Download or read book Mechanistic Studies of Photo induced Proton coupled Electron Transfer and Oxygen Atom Transfer Reactions in Model Systems written by Justin Mark Hodgkiss and published by . This book was released on 2006 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) The observed PCET rates are strongly attenuated compared with comparable covalentlybridged analogues, indicating that the PT interface reduces electronic coupling. Temperature-isotope dependence of the PCET rates reveals an unusual inverse isotope effect at low temperature, which is interpreted in a model of vibrationally-assisted PCET (chapter IV). Hangman porphyrin dyads have been developed to study bi-directional PCET in relation to oxygen activation. ET and PT coordinates are orthogonalized at fixed distances about a FeIII-OH center (Chapters V and VI). TA spectroscopy and electronic structure calculations reveal that the structural reorganization attendant to metal-centered PCET imposes a severe kinetic cost and alternative quenching pathways prevail. Finally, TA spectroscopy has been used to elucidate the mechanism of photocatalytic OAT for bridged diiron [mu]-oxo bisporphyrins (Chapter VII). The [mu]-oxo bond is photo-cleaved to generate a terminal iron(IV) oxo, which undergoes OAT to nucleophilic substrates. OAT rates are maximized when the bridge actively splays the porphyrin subunits apart to present the oxo before reclamping can occur.

Download or read book Spectroscopic Investigation of Photo induced Proton coupled Electron Transfer and Dexter Energy Transfer in Model Systems written by Elizabeth Renee Young and published by . This book was released on 2009 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectroscopic investigations of systems designed to advance the mechanistic interrogation of photo-induced proton coupled electron transfer (PCET) and proton-coupled (through-bond) energy transfer (PCEnT) are presented. PCET is ubiquitous in Nature, where it is at the heart of bioenergy conversion and catalysis (Chapter I). Systems of relevance to mechanistic studies of PCET and PCEnT are the central tenet of this work. In uni-directional PCET, electron transfer (ET) occurs from an electron donor (De) to an electron acceptor (Ae) through a hydrogen bonded proton interface. The proton interface plays a vital role in mediating ET. Thus, the exact ionization configuration of the interface must be uncovered to fuIIy realize the influence of the interface. SpecificaIIy, does the interface exists in the non-ionized (i.e. amidine-carboxylic acid) or ionized (i.e. amidinium-carboxylate) form. Strategies to spectraIIy monitor the interface ionization state by extending electronic communication from a porphyrinic chromophore to its pendant amidinium functionality are pursued through examination of an alkynylamidinium Ni(II) porphyrin (Chapter II) and an amidinium appended Zn(II) purpurin (Chapter III). With the ionization state of the interface resolved, mechanistic studies of photo-induced PCET between an identical De and Ae pair juxtaposed by a non-ionized (amidine-carboxylic acid) and an ionized (amidinium-sulfonate) interface are undertaken to reveal that PCET occurring through an ionized interface is more strongly coupled to the surrounding solvent environment (Chapter IV). Work on this system is extended to a second solvent of similar dielectric constant to establish that molecular variation of the solvent environment impacts PCET, likely through its interaction with the proton interface (Chapter V). Two water-soluble amidinium-appended ferrocene moieties are presented as building blocks for aqueous bi-directional PCET in which PT occurs to the bulk and ET occurs along a covalently bound coordinate (Chapter VI). ET and through-bond EnT are described by the semiclassical nonradiative decay formalism, meaning both processes should be sensitive to an intervening proton network. For the first time, PCEnT is established using ferrocenyl-amidine moieties bound through an amidinecarboxylic acid interface to Ru(II) polypyridyl complexes (Chapter VII).

