Understanding Organometallic Reaction Mechanisms And Catalysis

Author: Valentin P. Ananikov
Publisher: John Wiley & Sons
ISBN: 3527678220
Size: 33.11 MB
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Understanding Organometallic Reaction Mechanisms And Catalysis. 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.

Computational Modeling For Homogeneous And Enzymatic Catalysis

Author: Keiji Morokuma
Publisher: John Wiley & Sons
ISBN: 3527621970
Size: 71.53 MB
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Computational Modeling For Homogeneous And Enzymatic Catalysis. Here, the world's most active and productive computational scientists from academia and industry present established, effective and powerful tools for understanding catalysts. With its broad scope -- nitrogen fixation, polymerization, C-H bond activation, oxidations, biocatalysis and much more -- this book represents an extensive knowledge base for designing efficient catalysts, allowing readers to improve the performance of their own catalysts.

Computational Organometallic Chemistry

Author: Olaf Wiest
Publisher: Springer Science & Business Media
ISBN: 3642252575
Size: 15.82 MB
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Computational Organometallic Chemistry. Computational methods have become an indispensible tool for elucidating the mechanism of organometallic reactions. This snapshot of state-of-the-art computational studies provides an overview of the vast field of computational organometallic chemistry. Authors from Asia, Europe and the US have been selected to contribute a chapter on their specialist areas. Topics addressed include: DFT studies on zirconium-mediated reactions, force field methods in organometallic chemistry, hydrogenation of π-systems, oxidative functionalization of unactivated C-H bonds and olefins, the osmylation reaction, and cobalt carbonyl clusters. The breadth and depth of the contributions demonstrate not only the crucial role that computational methods play in the study of a wide range of organometallic reactions, but also attest the robust health of the field, which continues to benefit from, as well as inspire novel experimental studies.

Computational Studies Of Organic Organometallic And Enzyme Catalysis

Author: Elizabeth Lynn Noey
Size: 10.71 MB
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Computational Studies Of Organic Organometallic And Enzyme Catalysis. Computations are increasingly powerful tools for studying reaction mechanisms and protein catalysis. Various quantum mechanical (QM) and force field-based calculations are applied to problems in organic, organometallic, and protein chemistry. These studies span the chemistry-biology interface, progressing from theoretical studies of gold catalysis, to that of N-heterocyclic carbene (NHC) catalysis, and enzyme catalysis. The first study highlights a gold(I)-catalyzed enyne cyclization with a bifurcating potential energy surface. Several alkynylindoles undergo gold(I)-catalyzed cyclization reactions to form a single isomer in each case. This transformation involves a two-step no-intermediate mechanism with surface bifurcations leading to two or three products. The second gold study is on the mechanism of the rearrangement of acetylenic amine-N-oxides. Further work has been done on the mechanism of the Stetter reaction catalyzed by substituted NHCs. The leucine metabolic pathway was reengineered to produce biofuels, and computations showed that there is push-pull effect between the hydrophobic effect and steric clash, which dictates the LeuA substrate scope. The redesign of a transaminase to install the stereocenter in the blockbuster diabetes drug sitagliptin was attempted. The transaminase that was evolved for the industrial synthesis of sitagliptin, was studied computationally. This study elucidates the energetic details of the transamination mechanism to form sitagliptin, and makes progress toward understanding the role of mutations in the evolution. Finally, a computational, crystallographic, and kinetic study of ketoreductases (KREDs) shows how point mutations change the enantioselectively toward two small substrates, 3-oxa and 3-thiacyclopentanone. QM calculations of the ideal geometry for catalysis, and molecular dynamics (MD) simulations show how small changes in the size, shape, and hydrophobicity of the active site of the enzyme modulate the enantioselectively. Here, we develop an MD method, where simulations are run on the enzyme containing the theozyme for the reduction. This approach probes how well each enzyme stabilizes the transition structures and can predict the experimentally favored enantiomer. Although the subject matter varies, the underlying goal of understanding chemical reactions and catalysis from a physical organic perspective persists.

