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dc.contributor.authorKang, Yanlongen_US
dc.date.accessioned2007-08-23T01:55:57Z
dc.date.available2007-08-23T01:55:57Z
dc.date.issued2007-08-23T01:55:57Z
dc.date.submittedNovember 2005en_US
dc.identifier.otherDISS-1141en_US
dc.identifier.urihttp://hdl.handle.net/10106/41
dc.description.abstractSupramolecular chemistry has been defined as "chemistry beyond molecules", and involves investigating molecular systems held together reversibly by inter-molecular forces, not by covalent bonds. This dissertation discusses a supramolecular approach towards sensing, entrapment and utilization of NO2/N2O4 gases. Chapter 1 briefly discusses supramolecular chemistry and supramolecular chemistry of gases. In chapter 2, the interaction of NOx with metalloporphyrins is described. Specifically, ruthenium nitrosyl derivatives hold a special place in mimicking bio-relevant NO-metal interactions. A previously unnoticed reaction between NO2/N2O4 and a Ru(II) porphyrin is described. It causes disproportionation of N2O4 and leads to a stable nitrosyl nitrato complex. Our findings offer a new insight into the mechanism of sensing and fixation of NO2/N2O4 by metalloporphyrins. In chapter 3, the reaction between calixarenes and NO2/N2O4 gases was investigated. Exposure of tetra-O-alkylated cone or 1,3-alternate calix[4]arenes to NO2/N2O4, both in chloroform solution and in the solid state, resulted in deeply colored calixarene-nitrosonium (NO+) complexes. In the presence of a Lewis acid, such as SnCl4, stable calixarene-NO+ complexes were isolated in a quantitative yield and fully characterized. NO+ is found encapsulated within the calixarene cavity, and forms a stable charge-transfer complex. The NO+ encapsulation was also demonstrated in titration experiments with calixarenes and NO+SbF6- salt in chloroform. The complexation process is reversible, and the complexes dissociate upon addition of water and alcohol, recovering the parent calixarenes. Chapter 4 describes the polymer supported calixarenes. Functionalized calix[4]arenes were synthesized and attached to silica gels and polyethyleneglycol (PEG), which afforded solid materials capable of visual detection and entrapment of NO2/N2O4 both in the solid state and solution. The concept of encapsulated nitrosating reagent was introduced in chapter 5. Stable calixarene-NO+ complexes act as encapsulated nitrosating reagents; cavity effects control their reactivity and selectivity. They were effectively used for nitrosation of secondary amides. Unique size-shape selectivity was observed, allowing for favorable nitrosation of only less crowded N-Me amides. For robust, silica gel and PEG based calixarene materials, similar size-shape selectivity was observed. Enantiomerically pure encapsulating reagents were tested for nitrosation of racemic amide, showing modest but reproducible stereoselectivity.en_US
dc.description.sponsorshipRudkevich, Dmitryen_US
dc.language.isoENen_US
dc.publisherChemistry & Biochemistryen_US
dc.titleSupramolecular Chemistry Of Nitrogen Dioxideen_US
dc.typePh.D.en_US
dc.contributor.committeeChairRudkevich, Dmitryen_US
dc.degree.departmentChemistry & Biochemistryen_US
dc.degree.disciplineChemistry & Biochemistryen_US
dc.degree.grantorUniversity of Texas at Arlingtonen_US
dc.degree.leveldoctoralen_US
dc.degree.namePh.D.en_US
dc.identifier.externalLinkhttps://www.uta.edu/ra/real/editprofile.php?onlyview=1&pid=37
dc.identifier.externalLinkDescriptionLink to Research Profiles


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