Making And Breaking Symmetry In Chemistry: Syntheses, Mechanisms And Molecular Rearrangements


Book Description

The elucidation of reaction mechanisms generally requires the carefully designed control of molecular symmetry to distinguish between the many possible reaction pathways. Making and Breaking Symmetry in Chemistry emphasises the crucial role played by symmetry in modern synthetic chemistry. After discussion of a number of famous classical experiments, the advances brought about by the introduction of new techniques, in particular NMR spectroscopy, are exemplified in numerous cases taken from the recent literature. Experimental verification of many of the predictions made in Woodward and Hoffmann's explication of the Conservation of Orbital Symmetry are described. Applications that involve the breaking of molecular symmetry to resolve these and other mechanistic problems in organic, inorganic and organometallic chemistry are presented in the first sections of the book, together with many examples of the detection of hitherto hidden rearrangement processes.Subsequently, under the aegis of making molecular symmetry, examples of the preparation of highly symmetrical molecules found in the organic, organometallic or inorganic domains are discussed. These include Platonic hydrocarbons or boranes, tetrahedranes, cubanes, prismanes, dodecahedrane, fullerene fragments such as corannulene, sumanene or semibuckminsterfullerene, and other systems of unusual geometries or bonding characteristics (Möbius strips, molecular brakes and gears, Chauvin's carbomers, Fitjer's rotanes, persubstituted rings, metal-metal multiple bonds, etc.). The text also contains vignettes of many of the scientists who made these major advances, as well as short sections that briefly summarise key features of important topics that underpin the more descriptive material. These include some aspects of chirality, NMR spectroscopy, and the use of isotopic substitution to break molecular symmetry. A brief appendix on point group symmetry and nomenclature is also helpfully provided.




Making and Breaking Symmetry in Chemistry


Book Description

The elucidation of reaction mechanisms generally requires the carefully designed control of molecular symmetry to distinguish between the many possible reaction pathways. Making and Breaking Symmetry in Chemistry emphasises the crucial role played by symmetry in modern synthetic chemistry. After discussion of a number of famous classical experiments, the advances brought about by the introduction of new techniques, in particular NMR spectroscopy, are exemplified in numerous cases taken from the recent literature. Experimental verification of many of the predictions made in Woodward and Hoffmann's explication of the Conservation of Orbital Symmetry are described. Applications that involve the breaking of molecular symmetry to resolve these and other mechanistic problems in organic, inorganic and organometallic chemistry are presented in the first sections of the book, together with many examples of the detection of hitherto hidden rearrangement processes. Subsequently, under the aegis of making molecular symmetry, examples of the preparation of highly symmetrical molecules found in the organic, organometallic or inorganic domains are discussed. These include Platonic hydrocarbons or boranes, tetrahedranes, cubanes, prismanes, dodecahedrane, fullerene fragments such as corannulene, sumanene or semibuckminsterfullerene, and other systems of unusual geometries or bonding characteristics (Möbius strips, molecular brakes and gears, Chauvin's carbomers, Fitjer's rotanes, persubstituted rings, metal-metal multiple bonds, etc.). The text also contains vignettes of many of the scientists who made these major advances, as well as short sections that briefly summarise key features of important topics that underpin the more descriptive material. These include some aspects of chirality, NMR spectroscopy, and the use of isotopic substitution to break molecular symmetry. A brief appendix on point group symmetry and nomenclature is also helpfully provided.




Chemical Symmetry Breaking


Book Description

This book entitled “Chemical Symmetry Breaking” is a collective volume of state-of-the-art reports on unique nonlinear chemical and physical symmetry-breaking phenomena that were experimentally observed upon a thermally or photochemically induced phase transition in various organic condensed phases, such as metastable liquid crystals, crystals, amorphous solids, and colloidal polymer materials, only under nonequilibrium conditions. Each author summarizes the introductory section in simple terms but in detail for beginners in this field. We wish that many readers familiarize themselves with the general concepts and features of nonlinear and nonequilibrium (or out of equilibrium) complexity theory, which govern a variety of unique dynamic behaviors observed in chemistry, physics, life science and other fields, so that they may discover novel symmetry-breaking phenomena in their own research areas.




