Theoretical Studies on Structural and Mechanistic Aspects of Transition-metal Catalyzed Reactions PDF Download

Author: King Chung Lam
Publisher:
ISBN: 9781109839982
Category : Transition metal catalysts
Languages : en
Pages : 143

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Book Description
Theoretical studies on structural and bonding features of transition-metal complexes and reaction mechanisms of transition-metal-catalyzed reactions are reported in this thesis.

Author: Gernot Frenking
Publisher: Springer Science & Business Media
ISBN: 9783540235101
Category : Science
Languages : en
Pages : 284

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Book Description
Transition metal catalysis belongs to the most important chemical research areas because a ubiquitous number of chemical reactions are catalyzed by transition metal compounds. Many efforts are being made by industry and academia to find new and more efficient catalysts for chemical processes. Transition metals play a prominent role in catalytic research because they have been proven to show an enormous diversity in lowering the activation barrier for chemical reactions. For many years, the search for new catalysts was carried out by trial and error, which was costly and time consuming. The understanding of the mechanism of the catalytic process is often not very advanced because it is difficult to study the elementary steps of the catalysis with experimental techniques. The development of modern quantum chemical methods for calculating possible intermediates and transition states was a breakthrough in gaining an understanding of the reaction pathways of transition metal catalyzed reactions. This volume, organized into eight chapters written by leading scientists in the field, illustrates the progress made during the last decade. The reader will obtain a deep insight into the present state of quantum chemical research in transition metal catalysis.

Author: Gui-Juan Cheng
Publisher: Springer
ISBN: 9811045216
Category : Science
Languages : en
Pages : 140

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Book Description
This thesis presents detailed mechanistic studies on a series of important C-H activation reactions using combined computational methods and mass spectrometry experiments. It also provides guidance on the design and improvement of catalysts and ligands. The reactions investigated include: (i) a nitrile-containing template-assisted meta-selective C-H activation, (ii) Pd/mono-N-protected amino acid (MPAA) catalyzed meta-selective C-H activation, (iii) Pd/MPAA catalyzed asymmetric C-H activation reactions, and (iv) Cu-catalyzed sp3 C-H cross-dehydrogenative-coupling reaction. The book reports on a novel dimeric Pd-M (M = Pd or Ag) model for reaction (i), which successfully explains the meta-selectivity observed experimentally. For reaction (ii), with a combined DFT/MS method, the author successfully reveals the roles of MPAA ligands and a new C-H activation mechanism, which accounts for the improved reactivity and high meta-selectivity and opens new avenues for ligand design. She subsequently applies ion-mobility mass spectrometry to capture and separate the [Pd(MPAA)(substrate)] complex at different stages for the first time, providing support for the internal-base model for reaction (iii). Employing DFT studies, she then establishes a chirality relay model that can be widely applied to MPAA-assisted asymmetric C-H activation reactions. Lastly, for reaction (iv) the author conducts detailed computational studies on several plausible pathways for Cu/O2 and Cu/TBHP systems and finds a reliable method for calculating the single electron transfer (SET) process on the basis of benchmark studies.

Author: Jianbo Wang
Publisher: John Wiley & Sons
ISBN: 3527829156
Category : Science
Languages : en
Pages : 450

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Book Description
Presents an up-to-date overview of the rapidly growing field of carbene transformations Carbene transformations have had an enormous impact on catalysis and organometallic chemistry. With the growth of transition metal-catalyzed carbene transformations in recent decades, carbene transformations are today an important compound class in organic synthesis as well as in the pharmaceutical and agrochemical industries. Edited by leading experts in the field, Transition Metal-Catalyzed Carbene Transformations is a thorough summary of the most recent advances in the rapidly expanding research area. This authoritative volume covers different reaction types such as ring forming reactions and rearrangement reactions, details their conditions and properties, and provides readers with accurate information on a wide range of carbene reactions. Twelve in-depth chapters address topics including carbene C-H bond insertion in alkane functionalization, the application of engineered enzymes in asymmetric carbene transfer, progress in transition-metal-catalyzed cross-coupling using carbene precursors, and more. Throughout the text, the authors highlight novel catalytic systems, transformations, and applications of transition-metal-catalyzed carbene transfer. Highlights the dynamic nature of the field of transition-metal-catalyzed carbene transformations Summarizes the catalytic radical approach for selective carbene cyclopropanation, high enantioselectivity in X-H insertions, and bio-inspired carbene transformations Introduces chiral N,N'-dioxide and chiral guanidine-based catalysts and different transformations with gold catalysis Discusses approaches in cycloaddition reactions with metal carbenes and polymerization with carbene transformations Outlines multicomponent reactions through gem-difunctionalization and transition-metal-catalyzed cross-coupling using carbene precursors Transition Metal-Catalyzed Carbene Transformations is essential reading for all chemists involved in organometallics, including organic and inorganic chemists, catalytic chemists, and chemists working in industry.

