Halogen-substituted benzylamine crown ether inclusion complexes

Noncovalent interactions have received much attention in the fields of supramolecular chemistry and crystal engineering. Hydrogen bonding and weak interaction forces affect crystal stacking. Crown-ether-based host–guest inclusion compounds with hydrogen bonding and weak intermolecular interaction forces deserve our attention. In addition, Xiong and co-workers have proposed a molecular design strategy of H/F substitution. Based on this H/F substitution strategy, it is possible to develop halogen substitution, also known as the halogenation effect. Here, using benzylamine as an organic parent, the molecular design strategy of the halogenation effect was used. That is, halogen atoms (F, Cl, Br and I) were used to replace H atoms at the para site of the aromatic ring, and four halogenated benzylamine compounds were obtained, namely, 4-fluorobenzylaminium di(methanesulfonyl)amidate–18-crown-6 (1/1), C₇H₉FN⁺·C₂H₆NO₄S₂⁻·C₁₂H₂₄O₆ or [(4-FBA)(18-crown-6)][DMSA], 1; 4-chlorobenzylaminium di(methanesulfonyl)amidate–18-crown-6 (1/1), C₇H₉ClN⁺·C₂H₆NO₄S₂⁻·C₁₂H₂₄O₆ or [(4-ClBA)(18-crown-6)][DMSA], 2; 4-bromobenzylaminium di(methanesulfonyl)amidate–18-crown-6 (1/1), C₇H₉BrN⁺·C₂H₆NO₄S₂⁻·C₁₂H₂₄O₆ or [(4-BrBA)(18-crown-6)][DMSA], 3; and 4-iodobenzylaminium di(methanesulfonyl)amidate–18-crown-6 (1/1), C₇H₉IN⁺·C₂H₆NO₄S₂⁻·C₁₂H₂₄O₆ or [(4-IBA)(18-crown-6)][DMSA], 4. Clathrate 1 crystallizes in the space group P2₁, while 2–4 crystallize in the space group P2₁/n. In these compounds, extensive intermolecular interactions have been utilized for the self-assembly of diverse supramolecular architectures.