Significant progress in spherical rare-earth clusters assembly and magnetic exchange “fingerprints”

2018-03-19  []


Recently, under the guidance of Professor Zheng Yanzhen, XJTU PhD candidates Qin Lei and Zhou Guojun, from the Frontiers Institute of Science and Technology, successfully prepared four spherical gadolinium cluster compounds through ligand-controlled hydrolysis. Solution chemistry and solvothermal reaction were adopted for the parathion, while two intermediate cluster compounds were successfully captured. A high symmetry is found within the four spherical clusters with nuclear structure. The sizes of the compounds increase from 1.2nm to about 2.0 nm with the addition of the nuclei number. A topological structure analysis shows that these cluster compounds are integral spherical structures formed by many similar building units, such as triangles, squares, pentagon and hexagon through vertex-sharing, edge-sharing and face-sharing. Among them, Gd20 and Gd50 show a rare approximate Ih symmetry, while Gd32 reveals an exact Oh symmetry, Gd60 reveal a slightly distorted approximate Oh symmetry. Both the experiment and the Monte-Carlo theoretical studies based on the Heisenberg model showed a weak antiferromagnetic interaction in these compounds. According to the data of the  magnetization behaviors measurements by pulsed high magnetic fields, the magnetic exchange of different clusters is closely related to the Gd-O-Gd angles, and is of obvious regularity,from which an empirical relationship can be obtained:J = 0.0072φ − 0.85245 (cm−1). Interestingly, different magnetic exchange systems correspond to distinct differential curves of magnetization. This magnetic relationship is expected to be used as a "fingerprint"of these large rare-earth cluster compounds under a strong magnetic field, providing the opportunity to identify these compounds.


The above findings were published on the Journal of the American Chemical Society (impactfactor 13.86) with the title of “Topological Self-Assembly of Highly-Symmetric Lanthanide Clusters: A Magnetic Study of Exchange-Coupling ‘Fingerprints’ in Giant Gadolinium (III) Cages”.XJTUFrontiers Institute of Science and Technology is the institutional affiliation of the first authors and correspondence authors of the article.


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