Author: RAYBAUD Pascal
Publisher: Editions TECHNIP
ISBN: 2710809915
Category : Science
Languages : en
Pages : 368

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Book Description
The main application of Transition Metal Sulphides (TMS) as solid catalysts is for production of clean fuels in petroleum refineries. The various feedstocks to be processed all contain more or less sulphur, included in highly stable heteroaromatic molecules. In order to meet the stringent specifications imposed worldwide nowadays on transportation fuels to reduce their environmental impact, catalytic hydroprocessing remains essential. In this process, sulphur is removed as H2S following the reaction between molecular hydrogen and the heteroaromatics. The reaction conditions and reaction medium composition are such that only TMS provide stable catalysts, generally supported on alumina. Both for their fundamental and applied interest, these fascinating systems are still the subject of a very significant research effort, while major advances have been made over the past 30 years, involving innovative preparation routes, sophisticated surface science experiments for characterisation, detailed kinetic and mechanistic studies, and state of the art DFT simulations giving unprecedented insight into the local structure as well as elementary steps at microscopic level. This book aims at providing a complete, comprehensive and updated survey of the field, useful for anyone involved: the student starting a research project, the academic researcher or the refinery engineer willing to deepen their knowledge on the catalytic as well as on the process aspects. 37 specialists from IFP Energies nouvelles, CNRS, or French universities have contributed, reporting a unique synthesis of the last 15 years of research. The preface written by Michèle Breysse, a well known leading scientist who devoted most of her fruitful career to this topic, puts this collective work into a meaningful historical perspective. Contents : Part 1. Fundamental Aspects: Insights from DFT calculations and experimental surface sciences. 1. Periodic trends in catalysis by sulphides. 2. Atomic scale structures of mixed lamellar sulphides. 3. Theoretical and microkinetic studies of hydrotreatment reactions. 4. Models of supported Co(Ni)MoS Catalysts. Part 2. Progress in the preparation and characterisation of industrial hydrotreating catalysts. 1. Principles involved in the preparation of hydrotreatment catalysts. 2. Progress in the preparation of new catalysts. 3. Progress in the preparation of catalysts with controlled acidity: case of aluminosilicate supports. 4. Activation and genesis of the active phase by sulfidation. 5. life cycle of an HDT catalyst. 6. Charaterisation of catalysts. Part 3. Applications to the production of clean fuels. 1. An overview of refining. 2. Deep desulphurisation of middle distillates. 3. Selective desulphurisation of catalytic cracking gasolines. 4. Hydrocracking. 5. Hydroprocessing and hydroconversion of residue fractions. 6. Hydrotreatment of vegetable oils. 7. Hydroconversion of coals. Conclusion.

Author: Valentin P. Ananikov
Publisher: John Wiley & Sons
ISBN: 3527678220
Category : Science
Languages : en
Pages : 483

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Book Description
Exploring and highlighting the new horizons in the studies of reaction mechanisms that open joint application of experimental studies and theoretical calculations is the goal of this book. The latest insights and developments in the mechanistic studies of organometallic reactions and catalytic processes are presented and reviewed. The book adopts a unique approach, exemplifying how to use experiments, spectroscopy measurements, and computational methods to reveal reaction pathways and molecular structures of catalysts, rather than concentrating solely on one discipline. The result is a deeper understanding of the underlying reaction mechanism and correlation between molecular structure and reactivity. The contributions represent a wealth of first-hand information from renowned experts working in these disciplines, covering such topics as activation of small molecules, C-C and C-Heteroatom bonds formation, cross-coupling reactions, carbon dioxide converison, homogeneous and heterogeneous transition metal catalysis and metal-graphene systems. With the knowledge gained, the reader will be able to improve existing reaction protocols and rationally design more efficient catalysts or selective reactions. An indispensable source of information for synthetic, analytical, and theoretical chemists in academia and industry.

