Synthesis of a Functionalizable Water-Soluble Cryptophane-111
摘要:
The development of optimized xenon host systems is of crucial importance for the success of molecular imaging using hyperpolarized Xe-129 MRI. Cryptophane-111 is a promising candidate because of its encapsulation properties. The synthesis of cryptophane-111-based biosensors requires both water-solubilizing and chemically activatable groups. An expeditious synthesis of a water-soluble and functionalizable cryptophane-111 is described.
A Cryptophane Core Optimized for Xenon Encapsulation
摘要:
The smallest cryptophane ever synthesized, cryptophane-1.1.1 (1), whose internal volume is estimated to be 81 A(3), exhibits the highest binding constant (10000 M-1 at 293 K) in organic solution for xenon encapsulation determined to date. The very slow kinetics of decomplexation on the NMR time scale results in an extremely sharp Xe-129 NMR signal for the Xe@1 complex, which shows an unexpected low-frequency shift. The free energy of activation for decomplexation of xenon at 293 K is Delta G(out) = 64.9 +/- 3 kJ mol(-1) (Delta H-out = 43.2 +/- 1.6 kJ mol(-1); Delta S-out = -74 +/- 3 J mol(-1) K-1). These properties suggest that the cryptophane core of 1 is optimized for use in sensing applications in combination with laser-polarized xenon.
A Water-Soluble Xe@cryptophane-111 Complex Exhibits Very High Thermodynamic Stability and a Peculiar <sup>129</sup>Xe NMR Chemical Shift
作者:Robert M. Fairchild、Akil I. Joseph、K. Travis Holman、Heather A. Fogarty、Thierry Brotin、Jean-Pierre Dutasta、Céline Boutin、Gaspard Huber、Patrick Berthault
DOI:10.1021/ja1071515
日期:2010.11.10
[(Cp*Ru)(6)1]Cl(6) ([2]Cl(6)). [2]Cl(6) exhibits a very high affinity for xenon in water, with a binding constant of 2.9(2) × 10(4) M(-1) as measured by hyperpolarized (129)Xe NMR spectroscopy. The (129)Xe NMR chemical shift of the aqueous Xe@[2](6+) species (308 ppm) resonates over 275 ppm downfield of the parent Xe@1 species in (CDCl(2))(2) and greatly broadens the practical (129)Xe NMR chemical shift
Extreme Confinement of Xenon by Cryptophane-111 in the Solid State
作者:Akil I. Joseph、Saul H. Lapidus、Christopher M. Kane、K. Travis Holman
DOI:10.1002/anie.201409415
日期:2015.1.26
exceptionally stable, retaining xenon at temperatures of up to about 300 °C. The high kinetic stability is attributable not only to the high xenon affinity and cage‐like nature of the host, but also to the crystal packing of the clathrate, wherein each window of the molecular container is blocked by the bridges of adjacent containers, effectively imprisoning the noble gas in the solidstate. The results highlight
Temperature Controls Guest Uptake and Release from Zn<sub>4</sub>L<sub>4</sub> Tetrahedra
作者:Dawei Zhang、Tanya K. Ronson、Songül Güryel、John D. Thoburn、David J. Wales、Jonathan R. Nitschke
DOI:10.1021/jacs.9b07307
日期:2019.9.18
We report the preparation of triazatruxene-faced tetrahedral cage 1, which exhibits two diastereomeric configurations (T1 and T2) that differ in the handedness of the ligand faces relative to that of the octahedrally coordinated metal centers. At lower temperatures, T1 is favored, whereas T2 predominates at higher temperatures. Host-guest studies show that T1 binds small aliphatic guests, whereas T2 binds larger aromatic molecules, with these changes in binding preference resulting from differences in cavity size and degree of enclosure. Thus, by a change in temperature the cage system can be triggered to eject one bound guest and take up another.
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.
[EN] CRYPTOPHANE DERIVATIVES AND METHODS OF USE THEREOF<br/>[FR] DÉRIVÉS DE CRYPTOPHANE ET PROCÉDÉS D'UTILISATION DE CEUX-CI
申请人:UNIV GEORGETOWN
公开号:WO2012051323A2
公开(公告)日:2012-04-19
The present invention relates to the cryptophane derivatives of formula (I) capable of encapsulating small molecules such as noble gases for biological and environmental use. In particular, the invention relates to cryptophane derivatives with high affinity for xenon, which can be used as biosensors in clinical imaging. Formula (I)