Complexation of alkyl groups and ghrelin in a deep, water-soluble cavitand

Zhang, Kang‐Da; Ajami, Dariush; Gavette, Jesse V.; Rebek, Julius

doi:10.1039/c4cc01643b

Cited by 35 publications

(48 citation statements)

References 28 publications

(10 reference statements)

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“…These chains thus appear to be partly disordered and so presumably pay a lower penalty in configurational entropy on binding than the shorter chains. 21 …”

Section: Resultsmentioning

confidence: 99%

Attractive Interactions between Heteroallenes and the Cucurbituril Portal

Reany

Yefet

et al. 2017

J. Am. Chem. Soc.

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This study reports on the remarkable attractive interaction between organic azides and the portal carbonyls of cucurbiturils. Five homologous bis-α,ω-azidoethylammonium alkanes were prepared, where the number of methylene groups between the ammonium groups ranges from 4 to 8. Their interactions with cucurbit[6]uril were studied by NMR, IR and X-ray crystallography, and by computational methods. Remarkably, while the distance between the portal plane and most atoms at the guest end groups increase progressively with the molecular size, the β-nitrogen atoms maintain a constant distance from the portal plane in all homologs, pointing at a strong attractive interaction between the azide group and the portal. Both crystallography and NMR support a specific electrostatic interaction between the carbonyl and the azide β-nitrogen, which stabilizes the canonical resonance form with positive charge on the β-nitrogen and negative charge on the γ-nitrogen. Quantum computational analyses strongly support electrostatics, in the form of orthogonal dipole-dipole interaction, as the main driver for this attraction. The alternative mechanism of n→π* orbital delocalization does not seem to play a significant role in this interaction. The computational studies also indicate that the interaction is not limited to azides, but generalizes to other isoelectronic heteroallene functions, such as isocyanate and isothiocyanate. This essentially unexploited attractive interaction could be more broadly utilized as a tool not only in relation to cucurbituril chemistry, but also for the design of novel supramolecular architectures.

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“…These chains thus appear to be partly disordered and so presumably pay a lower penalty in configurational entropy on binding than the shorter chains. 21 …”

Section: Resultsmentioning

confidence: 99%

Attractive Interactions between Heteroallenes and the Cucurbituril Portal

Reany

Yefet

et al. 2017

J. Am. Chem. Soc.

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“…Based on earlier work by De Mendoza, 101 the dimeric capsule of 62 ( Figure 13 water solubility to the capsule. 104 In the presence of suitable guests (n-undecane through n-tetradecane), 62 forms a symmetrical capsular assembly, while for longer chains, the included alkane (C 14 -C 17 ) adopts a bent 'J' shape. 104 In the presence of suitable guests (n-undecane through n-tetradecane), 62 forms a symmetrical capsular assembly, while for longer chains, the included alkane (C 14 -C 17 ) adopts a bent 'J' shape.…”

Section: Capsular Assembliesmentioning

confidence: 99%

Water-Soluble Cavitands ☆

Jordan

Gibb

2017

Comprehensive Supramolecular Chemistry II

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“…For water-soluble cavitands such as 1,d epending on the size and nature of the guest molecules, monomeric open-ended cavitands 1 or dimeric capsules 1 2 host-guest complexes are formed in water. [20] The recently reported benzimidazolone capsule [19] has been investigated in detail, especiallyb yN MR spectroscopy.T o provide additional insights into this capsulea nd its ability to accommodate guests, we reasoned that EPR spectroscopy combinedw ithM Sa nd NMR spectroscopy could provide valuable complementary information.…”

Section: Introductionmentioning

confidence: 99%

EPR Studies of the Binding Properties, Guest Dynamics, and Inner‐Space Dimensions of a Water‐Soluble Resorcinarene Capsule

Ayhan

Casano

Karoui

et al. 2015

Chemistry A European J

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Nitroxide free radicals have been used to study the inner space of one of Rebek's water-soluble capsules. EPR and (1) H NMR spectroscopy, ESI-MS, and DFT calculations showed a preference for the formation of 1:2 complexes. EPR titrations allowed us to determine binding constants (Ka ) in the order of 10(7) M(-2) . EPR spectral-shape analysis provided information on the guest rotational dynamics within the capsule. The interplay between optimum hydrogen bonding upon capsule formation and steric strain for guest accommodation highlights some degree of flexibility for guest inclusion, particularly at the center of the capsule where the hydrogen bond seam can be barely distorted or slightly disturbed.

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Complexation of alkyl groups and ghrelin in a deep, water-soluble cavitand

Cited by 35 publications

References 28 publications

Attractive Interactions between Heteroallenes and the Cucurbituril Portal

Attractive Interactions between Heteroallenes and the Cucurbituril Portal

Water-Soluble Cavitands ☆

EPR Studies of the Binding Properties, Guest Dynamics, and Inner‐Space Dimensions of a Water‐Soluble Resorcinarene Capsule

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