A trefoil knot self-templated through imination in water

Ye, Lei; Li, Zhaoyong; Wu, Guangcheng; Zhang, Lijie; Lu, Tong; Tong, Tianyi; Chen, Qiong; Wang, Lingxiang; Ge, Chenqi; Wei, Yuxi; Pan, Yuanjiang; Sue, Andrew C.‐H.; Wang, Linjun; Huang, Feihe; Li, Hao

doi:10.1038/s41467-022-31289-1

Cited by 25 publications

(19 citation statements)

References 57 publications

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“…Our group thus envision that a molecule containing multiple imine bonds might be more robust compared to those counterparts containing only one or fewer bonds. ,, The enhanced stability of imine via multivalency might allow us to perform self-assembly in aqueous media. Charged precursors, either cationic or anionic, were used to enhance water solubility, allowing self-assembly to occur in a homogeneous manner.…”

Section: Characterization Of the Self-assembled Productsmentioning

confidence: 99%

Self-Assembly via Condensation of Imine or Its N-Substituted Derivatives

Chen,

Tang,

Chen

et al. 2023

Acc. Chem. Res.

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Conspectus Compared to traditionally used irreversible chemical reactions, dynamic covalent chemistry (DCC) including imine formation represents a more advanced technique in the preparation of molecules with complex structures and topologies, whose syntheses require the formation of many bonds. By allowing the occurrence of error checking and self-correcting, it is likely that the target molecules with high enough thermodynamic stability could be self-assembled in high or even quantitative yield. Two questions are raised herein. First, it becomes a central problem in self-assembly that how to endow a target product with high enough thermodynamic stability so that it can be produced as the major or the only product within the self-assembly library. Second, the reversible nature of dynamic bonds jeopardizes the intrinsic stability of the products. More specifically, the imine bond which represents the mostly used dynamic covalent bond, is apt to undergo hydrolysis in the presence of water. Developing new approaches to make imine more robust and compatible with water is thus of importance. In this account, we summarized the progress made in our group in the field of self-assembly based on CN bond formation. In organic solvent where an imine bond is relatively robust, we focus on studying how to enhance the thermodynamic stability of a target molecule by introducing intramolecular forces. These noncovalent interactions either release enthalpy to favor the formation of the target molecule or preorganize the building blocks into specific conformations that mimic the product, so that the entropy loss of the formation of the latter is thus suppressed. In water, which often leads to imine hydrolysis, we developed two strategies to enhance the water-compatibility. By taking advantage of multivalency, namely, multiple bonds are often more robust than a single bond, self-assembly via condensation of imine was performed successfully in water, a solvent that is considered as forbidden zone of imine. Another approach is to replace typical imine with its more robust and water compatible derivatives, namely, either hydrazone or oxime, whose CN bonds are generally less electrophilic compared to typical imine. With the water-compatible dynamic bonds in hand, a variety topological nontrivial molecules such as catenanes and knots was self-assembled successfully in aqueous media, driven by hydrophobic effect. When the self-assembled molecules in the form of rings and cages were designed for supramolecular purposes, water-compatibility endows a merit that allows the hosts to take advantage of hydrophobic effect to drive host–guest recognition, enabling various tasks to be accomplished, such as separation of guest isomers with similar physical properties, recognition of highly hydrated anions, as well as stabilization of guest dimers.

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Section: Characterization Of the Self-assembled Productsmentioning

confidence: 99%

Self-Assembly via Condensation of Imine or Its N-Substituted Derivatives

Chen,

Tang,

Chen

et al. 2023

Acc. Chem. Res.

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“…Very recently, the Li group also reported the formation of a molecular trefoil knot based on dynamic imine exchange in water. [61] Direct condensation of three equivalents of a tetraaldehyde precursor and six equivalents of a chiral amine produced a [3 + 6] imine knot. The handedness of the knot could be controlled through the inherent stereochemistry of the amine linkers, and the system self-sorted between left and right-handed knots when treated with a racemate of the diamine.…”

Section: Dynamic Imine Chemistry Based On Solvophobic Effectsmentioning

confidence: 99%

“…Many dynamic covalent reactions can occur in aqueous solution, [56,59,61] indicating possible synergy with biological systems. In 2019, Peinador, García and co-workers synthesized a cucurbit [7]uril-based [2]rotaxane in aqueous solution (Figure 7a).…”

