A molecular clip with allosteric binding properties

Sijbesma, RP Rint; Nolte, Roeland J. M.

doi:10.1021/ja00017a063

Cited by 89 publications

(51 citation statements)

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“…Recently, we described an approach to acyclic CB[n] congeners (83 a, Scheme 24) that circumvents these issues while maintaining the binding profile of CB [6] itself. [245, 263b] Based on the precedent of Nolte, [265] we hypothesized that employing alternating glycoluril and aromatic rings would preorganize 83 a into the a,a,a,a conformation required to act as an acyclic CB[n] congener. Indeed, 83 a displays several of the features characteristic of the CB[n] family, namely: 1) high affinity and selectivity for positively charged guests, 2) length-dependent affinity for alkanediammonium ions, 3) guest discrimination on the basis of size and shape, and 4) competitive binding with alkali metals present in solution.…”

Section: Preparation Of Acyclic Cucurbit[n]uril Congenersmentioning

confidence: 99%

The Cucurbit[n]uril Family

et al. 2005

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In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed "cucurbituril" by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants--the pumpkin. In the intervening years, the fundamental binding properties of CB[6]-high affinity, highly selective, and constrictive binding interactions--have been delineated by the pioneering work of the research groups of Mock, Kim, and Buschmann, and has led to their applications in waste-water remediation, as artificial enzymes, and as molecular switches. More recently, the cucurbit[n]uril family has grown to include homologues (CB[5]-CB[10]), derivatives, congeners, and analogues whose sizes span and exceed the range available with the alpha-, beta-, and gamma-cyclodextrins. Their shapes, solubility, and chemical functionality may now be tailored by synthetic chemistry to play a central role in molecular recognition, self-assembly, and nanotechnology. This Review focuses on the synthesis, recognition properties, and applications of these unique macrocycles.

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Section: Preparation Of Acyclic Cucurbit[n]uril Congenersmentioning

confidence: 99%

The Cucurbit[n]uril Family

et al. 2005

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“…Over the years, a large number of artificial receptors displaying positive (5)(6)(7)(8) and negative (9)(10)(11) homotropic and positive (12)(13)(14)(15)(16)(17)(18)(19)(20) and negative (21)(22)(23) heterotropic cooperative binding phenomena have been developed. Although in many cases the origins of the cooperative effects could be identified, few studies have dealt in detail with the kinetics and thermodynamics of such complicated multicomponent receptor-guest systems.…”

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confidence: 99%

Squaring cooperative binding circles

Deutman

Monnereau

Moalin

et al. 2009

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

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The cooperative binding effects of viologens and pyridines to a synthetic bivalent porphyrin receptor are used as a model system to study how the magnitudes of these effects relate to the experimentally obtained values. The full thermodynamic and kinetic circles concerning both activation and inhibition of the cage of the receptor for the binding of viologens were measured and evaluated. The results strongly emphasize the apparent character of measured binding and rate constants, in which the fractional saturation of receptors with other guests is linearly expressed in these constants. The presented method can be used as a simple tool to better analyze and comprehend the experimentally observed kinetics and thermodynamics of natural and artificial cooperative systems.kinetics ͉ slippage ͉ supramolecular chemistry ͉ thermodynamics C ooperative binding plays an important role in nature, where it is used to construct well-defined assemblies and is used as a tool to transfer information at the cellular level (1). The formation of the tobacco mosaic virus (2) and the binding of oxygen to hemoglobin (3) are 2 well-known examples of cooperative processes. Cooperative binding interactions can be homotropic or heterotropic, when the combined binding to a multivalent receptor involves the same or different types of guests. In additions, these interactions can be positive or negative, when the binding of a guest promotes or obstructs the binding of a second guest (4).One of the challenges in the field of supramolecular chemistry is to design artificial systems that display cooperative binding effects, not only to better understand the mechanisms involved in the natural processes but also to prepare functional materials and catalysts that benefit from such binding interactions. Over the years, a large number of artificial receptors displaying positive (5-8) and negative (9-11) homotropic and positive (12-20) and negative (21-23) heterotropic cooperative binding phenomena have been developed. Although in many cases the origins of the cooperative effects could be identified, few studies have dealt in detail with the kinetics and thermodynamics of such complicated multicomponent receptor-guest systems. This is surprising, because unlike the complex biological systems, the artificial receptor-guest systems can be easily studied, and the fine details of cooperative behavior can be uncovered. It is generally known that measured association constants are context dependent in the sense that apparent values that depend on, e.g., the solvent system, salt concentrations, pH, and in the worst case impurities, are obtained (4). As a consequence, the observed cooperative binding effects might often deviate from the intrinsic ones.To investigate how the measured cooperative binding effects as derived from the observed experimental binding constants are related to the intrinsic ones, we present a detailed study of the combined binding of viologens and pyridines to the bivalent zinc porphyrin receptor Zn1 (24, 25) (Scheme 1). Pyridine ligan...

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“…5,7,12,13b,13c,3,9,6a,12a,6/azuleno/2,1, H 6.18,N 10.10,found: C 77.65,H 6.03 N 9.88%. ' 5,7,12,13b,13c,3,9,6a,12a,6]azuleno [ 2,1,8- 2, 3,5,6,8,9,11,12,15,17,20,21,23,24,26,27,29,30,33,34b,34c,4,7,10,13,19,22,25,28,16a,33a,5'] 7, 9,16,…”

Section: Introductionmentioning

confidence: 96%

“…The binding properties of these receptors have been described elsew here5,6. 5,7,12,13b,13c,6a,12a,6] azuleno/2,1,. Method C. Compound lc (0.930 g,1.9 mmol) and A1C13 (1.6 g, 12 mmol) were refluxed in 8 ml of dry benzene (90 mmol) for 4 h under nitrogen.…”

Section: Introductionmentioning

confidence: 99%

“…> 330°C. 5,7,12,13b,13c,4,S,6a,12a,6] azuleno [ 2, 1,8-ija] 5,7,12,13b,13c,6a,12a,6]azuleno [2,1,8-ija]benz/f] azulene -6,13-dione and 5,7,12,13b, 13c, 14-hexahydro-1,11,-diacetoxy-4,8-dimethoxy-13b, 13c-diphenyl-6H, 13H-5a,6a, 12a, 13a-tetraazabenz-f 5,6] ,1,12,13b,13c,4,8,6a,12a,6]azuleno [2, l,8-ija] 5,7,12,13b,13c,4,8,6a,12a,6] 5,7,12,13b,13c,4,8,6a,12a,l,benzlf]azulene-6,13-dione (2g). Method B.…”

Section: Introductionmentioning

confidence: 99%

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