Design Synthesis And Study Of Biomimetic Catalysts
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Design Synthesis And Study Of Biomimetic Catalysts
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Author : Robert S. Brown
language : en
Publisher:
Release Date : 1987
Design Synthesis And Study Of Biomimetic Catalysts written by Robert S. Brown and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1987 with categories.
Biomimetic catalysts modelled after the alkaline phosphatases and acid phosphatases were synthesized, and their catalysis of the hydrolysis of phosphate triesters was studied. The compounds fall into three classes: those that bind one divalent M2+-ion; those that bind two M2+ - ions; and those that contain an imidazole with a pendant guanidinium ion. The syntheses of the compounds in the former two classes is described along with the summary of in vitro assays. the Zn2+ and Co2+-chelates of these are respectable catalysts for hydrolysis of triesters. The guanidinium imidazoles are ineffective catalysts. Keywords: Biomimetic, Catalyst, Organophosphate ester, Alkaline phosphatase, Acid phosphatase, Chelates.
Design Synthesis And Applications Of Biomimetic Flavin Based Organocatalysts
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Author : Mohammad Shawkat Hossain
language : en
Publisher:
Release Date : 2019
Design Synthesis And Applications Of Biomimetic Flavin Based Organocatalysts written by Mohammad Shawkat Hossain and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Catalysis categories.
Oxidation reactions are one of the most important transformations in synthetic chemistry. Most commonly used oxidants are metal oxides, which are neither green nor selective towards multi-functional molecules. The efficiency of the reactions can be improved by the introduction of a catalyst by lowering the activation energy. In nature, oxidation reactions are highly specific and are controlled by enzymes, co-enzymes, and availability of a renewable terminal oxidant, molecular oxygen. Among the various enzymatic oxidative transformations, our research was inspired by the oxidations controlled by co-enzymes FMN or FAD in the presence of flavoproteins and molecular oxygen. Flavin mimics were often studied/used to oxidize heteroatoms; however, the goal of this research was initialy focused on mimicking other chemoselective oxidations of flavins, primarily at carbon centers. In chapter one, the function of natural flavins in nature and different approaches to perform nucleophilic and electrophilic oxidation using artificial flavin is described. In chapter two, flavin reactivity was extended to the Dakin oxidation of electron-rich benzaldehydes. This conversion of aryl aldehyde to phenol worked efficiently under mild conditions with either hydrogen peroxide or molecular oxygen as terminal oxidant. The mechanism was understood by various reaction rates studies. Substituent effects of catalysts and substrates aided in the identification of the rate determining step. The order of reagents and extensive pH studies reveal the various way flavin catalysts enable oxo-transfer under mild, more neutral conditions, by altering both the pKa of the active nucleophilic oxygen source, and by lowering the energy of the oxide leaving group, as previously hypothesized by Briuce and coworkers. In chapter three, pre-heteroaromatic compounds (initially investigated as possible reducing agents for flavin mimics) were transformed to their aromatic form aerobically using flavin catalyst in arguably the most mild methods described to date. Chapters four through six describe the preparation and function of various classes of flavins. Chapter four discussed the bioactivity of new flavin species against cancerous and normal breast cells. Chapter five details the preparation of water-soluble classes of flavins and their photochemical properties (O2 activation and Methyl Orange degredation). And Chapter six discusses the preparation of redox active flavins that were prepared for tethering to metal oxide photocatalyst and various electrode surfaces. Chapter seven describes a new preparation of 5-deazaflavin cofactors - deazariboflavin, 8-hydroxydeazariboflavin (an F420-precursor), and 10-methyl deazaflavin. An improved route to these species is described, and their redox activity were investigated in F420-dependent enzymes. Finally, chapter eight shows a new, concise and high yielding synthetic route explored for the synthesis of flavin catalysts, which includes the synthesis of different o-phenylenediamine derivatives and alloxan derivatives.
Advances In Catalysis
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Author :
language : en
Publisher: Academic Press
Release Date : 2021-12-04
Advances In Catalysis written by and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-12-04 with Science categories.
