Towards Supramolecular Fixation of NOX Gases: Encapsulated Reagents for Nitrosation
作者:Yanlong Kang、Grigory V. Zyryanov、Dmitry M. Rudkevich
DOI:10.1002/chem.200400939
日期:2005.3.4
nitrosated with much lower yields (<8 %). Enantiomerically pure encapsulating reagent 2 d was tested for nitrosation of racemic amide 5 t, showing modest but reproducible stereoselectivity and approximately 15 % ee. Given high affinity to NO+ species, which can be generated by a number of NOX gases, these supramolecular reagents and materials may be useful for NOX entrapment and separation in the environment
Supramolecular fixation of NO2 with calix[4]arenes
作者:Grigory V. Zyryanov、Yanlong Kang、Stephen P. Stampp、Dmitry M. Rudkevich
DOI:10.1039/b207901a
日期:2002.11.18
Reaction of NO2 with simple calix[4]arenes in chloroform in the presence of a Lewis acid rapidly results in intense coloration caused by the encapsulation of nitrosonium cation.
Sensing and Fixation of NO<sub>2</sub>/N<sub>2</sub>O<sub>4</sub> by Calix[4]Arenes
作者:Grigory V. Zyryanov、Yanlong Kang、Dmitry M. Rudkevich
DOI:10.1021/ja029166l
日期:2003.3.1
NO(+) is found encapsulatedwithin the calixarene cavity, and stable charge-transfer complexes result with K(ass) > 10(6) M(-1) (CDCl(3)). The NO(+) encapsulation was also demonstrated in titration experiments with calixarenes 1, 2, and 5 and commercially available NO(+)SbF(6)(-) salt in chloroform. The complexation process is reversible, and the complexes dissociate upon addition of water and alcohol
A novel class of stable, mild, and size-shape-selective nitrosating agents for secondary amides is introduced. These are based on reversible entrapment and release of reactive nitrosonium species by calix[4]arenes. The NO+ encapsulation controls the reaction selectivity.
Toward Synthetic Tubes for NO<sub>2</sub>/N<sub>2</sub>O<sub>4</sub>: Design, Synthesis, and Host−Guest Chemistry
作者:Grigory V. Zyryanov、Dmitry M. Rudkevich
DOI:10.1021/ja0392869
日期:2004.4.1
Design of molecular nanotubes is proposed for entrapment and conversion of NO2/N2O4 gases. Synthesis of 1,3-alternate bis-calix[4]arene tube 3 of 5 x 11 Angstrom internal dimensions is presented, and its reversible reactions with NO2/N2O4 in solution are studied. Exposure of 3 to NO2/N2O4 in chlorinated solvents results in the rapid encapsulation of nitrosonium (NO+) cations within its interior. Mono- and dinitrosonium complexes 4 and 5, respectively, were isolated and characterized by UV-vis, FTIR, and H-1 NMR spectroscopies, and also molecular modeling. The NO+ entrapment process is reversible, and addition of water quickly recovered starting tube 3. Encapsulated within the tube NO+ species act as nitrosating agents for secondary amides. These findings open wider perspectives toward NO2/NOx storing and converting materials and also offer a promise for further development of supramolecular chemistry of synthetic nanotubes.