Related Experiment Video
Updated: Jun 12, 2026
09:33
Phthalic Acid Ester-Binding DNA Aptamer Selection, Characterization, and Application to an Electrochemical Aptasensor
Published on: March 21, 2018
Size selective recognition of small esters by a negative allosteric hemicarcerand
1University of Bonn, Kekulé-Institute of Organic Chemistry and Biochemistry, Gerhard-Domagk-Str. 1, D-53121 Bonn, Germany.
Beilstein Journal of Organic Chemistry
|May 21, 2010
Summary
This study shows a hemicarcerand selectively binds small esters. Allosteric control via rhenium complexation alters binding by changing molecular conformation, demonstrating tunable molecular recognition.
Area of Science:
- Supramolecular Chemistry
- Host-Guest Chemistry
- Organic Chemistry
Background:
- Bis(resorcinarene) substituted 2,2'-bipyridine acts as a host molecule.
- Hemicarcerands are known for molecular recognition capabilities.
- Allosteric effects can modulate host-guest interactions.
Purpose of the Study:
- To investigate the size-selective binding of esters by a novel hemicarcerand.
- To explore the influence of allosteric modulation on molecular recognition.
- To understand the conformational changes induced by metal coordination.
Main Methods:
- Synthesis of a bis(resorcinarene) substituted 2,2'-bipyridine.
- Binding studies with various esters (e.g., ethyl acetate).
- Coordination of a tris(carbonyl)rhenium chloride fragment.
- Analysis of conformational changes via spectroscopy or crystallography (implied).
Main Results:
- The hemicarcerand exhibited weak binding to small esters like ethyl acetate.
- Larger esters were not recognized, indicating size selectivity.
- Coordination of the rhenium fragment induced a conformational rearrangement.
- This rearrangement disrupted cooperative binding of the resorcinarene moieties.
Conclusions:
- The studied hemicarcerand displays size-selective ester recognition.
- Negative cooperative allosteric effects can control molecular binding.
- Conformational control offers a strategy for tuning host-guest interactions.
More Related Videos
Related Concept Videos
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
01:23Protecting Groups for Aldehydes and Ketones: Introduction
Protecting groups are compounds that can bind to a specific functional group in the presence of other functional groups to protect them from undesired chemical reactions. These compounds can selectively bind to particular functional groups and advance chemoselective reactions in polyfunctional systems (Figure 1). After the functional group has served its purpose, it is removed by reacting it with specific compounds.
01:33Regioselective Formation of Enolates
As depicted in the figure below, the unsymmetrical ketones can form two possible enolates: less substituted or more substituted enolates. Usually, the thermodynamic enolates are formed from the more substituted α-carbon atom, while the kinetic enolates are formed faster by deprotonation from the less substituted position. The thermodynamic enolates have lower energy, so they are more stable. But the energy required to form kinetic enolates is less.
01:08Allosteric Regulation
Allosteric regulation of enzymes occurs when the binding of an effector molecule to a site that is different from the active site causes a change in the enzymatic activity. This alternate site is called an allosteric site, and an enzyme can contain more than one of these sites. Allosteric regulation can either be positive or negative, resulting in an increase or decrease in enzyme activity. Most enzymes that display allosteric regulation are metabolic enzymes involved in the degradation or...
02:43E1 Reaction: Stereochemistry and Regiochemistry
One of the critical aspects of the E1 reaction mechanism, as also observed in E2, is the regiochemistry, with multiple regioisomers obtained as products. In the example discussed, the presence of water as a weak base favors elimination over substitution to generate two alkenes. Given that alkenes’ stability increases with the number of alkyl groups across the double bond, typically, E1 reactions lead to the Zaitsev product, for this is more substituted and stable than the Hofmann product.