Exploring the Reactivity and Decomposition of Ruthenium Nitrosyl Complexes for the Production of Nitrogen Oxides

Persistent Link:
http://hdl.handle.net/10150/243113
Title:
Exploring the Reactivity and Decomposition of Ruthenium Nitrosyl Complexes for the Production of Nitrogen Oxides
Author:
Hannon, Andrew Michael
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 09-Aug-2014
Abstract:
Nitric oxide (NO) has been shown to both suppress and promote tumor growth, depending in part on concentration. Exogenous delivery of NO may lead to tumor suppression. Recent studies have proposed ruthenium nitrosyl complexes as catalytic donors of NO in reductive environments. Catalytic donation can provide a long-term, elevated NO flux compared to single use donors. Site-specific delivery is desirable to reduce systemic side effects, such as lowering of blood pressure. Three new ruthenium nitrosyl complexes were synthesized to impart site-specificity through amide coupling to polymers, silica nanoparticles, iron oxide nanoparticles and antibodies. The catalytic activity of new and existing compounds was then assessed. However, upon one-electron reduction of ruthenium nitrosyl complexes, insignificant amounts of NO were detected, suggesting an alternative mechanism than that proposed in prior reports. The mechanism of [Ru(EDTA)NO]²⁻ decay was more thoroughly analyzed. Spectrophotometric decay of [Ru(EDTA)NO]²⁻ indicates that one or multiple nitrogen oxide species are released. Previous studies have suggested a disproportionation mechanism leading to the generation of more highly reduced species such as N₂ and NH₄⁺. Experiments were designed to analyze possible decomposition products such as [Ru(EDTA)NO]⁻ and [Ru(EDTA)H₂O]²⁻. A disproportionation mechanism was determined likely. Decomposition of [Ru(EDTA)NO]²⁻ was also observable following reductive nitrosylation of [Ru(EDTA)H₂O]⁻ in the presence of HNO. The decomposition product, [Ru(EDTA)H₂O]²⁻, was observed through the binding of pyrazine (pz) or dipyridine (bipy) and formation of [Ru(EDTA)pz]²⁻ or [Ru(EDTA)bipy]³⁻. Formation of [Ru(EDTA)bipy]³⁻ or [Ru(EDTA)pz]²⁻ via reductive nitrosylation of [Ru(EDTA)H₂O]⁻ also provides an indirect method of HNO detection that is selective from NO.
Type:
text; Electronic Dissertation
Keywords:
Nitroxyl; Ruthenium; Chemistry; Nitric Oxide; Nitrogen Oxides
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemistry
Degree Grantor:
University of Arizona
Advisor:
Miranda, Katrina M.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleExploring the Reactivity and Decomposition of Ruthenium Nitrosyl Complexes for the Production of Nitrogen Oxidesen_US
dc.creatorHannon, Andrew Michaelen_US
dc.contributor.authorHannon, Andrew Michaelen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.releaseRelease after 09-Aug-2014en_US
dc.description.abstractNitric oxide (NO) has been shown to both suppress and promote tumor growth, depending in part on concentration. Exogenous delivery of NO may lead to tumor suppression. Recent studies have proposed ruthenium nitrosyl complexes as catalytic donors of NO in reductive environments. Catalytic donation can provide a long-term, elevated NO flux compared to single use donors. Site-specific delivery is desirable to reduce systemic side effects, such as lowering of blood pressure. Three new ruthenium nitrosyl complexes were synthesized to impart site-specificity through amide coupling to polymers, silica nanoparticles, iron oxide nanoparticles and antibodies. The catalytic activity of new and existing compounds was then assessed. However, upon one-electron reduction of ruthenium nitrosyl complexes, insignificant amounts of NO were detected, suggesting an alternative mechanism than that proposed in prior reports. The mechanism of [Ru(EDTA)NO]²⁻ decay was more thoroughly analyzed. Spectrophotometric decay of [Ru(EDTA)NO]²⁻ indicates that one or multiple nitrogen oxide species are released. Previous studies have suggested a disproportionation mechanism leading to the generation of more highly reduced species such as N₂ and NH₄⁺. Experiments were designed to analyze possible decomposition products such as [Ru(EDTA)NO]⁻ and [Ru(EDTA)H₂O]²⁻. A disproportionation mechanism was determined likely. Decomposition of [Ru(EDTA)NO]²⁻ was also observable following reductive nitrosylation of [Ru(EDTA)H₂O]⁻ in the presence of HNO. The decomposition product, [Ru(EDTA)H₂O]²⁻, was observed through the binding of pyrazine (pz) or dipyridine (bipy) and formation of [Ru(EDTA)pz]²⁻ or [Ru(EDTA)bipy]³⁻. Formation of [Ru(EDTA)bipy]³⁻ or [Ru(EDTA)pz]²⁻ via reductive nitrosylation of [Ru(EDTA)H₂O]⁻ also provides an indirect method of HNO detection that is selective from NO.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectNitroxylen_US
dc.subjectRutheniumen_US
dc.subjectChemistryen_US
dc.subjectNitric Oxideen_US
dc.subjectNitrogen Oxidesen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMiranda, Katrina M.en_US
dc.contributor.committeememberEnemark, Johnen_US
dc.contributor.committeememberNjardardson, Jonen_US
dc.contributor.committeememberGlass, Richarden_US
dc.contributor.committeememberGuzman, Robertoen_US
dc.contributor.committeememberMiranda, Katrina M.en_US
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