Advances in Catalysis, Volume 69 fills the gap between journal papers and textbooks across the diverse areas of catalysis research. For more than 60 years, this series has dedicated itself to record and present the latest progress in the field of catalysis, providing the scientific community with comprehensive and authoritative reviews. This series is an invaluable and comprehensive resource for chemical engineers and chemists working in the field of catalysis in both academia and industry, with this release focusing on solid acids, surface acidity and heterogeneous acid catalysis. Contains authoritative reviews written by experts in the field Explores topics that reflect progress in the field, such as catalyst synthesis, catalyst characterization, catalytic chemistry, reaction engineering, computational chemistry and physics Provides insightful and critical articles that are fully edited to suit various backgrounds
Design Of Heterogeneous Catalysts
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Author : Umit S. Ozkan
language : en
Publisher: John Wiley & Sons
Release Date : 2009-02-11
Design Of Heterogeneous Catalysts written by Umit S. Ozkan and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009-02-11 with Science categories.
This long-awaited reference source is the first book to focus on this important and hot topic. As such, it provides examples from a wide array of fields where catalyst design has been based on new insights and understanding, presenting such modern and important topics as self-assembly, nature-inspired catalysis, nano-scale architecture of surfaces and theoretical methods. With its inclusion of all the useful and powerful tools for the rational design of catalysts, this is a true "must have" book for every researcher in the field.
Synthesis Of Metallo Deuteroporphyrin Derivatives And The Study Of Their Biomimetic Catalytic Properties
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Author : Bingcheng Hu
language : en
Publisher:
Release Date : 2011
Synthesis Of Metallo Deuteroporphyrin Derivatives And The Study Of Their Biomimetic Catalytic Properties written by Bingcheng Hu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Bioinspiration And Biomimicry In Chemistry
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Author : Gerhard Swiegers
language : en
Publisher: John Wiley & Sons
Release Date : 2012-10-30
Bioinspiration And Biomimicry In Chemistry written by Gerhard Swiegers and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-10-30 with Science categories.
Can we emulate nature's technology in chemistry? Through billions of years of evolution, Nature has generated some remarkable systems and substances that have made life on earth what it is today. Increasingly, scientists are seeking to mimic Nature's systems and processes in the lab in order to harness the power of Nature for the benefit of society. Bioinspiration and Biomimicry in Chemistry explores the chemistry of Nature and how we can replicate what Nature does in abiological settings. Specifically, the book focuses on wholly artificial, man-made systems that employ or are inspired by principles of Nature, but which do not use materials of biological origin. Beginning with a general overview of the concept of bioinspiration and biomimicry in chemistry, the book tackles such topics as: Bioinspired molecular machines Bioinspired catalysis Biomimetic amphiphiles and vesicles Biomimetic principles in macromolecular science Biomimetic cavities and bioinspired receptors Biomimicry in organic synthesis Written by a team of leading international experts, the contributed chapters collectively lay the groundwork for a new generation of environmentally friendly and sustainable materials, pharmaceuticals, and technologies. Readers will discover the latest advances in our ability to replicate natural systems and materials as well as the many impediments that remain, proving how much we still need to learn about how Nature works. Bioinspiration and Biomimicry in Chemistry is recommended for students and researchers in all realms of chemistry. Addressing how scientists are working to reverse engineer Nature in all areas of chemical research, the book is designed to stimulate new discussion and research in this exciting and promising field.
Design And Synthesis Of Flavin Based Organocatalysts For Biomimetic Aerobic Oxidation Reactions
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Author : Shuai Chen
language : en
Publisher:
Release Date : 2014
Design And Synthesis Of Flavin Based Organocatalysts For Biomimetic Aerobic Oxidation Reactions written by Shuai Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Catalysis categories.
