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Effect of pH and Counterions on the Encapsulation Properties of Xenon in Water‐Soluble Cryptophanes
Author(s) -
Berthault Patrick,
Desvaux Hervé,
Wendlinger Thierry,
Gyejacquot Marina,
Stopin Antoine,
Brotin Thierry,
Dutasta JeanPierre,
Boulard Yves
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001170
Subject(s) - xenon , ionic bonding , chemistry , biosensor , counterion , molecule , chemical physics , macromolecule , chemical engineering , combinatorial chemistry , nanotechnology , ion , organic chemistry , materials science , biochemistry , engineering
In the 129 Xe NMR‐based biosensing approach in which the hyperpolarized noble gas is transported to biological receptors for a sensitive molecular imaging, cryptophanes are excellent xenon host systems. However to avoid formation of self‐organized systems, these hydrophobic cage molecules can be rendered water soluble by introduction of ionic groups. We show that the sensitivity of xenon to its local environment and the presence of these ionic functions can lead to interesting properties. For a first water‐soluble cryptophane derivative, we show that a precise monitoring of the local pH can be performed. For a second cryptophane, the presence of ionic groups close to the cryptophane cavity modifies the xenon binding constant and in–out exchange rate. The latter allows the tuning of physical properties of xenon–cryptophane interactions without resorting to a change of the cavity size. These results open new perspectives on the influence of chemical modifications of cryptophanes for optimizing the biosensor properties.