Little Live Pets 28847 Cozy DOZYS, Multi-Colour

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Y. Ben-Tal, P. J. Boaler, H. J. A. Dale, R. E. Dooley, N. A. Fohn, Y. Gao, A. Garcia-Dominguez, K. M. Grant, A. M. R. Hall, H. L. D. Hayes, M. M. Kucharski, R. Wei and G. C. Lloyd-Jones, Prog. Nucl. Magn. Reson. Spectrosc., 2022, 129, 28 CrossRef CAS PubMed . The most recent method for broadband homonuclear decoupling is the pure shift yielded by chirp excitation (PSYCHE) method. 19 With PSYCHE, the separation between active and passive spins is based on the application of two consecutive pulses with a small tip angle β, as in the anti-z COSY pulse sequence. 20 The active spins are the statistical fraction of the spins that are refocused by the pair of pulses. Their contribution of decoupled spins to the signal (for small angles) scales as β 2, while that of undecoupled spins scales as β 4. Nuclear magnetic resonance (NMR) spectroscopy is a powerful approach for the analysis of mixtures. 1,2 The most common NMR experiment has several essential features that are highly favourable for mixture analysis. It relies on a “pulse-acquire” pulse sequence, carried out at thermal spin equilibrium, to yield 1D spectra, most commonly for 1H spins. This experiment is simple to implement, it can be fast, and it already yields a wealth of structural information, which is useful to identify components. It is also non-invasive and non-destructive, meaning that the sample can be retrieved after analysis for storage or other analyses, and also, in the case of monitoring applications, that experiments can be repeated multiple times on the same sample as a function of time. 1D 1H NMR also provides straightforward access to quantitative information on concentrations.

G. Hornung, C. A. Schalley, M. Dieterle, D. Schroder and S. Derek, Chem. – Eur. J., 1997, 3, 1866–1883 CrossRef CAS. E. G. Bagryanskaya and S. R. A. Marque, Electron Paramagn. Reson., 2017, 25, 180–235 Search PubMed.

DOSY

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Taking this data in combination, the absence of an encapsulation process would have been unlikely. Nevertheless, conclusive proof was found with 2D DOSY spectroscopy which recorded the diffusion coefficients of glutaric acid and of the hexameric cage, isolated and also when combined in solution. As expected, the free glutaric acid diffuses faster ( D = 1.05 × 10 −5 cm 2 s −1) than the hexameric cage ( D = 0.24 × 10 −5 cm 2 s −1) due to its smaller size. By contrast, when measuring the encapsulated guest, the diffusion coefficient is significantly reduced ( D = 0.24 × 10 −5 cm 2 s −1), showing approximately the same value as the cage. Therefore, it was proven that the complex diffuses through solution as one supramolecular entity. Study example B This example considers non-covalently bound oligomers, another relevant molecular class in the field of supramolecular chemistry. 31 In particular, a calix[5]arene, consisting of four methylene-bridged phenyl-ether units and a single 12-aminododecyl substituent (structure 3 in Fig. 2C), was synthesised and studied with 1H-NMR and DOSY NMR in the absence and the presence of acids. The aim of this study was to investigate possible oligomerisation of the calix[5]arene induced by the protonation of the amino-group and its subsequent inclusion in another calix[5]arene molecule ( Fig. 2C top). This was suggested by the 1H-NMR spectrum of 3 with HCl, showing different peak sets of either the unthreaded groups at the ends of the oligomer or the threaded core units.The analyses after thin-film shearing were performed with SANS involving neutrons of the wavelength λ = 5 Å. A range of scattering vectors q, which depend on the neutron wavelength λ and the scattering angle θ, were determined with a movable detector. Higher q-values are generally associated with local gel structure at shorter distances, whereas the lower q-region in the spectrum refers to the global structure in the bulk network ( Fig. 6). The obtained scattering curves were fitted with a fractal flexible cylinder model 61,66,67 and compared between the fluorinated and non-fluorinated bis-urea gels. The results of an earlier study, in which the authors also applied SANS, suggested a lamellar structure for both gels in their native state. 67 This conclusion and several other characteristic distances were derived from the model. A. Dawn, M. Mirzamani, C. D. Jones, D. S. Yufit, S. Qian, J. W. Steed and H. Kumari, Soft Matter, 2018, 14, 9489–9497 RSC. C. Capici, Y. Cohen, A. D’Urso, G. Gattuso, A. Notti, A. Pappalardo, S. Pappalardo, M. F. Parisi, R. Purrello, S. Slovak and V. Villari, Angew. Chem., Int. Ed., 2011, 50, 11956–11961 CrossRef CAS PubMed. S. J. Duncan, R. Lewis, M. A. Bernstein and P. Sandor, Magn. Reson. Chem., 2007, 45, 283 CrossRef CAS PubMed . R. Novoa-Carballal, E. Fernandez-Megia, C. Jimenez and R. Riguera, Nat. Prod. Rep., 2011, 28, 78 RSC .

C. J. Brown, F. D. Toste, R. G. Bergman and K. N. Raymond, Chem. Rev., 2015, 115, 3012–3035 CrossRef CAS PubMed. P. Kiraly, N. Kern, M. P. Plesniak, M. Nilsson, D. J. Procter, G. A. Morris and R. W. Adams, Angew. Chem., Int. Ed., 2021, 60, 666 CrossRef CAS PubMed . G. N. Manjunatha Reddy, M. Yemloul and S. Caldarelli, Magn. Reson. Chem., 2017, 55, 492 CrossRef CAS PubMed . T. Castaing-Cordier, D. Bouillaud, J. Farjon and P. Giraudeau, in Annual Reports on NMR Spectroscopy, ed. G. A. Webb, Academic Press, 2021, pp. 191–258 Search PubMed . M. Nilsson, M. A. Connell, A. L. Davis and G. A. Morris, Anal. Chem., 2006, 78, 3040 CrossRef CAS PubMed .K. Motiram-Corral, M. Perez-Trujillo, P. Nolis and T. Parella, Chem. Commun., 2018, 54, 13507 RSC . J. Ferrando-Soria, A. Fernandez, D. Asthana, S. Nawaz, I. J. Vitorica-Yrezabal, G. F. S. Whitehead, C. A. Muryn, F. Tuna, G. A. Timco, N. D. Burton and R. E. P. Winpenny, Nat. Commun., 2019, 10, 1–7 CrossRef CAS PubMed.