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

Taratula, Olena; Hill, P Aru; Khan, Najat S; Carroll, Patrick J; Dmochowski, Ivan J · Nat Commun · 2010

basic_science · Level V

Where this comes from

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.