Download or read book Mechanistic Studies of Proton coupled Electron Transfer Reactions Involving Antioxidants written by Kejie Meng and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the research was to investigate proton-coupled electron transfer (PCET) reactions involving antioxidants to gain insight into the detailed mechanisms of glutathione (GSH), Trolox, and [alpha]-tocopherol ([alpha]-TOH). PCET reactions are complex redox reactions that transfer electrons and protons sequentially or in concert. These reactions are ubiquitous in natural or artificial processes that produce electrochemical energy that is extractable as electricity or as chemical fuels of high energy content. Examples of processes based on PCET are photosynthesis, respiration, nitrogen fixation, carbon dioxide reduction, redox fuel cells, and artificial photosynthesis. Antioxidants were selected as a PCET model to understand the coupling between proton transfer (PT) and electron transfer (ET) in order to elucidate structure-reactivity relationships under different experimental conditions. PCET reactions were studied with a set of electrochemical techniques to propose a preliminary mechanism that could be validated with digital simulations matching the electrochemical response. In some cases, other analytical techniques were used to aid in the system characterization. This thesis presents the results and discussion of the effects of oxidant-base pairs on the mediated oxidation of GSH, the -2e−-H process of Trolox in aqueous and nonaqueous solvents with various pH values, and the particle collision electrolysis of [alpha]-tocopherol in oil-in-water emulsion droplets on an ultramicroelectrode. Ultimately our goal was to determine the kinetic and thermodynamic factors that control PCET reactions so that they can be applied in designing artificial systems for the production of energy using more abundant reagents with lower cost and better yields.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unraveling the Mechanistic Details of Proton Coupled Electron Transfer PCET Using Model Systems written by Afua Nti and published by . This book was released on 2012 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Chemical Physics written by Ilya Prigogine and published by John Wiley & Sons. This book was released on 2003-04-14 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest edition of the leading forum in chemical physics Edited by Nobel Prize winner Ilya Prigogine and renowned authority Stuart A. Rice. The Advances in Chemical Physics series provides a forum for critical, authoritative evaluations in every area of the discipline. In a format that encourages the expression of individual points of view, experts in the field present comprehensive analyses of subjects of interest. This stand-alone, special topics volume reports recent advances in electron-transfer research, with significant, up-to-date chapters by internationally recognized researchers. Volume 123 collects innovative papers on "Transition Path Sampling," "Dynamics of Chemical Reactions and Chaos," "The Role of Self Similarity in Renormalization Group Theory," and several other related topics. Advances in Chemical Physics remains the premier venue for presentations of new findings in its field.

Download or read book Photo induced Electron Transfer Applications and Relted Mechanistic Studies 2d2e72 written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanistic Studies of Oxygen Atom Transfer Reactions by Oxodiperoxo Complexes of Mo VI W VI and V V written by Arlene Feay Ghiron and published by . This book was released on 1989 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanistic Studies of Proton coupled Electron Transfer and Ligand Substitution Reactions in Biologically Relevant Systems written by David Sarauli and published by . This book was released on 2008 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanistic Studies of Oxygen Atom Transfer at Nonheme Iron Centers written by Jinheung Kim and published by . This book was released on 1995 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Expressed Protein Ligation written by Miquel Vila-Perelló and published by Humana. This book was released on 2020-03-07 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of Expressed Protein Ligation (EPL), detailing methods and protocols to generate site-specifically modified proteins. Chapters include an overview of the protein semi-synthesis field, as well as related areas that have contributed to the development of EPL such as protein splicing and peptide synthesis. Following the introductory chapters, the rest of the book guides readers through protocols to perform EPL reactions, methods to synthesize peptide thioesters and to perform peptide and protein ligations, label proteins inside living cells, protocols for the semi-synthesis of phorphorylated, glycosylated and ubiquitylated proteins, synthesis and assembly of assymetrically modified nucleosomes, use of ligation auxiliaries and synthesis of cyclic proteins, as well as novel desulfurization strategies and use of selective Cys side chain protection to obtain precisely modified proteins.Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Expressed Protein Ligation: Methods and Protocols will ensure successful implementation of protein semi-synthesis methods to further study the structure and function of proteins.

