A branched [8]catenane from an efficient one-pot synthesis (72 % HPLC yield, 59 % isolated yield) featuring the simultaneous use of three kinds of templates and cucurbit[6]uril-mediated azide-alkyne cycloaddition (CBAAC) for ring-closing is reported. Design and assembly of the [8]catenane precursors are unexpectedly complex that can involve cooperating, competing and non-influencing interactions. Due to the branched structure, dynamics of the [8]catenane can be modulated in different extent by rigidifying/loosening the mechanical bonds at different regions by using solvent polarity, acid-base and metal ions as the stimuli. This work not only highlights the importance of understanding the delicate interplay of the weak and non-obvious supramolecular interactions in the synthesis of high-order [n]catenane, but also demonstrates a complex control of dynamics and flexibility for exploiting [n]catenanes applications.
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http://dx.doi.org/10.1002/anie.202110200 | DOI Listing |
Angew Chem Int Ed Engl
June 2024
Department of Chemistry, The University of Manchester, Oxford Road, M13 9PL, Manchester, United Kingdom.
Over the last two decades ratchet mechanisms have transformed the understanding and design of stochastic molecular systems-biological, chemical and physical-in a move away from the mechanical macroscopic analogies that dominated thinking regarding molecular dynamics in the 1990s and early 2000s (e.g. pistons, springs, etc), to the more scale-relevant concepts that underpin out-of-equilibrium research in the molecular sciences today.
View Article and Find Full Text PDFJ Am Chem Soc
June 2023
Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
Crosslinking in polymer networks leads to intrinsic structural inhomogeneities that result in brittle materials. Replacing fixed covalent crosslinks with mobile ones in mechanically interlocked polymers (MIPs), such as in slide-ring networks (SRNs) in which interlocked crosslinks are formed when polymer chains are threaded through crosslinked rings, can lead to tougher, more robust networks. An alternative class of MIPs is the polycatenane network (PCN), in which the covalent crosslinks are replaced with interlocked rings that introduce the unusual catenane's mobility elements (elongation, rotation, and twisting) as connections between polymer chains.
View Article and Find Full Text PDFThe main-chain poly[]catenane consists of a series of interlocked rings that resemble a macroscopic chain-link structure. Recently, the synthesis of such intriguing polymers was reported a metallosupramolecular polymer (MSP) template that consists of alternating units of macrocyclic and linear thread-like monomers. Ring closure of the thread components has been shown to yield a mixture of cyclic, linear, and branched poly[]catenanes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2022
State Key Laboratory of Synthetic Chemistry, CAS-HKU Joint Laboratory of Metallomics on Health and Environment and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China.
A branched [8]catenane from an efficient one-pot synthesis (72 % HPLC yield, 59 % isolated yield) featuring the simultaneous use of three kinds of templates and cucurbit[6]uril-mediated azide-alkyne cycloaddition (CBAAC) for ring-closing is reported. Design and assembly of the [8]catenane precursors are unexpectedly complex that can involve cooperating, competing and non-influencing interactions. Due to the branched structure, dynamics of the [8]catenane can be modulated in different extent by rigidifying/loosening the mechanical bonds at different regions by using solvent polarity, acid-base and metal ions as the stimuli.
View Article and Find Full Text PDFAcc Chem Res
November 2021
Shanghai Key Laboratory of Green Chemistry and Chemical Processes & Chang-Kung Chuang Institute, School of Chemistry and Molecular Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, People's Republic of China.
During recent decades, the blossoming of the field of mechanically interlocked molecules (MIMs), i.e., molecules containing mechanical or topological bonds such as rotaxanes, catenanes, and knots, has been reported in the literature.
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