N Heterocyclic Carbenes

Author: Silvia Díez-González
Publisher: Royal Society of Chemistry
ISBN: 1849730423
Size: 72.50 MB
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N Heterocyclic Carbenes. Over the last fifteen years, N-heterocyclic carbenes (NHCs) have mostly been used as ancillary ligands for the preparation of transition metal-based catalysts. Compared to phosphorus-containing ligands, NHCs tend to bind more strongly to metal centres, avoiding the necessity for the use of excess ligand in catalytic reactions. The corresponding complexes are often less sensitive to air and moisture, and have proven remarkably resistant to oxidation. Recent developments in catalysis applications have been facilitated by the availability of carbenes stable enough to be bottled, particularly for their use as organocatalysts. This book shows how N-heterocyclic carbenes can be useful in various fields of chemistry and not merely laboratory curiosities or simple phosphine mimics. NHCs are best known for their contribution to ruthenium and palladium-catalysed reactions but the scope of this book is much broader. The synthesis of NHC ligands and their corresponding metal complexes are covered in depth. Moreover, the biological activity of NHC-containing complexes, as well as an overview of their theoretical aspects are included. Such metal species are further examined, not only in terms of their catalytic applications, but also of their stereoelectronic parameters and reactivity/stability. Finally, special attention is given to the hot topic of organocatalysis. The book will be of interest to postgraduates, academic researchers and those working in industry.

Investigations Of Organometallic Reaction Mechanisms Using Ultrafast Time Resolved Infrared Spectroscopy

Author: Justin Lomont
Size: 13.51 MB
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Investigations Of Organometallic Reaction Mechanisms Using Ultrafast Time Resolved Infrared Spectroscopy. Ultrafast time-resolved infrared spectroscopy provides a powerful tool for studying the photochemistry of organometallic complexes. The studies described herein focus on the mechanisms of photochemically initiated organometallic reactions with a particular emphasis on two topics: the role of spin states and spin state changes in organometallic reactions, and the primary photochemical dynamics of complexes containing metal-metal bonds (e.g. transition metal dimers and clusters). Many of these studies seek to uncover trends in reactivity based on the spin states of organometallic reaction intermediates, with the goal of being able to offer some level of predictive insight into the reactivity of complexes as classified by their spin multiplicity. The reactivity of various coordinatively unsaturated reaction intermediates are studied with respect to bond activation, electron transfer, excited state photoisomerization, and other classes of reactions important to organometallic catalysis. A second focus, which shares some degree of overlap with the topic of spin state changes, is the primary photochemistry of complexes containing metal-metal bonds. Several of the studies reported herein use time-resolved infrared spectroscopy to examine the primary photochemical processes occurring upon excitation of transition metal dimers and clusters, and often spin state changes also found to play an important role. Results of computational chemistry calculations are frequently used to facilitate interpretation of the experimental results by computation of structures, relative energies, infrared spectra, and spin-orbit coupling for the complexes studied experimentally. Additional studies outside these two primary areas of focus also investigated the ring-slippage of cyclopentadienyl ligands and the CO-delivery properties of a popular CO-Releasing Molecule.

Modeling Nmr Chemical Shifts

Author: Julio C. Facelli
Publisher: Amer Chemical Society
ISBN: 9780841236226
Size: 77.23 MB
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Modeling Nmr Chemical Shifts. This book reviews the history of NMR chemical shielding while surveying new developments in the field. Topics include new methods for calculating NMR chemical shifts, calculations of chemical shifts for important biological molecules, new theories about the role of chemical shifts, and modeling methods for chemical shifts in inorganic compounds.

Physical Inorganic Chemistry

Author: Andreja Bakac
Publisher: John Wiley & Sons
ISBN: 9780470602515
Size: 62.49 MB
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Physical Inorganic Chemistry. Physical Inorganic Chemistry contains the fundamentals of physical inorganic chemistry, including information on reaction types, and treatments of reaction mechanisms. Additionally, the text explores complex reactions and processes in terms of energy, environment, and health. This valuable resource closely examines mechanisms, an under-discussed topic. Divided into two sections, researchers, professors, and students will find the wide range of topics, including the most cutting edge topics in chemistry, like the future of solar energy, catalysis, environmental issues, climate changes atmosphere, and human health, essential to understanding chemistry.