Switching of the solid-state guest selectivity: solvent-dependent selective guest inclusion in a crystalline macrocyclic boronic ester

Social Self-Sorting of Quasi-Racemates: A Unique Approach for Dual-Pore Molecular Crystals

Despite recent advances in porous organic molecular crystals, the engineering of dual-pore systems within the intermolecular voids remains a significant challenge. In this study, we have achieved the crystallization-induced social self-sorting of "quasi-racemic" dialdehydes into a macrocyclic imine. X-ray crystallographic analysis unambiguously characterizes the resulting structure as incorporating two quasi-racemate pairs with four diamine molecules. Notably, different alkyl substituents on the quasi-racemates afford two types of one-dimensional pores within the macrocyclic imine crystal. The different adsorption properties of these pores were substantiated through adsorption experiments. An intriguing helical arrangement of guest molecules was observed within one of the pores. This study provides pioneering evidence that the social self-sorting of quasi-racemates offers a new methodology for creating dual-functional supramolecular materials.

3D-Boronic Ester Architectures: Synthesis, Host-Guest Chemistry, Dynamic Behavior, and Supramolecular Catalysis

Boronic esters are known to be formed simply by mixing boronic acids and alcohols under neutral conditions, and the equilibrium is in favor of the boronic esters when 1,2- or 1,3-diols are employed as alcohols. By utilizing the dynamic nature of the boronic ester formation, our group successfully constructed unique boron-containing 3D structures, such as ring-shaped macrocycles, cages, and tubes, based on the boronic ester formation of various aromatic di-, tri-, or hexaboronic acids with an originally designed tetrol 1 containing two sets of fixed 1,2-diol units oriented on the same face of an indacene framework. Various functions of the obtained boronates were further pursued to disclose the characteristic features of this system. This personal account describes our self-assembled boronate system using tetrol 1 including synthesis, host-guest chemistry, kinetic connection, characteristic dynamic behaviors, and supramolecular catalysis.

A K+-promoted Diels-Alder reaction by using a self-assembled macrocyclic boronic ester containing two crown ether moieties

A K+-promoted Diels-Alder reaction of 1,4,9,10-anthradiquinone with various dienes is achieved in the presence of a self-assembled macrocyclic boronic ester [2+2]crown containing two crown ether moieties. The reaction rate is remarkably accelerated (up to 206-fold) compared to that in the absence of the promoter. Furthermore, the reaction proceeds regioselectively to yield an internal adduct. The self-assembly protocol was also demonstrated.