德国德累斯顿工业大学S. Kaskel团队报道了金属有机框架通过可逆的无序-无序转变的适应性响应。 相关研究成果于2021年5月27日发表在国际顶尖学术期刊《Nature Chemistry》。

多孔金属有机框架的超高孔隙率和多功能使其成为从气体储存和分离到催化和传感等广泛应用领域的优秀候选材料。一些框架令人感兴趣的的特性是能够向特定的客户打开它们的孔，从而实现高度选择性的分离。其先决条件是能使框架呼吸的主机结构的双稳定性，也就是说，根据环境在两个稳定性极小值之间切换。

该文中，研究人员描述了一种由镍桨轮簇和羧酸盐连接体组成的多孔骨架DUT-8（Ni），其在特定客体的存在下采用了无序态的构型简并族。这种无序源于非线性连接器将簇排列在不同局部对称性的闭环中，这些闭环又以复杂的平铺形式传播。高分辨率透射电子显微镜和衍射技术证明溶剂交换刺激形成明显的无序框架。客体交换可以刺激不同无序状态之间的可重复转换。

附：英文原文

Title: Adaptive response of a metal–organic framework through reversible disorder–disorder transitions

Author: S. Ehrling, E. M. Reynolds, V. Bon, I. Senkovska, T. E. Gorelik, J. D. Evans, M. Rauche, M. Mendt, M. S. Weiss, A. Pppl, E. Brunner, U. Kaiser, A. L. Goodwin, S. Kaskel

Issue&Volume: 2021-05-27

Abstract: The ultrahigh porosity and varied functionalities of porous metal–organic frameworks make them excellent candidates for applications that range widely from gas storage and separation to catalysis and sensing. An interesting feature of some frameworks is the ability to open their pores to a specific guest, enabling highly selective separation. A prerequisite for this is bistability of the host structure, which enables the framework to breathe, that is, to switch between two stability minima in response to its environment. Here we describe a porous framework DUT-8(Ni)—which consists of nickel paddle wheel clusters and carboxylate linkers—that adopts a configurationally degenerate family of disordered states in the presence of specific guests. This disorder originates from the nonlinear linkers arranging the clusters in closed loops of different local symmetries that in turn propagate as complex tilings. Solvent exchange stimulates the formation of distinct disordered frameworks, as demonstrated by high-resolution transmission electron microscopy and diffraction techniques. Guest exchange was shown to stimulate repeatable switching transitions between distinct disorder states.

DOI: 10.1038/s41557-021-00684-4

Source: https://www.nature.com/articles/s41557-021-00684-4