4,620 research outputs found
Kenneth Raymond '64 receives Vollum Award.
No full texthttps://rdc.reed.edu/v1/resources/0af2b211-dea5-4ac7-ac6d-1481f3b4e66d/thumb/128.jpgNote on convocation and the awarding of the Vollum Award for Distinguished Accomplishment in Science and Technology to Kenneth N. Raymond for his work in bio-inorganic chemistry
Batsto Nature Area brochure front
No full textFront of brochure features a year by year history of the Batsto family lands, furnace and glass works. There is also a small road map showing directions to Batsto. Brochure and historical village administered by the state Department of Conservation and Economic Development, Robert A. Roe, Commissioner and Kenneth H. Creveling, Director, Division of Resource Development. Arthur D. Pierce, author and Raymond N. Baker, artist
Three promising young jumpers standing on the outrun of Ecker Hill, circa 1930. L - R: ?, Kenneth Strand, Raymond Ecker
No full textPhoto shows three promising young jumpers standing on the outrun of Ecker Hill, 1930. Left to right: William "Shog" Bailey, Kenneth Strand, Raymond Ecke
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The Development of Synthetic Supramolecular Hosts as Mechanistic Probes and Selective Catalysts
No full textAbstractThe Development of Synthetic Supramolecular Hosts as Mechanistic Probes and Selective CatalystsByMariko Morimoto
Doctor of Philosophy in Chemistry
University of California, Berkeley
Professor F. Dean Toste, Co-Chair
Professor Kenneth N. Raymond, Co-ChairChapter 1. An overview of various supramolecular hosts and their application as synthetic catalysts is presented. Particular emphasis is placed on more recent advances in the field, ranging from organic and organometallic reactivity, through site-selective modifications, to challenging photochemical reactivity enabled by these hosts. By introduction of the various modes of catalytic reactivity, the unique advantages of non-covalent, macromolecular catalysis as a synthetic tool and its powerful potential for practical applications are discussed. Chapter 2. The effects of host structural features on supramolecular catalysis are experimentally determined by employing a series of [M4L6]n- hosts as mechanistic probes. The synthesis of a novel supramolecular [Si4L6]8- host is first described, which serves as an isostructural analogue to [Ga4L6]12- Raymond tetrahedron differing only in overall charge. Through a number of parallel kinetic experiments, the specific role of host charge on the efficacy of microenvironment catalysis is quantitatively determined. Next, the syntheses of catalytically active [In4L6]12- and [Ge4L6]8- hosts are presented, and the effect of altering the metal vertices on host reactivity is elucidated. This work represents the first example of a thorough investigation that connects discrete structural components of a synthetic supramolecular catalyst to specific mechanisms of reactivity.
Chapter 3. Challenging oxidative addition reactions of iodoarenes across CuI and PdII organometallics facilitated by the [Ga4L6]12- Raymond tetrahedron under unusually mild, room temperature conditions are described. Atypical reactivity and selectivity are observed among regio-isomeric iodotoluene substrates, which demonstrate that the transformation is specific to strongly bound guests. Background reactivity in the absence of host is assessed by a series of control experiments with various solvents and additives, which result either in no observable reactivity or degradation of the starting material. This lack of observable background reactivity is indicative of a rare circumstance in which the host not only accelerates but alters the lowest energy reaction pathway of an organometallic reaction from that in bulk solution.
Chapter 4. A series of chemo- and site-selective reduction reactions mediated by the Raymond tetrahedron using a pyridine borane reductant are described. The host-catalyzed reaction demonstrates an unusually broad substrate scope for small molecule reduction, including ketones, enones, oximes, hydrazones, and imines. Furthermore, reactivity is maintained for partially encapsulated pendant carboxylate substrates, which enables high ε-selective reductive amination of lysine with a variety of halogenated benzaldehyde electrophiles. Inspired by the post-translational modification of complex biomolecules by enzymatic systems, this supramolecular reaction is then applied to the lysine-selective labeling of peptides and proteins
Public Policy. A Yearbook of the Graduate School of Public Administration. Vol. V edited by Carl Friedrich and J. Kenneth Galbraith.
No full textBarre Raymond. Public Policy. A Yearbook of the Graduate School of Public Administration. Vol. V edited by Carl Friedrich and J. Kenneth Galbraith.. In: Revue économique, volume 8, n°3, 1957. p. 512
Public Policy. A Yearbook of the Graduate School of Public Administration. Vol. V edited by Carl Friedrich and J. Kenneth Galbraith.