Author: Elena Soriano
Publisher: Springer Science & Business Media
ISBN: 3642210821
Category : Science
Languages : en
Pages : 265

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Book Description
Structure, Bonding, and Reactivity of Reactant Complexes and Key Intermediates, by Elena Soriano and José Marco-Contelles.- Cycloisomerization of 1,n-Enynes Via Carbophilic Activation, by Patrick Yves Toullec and Véronique Michelet.- DFT-Based Mechanistic Insights into Noble Metal-Catalyzed Rearrangement of Propargylic Derivatives: Chirality Transfer Processes, by Olalla Nieto Faza and Angel R. de Lera.- N-Heterocyclic Carbene Complexes of Au, Pd, and Pt as Effective Catalysts in Organic Synthesis, by Andrea Correa, Steven P. Nolan and Luigi Cavallo.- Activation of Allenes by Gold Complexes: A Theoretical Standpoint, by Max Malacria, Louis Fensterbank and Vincent Gandon.- Heterocyclization of Allenes Catalyzed by Late Transition Metals: Mechanisms and Regioselectivity, by Benito Alcaide, Pedro Almendros, Teresa Martínez del Campo, Elena Soriano and José Marco-Contelles.- Gold-Catalyzed Cycloadditions Involving Allenes: Mechanistic Insights from Theoretical Studies, by Sergi Montserrat, Gregori Ujaque, Fernando López, José L. Mascareñas and Agustí Lledós.-

Author: Lutz H. Gade
Publisher: John Wiley & Sons
ISBN: 3527673296
Category : Technology & Engineering
Languages : en
Pages : 632

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Book Description
Highlighting the key aspects and latest advances in the rapidly developing field of molecular catalysis, this book covers new strategies to investigate reaction mechanisms, the enhancement of the catalysts' selectivity and efficiency, as well as the rational design of well-defined molecular catalysts. The interdisciplinary author team with an excellent reputation within the community discusses experimental and theoretical studies, along with examples of improved catalysts, and their application in organic synthesis, biocatalysis, and supported organometallic catalysis. As a result, readers will gain a deeper understanding of the catalytic transformations, allowing them to adapt the knowledge to their own investigations. With its ideal combination of fundamental and applied research, this is an essential reference for researchers and graduate students both in academic institutions and in the chemical industry. With a foreword by Nobel laureate Roald Hoffmann.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 212

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Book Description
Transition states are the gate keepers of chemical reactions. The free energies associated with transition states determine everything of interest in a chemical reaction, namely the rate and product distribution. Attempts to categorize the repulsive and attractive forces that dictate structural and energetic features of transition states dominate mechanistic organic chemistry. Kinetic isotope effects (KIEs) provide a direct quantitative probe into transition structure because they report directly upon changes in bond strength. Furthermore, KIEs provide a satisfying means of comparison with computational efforts. However, KIE methods are almost exclusively applied to spot to spot reactions with only a single product. The information provided by studying these somewhat rare, well-behaved reactions, can be helpful, but more versatile methods are needed to investigate reactions that yield more than one product. In this dissertation, product-specific KIE, a new method developed in the lab which can simultaneously measure the KIE of all pathways in a multi-product reaction, will be introduced. In principle, the product-specific KIE methodology is able to reveal the energetic landscape of all pathways by analysis of the isotopic fractionation which records the bonding changes that occur along a reaction pathway. The information provided can be illuminating to discover the branching events in chemo-, regio- and stereo-selective reactions. Secondly, the mechanisms of two transition-metal catalyzed multi-product reactions have been discussed as examples for the application of this method with both natural abundance 13C and deuterium KIE experiments. One of them is cobalt catalyzed [2+2] and Alder-ene reaction, where a common intermediate was found before it branches to two different products. In another case, a dirhodium tetraacetate catalyzed C-H insertion was found to proceed via an initial hydride transfer transition state, followed by formation of two interconverting zwitterion intermediates before the formation of two diastereomers. Product-specific KIEs have the potential to address mechanistic questions in reactions under development and provide a basic understanding of the key transition state features necessary to develop more selective catalysis.

Author: Yu Lan
Publisher: John Wiley & Sons
ISBN: 3527346058
Category : Science
Languages : en
Pages : 672

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Book Description
The book includes a historical introduction to organometallic chemistry, a survey of mechanisms, and an extensive introduction to quantum mechanical computational methods.