Chemical Transformations Supported by the [Re₆(μ₃-Se)₈]²⁺ Cluster Core

Persistent Link:
http://hdl.handle.net/10150/594937
Title:
Chemical Transformations Supported by the [Re₆(μ₃-Se)₈]²⁺ Cluster Core
Author:
Corbin, William C.
Issue Date:
2015
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 01-Aug-2016
Abstract:
Hexanuclear transition metal clusters are a distinct class of chemical compounds that have some very interesting chemical and physical properties. Of recent interest in this field has been the [Re₆(μ₃-Se)₈]²⁺ cluster core. This Lewis acidic cluster core contains six substitutable coordination sites, and site differentiation can be accessed through protecting group ligands. The Lewis acidity has been shown to activate unsaturated cluster-bound ligands, and the expanded atom-like structure and high symmetry of the cluster core has potential use in synthesizing some fascinating and novel hybrid materials. Little work has been performed in establishing the scope of these chemical transformations. The work herein describes the efforts and successes of such work. Chapter 1 provides the essential background required for understanding the [Re₆(μ₃-Se)₈]²⁺ cluster core's synthesis, properties, and currently known research directions and successes. This chapter first introduces hexanuclear clusters in a general format, then focuses on the established catalytic and material capabilities that have been determined using this specific cluster core. Chapter 2 discusses the synthesis, characterization, and hydrogen-bonded assemblies formed from [Re₆(μ₃-Se)₈]²⁺ cluster-isonicotinic acid cluster complexes. These complexes have potential uses as hybrid inorganic/organic linkers for the generation of luminescent Lewis acidic metal-organic frameworks (MOFs). Prospective applications of such materials include catalysis, separations, and gas storage. Chapter 3 focuses on the novel chemistry of [Re₆(μ₃-Se)₈]²⁺ cluster-activated CH₃CN with N-based nucleophiles to form acetamidines. These ligands are of interest due to their use in medicinal chemistry, CO₂/CS₂ sequestration, and the formation of synthetically-relevant species. Quantitative yields are obtained and single-crystal XRD analyses reveal specific stereochemical outcomes. Trifluoroacetic acid (TFA) in a cluster-amidine CH₃CN solution removes the ligand as the acetamidinium TFA salt, and the starting cluster solvate is reproduced making a recyclable catalyst. Chapter 4 expands on a project similar to that of chapter 3, except that O-based nucleophiles are utilized for specific cluster isomers. The newly formed ligands, imino esters, are of interest in organic synthesis as valuable starting materials for the generation of β-lactams and heterocycles. ³¹P NMR and single–crystal XRD reveal Z stereochemistry is preferred in the cis isomer, but conflicting results for the hexasubstituted isomer leave stereochemical analyses unresolved. Chapter 5 attempts to incorporate the chemistry established in chapters 2-4 to provide some fresh and interesting research outlooks possible with the [Re₆(μ₃-Se)₈]²⁺ cluster core. Incorporation of the cluster into MOFs is discussed, and the possibility of post-synthetic modifications for metal sequestration, catalysis, and sensing is explained. Appendix A provides all the NMR data obtained for synthesized materials with peak picks and integrations provided. Appendix B entails all crystallographic information for structures determined after syntheses. Appendix C provide high-resolution mass spectra.
Type:
text; Electronic Dissertation
Keywords:
Hybrid Materials; Metal Clusters; Rhenium; Transformations; Chemistry; Catalysis
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemistry
Degree Grantor:
University of Arizona
Advisor:
Zheng, Zhiping

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleChemical Transformations Supported by the [Re₆(μ₃-Se)₈]²⁺ Cluster Coreen_US
dc.creatorCorbin, William C.en
dc.contributor.authorCorbin, William C.en
dc.date.issued2015en
dc.publisherThe University of Arizona.en
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
dc.description.releaseRelease 01-Aug-2016en
dc.description.abstractHexanuclear transition metal clusters are a distinct class of chemical compounds that have some very interesting chemical and physical properties. Of recent interest in this field has been the [Re₆(μ₃-Se)₈]²⁺ cluster core. This Lewis acidic cluster core contains six substitutable coordination sites, and site differentiation can be accessed through protecting group ligands. The Lewis acidity has been shown to activate unsaturated cluster-bound ligands, and the expanded atom-like structure and high symmetry of the cluster core has potential use in synthesizing some fascinating and novel hybrid materials. Little work has been performed in establishing the scope of these chemical transformations. The work herein describes the efforts and successes of such work. Chapter 1 provides the essential background required for understanding the [Re₆(μ₃-Se)₈]²⁺ cluster core's synthesis, properties, and currently known research directions and successes. This chapter first introduces hexanuclear clusters in a general format, then focuses on the established catalytic and material capabilities that have been determined using this specific cluster core. Chapter 2 discusses the synthesis, characterization, and hydrogen-bonded assemblies formed from [Re₆(μ₃-Se)₈]²⁺ cluster-isonicotinic acid cluster complexes. These complexes have potential uses as hybrid inorganic/organic linkers for the generation of luminescent Lewis acidic metal-organic frameworks (MOFs). Prospective applications of such materials include catalysis, separations, and gas storage. Chapter 3 focuses on the novel chemistry of [Re₆(μ₃-Se)₈]²⁺ cluster-activated CH₃CN with N-based nucleophiles to form acetamidines. These ligands are of interest due to their use in medicinal chemistry, CO₂/CS₂ sequestration, and the formation of synthetically-relevant species. Quantitative yields are obtained and single-crystal XRD analyses reveal specific stereochemical outcomes. Trifluoroacetic acid (TFA) in a cluster-amidine CH₃CN solution removes the ligand as the acetamidinium TFA salt, and the starting cluster solvate is reproduced making a recyclable catalyst. Chapter 4 expands on a project similar to that of chapter 3, except that O-based nucleophiles are utilized for specific cluster isomers. The newly formed ligands, imino esters, are of interest in organic synthesis as valuable starting materials for the generation of β-lactams and heterocycles. ³¹P NMR and single–crystal XRD reveal Z stereochemistry is preferred in the cis isomer, but conflicting results for the hexasubstituted isomer leave stereochemical analyses unresolved. Chapter 5 attempts to incorporate the chemistry established in chapters 2-4 to provide some fresh and interesting research outlooks possible with the [Re₆(μ₃-Se)₈]²⁺ cluster core. Incorporation of the cluster into MOFs is discussed, and the possibility of post-synthetic modifications for metal sequestration, catalysis, and sensing is explained. Appendix A provides all the NMR data obtained for synthesized materials with peak picks and integrations provided. Appendix B entails all crystallographic information for structures determined after syntheses. Appendix C provide high-resolution mass spectra.en
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectHybrid Materialsen
dc.subjectMetal Clustersen
dc.subjectRheniumen
dc.subjectTransformationsen
dc.subjectChemistryen
dc.subjectCatalysisen
thesis.degree.namePh.D.en
thesis.degree.leveldoctoralen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineChemistryen
thesis.degree.grantorUniversity of Arizonaen
dc.contributor.advisorZheng, Zhipingen
dc.contributor.committeememberZheng, Zhipingen
dc.contributor.committeememberLichtenberger, Dennisen
dc.contributor.committeememberLoy, Dougen
dc.contributor.committeememberWalker, Annen
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