Crystalline Molecular Cleft Clathrates

Lynch, Abbie V.; Blundell, Toby J.; Steed, Jonathan W.

Abstract

A rigid bis­(urea) molecular cleft (BU1) based on the cis diastereomer of a rigid isophorone-derived spacer forms solid-state inclusion complexes with a range of small molecular guests. Larger guests can be accommodated by a shift in orientation to open up crystalline channels while retaining the same overall hydrogen-bonded topology. The introduction of molecular flexibility to give BU2, which possesses a methylene spacer, destroys the host–guest complexation behavior and restores the more conventional urea α-tape packing, giving viscous solutions due to columnar aggregation. Crystallization of both BU1 and BU2 from a mixture of cis and trans diastereomeric forms is highly diastereoselective with the cis isomers being significantly less soluble. Isolation of a trans isomer of BU2 from crystallization of cis-depleted mother liquor reveals an unusual intramolecular hydrogen bond arrangement, explaining its greater solubility.

Citation

Lynch, A. V., Blundell, T. J., & Steed, J. W. (2024). Crystalline Molecular Cleft Clathrates. Crystal Growth and Design, 24(17), 7271-7277. https://doi.org/10.1021/acs.cgd.4c00928

• Journal Article Type: Article
• Acceptance Date: Aug 16, 2024
• Online Publication Date: Aug 21, 2024
• Publication Date: Aug 21, 2024
• Deposit Date: Sep 4, 2024
• Publicly Available Date: Sep 4, 2024
• Journal: Crystal Growth & Design
• Print ISSN: 1528-7483
• Electronic ISSN: 1528-7505
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 24
• Issue: 17
• Pages: 7271-7277
• DOI: https://doi.org/10.1021/acs.cgd.4c00928
• Public URL: https://durham-repository.worktribe.com/output/2785439