M. Diez-Castellnou, M. V. Salvia, S. Springhetti, F. Rastrelli and F. Mancin, Chemistry, 2016, 22, 16957 CrossRef CAS PubMed .

Jean-Nicolas Dumez is a CNRS researcher (Centre National de la Recherche Scientifique) currently working at Nantes Université. He received his PhD in 2011 from Ecole Normale Supérieure de Lyon, and carried out post-doctoral research at the Weizmann Institute of Science and Southampton University, before moving in 2014 to Université Paris-Saclay as a CNRS researcher, then to Nantes in 2018. His research interests include the development of methods for the analysis of mixtures, NMR pulse sequences, and spin dynamics. Most recently we have been investigating the potential of pure shift methods, in which the efffects of scalar couplings are suppressed so that the multiplet structure normally encountered in proton NMR is collapsed, to provide a major improvement in the resolution of proton DOSY experiments ( Chemical Communications designated this a " hot paper"). Other recent developments include a variety of uses of multivariate statistics to enhance the chemical information obtainable with DOSY, and the use of matrix-assisted DOSY methods to improve diffusion resolution, for example allowing the resolution of the NMR spectra of isomers. P. Sakhaii, B. Haase, W. Bermel, R. Kerssebaum, G. E. Wagner and K. Zangger, J. Magn. Reson., 2013, 233, 92 CrossRef CAS PubMed . Left) array of 1H PFGSTE spectra measured with linearly increasing field gradient, for a mixture containing TSP, choline and acetone in D 2O, and (right) the resultant DOSY spectrum, showing TSP signals in blue, choline in green and acetone in red. J. V. Duynhoven, E. V. Velzen and D. M. Jacobs, Annu. Rep. NMR Spectrosc., 2013, 80, 181 CrossRef .B. Gouilleux, B. Charrier, S. Akoka, F.-X. Felpin, M. Rodriguez-Zubiri and P. Giraudeau, TrAC, Trends Anal. Chem., 2016, 83, 65 CrossRef CAS .

L. Sellies, R. Aspers, M. C. Feiters, F. Rutjes and M. Tessari, Angew. Chem., Int. Ed., 2021, 60, 26954 CrossRef CAS PubMed . G. Liu, M. Levien, N. Karschin, G. Parigi, C. Luchinat and M. Bennati, Nat. Chem., 2017, 9, 676 CrossRef CAS PubMed . G. Dal Poggetto, L. Castanar, R. W. Adams, G. A. Morris and M. Nilsson, J. Am. Chem. Soc., 2019, 141, 5766 CrossRef CAS PubMed . Cryogenic transmission electron microscopy Techniques Microscopic techniques provide useful complementary tools with which to investigate structures of supramolecular assemblies. In contrast to the previously discussed methods, microscopy enables the direct imaging of macromolecular structures without having the need to interpret complex spectra. A wide range of microscopic techniques were successfully applied to supramolecular molecules with all of them showing different strengths and weaknesses. 12,71 However, cryogenic transmission electron microscopy (cryo-TEM) has arguably emerged as the most promising tool and will therefore be discussed further in this section.

R. Freeman, Spin Choreography: Basic Steps in High Resolution NMR, Oxford University Press, 1998 Search PubMed .

K. Kristinaityte, A. Mames, M. Pietrzak, F. F. Westermair, W. Silva, R. M. Gschwind, T. Ratajczyk and M. Urbańczyk, J. Am. Chem. Soc., 2022, 144, 13945 CrossRef PubMed . An increasing number of development and applications is also observed in the emerging and fast-growing area of benchtop NMR, which was not covered in this article. Compact instruments provide access to previously inaccessible samples. This is the case for profiling application, which in principle are possible also at high field, but in practice are precluded by cost and availability reasons. This is also true for monitoring applications, which can now be implemented in the fume hood, on in industrial plants. Flow NMR at low and high field also significantly broaden the scope or reactions and processes that can be analysed. M. Foroozandeh, R. W. Adams, N. J. Meharry, D. Jeannerat, M. Nilsson and G. A. Morris, Angew. Chem., Int. Ed., 2014, 53, 6990 CrossRef CAS PubMed . Additionally to the experimental techniques previously discussed, theoretical calculations have emerged as game changers in supramolecular chemistry. The rapid progress made in the last decades ( e.g. in DFT calculations and empirical methods) is inevitably connected to the massive advance of the field. Because this development will likely continue in the future, it deserves even more attention in the supramolecular regime. O. Dunne, M. Weidenhaupt, P. Callow, A. Martel, M. Moulin, S. J. Perkins, M. Haertlein and V. T. Forsyth, Eur. Biophys. J., 2017, 46, 425–432 CrossRef CAS PubMed.

2D 1H-13C HMBC

J. J. Alcázar, N. Geue, V. Valladares, A. Cañete, E. G. Pérez, L. García-Río, J. G. Santos and M. E. Aliaga, ACS Omega, 2021, 6, 10333–10342 CrossRef PubMed. V. Daniele, F.-X. Legrand, P. Berthault, J.-N. Dumez and G. Huber, Chem. Phys. Chem., 2015, 16, 3413 CrossRef CAS PubMed . E. Persch, O. Dumele and F. Diederich, Angew. Chem., Int. Ed., 2015, 54, 3290–3327 CrossRef CAS PubMed. The authors further tested the molecules’ shuttling behaviour caused by the pH-sensitivity of the rotaxane moieties. After deprotonation, strong signal shifts were observed in the 1H-NMR spectra compared to the protonated species. The amine group protons significantly shifted upfield, suggesting the loss of the hydrogen bond to the macrocycle. Contrary, the protons located at the triazole units, which were formed via CuAAC, shifted downfield indicating the new location of the macrocycle. This was also confirmed by NOESY, which showed cross peaks through-space between the triazole unit and the crown ether macrocycle, and a density-functional based tight binding calculation (DFTB+), revealing the preference of the crown ether for the triazole unit in the deprotonated species. Furthermore, the PF 6 − counterions should have been completely removed upon deprotonation. This was shown by 31P-NMR, which did not yield any signal. Additionally, MALDI-MS confirmed the synthesis of the deprotonated G1 and G2 dendrimers, whereas the authors could not obtain the high molecular-weight peak for G3.