Limits...
Crystallographic observation of 'induced fit' in a cryptophane host-guest model system.

Taratula O, Hill PA, Khan NS, Carroll PJ, Dmochowski IJ - Nat Commun (2010)

Bottom Line: Cryptophane-A, comprised of two cyclotriguaiacylenes joined by three ethylene linkers, is a prototypal organic host molecule that binds reversibly to neutral small molecules via London forces.Of note are trifunctionalized, water-soluble cryptophane-A derivatives, which exhibit exceptional affinity for xenon in aqueous solution.Cryptophane internal volume varied by more than 20% across this series, which exemplifies 'induced fit' in a model host-guest system.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
Cryptophane-A, comprised of two cyclotriguaiacylenes joined by three ethylene linkers, is a prototypal organic host molecule that binds reversibly to neutral small molecules via London forces. Of note are trifunctionalized, water-soluble cryptophane-A derivatives, which exhibit exceptional affinity for xenon in aqueous solution. In this paper, we report high-resolution X-ray structures of cryptophane-A and trifunctionalized derivatives in crown-crown and crown-saddle conformations, as well as in complexes with water, methanol, xenon or chloroform. Cryptophane internal volume varied by more than 20% across this series, which exemplifies 'induced fit' in a model host-guest system.

No MeSH data available.


Related in: MedlinePlus

Zoomed view of the Xe-2 complex. This highlights van der Waals interactions between phenyl carbon atoms and xenon. Hydrogen atoms and side chains were removed for clarity. Only Xe atom and two phenyl groups from opposing CTG units are depicted with van der Waals radii.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3105606&req=5

f3: Zoomed view of the Xe-2 complex. This highlights van der Waals interactions between phenyl carbon atoms and xenon. Hydrogen atoms and side chains were removed for clarity. Only Xe atom and two phenyl groups from opposing CTG units are depicted with van der Waals radii.

Mentions: Figure 3 illustrates how xenon is sandwiched by three pairs of phenyl rings belonging to the two opposing CTG units. As noted previously, many of the phenyl carbon atoms nearly achieve van der Waals contact with Xe. In contrast, the Xe-C distances at the linkers are larger (range=4.54–5.41 Å, average=5.00 Å, Supplementary Table S1), when the van der Waals interaction distance for Xe and tetrahedral carbon is 4.16 Å30. The flexible ethylene linkers reside farther away (Fig. 3) and interact more weakly with Xe, on average, but provide the CTG units with mobility to accommodate Xe in the cavity and optimize Xe–phenyl interactions.


Crystallographic observation of 'induced fit' in a cryptophane host-guest model system.

Taratula O, Hill PA, Khan NS, Carroll PJ, Dmochowski IJ - Nat Commun (2010)

Zoomed view of the Xe-2 complex. This highlights van der Waals interactions between phenyl carbon atoms and xenon. Hydrogen atoms and side chains were removed for clarity. Only Xe atom and two phenyl groups from opposing CTG units are depicted with van der Waals radii.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105606&req=5

f3: Zoomed view of the Xe-2 complex. This highlights van der Waals interactions between phenyl carbon atoms and xenon. Hydrogen atoms and side chains were removed for clarity. Only Xe atom and two phenyl groups from opposing CTG units are depicted with van der Waals radii.
Mentions: Figure 3 illustrates how xenon is sandwiched by three pairs of phenyl rings belonging to the two opposing CTG units. As noted previously, many of the phenyl carbon atoms nearly achieve van der Waals contact with Xe. In contrast, the Xe-C distances at the linkers are larger (range=4.54–5.41 Å, average=5.00 Å, Supplementary Table S1), when the van der Waals interaction distance for Xe and tetrahedral carbon is 4.16 Å30. The flexible ethylene linkers reside farther away (Fig. 3) and interact more weakly with Xe, on average, but provide the CTG units with mobility to accommodate Xe in the cavity and optimize Xe–phenyl interactions.

Bottom Line: Cryptophane-A, comprised of two cyclotriguaiacylenes joined by three ethylene linkers, is a prototypal organic host molecule that binds reversibly to neutral small molecules via London forces.Of note are trifunctionalized, water-soluble cryptophane-A derivatives, which exhibit exceptional affinity for xenon in aqueous solution.Cryptophane internal volume varied by more than 20% across this series, which exemplifies 'induced fit' in a model host-guest system.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, USA.

ABSTRACT
Cryptophane-A, comprised of two cyclotriguaiacylenes joined by three ethylene linkers, is a prototypal organic host molecule that binds reversibly to neutral small molecules via London forces. Of note are trifunctionalized, water-soluble cryptophane-A derivatives, which exhibit exceptional affinity for xenon in aqueous solution. In this paper, we report high-resolution X-ray structures of cryptophane-A and trifunctionalized derivatives in crown-crown and crown-saddle conformations, as well as in complexes with water, methanol, xenon or chloroform. Cryptophane internal volume varied by more than 20% across this series, which exemplifies 'induced fit' in a model host-guest system.

No MeSH data available.


Related in: MedlinePlus