Multi-step spin-crossover in a 2D Hofmann-type clathrate with bisubstituted pyrazine
Xiangkun Wen1, Mengling Wu1, Yancong Chen1
1Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Institute of Green Chemistry and Molecular Engineering, Guangdong Basic Research Center of Excellence for Functional Molecular Engineering, Sun Yat-Sen University, Guangzhou 510275, China. nizhp@mail.sysu.edu.cn.
None:
Multi-step spin-crossover (SCO) materials, which exhibit multiple distinct spin states, are considered promising candidates for high-order data storage and multiple switches. However, such materials remain rare, necessitating the development of innovative design strategies. Here, we chose an inexpensive asymmetric ligand, 2-chloro-6-methylpyrazine (ClMepz), and synthesized two-dimensional (2D) Hofmann-type clathrates [Fe(ClMepz)2{M(CN)2}2]·ClMepz (M = Au (1), Ag (2)), in which ClMepz serves as a monodentate ligand and a guest molecule. Unlike the two-step SCO behavior in 2, compound 1 possesses more spin states and exhibits multi-step SCO behavior. The magneto-structural analysis reveals that the more linear [Au(CN)2]- unit exerts greater stress on the Hofmann layer, leading to the antiferro-elastic interactions. Additionally, the asymmetric host-guest interactions contribute to the stepwise SCO properties. Thus, the incorporation of asymmetric bisubstituted ligands into 2D Hofmann-type systems represents a viable and cost-effective strategy for the development of multi-step SCO materials.
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