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BIT’s progress in the study of magnetic porous materials

News Resource: School of Chemistry and Chemical Engineering

Editor: News Agency of BIT

Translator: Ren Xinglei, News Agency of BIT

Recently, Professor Jun Tao has made progress in structuring flexible spin-crossover porous material. The relating result has been published in the world-renowned journal Nature Communications titled “A spin-crossover framework endowed with pore-adjustable behavior by slow structural dynamics” (DOI:10.1038/s41467-022-31274-8). Beijing Institution of Technology is the only author’s affiliation . Professor Jun Tao and  Special Researcher Zi-Shuo Yao from the School of Chemistry and Chemical Engineering are the joint corresponding authors. Doctoral candidate Jin-Peng Xue is the first author. Professor Jing Xie contributed to the calculating work.

Host-guest interaction plays an important role in enabling the switchable structure and function of materials but design and control remains challenging. Flexible metal-organic frameworks (FMOFs) have attracted widespread attention from researchers because of its structural adjustability and the close correlation between host-guest interaction. In the process of structural transformation, the coordination geometry of the metal center may lead to changes in the magnetic properties of the material. This magnetic porous material broadens the application prospects of porous materials and provides a new way to understand the interaction mechanism of host-guest.

Based on the extensive previous work of spin-crossover materials and flexible single crystal materials (Inorg. Chem ., 2019, 58, 23, 15705–15709;  Inorg. Chem ., 2021, 60, 10, 7337–7344;  Nat. Commum. 2019, 10, 4805;  Nat. Commum. 2021, 12, 6908.), combined with the classical Hofmann structure type of spin-crossover, the research group successfully synthesized a flexible spin-crossover porous material with special water adsorption response properties by introducing an axial ligand that can occur pedal motion. In the process of adsorption of water, the pore structure can be changed from narrow quasi-discrete pore to large channel-type pore. And unlike other flexible porous materials, some narrow pores are completely closed during the adsorption process, while some pores are completely opened, that is, the special pore rearrangement behavior that occurs at the same time as local pore opening-closing during the adsorption process is exhibited. This special pore structure change is directly reflected in the adsorption properties of the material: the narrow pore phase structure must be activated by a long period of water atmosphere to complete the opening of the pore channel; the large pore phase can only be transformed into a completely narrow pore phase after a long period of high temperature vacuum treatment; when the material has two-phase structural characteristics at the same time, the gate-opening/closing can occur quickly. Detailed single crystal structure analysis confirmed that this pore change was due to the non-uniform pedal motion of the axial ligand and the folding/unfolding of the two-dimensional layered structure. By comparing the transformation of the single crystal structure and combining the energy calculation of the different hydration states of the two pore structures, the authors conducted an in-depth analysis of the process mechanism of the structural change and the interaction between the host and the guest. At the same time, the former and latter structures have different spin crossover properties, that is, the narrow pore phase structure shows the two-step spin cross property with no plateau, while the large pore phase structure shows the two-step spin crossover property of the large plateau, reflecting the influence of the rearrangement of the two structures and the change of the host-guest interaction on the spin crossover properties.

The research was supported by the National Natural Science Foundation of China (21971016, 92061106 and 22071009) and Innovative Talents Technology Funding Special Scheme of BIT.

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Fig. 1 Water absorption-induced pore rearrangement

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Fig. 2 Changes in the magnetic properties of the material corresponding to pore rearrangement

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Fig. 3 Water adsorption isotherms and corresponding structural transformations probed by PXRD


Paper link: https://www.nature.com/articles/s41467-022-31274-8


Bi-stable functional material research group profile attached:

Jun Tao, Distinguished Professor of the School of Chemistry and Chemical Engineering of Beijing Institute of Technology is a recipient of the National Science Foundation for Outstanding Young Scholars, mainly engaging in the research of molecular magnetic and functional materials And he has published several high=level academic papers and other high-level academic journals in Chem. Soc. Rev. , J. Am. Chem. Soc., Angew. Chem., Int. Ed. and other high-level academic journals.

Zi-Shuo Yao, the special researcher from the School of Chemistry and Chemical Engineering of BIT, Ph.D. and postdoctoral at Kyushu University, Japan, has published many academic papers in high-level journals, mainly engaged in the research of multifunctional flexible molecular-based materials such as mechanical, magnetic and electrical materials, as the first author or corresponding author has published a number of papers in Nat. Chem., Nat. Commun., J. Am. Chem. Soc., Angew. Chem., Int. Ed. and other authoritative journals.


Homepage of Tao’s research group: http://www.tao-lab.cn/