No full textBarre Raymond. Public Policy. A Yearbook of the Graduate School of Public Administration. Vol. V edited by Carl Friedrich and J. Kenneth Galbraith.. In: Revue économique, volume 8, n°3, 1957. p. 512
Three promising young jumpers standing on the outrun of Ecker Hill, 1930. L - R: William "Shog" Bailey, Kenneth Strand, Raymond Ecker
No full textPhoto shows three promising young jumpers standing on the outrun of Ecker Hill, 1930. Left to right: William "Shog" Bailey, Kenneth Strand, Raymond Ecke
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Mechanistic Studies of Biomimetic Reactions by Synthetic Enzyme Mimics
No full textAbstractMechanistic Studies of Biomimetic Reactions by Synthetic Enzyme MimicsByWilliam Michael Hart-CooperDoctor of Philosophy in ChemistryUniversity of California, BerkeleyProfessor Kenneth N. Raymond, Co-chairProfessor Robert G. Bergman, Co-chairChapter 1. A brief introduction to common synthetic host structures and justification for the work described herein is provided.Chapter 2. The development of 1 and related hosts as a new class terpene synthase mimics that catalyze intramolecular Prins cyclizations. The property of water exclusion is observed. Host 1 is also shown to compensate for the gem-disubstituent effect. Chapter 3. The development of new terephthalamide hosts enabled an investigation of the effect of host structure on the enantio- and diastereoselectivity of these reactions, as well as a simple kinetic analysis. Rate accelerations and turnover numbers are notably high. Chapter 4. The mechanism of proton transfer in an archetypal enzyme mimic is studied using amide hydrogen deuterium exchange (HDX) kinetics. Collectively, these data shed light on the role of acid, base and water-mediated proton transfer in a synthetic active site with relevance to proton-mediated catalysis. Moreover, the emergent mechanism of solvent-occupied proton transfer raises the prospect of designable hosts with properties that are unique to the integration of their partsChapter 5. A short overview is provided, which places the results of chapters 2-4 in context with some broader goals of biomimetic supramolecular chemistry
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Siderophore-mediated Competition for Iron Between Humans and Pathogenic Bacteria
No full textAbstractSiderophore-mediated Competition for Iron Between Humans and Pathogenic BacteriabyAllyson Kawile SiaDoctor of Philosophy in ChemistryUniversity of California, BerkeleyProfessor Kenneth N. Raymond, Chair Iron is the most abundant and essential transition metal used by many living organisms. To understand the means by which organisms acquire, transport and use iron expands the understanding we humans have of life. Organisms evolved multiple strategies to solubilize iron hydroxides from the environment and to increase iron bioavailability. Most bacteria, fungi and plants solubilize iron from the environment by synthesis and secretion of siderophores, or small molecules that have a high affinity for ferric iron. Alternative iron acquisition strategies are often employed simultaneously which include piracy of iron stores from other organisms and exploitative uptake of nonnative siderophores and hemes. Generally this work is meant to provide detailed information for mechanisms and strategies involved in iron competition between pathogenic bacteria and human hosts. Detailed structural and kinetic investigations of iron acquisition pathways in the Bacillus cereus group of bacteria are discussed in Chapters 1-4. The B. cereus group of bacteria includes threatening pathogens such as the anthrax pathogen (B. anthracis) and enterotoxic bacteria (B. cereus). Iron complexes of molecules as small as citrate and as large as a polymeric bacterial capsule are probed for structural and kinetic data related to iron acquisition and transport. Studies of the iron binding ability and subsequent transport of synthetic analogs of the B. anthracis stealth siderophore petrobactin are also included. Taken together, these studies shed light on multiple mechanisms and structure-function relationships necessary for the pathogenic bacteria to obtain an adequate iron supply and regulate virulence. Bacillus bacteria can infect humans and compete with the host iron supply. The consequences of iron piracy by Bacillus anthracis are especially likely to be fatal. Crucial to the human defense against bacterial infections is the immune protein siderocalin. Siderocalin is antibacterial and limits bacterial growth by intercepting bacterial siderophores. Chapter 5 highlights siderocalin and its recently established alternative role as an iron transport protein. For siderocalin to transport iron, an endogenous siderophore equivalent is required. A putative endogenous, or `mammalian' siderophore, is evaluated by solution thermodynamic analyses, inorganic spectroscopy and biochemical assays. The multipurpose role of siderocalin could have important clinical impact, and it is important that the foundation of these studies are clear and consistent at the chemical level. The elucidated roles of siderocalin in humans convey key iron-restricting strategies by humans to compete with invading pathogens for iron. The collection of chapters in this work portrays the competition for iron as dynamic, aggressive and evolving by both humans and invading bacterial pathogens and is meant to provide a snapshot of the competition in current times
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Expanding the Structural Scope of Supramolecular Assemblies and their Applications as Mechanistic Probes
No full textAbstract Expanding the Structural Scope of Supramolecular Assemblies and their Applications as Mechanistic Probes by Cynthia Marilyn Hong Doctor of Philosophy in Chemistry University of California, Berkeley Professor F. Dean Toste, Co-Chair Professor Kenneth N. Raymond, Co-Chair Professor Robert G. Bergman Chapter 1. A brief background and perspective is provided for the field of supramolecular chemistry. Justification for the continued expansion of the field as well as the work described in this dissertation are presented. Chapter 2. A new synthetic strategy for the rapid diversification of M4L6 host structures is described. The outlined approach consists of two components: the first is the late-stage functionalization of a ligand precursor to access structural variation while preserving favorable self-assembly properties, and the second is the post-synthetic modification of these functional groups after host assembly. Through this approach, new amine-, azide-, and carboxylatefunctionalized hosts are described with preliminary work and outlook for future applications. Chapter 3. A novel supramolecular mechanistic probe is introduced, which serves as an experimental platform for isolating and evaluating the role of host charge in supramolecular catalysis. The probe consists of two isostructural metal–ligand catalysts of M4L6 stoichiometry with a significant variation in overall anionic charge: 12- versus 8-. Together, they enable a unique experimental investigation that allows supramolecular structural features to be connected to specific mechanisms of reactivity. Though the importance of charge and electrostatic effects have been highlighted in enzymes and other supramolecular catalysts, this is the first example in which these effects have been experimentally defined in a synthetic microenvironment. Chapter 4. An unusual enzyme-like mechanism of host–guest binding is described in a new metal–ligand host of Ga4L4 stoichiometry. The introduction of a sufficiently large and tightly bound guest enforces a configurational isomerization in the host from an S4-symmetric conformation to a T-symmetric conformation with a proposed larger internal volume. Detailed mechanistic investigations reveal that this configurationally adaptive binding phenomenon proceeds via a conformational selection mechanism, a unique enzymatic mechanism that has never been definitively recapitulated in a synthetic system prior to this work. This comprehensive study shows that a simple chemical system can stand as a model for analogous behavior in biological systems that are often too challenging to experimentally deconvolute and speaks to the symbiotic relationship between the fields of enzymology and supramolecular chemistry
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