In–out interactions of different guests with the hexameric capsule of resorcin[4]arene

Slovak, Sarit; Cohen, Yoram

doi:10.1080/10610278.2010.506549

Cited by 22 publications

(23 citation statements)

References 63 publications

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“…The same result was obtained for the solution of alcohol 14 in the presence of 1 a (see Figure S6 in the Supporting Information). This is in contrast to what was recently found for large trialkylamines and tetraalkylammonium salts in the presence of the hexameric capsule of 1 a 10e. For alcohols 2 , 5 , 6 , 13 , and 19 the branching and the size of the alcohols do not allow them to participate in the supramolecular assembly of the hexameric structure of 1 a , but they still can be encapsulated within the hexamer of 1 a .…”

Section: Resultscontrasting

confidence: 89%

The Effect of Alcohol Structures on the Interaction Mode with the Hexameric Capsule of Resorcin[4]arene

Slovak

Cohen

2012

Chemistry A European J

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After more than a century of research on resorcin[4]arenes (1) it is clear that such systems form spontaneously [1(6)(H(2)O)(8)]-type hexameric capsules in wet, non-polar, organic solvents. However, the interactions of these hexameric capsules with alcohols are far from being solved. Here we provide the results of an extensive study on the interaction of different alcohols with the hexameric capsules of resorcin[4]arene 1a by focusing on the exchange of magnetization manifested in diffusion NMR measurements of such capsular systems. We found that some alcohols such as 2-octyl-1-dodecanol and 1-octadecanol do not interact with the hexamers of 1a, whereas other alcohols such as 3-ethyl-3-pentanol, 2-ethyl-1-butanol and more act as simple guests and are simply encapsulated in the hexamers. Others alcohols such as 3-pentanol, 2-methyl-1-butanol and others, are part of the hexameric structure where they can exchange magnetization with alcohols in the bulk. The bulkier alcohols, due to an increase of the chain length or in branching, have a higher tendency to be encapsulated rather than being part of the hexameric capsule superstructure. This study demonstrate the unique information that diffusion NMR spectroscopy can provide on supramolecular systems in solution and on the precaution that should be exercised when analyzing diffusion NMR data of such dynamic supramolecular capsules.

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Section: Resultscontrasting

confidence: 89%

The Effect of Alcohol Structures on the Interaction Mode with the Hexameric Capsule of Resorcin[4]arene

Slovak

Cohen

2012

Chemistry A European J

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“…87 More recently, diffusion NMR was instrumental in showing that both trialkylamines and tetraalkyl ammonium cations interact with hexamers of 14c, both from the inside and from the outside. 89 Diffusion NMR also enabled us to follow the disintegration of the different non-covalent interactions in the chloroform solutions of 16), and (b) schematic representation of the structure of the hexamers of 14b/14c in a CHCl 3 solution as concluded from diffusion NMR. 39,40 the hexamers of 14c and trialkylamines upon addition of methanol, which disrupts the hydrogen bonds, as shown in Fig.…”

Section: Hydrogen Bond-based Molecular Capsules: From Dimers To Highe...mentioning

confidence: 99%

“…6. 89 For example, adding up to 40 equivalents of methanol does not disrupt the hexamer of 14c, and trioctyl amine (17) is still encapsulated in the hexamer of 14c. However, the external interaction of 17 with the hexamers of 14c is disrupted (Fig.…”

Section: Hydrogen Bond-based Molecular Capsules: From Dimers To Highe...mentioning

confidence: 99%

Diffusion NMR of molecular cages and capsules

2015

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In the last decade diffusion NMR and diffusion ordered spectroscopy (DOSY) have become important analytical tools for the characterization of supramolecular systems in solution. Diffusion NMR can be used to glean information on the (effective) size and shape of molecular species, as well as to probe inter-molecular interactions and can be used to estimate the association constant (Ka) of a complex. In addition, the diffusion coefficient, as obtained from diffusion NMR, is a much more intuitive parameter than the chemical shift for probing self-association, aggregation and inter-molecular interactions. The diffusion coefficient may be an even more important analytical parameter in systems in which the formed supramolecular entity has the same symmetry as its building units, when there is a large change in the molecular weight, where many molecular species are involved in the formation of the supramolecular systems, and when proton transfer may occur which, in turn, may affect the chemical shift. Some of the self-assembled molecular capsules and cages prepared in the last decade represent such supramolecular systems and in the present review, following a short introduction on diffusion NMR, we survey the contribution of diffusion NMR and DOSY in the field of molecular containers and capsules. We will first focus on the role played by diffusion NMR in the field of hydrogen bond driven self-assembled capsules. We then survey the contributions of diffusion NMR and DOSY to the study and characterization of metal-ligand cages and capsules. Finally, we describe a few recent applications of diffusion NMR in the field of hydrophobic, electrostatic and covalent containers.

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“…16 According to NMR studies, such guests also show a significant interaction with the external surface of the hexamer. 17 Other suitable guests like alcohols and carboxylic acids rely on their ability to form hydrogen bonds with the hexameric host and, depending on their size, are coencapsulated with residual solvent molecules to reach an optimum packing coefficient of about 0.55. 1c,15c,18 Furthermore, it was shown that suitable alcohol molecules can be integrated into the hexameric structure by replacing some of the water molecules.…”

Section: Molecular Capsules: Structures and Backgroundmentioning

confidence: 99%

Self-Assembled Supramolecular Structures as Catalysts for Reactions Involving Cationic Transition States

2015

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Self-assembled supramolecular structures represent easily accessible systems for the study of enzyme-like catalysis. The hydrophobic cavities of the assemblies provide a distinct chemical environment that can lead to unusual chemo-and stereoselectivities. This review summarizes the application of such host structures in the catalysis of reactions involving cationic transition states and includes detailed discussion of mechanisms and substrate-host interactions. The literature up to April 2015 is covered. 1 Introduction 2 Molecular Capsules: Structures and Background 3 Catalyzed Reactions 4 Summary and Outlook

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In–out interactions of different guests with the hexameric capsule of resorcin[4]arene

Cited by 22 publications

References 63 publications

The Effect of Alcohol Structures on the Interaction Mode with the Hexameric Capsule of Resorcin[4]arene

The Effect of Alcohol Structures on the Interaction Mode with the Hexameric Capsule of Resorcin[4]arene

Diffusion NMR of molecular cages and capsules

Self-Assembled Supramolecular Structures as Catalysts for Reactions Involving Cationic Transition States

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