Cryptophane-Xenon Complexes in Organic Solvents Observed through NMR Spectroscopy
摘要:
The interaction of xenon with cryptophane derivatives is analyzed by NMR by using either thermal or hyperpolarized. noble gas. Twelve hosts differing by their stereochemistry, cavity size, and the nature and the number of the substituents on the aromatic rings have been included in the study, in the aim of extracting some clues for the optimization of Xe-129-NMR based biosensors derived from these cage molecules. Four important properties have been examined: xenon-host binding constant, in-out exchange rate of the noble gas, chemical shift, and relaxation of caged xenon. This work aims at understanding the main characteristics of the host-guest interaction in order to choose the best candidate for the biosensing approach. Moreover, rationalizing xenon chemical shift as a function of structural parameters would also help for setting up multiplexing applications. Xenon exhibits the highest affinity for the smallest cryptophane, namely cryptophane-111, and a long relaxation time inside it, convenient for conservation of its hyperpolarization. However, very slow in-out xenon exchange could represent a limitation for its future applicability for the biosensing approach, because the replenishment of the cage in laser-polarized xenon, enabling a further gain in sensitivity, cannot be fully exploited.
Investigation of chloromethane complexes of cryptophane-A analogue with butoxy groups using<sup>13</sup>C NMR in the solid state and solution along with single crystal X-ray diffraction
rationalize this unexpected result, we performed single crystal X-raydiffraction studies, which confirmed that both guest molecules indeed were present inside the cryptophane cavity, with a certain level of disorder. To improve the insight in the dynamics, we performed a (13)C NMR spin-lattice relaxation study for the dichloromethane guest in solution. The system was characterized by chemical exchange, which
Cryptophane-Xenon Complexes in Organic Solvents Observed through NMR Spectroscopy
作者:Gaspard Huber、Lætitia Beguin、Hervé Desvaux、Thierry Brotin、Heather A. Fogarty、Jean-Pierre Dutasta、Patrick Berthault
DOI:10.1021/jp807425t
日期:2008.11.13
The interaction of xenon with cryptophane derivatives is analyzed by NMR by using either thermal or hyperpolarized. noble gas. Twelve hosts differing by their stereochemistry, cavity size, and the nature and the number of the substituents on the aromatic rings have been included in the study, in the aim of extracting some clues for the optimization of Xe-129-NMR based biosensors derived from these cage molecules. Four important properties have been examined: xenon-host binding constant, in-out exchange rate of the noble gas, chemical shift, and relaxation of caged xenon. This work aims at understanding the main characteristics of the host-guest interaction in order to choose the best candidate for the biosensing approach. Moreover, rationalizing xenon chemical shift as a function of structural parameters would also help for setting up multiplexing applications. Xenon exhibits the highest affinity for the smallest cryptophane, namely cryptophane-111, and a long relaxation time inside it, convenient for conservation of its hyperpolarization. However, very slow in-out xenon exchange could represent a limitation for its future applicability for the biosensing approach, because the replenishment of the cage in laser-polarized xenon, enabling a further gain in sensitivity, cannot be fully exploited.