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Abstract The accumulation of organic micropollutants (OMP) in aquatic systems is a major societal problem that can be addressed by approaches including nanofiltration, flocculation, reverse osmosis and adsorptive methods using insoluble materials (e.g. activated carbon, MOFs, nanocomposites). More recently, polymeric versions of supramolecular hosts (e.g. cyclodextrins, calixarenes, pillararenes) have been investigated as OMP sequestrants. Herein, we report our study of the use of water insoluble dimethylcatechol walled acyclic cucurbit[n]uril (CB[n]) hosts as solid state sequestrants for a panel of five OMPs. A series of hosts (H1–H4) were synthesized by reaction of glycoluril oligomer (monomer–tetramer) with 3,6‐dimethylcatechol and fully characterized by spectroscopic means and x‐ray crystallography. The solid hosts sequester OMPs from water with removal efficiencies exceeding 90 % in some cases. The removal efficiencies of the new hosts parallel the known molecular recognition properties of analogous water soluble acyclic CB[n]. OMP uptake by solid host occurs rapidly (≈120 seconds). Head‐to‐head comparison with CB[6] in batch‐mode separation and DARCO activated carbon in flow‐through separation mode show that tetramer derived host (H4)performs very well under identical conditions. The work establishes insoluble acyclic CB[n]‐type receptors as a promising new platform for OMP sequestration.
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Structural Deformations in Cucurbit[n]urils: Analysis, Host‐Guest Dependence, and Automated Ellipticity Measurements Using ElliptiCB[n]
Abstract Cucurbit[n]urils (CB[n]s) are cyclic macrocycles with rich host‐guest chemistry. In many cases, guest binding in CB[n]s results in host structural deformations. Unfortunately, measuring such deformations remains a major challenge, with only a handful of manual estimations reported in the literature. To address this challenge, we have developed the public program ElliptiCB[n], which is available on GitHub, that provides a robust and automated method for measuring the elliptical deformations in CB[n] hosts. We outline the development and validation of this approach, apply ElliptiCB[n] to measure the ellipticity of the 1113 available CB[n] structures from the Cambridge Structural Database (CSD), and directly investigate the structural deformations of CB[5], CB[6], CB[7], CB[8], and CB[10] hosts. We also report the general landscape of accessible CB[n] elliptical deformations and compare ellipticity distributions across CB[n] hosts and host‐guest complexes. We found that in almost all cases guest binding significantly impacts the distribution of host ellipticity distributions and that these distributions are dissimilar across host‐guest complexes of differently sized CB[n]s. We anticipate that this work will provide a useful approach for understanding of the flexibility of CB[n] hosts and will also enable future measurement and standardization of ellipticity measurements of CB[n]s.
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- Award ID(s):
- 2004150
- PAR ID:
- 10550114
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 30
- Issue:
- 57
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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