Download or read book Proton Coupled Electron Transfer Mediated by a Salt Bridge written by James A. Roberts and published by . This book was released on 1997 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proton Coupled Electron Transfer written by Sebastiao Formosinho and published by Royal Society of Chemistry. This book was released on 2011-12-07 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton-coupled electron transfer (PCET) is emerging as an important new class of reactions and, over the past decade, great strides have been made in our understanding of them. PCET reactions are studied in many branches of chemistry and are omnipresent in biological processes. This book covers recent developments from both the theoretical and experimental points of view. It concentrates on the importance of PCET in biological systems and for bioenergetic conversion. The oxidation of water in Photosystem II to produce oxygen, and the reduction of protons to hydrogen by hydrogenase, for energy storage gets particular emphasis. Chemical reactivity is currently explained in terms of several scientific principles. One of them is the bond-breaking-bond-forming process and is conceptually based on potential energy surfaces. Another incorporates the role of Franck-Condon factors resulting from the overlap of vibrational wavefunctions. A third, the so-called solvent reorganization, involves solvent configuration around a charged species. PCET brings together such concepts and links them to quantum mechanical tunnelling of the electron particle. This book uses personal accounts of experimental examples to provide additional insight on this important topic. It starts by presenting a general overview of the main theoretical approaches and experimental applications. The chapters then go on to cover topics including: the application of the Marcus Cross Relation; the solvation of ionic systems; experimental approaches in biological redox systems; metal ion-coupled electron transfer, and electrochemical concerted proton-electron transfers.

Download or read book Mechanistic Studies of Electron transfer induced Photocyclization Reactions of Allylsilane iminium Salt Systems written by Chunglan Tu and published by . This book was released on 1988 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photoinduced Electron Transfer written by Marye Anne Fox and published by . This book was released on 1988 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron transfer reactions are of great importance to nearly every subdiscipline of chemistry. The simple transfer of a single electron has been shown repeatedly to be a common activating mode for organic, inorganic, and biological molecules, and the very ubiquity of such reactions has guaranteed that their investigation would involve the most fundamental questions of modern chemistry. The fact that photoexcitation induces enhanced redox reactivity via electron transfer also provides a convenient method for experimentally testing theoretical predictions regarding structural and energetic effects. As can be seen from the very size of this work there is a great deal known about photoinduced electron transfer reactions and the editors have tried to capture the diversity and excitement inherent in this broad field. The reader will find contributions from theorists and experimentalists, from organic and inorganic chemists, from the perspective of the synthetic and mechanistic viewpoint. Some contributions are fundamental basic research, while others clearly show practical applications of these principles.These volumes are intended to serve a joint purpose: as a reference resource and an introductory overview to the diverse research accomplished via photoexcitation of electron donor-acceptor systems. The information is organized in four parts. The first deals with the theoretical and conceptual factors which influence electron transfer. The second covers experimental methodology and medium effects. The third and fourth deal with reactivity, with most organic transformation being addressed in Part C and most inorganic reactions covered in Part D. Each part thus provides an overview of typical reactions observed for these classes of compounds. Part D also provides examples of photoinduced electron transfer in current use in important applications. There is of course a significant interdependence between the four parts. Subject, chemical, and author citation indices appear at the end of each of Parts A, B and C, and comprehensive indices are included in Part D.

Download or read book Dynamics and Mechanisms of Photoinduced Electron Transfer and Related Phenomena written by N. Mataga and published by Elsevier. This book was released on 2012-12-02 with total page 587 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains papers which examine fundamental aspects of photoinduced electron transfer reactions, an area in which a number of breakthroughs have recently occurred. The book is divided into four parts. Parts I and II are mainly concerned with the fundamental aspects of the inter- and intra-molecular charge transfer, electron transfer and related phenomena such as solvent effects, solvation dynamics, energy gap dependences and radical pair dynamics. Part III is concerned with electron transfer and energy transfer phenomena in polymers, films, crystals, and other confined systems. In Part IV, the mechanisms of the energy and electron transfer in biological photosynthetic systems, proteins and reaction center systems are discussed.

Download or read book Ruthenium Complexes written by Alvin A. Holder and published by John Wiley & Sons. This book was released on 2018-02-27 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edited by a team of highly respected researchers combining their expertise in chemistry, physics, and medicine, this book focuses on the use of rutheniumcontaining complexes in artificial photosynthesis and medicine. Following a brief introduction to the basic coordination chemistry of ruthenium complexes and their synthesis in section one, as well as their photophysical and photochemical properties, the authors discuss in detail the major concepts of artificial photosynthesis and mechanisms of hydrogen production and water oxidation with ruthenium in section two. The third section of the text covers biological properties and important medical applications of ruthenium complexes as therapeutic agents or in diagnostic imaging. Aimed at stimulating research in this active field, this is an invaluable information source for researchers in academia, health research institutes and governmental departments working in the field of organometallic chemistry, green and sustainable chemistry as well as medicine/drug discovery, while equally serving as a useful reference also for scientists in industry.