A series of hetero [4]-, [5]- and [6]rotaxanes containing both cucurbit[6]uril (CB[6]) and γ-cyclodextrin (γ-CD) as the macrocyclic components have been synthesized via a threading-followed-by-stoppering approach. Due to the orthogonal binding of CB[6] to ammonium and γ-CD to biphenylene/tetra(ethylene glycol), the []rotaxanes display a specific sequence of the interlocked macrocycles. In addition, despite of the asymmetry of γ-CD with respect to the orthogonal plane of the axle, only one stereoisomer of the [6]rotaxane was obtained.
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http://dx.doi.org/10.3762/bjoc.15.177 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Henan University, Colleg of Chemistry and Molecular Sciences, Jingmin, 475004, Kaifeng, CHINA.
Cycloparaphenylenes (CPPs) represent a significant challenge for the synthesis of mechanically interlocked architectures, because they lack heteroatoms, which precludes traditional active and passive template methods. To circumvent this problem and explore the fundamental and functional properties of CPP rotaxanes and catenanes, researches have resorted to unusual non-covalent and even to labor-intensive covalent template approaches. Herein, we report a ring-in-ring non-covalent template strategy that makes use of the surprisingly strong non-covalent inclusion of crown ethers into suitably sized CPPs.
View Article and Find Full Text PDFCommun Chem
November 2024
Department of Chemistry "Giacomo Ciamician", University of Bologna, Via P. Gobetti 85, I-40129, Bologna, Italy.
Beilstein J Org Chem
November 2024
Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
Owing to their dynamic natures, rotaxane-based polymers are attractive motifs for developing stimuli-responsive materials. However, the accurate control of the rotaxane structure, which can be achieved via multistep synthesis, is key to utilizing the material. Concurrently, implementing a scale-up synthesis procedure to exploit the application potential of rotaxane-based polymers induces structural ambiguities, thereby presenting a significant trade-off between realizing inexpensive production and defined structures.
View Article and Find Full Text PDFJ Nanobiotechnology
November 2024
Guangdong Provincial Key Laboratory of Spine and Spinal Cord Reconstruction, The Fifth Affiliated Hospital (Heyuan Shenhe People's Hospital), Jinan University, Heyuan, 517000, China.
Bacterial biofilms are one of the major contributors to the refractoriness of septic arthritis. Although nitric oxide (NO)-enhanced photodynamic (PDT) therapy has been involved in biofilm eradication, the anti-biofilm efficacy is usually hindered by the short half-life and limited diffusion distance of active molecules. Herein, we report a three-arm structure using the photosensitive core chlorin e6 to integrate three α-cyclodextrin (α-CD) polyrotaxane chains as the supramolecular nanocarrier of NO-enhanced PDT therapy, in which NO was loaded on the cationic rings (α-CDs).
View Article and Find Full Text PDFChem Sci
November 2024
KTH Royal Institute of Technology, Department of Chemistry Teknikringen 30 10044 Stockholm Sweden
We report on the synthesis of [2]rotaxanes from vicinal diols through dynamic covalent boronic ester templates, as well as the use of the boronic ester for rotaxane post-functionalisation. A boronic acid pincer ligand with two alkene-appended arms was condensed with a linear diol-containing thread, and ring-closing metathesis established a pre-rotaxane architecture along with a non-entangled isomer. Advanced NMR spectroscopy and mass spectrometry unambiguously assigned the isomers and revealed that the pre-rotaxane was in equilibrium with its hydrolyzed free [2]rotaxane form.
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