자료유형  

 학위논문

Control Number  

0017163620

International Standard Book Number  

9798384012795

Dewey Decimal Classification Number  

547

Main Entry-Personal Name  

Anferov, Sophie Whitmeyer.

Publication, Distribution, etc. (Imprint  

[S.l.] : The University of Chicago., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

389 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Anderson, John S.

Dissertation Note  

Thesis (Ph.D.)--The University of Chicago, 2024.

Summary, Etc.  

요약Metal-ligand cooperativity is ubiquitous throughout both biological and chemical catalysis, but often goes unattributed or underutilized in organic catalysis. Practically, utilizing every resource available and not discriminating metal vs. ligand is a powerful strategy to getting more tunability as well as more efficiency in any kind of chemical transformation, and nature, and an ever-increasing number of chemists, realizes this. By building in this biomimetic strategy, first row metals can also be enhanced past their native one-electron preferences, opening the door to multi-proton, multi-electron chemistry. In particular, hydrogen transfer chemistry is important due to its wide variety of applications in industrial processes and pharmaceutical development. For this reason, there has been extensive research into catalyst design for reactions involving hydrogen transfer reactivity. Homogenous catalysts are attractive for studies due to the relative ease of their characterization. However, any reaction that involves the movement of protons and electrons, even in a redox-neutral fashion, can benefit from a multifunctional ligand. In these studies, a 2,5- dihydrazonopyrrole (tBu,TolDHP) ligand scaffold, which has previously been shown to store a full H2 equivalent (in addition to any redox-capabilities of the metal center), was utilized in complexes with Co, and with these complexes alone, I show the diversity of reactivity, enhanced and altered selectivity, and broad applicability afforded by ligands as complex as the metals they bind.In Chapter I, I discuss the precedence for proton and electron storing ligands in catalysis, and the distinct benefits of coupling their advantages with the catalytic powerhouse of Co metal-centers in particular.In Chapter II, I discuss a tBu,TolDHP complex with Co, where an H2 equivalent can be stored on the ligand periphery and can be leveraged for mild, catalytic olefin hydrogenations. Computational and reaction analysis suggests ligand hydrogenation proceeds by H2 association followed by H-H scission, with radical intermediates playing a prominent role in driving turnover. This complex is an unusual example where a synthetic system can mimic biology's ability to mediate H2 transfer via secondary coordination sphere-based processes.In Chapter III, I discuss the synthesis of a previously unobserved oxidation state of TEMPO (another proton and electron storing ligand) bound to a metal center, Co. This complex is stabilized by the tBu,TolDHP ligand electronic rearrangement, and a putative Co(I) complex. IBO analysis reveals an initial proton transfer from a free TEMPOH to a bound TEMPOH species, followed by rapid electron transfer to the metal center from a dissociated TEMPO- . This demonstrates a previously unproposed, but clearly possible, intermediate in TEMPO dehydrogenative reactivity, which is facilitated by our similarly bifunctional ligand scaffold.In Chapter IV, I discuss the oxidative reactivity of these [ tBu,TolDHP]Co complexes with H2O. Upon addition of H2O to these complexes, both H2O2 and the reduced [ tBu,TolDHP]Co complex are detectable as the major products. This chemistry can be rendered catalytic with oxidative potential, and I observed selective H2O2 production in all cases, with no O2 observed. This unusual selectivity is engendered by the redox-stabilization and electron accepting nature of the tBu,TolDHP ligand.In Chapter V, I discuss my most recent work, building onto the hydrogenation catalysis previously observed, to study olefin isomerization of [ tBu,TolDHP]Co complex with boranes. We are able to demonstrate post-synthetic modification of the tBu,TolDHP ligand with a family of boranes, allowing for tunable olefin-isomerization, including some trans-to-cis isomerization of pre-existing double bonds.In Chapter VI, I discuss another unusual species-of a [ tBu,TolDHP]CoOK complex, with an unusual depronated oxyl moiety. The pKa of the OH bond of the [ tBu,TolDHP]CoOH complex is assessed, and the reactivity of the potassium complex investigated.This thesis also contains multiple appendices which contain supporting data for the previous chapters, as well as some cherished, but unpublished explorations.Please note, all chapters have an independent compound numbering system. Characterization spectra are provided in the corresponding appendix for each chapter.

Subject Added Entry-Topical Term  

Organic chemistry.

Subject Added Entry-Topical Term  

Inorganic chemistry.

Subject Added Entry-Topical Term  

Physical chemistry.

Subject Added Entry-Topical Term  

Pharmaceutical sciences.

Index Term-Uncontrolled  

Catalysis

Index Term-Uncontrolled  

Cobalt

Index Term-Uncontrolled  

Electrosynthesis

Index Term-Uncontrolled  

Redox-noninnocence

Index Term-Uncontrolled  

Hydrogenation catalysis

Added Entry-Corporate Name  

The University of Chicago Chemistry

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

로그인을 한후 보실 수 있는 자료입니다.

Control Number  

joongbu:657883