Chinese scholars have made progress in the research of silver-copper nanoclusters

Figure Magnetic changes in the assembly and unassembly of ag_77Cu22 clusters

With the support of the National Natural Science Foundation of China (approval numbers: 21925303, 21771186, 91961204, 22171268), Wu Zhikun and Zeng He, researchers from the Institute of Solid State Physics, Chinese Academy of Sciences, and Professor Zhao Jijun of Dalian University of Technology cooperated to discover the new phenomenon
of magnetic moment transfer and coupling of metal nanoclusters and sulfur through the straight-chain assembly of metal nanoclusters and sulfur 。 The related research results, titled "Assembly-induced spin transfer and distance-dependent spin coupling in atomically precise AgCu nanoclusters", were published in Nature in October 2022 Communications), link to the paper: _istranslated="1">.

Precise assembly of metal nanoparticles can not only enhance the intrinsic properties and structure-activity relationship of nanoparticles, but also understand the interaction between particles associated with assembly, which is also a frontier
hotspot in structural chemistry.
Traditional metal nanoparticles are multi-distributed and it is extremely difficult to obtain the precise composition structure of atoms, so it is difficult to achieve the precise construction and regulation
of their assembly structure.
Metal nanoclusters can be regarded as ultra-small metal nanoparticles, which can obtain precise atomic composition structures, which provides opportunities for the precise assembly of nanoparticles
.
However, due to difficulties in synthesis and characterization, precise assembly of clusters larger than 1 nm has rarely been reported
.
Designing and assembling new strategies is the key to
achieving accurate assembly of large-size metal nanoclusters.

The team prepared a linear structure
formed by joining two Ag_77Cu22 clusters with sulfur ions through a new assembly strategy.
In the linear assembled metal nanocluster structure, paramagnetic sulfur free radicals are formed due to the transfer of magnetic moment from cluster to sulfur, and the sulfur-sulfur spacing is large, and the overall magnetic isotropy
is displayed.
When ungrouped in solution, the paramagnetism disappears
due to the transfer of the magnetic moment from sulfur back to the cluster and the magnetic moment coupling occurs, that is, two single electrons in the two metal clusters are paired.
At the same time, studies have shown that coupling can only occur when the distance between clusters is small to a certain extent, further indicating that the occurrence of magnetic moment coupling depends on the distance
between clusters.

Through the rational design of assembly strategies, this research work has successfully realized the linear assembly of cluster particles with a size greater than 1 nm, and discovered and clarified the nature of magnetic moment transfer and distance-related magnetic moment coupling of the assembly, which has important inspiration for the subsequent study of cluster structure chemistry and properties, and also provides reference
for the development of new functional structural materials.