Vertically expanded crystalline porous covalent organic frameworks

Xie, S, Addicoat, MA ORCID: https://orcid.org/0000-0002-5406-7927 and Jiang, D, 2024. Vertically expanded crystalline porous covalent organic frameworks. Journal of the American Chemical Society, 146 (47), pp. 32640-32650. ISSN 0002-7863

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Abstract

Covalent organic frameworks (COFs) could be developed for molecular confinement and separation. However, their proximate π stacks limit the interlayer distance to be only 3–6 Å, which is too small for guests to enter. As a result, COFs block the access to the x-y space and limit guest entry/exit strictly to only the pores along the z direction. Therefore, the extended faces of each layer are hidden between layers, precluding the possibility of any interactions with guest molecules. Here we report a strategy for opening interlayer spaces of COFs to attain newly accessible nanospace between layers. This becomes possible by using coordination bonds to replace the conventional π-π stacks between layers. We demonstrate this concept by synthesizing two-dimensional covalent cobalt(II) porphyrin layers through topology-guided polymerization, which were piled up by bidentate axial pillars through coordination bonds with cobalt(II) porphyrin along the z direction, assembling vertically expanded COFs via one-pot reaction. The resultant frameworks separate the layers with axial pillars and create discrete apertures between layers defined by the molecular length of pillars. Consequently, the originally inaccessible interlayers are open for guest access, while the polygonal π planes are exposed to trigger various supramolecular interactions. Vapor sorption, breakthrough experiments, and computational studies mutually revealed that the vertically expanded frameworks with optimal interlayer slits induce additional interactions to discriminate benzene and cyclohexane and separate their mixtures efficiently under ambient conditions.

Item Type:	Journal article
Publication Title:	Journal of the American Chemical Society
Creators:	Xie, S., Addicoat, M.A. and Jiang, D.
Publisher:	American Chemical Society (ACS)
Date:	27 November 2024
Volume:	146
Number:	47
ISSN:	0002-7863
Identifiers:	Number Type 10.1021/jacs.4c11880 DOI 2402156 Other
Rights:	This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/jacs.4c11880
Divisions:	Schools > School of Science and Technology
Record created by:	Laura Borcherds
Date Added:	24 Mar 2025 09:23
Last Modified:	24 Mar 2025 09:23
URI:	https://irep.ntu.ac.uk/id/eprint/53281

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