Section: Dynamic Rotaxane Stopperingmentioning

confidence: 99%

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Dynamic Covalent Chemistry for Synthesis and Co‐conformational Control of Mechanically Interlocked Molecules

Gaedke

Schaufelberger

2022

Eur J Org Chem

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Mechanically interlocked molecules have found extensive applications in areas all across the physical sciences, from materials to catalysis and sensing. However, introducing mechanical bonds and entanglements at the molecular level is still a significant challenge due to the inherent restriction in entropy needed to preorganize strands before interlocking. Over the last decade, dynamic covalent chemistry has emerged as one of the most efficient methods of forming rotaxanes, catenanes and molecular knots. By using reversible bonds such as imines, disulfides and boronate esters, one can use the inherent error‐correction in these linkages to form interlocked architectures with high fidelity and often in excellent yields. This review reports on recent advances in the use of dynamic covalent chemistry to make mechanically interlocked molecules, systematically surveying clipping, capping and templating approaches with dynamic bonds. Furthermore, it is also discussed how dynamic bonds can be used to control motion, co‐conformational expression and catalytic activity in mechanically interlocked molecular machinery.

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“…Cationic cyclophane as novel macrocyclic hosts has been widely used in host–guest chemistry, − mechanically interlocked molecules, − luminescent materials, − drug delivery, − molecular catalysis, − and other fields due to their advantages of the rigid cavity, excellent electron-deficient, good redox properties, and so on. − Especially, cyclobis(paraquant- p -phenylene), also known as the blue box ( 1 ), was developed by Stoddart and co-workers, which exhibited excellent applications in supramolecular architectures, host–guest complexes, catalysis, and mechanically interlocked molecules during the past 35 years. − Inspired by this, some novel box-like derivatives have been reported . For example, Stoddart and co-workers designed and synthesized the tetrazine box, a structurally transformative tetrazine-containing tetracationic cyclophane, existing in three different reversible redox states which can be manipulated and visited by delicately controlled redox chemistry .…”

Section: Introductionmentioning

confidence: 99%

The Green Box: Selenoviologen-Based Tetracationic Cyclophane for Electrochromism, Host–Guest Interactions, and Visible-Light Photocatalysis

et al. 2023

J. Am. Chem. Soc.

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The novel selenoviologen-based tetracationic cyclophanes (green boxes 3 and 5) with rigid electron-deficient cavities are synthesized via SN2 reactions in two steps. The green boxes exhibit good redox properties, narrow energy gaps, and strong absorption in the visible range (370–470 nm), especially for the green box 5 containing two selenoviologen (SeV2+) units. Meanwhile, the femtosecond transient absorption (fs-TA) reveals that the green boxes have a stabilized dicationic biradical, high efficiency of intramolecular charge transfer (ICT), and long-lived charge separation state due to the formation of cyclophane structure. Based on the excellent photophysical and redox properties, the green boxes are applied to electrochromic devices (ECDs) and visible-light-driven hydrogen production with a high H2 generation rate (34 μmol/h), turnover number (203), and apparent quantum yield (5.33 × 10–2). In addition, the host–guest recognitions are demonstrated between the green boxes and electron-rich guests (e.g., G1:1-naphthol and G2:platinum(II)-tethered naphthalene) in MeCN through C–H···π and π···π interactions. As a one-component system, the host–guest complexes of green box⊃G2 are successfully applied to visible-light photocatalytic hydrogen production due to the intramolecular electron transfer (IET) between platinum(II) of G2 and SeV2+ of the green box, which provides a simplified system for solar energy conversion.

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A trefoil knot self-templated through imination in water

Cited by 25 publications

References 57 publications

Self-Assembly via Condensation of Imine or Its N-Substituted Derivatives

Self-Assembly via Condensation of Imine or Its N-Substituted Derivatives

Dynamic Covalent Chemistry for Synthesis and Co‐conformational Control of Mechanically Interlocked Molecules

The Green Box: Selenoviologen-Based Tetracationic Cyclophane for Electrochromism, Host–Guest Interactions, and Visible-Light Photocatalysis

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