Kinetics And Spectroscopy Of Carbenes And Biradicals

The development of mechanistic organic chemistry is filled with claims of short-lived reactive intermediates connecting starting material to product. In many ways this book represents a personal odyssey of the editor in this area of chemistry. I well remember my introduction to organic chemistry as an undergraduate working in the laboratories of Shelton Bank at SUNY Albany in the early 1970s, and the excitement and frustration attending the piecing together of the details of a reaction mechanism by working backwards from the stable products of the reaction. In those days the reaction and the reactive intermediates flew by too rapidly to permit direct observation. Thus it came as something of a revelation to me as a graduate student at Yale that it was possible to slow down a reaction and actually "see" such ephemeral species as carbenes and biradicals by spectroscopic methods, by generating them photochemically at cryogenic temperatures. In this monograph several chap ters are devoted to low-temperature studies. Dougherty has described the matrix EPR spectra of biradicals, which were pure conjecture only ten years ago. Michl and Arnold have described the matrix spectroscopy of cyciobutadiene, a molecule that has fascinated organic chemists for over a hundred years. They have shown that by using a combination of matrix spec troscopic methods it is possible to learn nearly as much about the structure of cyciobutadiene, the prototypical antiaromatic biradicaloid, as about that of a common shelf-stable reagent.

Our understanding of carbene chemistry has advanced dramatically, especially in the last decade, and new developments continue to emerge. Some of the recent exciting findings have been collected in the first and second volumes of Advances in Carbene Chemistry. With the third volume, the series continues to provide a periodic coverage of carbene chemistry in its broadest sense. Beginning as chemical curiosities, carbenes are now solidly established as reactive intermediates with fascinating and productive research areas of their own. Five decades of divalent carbon chemistry have provided us with a vast repertoire of new, unusual, and surprising reactions. Some of those reactions, once classified as exotic, have become standard methods in organic synthesis. These highly reactive carbene species have been harnessed and put to work to achieve difficult synthetic tasks other reactive intermediates cannot easily perform. The fruitful relationship between experiment and theory has pushed carbene chemistry further toward the direction of reaction control; that is, regio- and stereoselectivity in intra- and intermolecular addition and insertion reactions. The interplay between experiment and modern spectroscopy has led to the characterization of many carbenes that are crucial to both an understanding and further development of this field.

Reactive Intermediate Chemistry presents a detailed and timely examination of key intermediates central to the mechanisms of numerous organic chemical transformations. Spectroscopy, kinetics, and computational studies are integrated in chapters dealing with the chemistry of carbocations, carbanions, radicals, radical ions, carbenes, nitrenes, arynes, nitrenium ions, diradicals, etc. Nanosecond, picosecond, and femtosecond kinetic realms are explored, and applications of current dynamics and electronic structure calculations are examined. Reactive Intermediate Chemistry provides a deeper understanding of contemporary physical organic chemistry, and will assist chemists in the design of new reactions for the efficient synthesis of pharmaceuticals, fine chemicals, and agricultural products. Among its features, this authoritative volume is: Edited and authored by world-renowned leaders in physical organic chemistry. Ideal for use as a primary or supplemental graduate textbook for courses in mechanistic organic chemistry or physical chemistry. Enhanced by supplemental reading lists and summary overviews in each chapter.

Carbenes are important molecules in chemistry because of their photochemistry and high reactivity. They have many potential applications in medicinal and materials chemistry. This book provides a comprehensive introduction to carbenes and discusses their characteristics, structure, and synthesis procedures. It gives special emphasis to N-heterocyclic carbenes (NHCs) and their metal complexes.

The chemistry of reactive intermediates is central to a modern mechanistic and quantitative understanding of organic chemistry. Moreover, it underlies a significant portion of modern synthetic chemistry and is integral to a molecular view of biological chemistry. Reviews in Reactive Intermediate Chemistry presents an up-to-date, authoritative guide to this fundamental topic. Although it follows Reactive Intermediate Chemistry by the same authors, it serves as a free-standing resource for the entire chemical and biochemical community. The book includes: Relevant, practical applications Coverage of such topics as mass spectrometry methods, reactive intermediates in interstellar medium, quantum mechanical tunnelling, solvent effects, reactive intermediates in biochemical processes, and excited state surfaces Discussions of emerging areas, particularly those involving dynamics and theories Concluding sections identifying key directions for future research are provided at the end of each chapter

