爱尔兰利默里克大学Zaworotko, Michael J.团队报道了由瞬态孔隙率实现的柔性配位网络的无孔相之间的可逆转换。相关研究成果发表在2023年2月13日出版的《自然—化学》。

柔性金属-有机材料在气体分子诱导的封闭（非多孔）和开放（多孔）结构之间表现出刺激响应切换，在气体储存和分离中具有潜在用途。这种行为目前仅限于几十种物理吸附剂，它们通常通过需要结构扭曲的呼吸机制进行转换。

该文中，研究人员展示了一个笼状物（非多孔）配位网络，该网络通过瞬时孔隙度在多个非多孔相之间进行气体诱导切换，这涉及通过网络内畸变在离散孔隙之间的客体扩散。这种材料被合成为具有溶剂填充腔的包合物相；抽气后获得了到具有较小空腔的相的单晶到单晶的转变。在298K下，二氧化碳、乙炔、乙烯和乙烷在无客体和负载气体的包合物相之间诱导可逆切换。对于低温下的二氧化碳和乙炔，使用原位X射线衍射观察并表征了负载逐渐升高的相，并通过计算阐明了扩散机制。

附：英文原文

Title: Reversible transformations between the non-porous phases of a flexible coordination network enabled by transient porosity

Author: Nikolayenko, Varvara I., Castell, Dominic C., Sensharma, Debobroto, Shivanna, Mohana, Loots, Leigh, Forrest, Katherine A., Solanilla-Salinas, Carlos J., Otake, Ken-ichi, Kitagawa, Susumu, Barbour, Leonard J., Space, Brian, Zaworotko, Michael J.

Issue&Volume: 2023-02-13

Abstract: Flexible metal–organic materials that exhibit stimulus-responsive switching between closed (non-porous) and open (porous) structures induced by gas molecules are of potential utility in gas storage and separation. Such behaviour is currently limited to a few dozen physisorbents that typically switch through a breathing mechanism requiring structural contortions. Here we show a clathrate (non-porous) coordination network that undergoes gas-induced switching between multiple non-porous phases through transient porosity, which involves the diffusion of guests between discrete voids through intra-network distortions. This material is synthesized as a clathrate phase with solvent-filled cavities; evacuation affords a single-crystal to single-crystal transformation to a phase with smaller cavities. At 298K, carbon dioxide, acetylene, ethylene and ethane induce reversible switching between guest-free and gas-loaded clathrate phases. For carbon dioxide and acetylene at cryogenic temperatures, phases showing progressively higher loadings were observed and characterized using in situ X-ray diffraction, and the mechanism of diffusion was computationally elucidated.

DOI: 10.1038/s41557-022-01128-3

Source: https://www.nature.com/articles/s41557-022-01128-3