Separation of acetylene from carbon dioxide and ethylene is challenging in view of their similar sizes and physical properties. Metal-organic frameworks (MOFs) in general are strong candidates for these separations owing to the presence of functional pore surfaces that can selectively capture a specific target molecule. Here, we report a novel 3D microporous cationic framework named JCM-1. This structure possesses imidazolium functional groups on the pore surfaces and pyrazolate as a metal binding group, which is well known to form strong metal-to-ligand bonds. The selective sorption of acetylene over carbon dioxide and ethylene in JCM-1 was successfully demonstrated by equilibrium gas adsorption analysis as well as dynamic breakthrough measurement. Furthermore, its excellent hydrolytic stability makes the separation processes highly recyclable without a substantial loss in acetylene uptake capacity.

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The development of new approaches to installing diverse carbon fragments to a nitrogen atom has attracted considerable attention in chemical science. While numerous strategies have been devised to forge C(sp3)−N bonds, one conceptually powerful and straightforward approach is to insert a transformable sp3‐carbon unit onto a nitrogen atom for modular diversification. Here we describe the successful synthesis of halo‐diborylmethanes and their applications to the preparation of nitrogen‐substituted diborylmethanes through their homologative coupling with a variety of nitrogen nucleophiles including biologically relevant molecules. This process exhibits a remarkably broad substrate scope, and the usefulness of the obtained compounds is demonstrated by the modular diversification of the diborylmethyl group to access various nitrogen‐containing molecules.

The rational design of organic semiconductors based on crystalline covalent organic frameworks (COFs) as efficient photocatalysts is highly desirable. In this study, the first example of phenanthroimidazole-based COFs is reported: PIm-COF1 with an imine linkage and PIm-COF2 with a β-ketoenamine-linkage. Both COF materials showed substantial optical properties. The average hydrogen evolution rate was 7417.5 μmolg −1 h −1 for PIm-COF2, which was 14 times higher than that of PIm-COF1 (528.5 μmolg −1 h −1 ). This can be attributed to the strong donor− acceptor effect of PIm-COF2 and the continuous separation and transfer of the photoexcited electron−hole pair from the phenanthro[9,10-d] imidazole moiety which are verified by timedependent density functional theory and excitation state analysis.

A one-dimensional (1D) metal-organic caged framework (YMOF-Y) was obtained via self-assembly of yttrium cations with a U-shape imidazolium based ligand and the structure was elucidated by single-crystal Xray diffraction analysis. The YMOF-Y has a unique 1D chain structure composed of octa-imidazolium based cages. Inside the cage, an inner Y 4 cluster connected to yttrium cations of the cage through formate anions is present. The microporosity and flexibility of YMOF-Y can be improved by an unprecedented postsynthetic removal of the Y 4 clusters from the cage by washing with alkali metal solutions. The removal of the Y 4 cluster is reflected in a significant change in the properties of the metal-organic framework (MOF), as confirmed by carbon dioxide sorption measurements and variable temperature powder X-ray diffraction analysis.