Beginning as chemical curiosities, carbenes are now solidly established as reactive intermediates with fascinating and productive research areas of their own. Five decades of divalent carbon chemistry have provided us with a vast repertoire of new, unusual and surprising reactions. Some of those reactions, once classified as exotic, have become standard methods in organic synthesis. These highly reactive carbene species have been harnessed and put to work to achieve difficult synthetic tasks that other reactive intermediates cannot easily perform. The fruitful relationship between experiment and theory has pushed carbene chemistry further toward the direction of reaction control; that is, regio- and stereoselectivity in intra- and intermolecular addition and insertion reactions. The interplay between experiment and modern spectroscopy has led to the characterisation of many carbenes that are crucial to both an understanding and a further development of this field. Understanding of carbene chemistry has advanced dramatically, especially in the last decade, and new developments continue to emerge. Some of the recent exciting findings have been collected in the first volume of Advances in Carbene Chemistry. With this second volume, the series will continue to provide a periodic coverage of carbene chemistry in its broadest sense - leading into the next century.

Organic photochemistry is the science arising from the application of photochemicalmethods to organic chemistry and organic chemical methods to photochemistry. It is aninterdisciplinary frontier.Intense activity in organic photochemistry in the last decade has produced so vast anaccumulation of factual knowledge that chemists in general have viewed it with awe.Even those chemists engaged in the study of organic photochemistry will find the rate ofdevelopment in the field perplexing to a high degree. This series originated to fill theneed for a critical summary of this vigorously expanding field with the purpose ofdrawing together seemingly unrelated facts, summarizing progress, and clarifyingproblems.Volume 11 continues to fulfill the original, essential role of this unique series byproviding a convenient review of the structural aspects of organic photochemistry. Aswith earlier volumes, this new book offers the research findings of distinguishedauthorities. It stresses timely aspects of organic photochemistry-previously scatteredthroughout the large body of literature-for which necessary critical review has beenlacking.This volume of the series emphasizes the mechanistic details of the di-n:-methanerearrangement . .. the synthetic aspects of the oxadi-n:-methane reaction ... thephotochemistry of carbenium ions and related species .. . photoinduced hydrogen atomabstraction by carbonyl compounds ... and matrix photochemistry of nitrenes, carbenes,and excited triplet states. Complete with numerous illustrations and bibliographiccitations of the literature, this book explores these important processes to the advantageof organic chemists, as an aid to research and as a source for supplementary knowledgeon particular topics .

Presents the most innovative results in carbene chemistry, setting the foundation for new discoveries and applications The discovery of stable carbenes has reinvigorated carbene chemistry research, with investigators seeking to develop carbenes into new useful catalysts and ligands. Presenting the most innovative and promising areas of carbene research over the past decade, this book explores newly discovered structural, catalytic, and organometallic aspects of carbene chemistry, with an emphasis on new and emerging synthetic applications. Contemporary Carbene Chemistry features contributions from an international team of pioneering carbene chemistry researchers. Collectively, these authors have highlighted the most interesting and promising areas of investigation in the field. The book is divided into two parts: Part 1, Properties and Reactions of Carbenes, explores new findings on carbene stability, acid-base behavior, and catalysis. Carbenic structure and reactivity are examined in chapters dedicated to stable carbenes, carbodicarbenes, carbenes as guests in supramolecular hosts, tunneling in carbene and oxacarbene reactions, and ultrafast kinetics of carbenes and their excited state precursors. Theoretical concerns are addressed in chapters on computational methods and dynamics applied to carbene reactions. Part 2, Metal Carbenes, is dedicated to the synthetic dimensions of carbenes, particularly the reactions and catalytic properties of metal carbenes. The authors discuss lithium, rhodium, ruthenium, chromium, molybdenum, tungsten, cobalt, and gold. All the chapters conclude with a summary of the current situation, new challenges on the horizon, and promising new research directions. A list of key reviews and suggestions for further reading also accompanies every chapter. Each volume of the Wiley Series on Reactive Intermediates in Chemistry and Biology focuses on a specific reactive intermediate, offering a broad range of perspectives from leading experts that sets the stage for new applications and further discoveries.

Highlights recent discoveries in the development of rapid kinetic techniques that allow for direct visualization and state-of-the-art computational methods.