Supramolecular crowns: a new class of cyclic hydrogen-bonded cavitands

Chen, Qiang; Su, Xiaoshi; Orentas, Edvinas; Shi, Qixun

doi:10.1039/c9qo00037b

Cited by 6 publications

(7 citation statements)

References 57 publications

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“…The enantiopure bicyclo[3.3.1]nonane scaffold appended with two H-bonding units at each end was selected as the working unit based on the previous successful utilization of similar compounds in creating extremely stable square-shaped or tubular cavity aggregates. − The nearly 90° angle between the complementary ends renders these monomers highly preorganized for tetrameric cyclic aggregation. Moreover, their chirality-assisted aggregation provides full control over the formation of cavity aggregates and excludes the competing formation of unwanted zig-zag type H-bonded polymers.…”

Section: Results and Discussionmentioning

confidence: 99%

“…In the simplest hypothetical strategy towards a supramolecular tweezer, the C 2 -symmetric derivative UPy - UPy can be envisioned as a suitable building block (Figure a). It has been previously shown that UPy - UPy monomers of this type form stable tetrameric aggregates in a variety of solvents via quadruple H-bonding. , In order to form a tweezer aggregate, the monotopic UPy 1 derivative would be required as a partner. However, such an approach will potentially suffer from a serious drawback of having two competing monomers of the same strength (herein, we use the term “order” to define the multiplicity of the H-bonding array), whereas the cyclic aggregate formed by the ditopic monomer would be strongly reinforced by a chelation effect.…”

Section: Results and Discussionmentioning

confidence: 99%

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Fully Supramolecular Chiral Hydrogen-Bonded Molecular Tweezer

et al. 2022

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Molecular tweezers are open-ended, cavity-possessing U-shaped molecular architectures with high potential for various applications in supramolecular chemistry. Their covalent synthesis, however, is often tedious and the structures obtained lack structural responsiveness beyond the limited conformational flexibility of the scaffold. Herein we present a proof-of-concept study on the design, synthesis, assembly, and transformations of a novel supramolecular constructa fully noncovalent molecular tweezer. The supramolecular tweezer was assembled from a set of four building blocks, composed of two identical molecular angle bars and two flat aromatic extension wings, using hydrogen bonding only. The chirality-assisted aggregation process was utilized to ensure scaffold bending directionality using enantiomerically pure bicyclic angle bars. To address the challenges associated with shifting of the equilibrium from strong cooperative narcissistic self-sorting of self-complementary angle bars in cyclic aggregates toward integrative self-sorting in molecular tweezers, a rational desymmetrization strategy was applied. The dynamic supramolecular tweezer has been shown to display rich supramolecular chemistry, allowing for stimuli-responsive change in aggregate topology and solvent-responsive supramolecular polymerization.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Fully Supramolecular Chiral Hydrogen-Bonded Molecular Tweezer

et al. 2022

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“…As another feature, the encapsulation that could be observed in toluene, but not in CHCl3, hindered scrambling between the two types of monomers 72a and 72b. In contrast to these compounds with the bicyclo[3.3.1]nonane framework, only the tetramer of the dioxabicyclo[3.3.1]nonane derivative 73 was observed, either in CHCl3 or in benzene [89]. Reversible formation of dimeric capsules from other star shaped molecules ( 71) was used for the purification of fullerenes that could be encapsulated in the cavity [87].…”

Section: Formation Of Different Molecular Architectures Via Supramole...mentioning

confidence: 99%

Urea-Functionalized Heterocycles: Structure, Hydrogen Bonding and Applications

Keszei,

Váradi,

Skoda-Földes

2023

Molecules

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Ureido-heterocycles exhibiting different triple- and quadruple H-bonding patterns are useful building blocks in the construction of supramolecular polymers, self-healing materials, stimuli-responsive devices, catalysts and sensors. The heterocyclic group may provide hydrogen bond donor/acceptor sites to supplement those in the urea core, and they can also bind metals and can be modified by pH, redox reactions or irradiation. In the present review, the main structural features of these derivatives are discussed, including the effect of tautomerization and conformational isomerism on self-assembly and complex formation. Some examples of their use as building blocks in different molecular architectures and supramolecular polymers, with special emphasis on biomedical applications, are presented. The role of the heterocyclic functionality in catalytic and sensory applications is also outlined.

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“…3.1]nonane central blocks, to create chiral cavities with tuneable stability, size and function. [111][112][113][114][115] For instance, bis-UPy molecule 13 112 allowed the formation of a cyclic tetramer by quadruple H-bonding interactions between monomers (Fig. 11a).…”

Section: Template Effectsmentioning

confidence: 99%