Supramolecular assembly dynamics

Davis, Anna V.; Yeh, Robert M.; Raymond, Kenneth N.

doi:10.1073/pnas.052018299

Cited by 227 publications

(137 citation statements)

References 34 publications

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“…The concepts of supramolecular chemistry (33,34) can be usefully applied to the study of radon binding. For example, many organic cavitands should bind radon with appreciable affinity, based on radon's considerable polarizability and molecular volume, which is similar to that of dichloromethane.…”

Section: Discussionmentioning

confidence: 99%

Measurement of radon and xenon binding to a cryptophane molecular host

Jacobson

Khan²,

Collé³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Xenon and radon have many similar properties, a difference being that all 35 isotopes of radon ( 195 Rn– 229 Rn) are radioactive. Radon is a pervasive indoor air pollutant believed to cause significant incidence of lung cancer in many geographic regions, yet radon affinity for a discrete molecular species has never been determined. By comparison, the chemistry of xenon has been widely studied and applied in science and technology. Here, both noble gases were found to bind with exceptional affinity to tris-(triazole ethylamine) cryptophane, a previously unsynthesized water-soluble organic host molecule. The cryptophane–xenon association constant, K a = 42,000 ± 2,000 M -1 at 293 K, was determined by isothermal titration calorimetry. This value represents the highest measured xenon affinity for a host molecule. The partitioning of radon between air and aqueous cryptophane solutions of varying concentration was determined radiometrically to give the cryptophane–radon association constant K a = 49,000 ± 12,000 M -1 at 293 K.

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Section: Discussionmentioning

confidence: 99%

Measurement of radon and xenon binding to a cryptophane molecular host

Jacobson

Khan²,

Collé³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…[245] Quantifying such dynamic processes are important for determining self-association mechanisms. [68] Such mechanistic insight, when coupled with structural knowledge, will surely guide the design of improved selfassembling systems.…”

Section: Dynamic Exchange In Self-assembled Ionophoresmentioning

confidence: 99%

“…[64][65][66][67] Another topical area of supramolecular chemistry involves the mechanisms of assembly and disassembly. [68] Again, the early studies with GMP were also concerned with such issues. Multinuclear NMR studies by Laszlo, Detellier, and co-workers were especially insightful.…”

Section: ·4 Picmentioning

confidence: 99%

G‐Quartets 40 Years Later: From 5′‐GMP to Molecular Biology and Supramolecular Chemistry

Davis¹

2004

Angew Chem Int Ed

1,544

525

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Molecular self-assembly is central to many processes in both biology and supramolecular chemistry. The G-quartet, a hydrogen-bonded macrocycle formed by cation-templated assembly of guanosine, was first identified in 1962 as the basis for the aggregation of 5'-guanosine monophosphate. We now know that many nucleosides, oligonucleotides, and synthetic derivatives form a rich array of functional G-quartets. The G-quartet surfaces in areas ranging from structural biology and medicinal chemistry to supramolecular chemistry and nanotechnology. This Review integrates and summarizes knowledge gained from these different areas, with emphasis on G-quartet structure, function, and molecular recognition.

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“…Although the dynamic nature of the defining interactions is often the attribute that distinguishes supramolecular materials from their covalent counterparts, [6] direct mechanistic studies of the molecular contributions to the dynamic properties of materials are less abundant than structural studies.[7] Herein, we report that a simple structural variation in the networks of supramolecular sols and organogels provides a direct and quantitative measure of the relationship between molecular dynamics and macroscopic rheological properties. The approach is akin to a macromolecular "kinetic isotope effect", in that kinetic contributions to rate-determining processes are revealed by the differences in two isostructural systems.…”

mentioning

confidence: 99%

Strong Means Slow: Dynamic Contributions to the Bulk Mechanical Properties of Supramolecular Networks

2005

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The desire to control rationally, through small-molecule synthesis, the properties of bulk materials has led to supramolecular approaches to, for example, polymers, [1,2] strong and weak organogels, [3] amphiphilic assemblies, [4] and liquid crystals.[5] In these materials, specific and well-defined interactions between molecules contribute to bulk material properties on two levels: structure and dynamics. Although the dynamic nature of the defining interactions is often the attribute that distinguishes supramolecular materials from their covalent counterparts, [6] direct mechanistic studies of the molecular contributions to the dynamic properties of materials are less abundant than structural studies.[7] Herein, we report that a simple structural variation in the networks of supramolecular sols and organogels provides a direct and quantitative measure of the relationship between molecular dynamics and macroscopic rheological properties. The approach is akin to a macromolecular "kinetic isotope effect", in that kinetic contributions to rate-determining processes are revealed by the differences in two isostructural systems. We find that it is the dynamics of molecular crosslinks, much more so than their thermodynamics, which are specifically and quantitatively responsible for the bulk viscoelastic properties of the supramolecular networks.The system under consideration is poly(4-vinylpyridine) (PVP) that is cross-linked by bis(M ii -pincer) compounds 1 (see Figure 2) derived from the work of van Koten [8] (M = Pd or Pt, Figure 1). [9] We recently reported that simple steric effects in the alkylamino ligands of 1 and related compounds change the rate of ligand exchange by approximately two orders of magnitude while leaving the thermodynamics of association effectively constant. [10] This independent control of dynamics is particularly significant; cross-linkers 1 a and 1 b (Figure 2) are structurally identical components within the network, and so their similar thermodynamics ensure that the extent and nature of cross-linking is essentially the same in the samples prepared from them. By extending the family of cross-linkers to the Pt II -pincer molecules 1 c and 1 d (Figure 2) we are able to probe the effect of a wide range of molecular dynamics.The addition of 2 % (by functional group) 1 b to a 100 mg mL À1 DMSO solution of PVP (Aldrich, M r = 60 000) gives rise to a clear, thick, deep yellow solution whose viscosity is approximately 2000-times greater than that of PVP alone (33 Pa s vs. 0.016 Pa s). Two control experiments confirm that the viscosity increase is due to coordinative cross-linking of the PVP by 1 b. First, the viscosity does not increase upon the addition of the same quantity of monomeric À .

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Supramolecular assembly dynamics

Cited by 227 publications

References 34 publications

Measurement of radon and xenon binding to a cryptophane molecular host

Measurement of radon and xenon binding to a cryptophane molecular host

G‐Quartets 40 Years Later: From 5′‐GMP to Molecular Biology and Supramolecular Chemistry

Strong Means Slow: Dynamic Contributions to the Bulk Mechanical Properties of Supramolecular Networks

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