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Braun, Oliver; Hünten, Annette; Vögtle, Fritz

doi:10.1002/(sici)1521-3897(199908)341:6<542::aid-prac542>3.3.co;2-3

Cited by 4 publications

(5 citation statements)

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“…TLMs 1a,b (Scheme 1) were synthesized by an established literature procedure. 22 Macrocycle 1a contains a pyridine-2,6dicarboxamide on one side whose N atom points into the cavity and forms two intramolecular ( pyridine)N⋯HN(amide) hydrogen bonds. They force the amide NH atoms to converge into the cavity and thus provide preorganization for a better binding of the axle's carbonyl groups.…”

Section: Resultsmentioning

confidence: 99%

“…TLMs 1a,b were synthesized according to literature procedures. 22 The acid chloride for the synthesis of guest 4 was obtained from the corresponding triphenyl acetic acid by reaction with oxalyl chloride and a few drops of dry DMF in CH 2 Cl 2 . After a clear solution formed while stirring the reaction mixture at r.t., the solvents were evaporated under reduced pressure and the residue was used without further purification.…”

Section: General Methodsmentioning

confidence: 99%

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Substituent effects on axle binding in amide pseudorotaxanes: comparison of NMR titration and ITC data with DFT calculations

et al. 2012

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The binding behaviour of differently substituted diamide axle molecules to Hunter/Vögtle tetralactam macrocycles was studied with a combination of NMR titration, isothermal titration calorimetry (ITC) experiments and calculations employing density functional theory (DFT), along with dispersion-corrected exchange-correlation functionals. Guests with alkyl or alkenyl chains attached to the diamide carbonyl groups have a significantly higher binding affinity to the macrocycle than guests with benzoyl amides and their substituted analogues. While the binding of the benzoyl and alkenyl substituted axles is enthalpically driven, the alkyl-substituted guest binds mainly because of a positive binding entropy. The electronic effects of para-substituents at the benzoyl moieties have an influence on the binding affinities. Electron donating substituents increase, while electron-withdrawing substituents decrease the binding energies. The binding affinities obtained from both NMR titration and ITC experiments correlate well with each other. The substituent effects observed in the experimental data are reflected in adiabatic interaction energies calculated with density functional methods. The calculated structures also agree well with pseudorotaxane crystal structures.

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Section: Resultsmentioning

confidence: 99%

Section: General Methodsmentioning

confidence: 99%

Substituent effects on axle binding in amide pseudorotaxanes: comparison of NMR titration and ITC data with DFT calculations

et al. 2012

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“…TLMs 1a, b were synthesized according to established literature procedures. 111 They contain one pyridine-2,6-dicarboxamide unit providing higher yields, increasing solubility, and facilitating NMR spectral analysis. 112 Monovalent 1a can easily be converted into di-or trivalent analogues through Sonoga-Scheme 1 Synthesis of di-and trivalent hosts 2 and 3 from the iodide-substituted tetralactam macrocycle 1a.…”

Section: Conceptual Considerations and The Synthesis Of Pseudorotaxan...mentioning

confidence: 99%

Evaluation of multivalency as an organization principle for the efficient synthesis of doubly and triply threaded amide rotaxanes

et al. 2014

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Mono-, di-and trivalent pseudorotaxanes with tetralactam macrocycle hosts and axles containing diamide binding stations as the guests have been synthesised. Their threading behaviour was analyzed in detail by NMR experiments and isothermal titration calorimetry. An X-ray crystal structure of the monovalent pseudorotaxane confirms the binding motif. Double mutant cycle analysis provides the effective molarities and insight into the chelate cooperativity of multivalent binding. While the second binding event in a trivalent pseudorotaxane exhibits a slightly positive cooperativity, the third binding is nearly non-cooperative. Nevertheless, the enhanced binding affinities resulting from the multivalent interaction are the basis for a highly efficient synthesis of di-and trivalent rotaxanes through stoppering the axle termini by "click" chemistry. Evidence for the multiply threaded geometry comes from NMR spectroscopy as well as tandem mass-spectrometric fragmentation experiments of mass-selected rotaxane ions in the gas phase. Furthermore, the trivalent rotaxane can be controlled by external stimuli (chloride addition and removal) which lead to an elevator-type movement of the wheel along the axle.

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“…Also, the stoppers have been exchanged against porphyrins [147] and calixarenes [148]. While all rotaxanes mentioned so far have been synthesized from acid chloride center pieces and amine stopper groups, it is also possible to use isocyanates together with trityl aniline or trityl phenol stoppers providing access to urea and urethane groups in the axle [149,150].…”

Section: Synthesis and Structural Variability Of Amide Catenanes And mentioning

confidence: 99%

Hydrogen-Bond-Mediated Template Synthesis of Rotaxanes, Catenanes, and Knotanes

Schalley

Weilandt

Brüggemann

et al. 2005

Topics in Current Chemistry

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Cited by 4 publications

References 0 publications

Substituent effects on axle binding in amide pseudorotaxanes: comparison of NMR titration and ITC data with DFT calculations

Substituent effects on axle binding in amide pseudorotaxanes: comparison of NMR titration and ITC data with DFT calculations

Evaluation of multivalency as an organization principle for the efficient synthesis of doubly and triply threaded amide rotaxanes

Hydrogen-Bond-Mediated Template Synthesis of Rotaxanes, Catenanes, and Knotanes

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