Oxidation reactions are among the most costly and least selective transformations in synthetic chemistry. Catalytic methods that utilize O2 as a terminal oxidant strive to reduce the inefficiency in this large area of synthesis. Recent efforts have been aimed primarily at metal-/organometallic- or enzyme-catalyzed transformations. The goal of the research described in this dissertation was to develop organocatalytic systems based on natural biosynthetic catalysts in order to develop selective metal-free aerobic oxidations that function at room temperature. Prior to our work, riboflavin mimics were previously investigated to understand flavoenzyme function and to perform catalytic oxidations of primarily heteroatom systems. We set out to extend this relatively limited area of organocatalysis to the oxidation of more valuable carbon centers in a mild, chemoselective and stereoselective manner. In Chapter 1, a description of the development and application of biomimetic flavin organocatalysts thus far reported in the literature are summarized. In Chapter 2, the flavin-catalyzed Dakin oxidation is discussed. A range of riboflavin derivatives is used as catalysts to accelerate the transformation of o- or p- hydroxyl benzaldehydes into dihydroxybenzenes using H2O2 as the terminal oxidant. An aerobic version of this transformation is developed using the flavin catalysts and NAD(P)H mimics. In Chapter 3, an aerobic asymmetric Weitz-Scheffer epoxidation of enals using flavin and chiral, non-racemic pyrrolidines in a dual catalysis strategy is discussed. High enantioselectivity and diastereoselectivity are observed in the epoxides obtained using this method. A mechanical study is conducted to elucidate the characteristics of the reaction pathway. In Chapter 4, the flavin catalyzed aerobic aromatization of heterocycles is discussed. Riboflavin derivatives are used to convert substituted dihydropyridines and benzothiazolines to pyridines and benzothiazoles with molecular oxygen as terminal oxidant under mild reaction conditions.
Frontiers Of Green Catalytic Selective Oxidations
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Author : Konstantin P. Bryliakov
language : en
Publisher: Springer Nature
Release Date : 2019-10-02
Frontiers Of Green Catalytic Selective Oxidations written by Konstantin P. Bryliakov and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-10-02 with Science categories.
The demand for novel efficient and environmentally sustainable chemo, regio- and stereoselective catalyst systems for the oxidation of organic substrates is continuously growing in line with toughening economic and environmental constraints. This book addresses these issues; it consists of eleven chapters written by world-recognized experts in green and sustainable oxidation catalysis. The most urgent and challenging topics, in the judgment of the editor, such as green asymmetric epoxidations, sulfoxidatiuons, C–H oxidations; oxidation catalysis by polyoxometalates and oxidations in non-conventional solvents, etc. have been critically reviewed in this book. Both fundamental aspects, such as catalysts design, catalytic properties, nature of catalytically active sites and reaction mechanisms, and practical outlook of the oxidations have been addressed by the authors. The book appeals to a broad readership, particularly graduate students, employees of universities and research organizations, and industrial researchers, particularly those working in the areas of homogeneous oxidation catalysis, asymmetric synthesis, organocatalysis, sustainable catalytic processes and green chemistry, mechanisms of catalytic reactions, synthesis of bioactive compounds, biomimetic chemistry, etc. Konstantin Bryliakov is Leading Researcher at the Boreskov Institute of Catalysis. In 2016, he was elected Honorary Professor of the Russian Academy of Sciences.
Design And Applications Of Single Site Heterogeneous Catalysts Contributions To Green Chemistry Clean Technology And Sustainability
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Author : John Meurig Thomas
language : en
Publisher: World Scientific Publishing Company
Release Date : 2012-04-16
Design And Applications Of Single Site Heterogeneous Catalysts Contributions To Green Chemistry Clean Technology And Sustainability written by John Meurig Thomas and has been published by World Scientific Publishing Company this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-04-16 with Science categories.
