Crystallographic observation of 'induced fit' in a cryptophane host–guest model system
نویسندگان
چکیده
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.
منابع مشابه
Host–guest complexes between cryptophane-C and chloromethanes revisited
Cryptophane-C is composed of two nonequivalent cyclotribenzylene caps, one of which contains methoxy group substituents on the phenyl rings. The two caps are connected by three OCH(2)CH(2)O linkers in an anti arrangement. Host-guest complexes of cryptophane-C with dichloromethane and chloroform in solution were investigated in detail by nuclear magnetic resonance techniques and density function...
متن کاملInvestigation of chloromethane complexes of cryptophane‐A analogue with butoxy groups using 13C NMR in the solid state and solution along with single crystal X‐ray diffraction
Host-guest complexes between cryptophane-A analogue with butoxy groups (cryptophane-But) and chloromethanes (chloroform, dichloromethane) were investigated in the solid state by means of magic-angle spinning (13)C NMR spectroscopy. The separated local fields method with (13)C-(1)H dipolar recoupling was used to determine the residual dipolar coupling for the guest molecules encaged in the host ...
متن کاملA bis(disulfide)-linked offset cryptophane.
A new bis(disulfide)-linked offset dimer is formed from a dithiolated analogue of cyclotriguaiacylene. Unlike a similar tris(disulfide)-linked example, this is not a true cryptophane as the offset nature of the dimerisation and intramolecular host-guest interactions preclude its use as a host.
متن کاملNMR Investigation of Chloromethane Complexes of Cryptophane-A and Its Analogue with Butoxy Groups
Host-guest complexes between cryptophane-A as host and dichloromethane and chloroform as guests are investigated using (1)H and (13)C NMR spectroscopy. Moreover, a related cryptophane, with the methoxy groups replaced by butoxy units (cryptophane-But), and its complexes with the same guests were also studied. Variable temperature spectra showed effects of chemical exchange between the free and ...
متن کاملConformational Selection as the Mechanism of Guest Binding in a Flexible Supramolecular Host.
This study offers a detailed mechanistic investigation of host-guest encapsulation behavior in a new enzyme-mimetic metal-ligand host and provides the first observation of a conformational selection mechanism (as opposed to induced fit) in a supramolecular system. The Ga4L4 host described features a C3-symmetric ligand motif with meta-substituted phenyl spacers, which enables the host to initia...
متن کامل