron-Au4 associated gold-core evolution pattern and the periodic or
symmetric growth of gold cores and ligand shells. According to the
structural evolution map, a topological structure–electronic
structure relationship is also proposed. The delocalized valence electronic
properties of any fcc-structured gold clusters may be expressed as
the linear combinations of the molecular orbitals of the fragment
2e units (Au3
+ and Au4
2+). The structural disciplines and topological structure–electronic
structure relationships reported in this work laid a basis for understanding
the structural evolution and electronic structure of fcc-structured
thiolate-protected gold nanoclusters. Particularly, the established
structural evolution map provides a tool to explore new magic-sized
clusters and cluster structures. In this work, a new fcc-structured
4e Au17(SR)13 and a new isomer structure of
the 8e Au28(SR)20 cluster were predicted. The
medium-sized fcc-structured gold clusters locating in the size range
from 52 to 92 gold atoms and even larger-sized gold clusters can be
also explored from the structural regularities described in the map.
Deciphering the complicated excited-state process is critical for the development of luminescent materials with controllable emissions in different applications. Here we report the emergence of a photo-induced structural distortion accompanied by an electron redistribution in a series of gold nanoclusters. Such unexpected slow process of excited-state transformation results in near-infrared dual emission with extended photoluminescent lifetime. We demonstrate that this dual emission exhibits highly sensitive and ratiometric response to solvent polarity, viscosity, temperature and pressure. Thus, a versatile luminescent nano-sensor for multiple environmental parameters is developed based on this strategy. Furthermore, we fully unravel the atomic-scale structural origin of this unexpected excited-state transformation, and demonstrate control over the transition dynamics by tailoring the bi-tetrahedral core structures of gold nanoclusters. Overall, this work provides a substantial advance in the excited-state physical chemistry of luminescent nanoclusters and a general strategy for the rational design of next-generation nano-probes, sensors and switches.
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