Dynamic chiral cyclohexanohemicucurbit[12]uril

Mishra, Kamini A.; Adamson, Jasper; Öeren, Mario; Kaabel, Sandra; Fomitšenko, Maria; Aav, Riina

doi:10.1039/d0cc06817a

Cited by 9 publications

(7 citation statements)

References 40 publications

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“…This inspired us to explore further complexation and chirogenesis with bis-ZnOEP due to its aforementioned binding and chirality Recently, we reported that carbonyl groups of (R,R)-and (S,S)-enantiomers of barrelshaped macrocycles, cyclohexanohemicucurbit[n]urils (cycHC[n], n = 6, 8) (Figure 1), can externally bind multiple zinc porphyrins through the Lewis acid-base interactions and subsequently induce chirality at the porphyrin core [36]. A family of cycHC[n]s consists of chiral and nonchiral (n = 6, 8, 12) members [37][38][39][40] and features, analogous to all single bridged cucurbiturils [41,42], binding anions inside the macrocycle cavity. Additionally, cycHC[n]s bind hydrogen bond donors and electron-rich organic molecules [43,44].…”

Section: Introductionmentioning

confidence: 99%

Self-Assembly of Chiral Cyclohexanohemicucurbit[n]urils with Bis(Zn Porphyrin): Size, Shape, and Time-Dependent Binding

et al. 2022

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In order to investigate the ability of bis(zinc octaethylporphyrin) (bis–ZnOEP) to discriminate cyclohexanohemicucurbit[n]urils (cycHC[n]) of different shapes and sizes, the self-assembly of barrel-shaped chiral cycHC[n] with bis–ZnOEP was studied by various spectroscopic methods (absorption, fluorescence, circular dichroism (CD), and NMR). While the binding of 6-membered cycHC[6] induced a tweezer-like conformation followed by the formation of anti-form of bis–ZnOEP upon further addition of cycHC[6], the interaction of 8-membered cycHC[8] is more complex and proceeds through the featured syn-to-anti conformational change of bis–ZnOEP and further intermolecular self-assembly via multiple noncovalent associations between cycHC[8] and bis–ZnOEP. Whilst bis–porphyrins are known to be effective chemical sensors able to differentiate various guests based on their chirality via induced CD, their ability to sense small differences in the shape and size of relatively large macrocycles, such as chiral cycHC[6] and cycHC[8], is scarcely examined. Both studied complexes exhibited characteristic induced CD signals in the region of porphyrin absorption upon complexation.

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Section: Introductionmentioning

confidence: 99%

Self-Assembly of Chiral Cyclohexanohemicucurbit[n]urils with Bis(Zn Porphyrin): Size, Shape, and Time-Dependent Binding

et al. 2022

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“…In Aav’s group, the first enantiomerically pure, inherently chiral member of the family—specifically cyclohexanohemicucurbit[6]uril (cycHC[6]) ( Aav et al, 2013 )—was prepared. Later, its larger homologs, cycHC[8] ( Prigorchenko et al, 2015 ) and cycHC[12] ( Mishra et al, 2020 ), were also made.…”

Section: Introductionmentioning

confidence: 99%

Binding Between Cyclohexanohemicucurbit[n]urils and Polar Organic Guests

et al. 2021

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Inherently chiral, barrel-shaped, macrocyclic hosts such as cyclohexanohemicucurbit[n]urils (cycHC[n]) bind zinc porphyrins and trifluoroacetic acid externally in halogenated solvents. In the current study, we tested a set of eighteen organic guests with various functional groups and polarity, namely, thiophenols, phenols, and carboxylic and sulfonic acids, to identify a preference toward hydrogen bond–donating molecules for homologous cycHC[6] and cycHC[8]. Guests were characterized by Hirshfeld partial charges on acidic hydrogens and their binding by 1H and 19F NMR titrations. Evaluation of association constants revealed the complexity of the system and indirectly proved an external binding with stoichiometry over 2:1 for both homologs. It was found that overall binding strength is influenced by the stoichiometry of the formed complexes, the partial atomic charge on the hydrogen atom of the hydrogen bond donor, and the bulkiness of the guest. Additionally, a study on the formation of complexes with halogen anions (Cl− and Br−) in methanol and chloroform, analyzed by 1H NMR, did not confirm complexation. The current study widens the scope of potential applications for host molecules by demonstrating the formation of hydrogen-bonded complexes with multisite hydrogen bond acceptors such as cycHC[6] and cycHC[8].

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“…The latter grants these macrocycles the ability to encapsulate anions ( Buschmann et al, 2005 ; Cucolea et al, 2016 ; Kaabel et al, 2017 ; Assaf and Nau, 2018 ; Reany et al, 2018 ; Vázquez and Sindelar, 2018 ; Andersen et al, 2019 ; Kandrnálová et al, 2019 ; Valkenier et al, 2019 ; Maršálek and Šindelář, 2020 ); in addition, the formation of complexes with acids and some neutral species has been reported in the previous work. In particular, unsubstituted hemicucurbit[ n ]urils ( n = 6, 12) bind phenol derivatives ( Jin et al, 2016a ; 2016b ) and ferrocene ( Jin et al, 2017 ), and cyclohexanohemicucurbit[ n ]urils cycHC [ n ] ( n = 6, 8, 12) ( Li et al, 2009 ; Aav et al, 2013 ; Prigorchenko et al, 2015 , 2019 ; Mishra et al, 2020 ) form external complexes with both inorganic and organic acids ( Öeren et al, 2014 ; Ustrnul et al, 2019 , 2021 ). We envisioned that heterocycles 1–13 have relatively high electron densities compared to carbocycles and may therefore be able to occupy space within the eight-membered cycHC[8] ( Figure 1 ).…”

Section: Introductionmentioning

confidence: 99%

Cyclohexanohemicucurbit[8]uril Inclusion Complexes With Heterocycles and Selective Extraction of Sulfur Compounds From Water

et al. 2021

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Solid-phase extraction that utilizes selective macrocyclic receptors can serve as a useful tool for removal of chemical wastes. Hemicucurbiturils are known to form inclusion complexes with suitably sized anions; however, their use in selective binding of non-charged species is still very limited. In this study, we found that cyclohexanohemicucurbit[8]uril encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles, which is investigated by single-crystal X-ray diffraction, NMR spectroscopy, isothermal titration calorimetry, and thermogravimetry. The macrocycle acts as a promising selective sorption material for the extraction of sulfur heterocycles, such as 1,3-dithiolane and α-lipoic acid, from water.

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Dynamic chiral cyclohexanohemicucurbit[12]uril

Abstract: NMR spectroscopy and DFT modeling studies of chiral cyclohexanohemicucurbit[12]uril indicate that the macrocycle adopts a concave octagonal shape with two distinct conformational flexibilities in solution. Methylene bridge flipping occurs at...

Cited by 9 publications

References 40 publications

Self-Assembly of Chiral Cyclohexanohemicucurbit[n]urils with Bis(Zn Porphyrin): Size, Shape, and Time-Dependent Binding

Self-Assembly of Chiral Cyclohexanohemicucurbit[n]urils with Bis(Zn Porphyrin): Size, Shape, and Time-Dependent Binding

Binding Between Cyclohexanohemicucurbit[n]urils and Polar Organic Guests

Cyclohexanohemicucurbit[8]uril Inclusion Complexes With Heterocycles and Selective Extraction of Sulfur Compounds From Water

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