자료유형  

 학위논문

Control Number  

0016931939

International Standard Book Number  

9798379649791

Dewey Decimal Classification Number  

540

Main Entry-Personal Name  

Keown, William Jay.

Publication, Distribution, etc. (Imprint  

[S.l.] : Stanford University., 2021

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2021

Physical Description  

1 online resource(251 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

General Note  

Advisor: Cui, Yi;Solomon, Edward;Stack, Daniel.

Dissertation Note  

Thesis (Ph.D.)--Stanford University, 2021.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Biological enzymes utilize various copper-based active sites to activate dioxygen creating a variety of copper-dioxygen assemblies. These assemblies carry out highly selective and difficult oxidative transformations vital to biological life. Insight into how Nature has optimized these active sites can be gleaned by studying synthetic structural mimics and has potential to be of great benefit to the industrial design of catalysts. While the resting structures of many of these active sites are known, the nature of the active oxidants are often less well-defined. In this thesis, efforts towards the cryogenic synthesis and spectroscopic characterization of copper(III)-containing oxidants, formed directly via dioxygen activation of biomimetic copper precursors, will be discussed. This work demonstrates both the kinetic and thermodynamic accessibility of the copper(III) oxidation state under biological ligation, which challenges existing assumptions in the literature through the identification of reactive intermediates.Chapter 1 of this thesis provides an introduction to the field of copper-dioxygen chemistry. The structures, formation, and reactivity of the many various copper-dioxygen assemblies are discussed in both synthetic and biological contexts. The methods by which we study these systems are also introduced. The focus of this work is on the synthesis and characterization of high-valent systems - systems containing copper in the 3+ (III) oxidation state - and so these assemblies are discussed in greater detail.Chapter 2 describes the original project on modeling an enzyme known as Tyrosinase - the results of which the remaining work was inspired by. Tyrosinases (Ty) are ubiquitous binuclear copper enzymes that oxygenate to Cu(II)2O2 ( SP) cores bonded by three histidine Nt-imidazoles per Cu center. Synthetic monodentate imidazole bonded SP species self-assemble in a near quantitative manner at -125°C, but Np-ligation has been required. This work discloses the syntheses and reactivity of three Nt-imidazole bonded SP species at solution temperatures of -145°C, which was achieved using a eutectic mixture of THF and 2-MeTHF. The addition of anionic phenolates affords a Cu(III)2O2 (O) species, where the bonded phenolates hydroxylate to catecholates in high yields.Chapter 3 of this thesis expands upon the Cu(III)-containing reactive intermediates in biological ligation identified in Chapter 2 by identifying stable Cu(III)- containing species which are exclusively ligated by imidazole ligands. This work describes the synthesis and structural characterization of L2Cu(III)2O2 and L3Cu(III)Cu(II)2O2 complexes formed directly from the oxygenation of LCu(I) precursors with exclusive imidazole ligation for the first time. These complexes inform on the kinetic and thermodynamic viability of Cu(III) under such oxygenation conditions in synthetic systems, and by extension in biological systems. Contrary to expectations based on pKa's, imidazole ligation stabilizes the Cu(III) oxidation state to the greatest degree relative to other neutral, nitrogenous ligands, a result rationalized through its greater proton affinity. An analysis suggests that imidazole possesses the s-donating power of trimethylamine yet the steric demands of methylamine, rationalizing its superior ligating abilities.Finally, Chapter 4 focuses on the direct oxygenation capabilities of Cu(I) ligated by bidentate, nitrogenous ligands including imidazoles, amines, and pyridines.

Subject Added Entry-Topical Term  

Crystal structure.

Subject Added Entry-Topical Term  

Oxidation.

Subject Added Entry-Topical Term  

Fourier transforms.

Subject Added Entry-Topical Term  

Sodium.

Subject Added Entry-Topical Term  

Endangered & extinct species.

Subject Added Entry-Topical Term  

Solvents.

Subject Added Entry-Topical Term  

Symmetry.

Subject Added Entry-Topical Term  

Energy.

Subject Added Entry-Topical Term  

Enzymes.

Subject Added Entry-Topical Term  

Extinction.

Subject Added Entry-Topical Term  

Mathematics.

Subject Added Entry-Topical Term  

Wildlife conservation.

Added Entry-Corporate Name  

Stanford University.

Host Item Entry  

Dissertations Abstracts International. 84-12B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:639994