For far too long chemists and industrialists have relied on the use of aggressive reagents such as nitric and sulphuric acids, permanganates and dichromates to prepare the massive quantities of both bulk and fine chemicals that are needed for the maintenance of civilised life — materials such as fuels, fabrics, foodstuffs, fertilisers and pharmaceuticals. Such aggressive reagents generate vast quantities of environmentally harmful and often toxic by-products, including the oxides of nitrogen, of metal oxides and carbon dioxide.Now, owing to recent advances made in the synthesis of nanoporous solids, it is feasible to design new solid catalysts that enable benign, mild oxidants to be used, frequently without utilising solvents, to manufacture the products that the chemical, pharmaceutical, agro- and bio-chemical industries require. These new solid agents are designated single-site heterogeneous catalysts (SSHCs). Their principal characteristics are that all the active sites present in the high-area solids are identical in their atomic environment and hence in their energy of interaction with reactants, just as in enzymes.Single-site heterogeneous catalysts now occupy a position of growing importance both academically and in their potential for commercial exploitation. This text, the only one devoted to such catalysts, dwells both on principles of design and on applications, such as the benign synthesis of nylon 6 and vitamin B3. It equips the reader with unifying insights required for future catalytic adventures in the quest for sustainability in the materials used by humankind.Anyone acquainted with the language of molecules, including undergraduates in the physical and biological sciences, as well as graduates in engineering and materials science, should be able to assimilate the principles and examples presented in this book. Inter alia, it describes how clean technology and ‘green’ processes may be carried out in an environmentally responsible manner.
Biomimetic Catalysts Responsive To Specific Chemical Signals
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Author :
language : en
Publisher:
Release Date : 2015
Biomimetic Catalysts Responsive To Specific Chemical Signals written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Part 1. Design of Biomimetic Catalysts Based on Amphiphilic Systems The overall objective of our research is to create biomimetic catalysts from amphiphilic molecules. More specifically, we aim to create supramolecular systems that can be used to control the microenvironment around a catalytic center in a biomimetic fashion and apply the learning to construct supramolecular catalysts with novel functions found in enzymatic catalysts. We have prepared synthetic molecules (i.e., foldamers) that could fold into helical structures with nanometer-sized internal hydrophilic cavities. Cavities of this size are typically observed only in the tertiary and quaternary structures of proteins but were formed in our foldamer prepared in just a few steps from the monomer. Similar to many proteins, our foldamers displayed cooperativity in the folding/unfolding equilibrium and followed a two-state conformational transition. In addition, their conformational change could be triggered by solvent polarity, pH, or presence of metal ions and certain organic molecules. We studied their environmentally dependent conformational changes in solutions, surfactant micelles, and lipid bilayer membranes. Unlike conventional rigid supramolecular host, a foldamer undergoes conformational change during guest binding. Our study in the molecular recognition of an oligocholate host yielded some extremely exciting results. Cooperativity between host conformation and host-guest interactions was found to "magnify" weak binding interactions. In other words, since binding affinity is determined by the overall change of free energy during the binding, guest-induced conformational change of the host, whether near or far from the binding site, affects the binding. This study has strong implications in catalysis because enzymes have been hypothesized to harvest similar intramolecular forces to strengthen their binding with the transition state of an enzyme-catalyzed reaction. The supramolecular and amphiphilic principles used in the foldamer catalysts were extended to a few other systems, particularly to interfacially cross-linked reverse micelles and micelles. These features enabled unusual catalytic features such as basic/nucleophilic catalysis under acidic conditions. We were able to create highly active metal nanoclusters catalysts whose local environment could be tuned by the organic framework. We were even able to create a "catalytic nanomachine" that grabs the substrate to the encapsulated Au clusters, which efficiently convert the substrate to the product that is rapidly ejected due to its different binding properties. Our research has important impacts on fundamental and applied energy-related sciences. On the fundamental level, it tests important biocatalytic principles on relatively simple synthetic systems and is expected to afford deeper understanding of biological catalysis. On the practical level, the research is anticipated to lead to "smart" catalysts and open up exiting applications in chemical analysis, reaction control, and materials synthesis. Part 2. Electrochemical Reduction of CO2 The primary objective of our research involving the electrochemical reduction of carbon dioxide is to apply a multidisciplinary approach toward developing a greater understanding of the problem of efficiently converting CO2 to hydrocarbons through electrochemical routes. Our goal is to provide a better understanding of the principles that underlie the electrocatalytic reduction of CO2 at electrode surfaces and the molecular pathways that lead to desired compounds. This understanding is essential for the design and development of new catalytic materials for the selective production of renewable feedstocks. The electrochemical reduction of CO2 involves the formation of various reaction products and adsorbed intermediates whose distribution depends upon the nature of the electrode material and the electrochemical conditions, including applied potential, solvent, and elect ...