Making and Breaking Symmetry in Chemistry


Book Description

"This book emphasises the crucial role played by symmetry in modern synthetic chemistry, from famous classical experiments to advances brought about by the introduction of new techniques. The first part presents the breaking of molecular symmetry to resolve mechanistic problems, while the second part discusses the making of molecular symmetry, i.e., preparation of highly symmetrical molecules"--




Symmetry Breaking in Biology


Book Description

Experts examine the mechanisms by which cells polarize, divide asymmetrically, and produce asymmetric structures, providing examples from bacteria, yeast, plants, invertebrates, and mammals. Discussion include the molecular basis of polarization, mechanisms, and more.




Symmetry, Broken Symmetry, and Topology in Modern Physics


Book Description

A pedagogical introduction to the modern applications of groups, algebras, and topology for undergraduate and graduate students in physics.




Broken Symmetry


Book Description

This text contains selected papers of the particle theorist, Professor Nambu. It comprises about 40 papers which made fundamental contributions to our understanding of particle physics during the last few decades. The unpublished lecture note on string theory (1969) and the first paper on spontaneous symmetry breaking (1961) are retyped and included. The book also contains a memoir of Professor Nambu on his research career.




Symmetry (Group Theory) and Mathematical Treatment in Chemistry


Book Description

The aim of this book Symmetry (Group Theory) and Mathematical Treatment in Chemistry is to be a graduate school-level text about introducing recent research examples associated with symmetry (group theory) and mathematical treatment in inorganic or organic chemistry, physical chemistry or chemical physics, and theoretical chemistry. Chapters contained can be classified into mini-review, tutorial review, or original research chapters of mathematical treatment in chemistry with brief explanation of related mathematical theories. Keywords are symmetry, group theory, crystallography, solid state, topology, molecular structure, electronic state, quantum chemistry, theoretical chemistry, and DFT calculations.




Chiral Nanomaterials


Book Description

Thorough and up-to-date, this book presents recent developments in this exciting research field. To begin with, the text covers the fabrication of chiral nanomaterials via various synthesis methods, including electron beam lithography, ion beam etching, chemical synthesis and biological DNA directed assembly. This is followed by the relevant theory and reaction mechanisms, with a discussion of the characterization of chiral nanomaterials according to the optical properties of metal nanoparticles, semiconductor nanocrystals, and nanoclusters. The whole is rounded off by a summary of applications in the field of catalysis, sensors, and biomedicine. With its comprehensive yet concise coverage of the whole spectrum of research, this is invaluable reading for senior researchers and entrants to the field of nanoscience and materials science.




The Origin of Chirality in the Molecules of Life


Book Description

This book provides an interdisciplinary review of one of the great unsolved mysteries that has fascinated scientists for over 150 years: the origin of chirality in biomolecules. It was Pasteur who first initiated the search for a deterministic theory to explain the 'handedness' of biomolecules. His theory, that a 'dissimetric' force was involved, was correct in essence but he never saw the fruits of his labour. Current thinking tells us that asymmetry in the universe has its origins in the forces that unfolded after the Big Bang and, more specifically, the weak force. Being 'left handed', the weak force imprinted its signature on the evolving Universe. However, at the molecular level, the weak force does not provide a straightforward explanation of biomolecular homochirality. In fact, it is yet to be proved beyond doubt that a causal link exists at all. Many alternative theories have been put forward, some of them resting on solid ground, but all lacking definitive experimental evidence to back them up. Some postulate that the handedness of molecules in the biosphere arose by chance but this is hard to test. Others rely on discovering life on similar planets and making comparisons with Earth. Alternative theories have emerged from a range of backgrounds including geology, biology, chemistry, physics and astronomy. Current advances in fields as diverse as space exploration, prebiotic chemistry and high-energy physics may help to provide an answer. Important pieces of information will come from observations at the two frontiers of science: outer space and the subatomic world. Observation of distant planets, galaxies, and even actual sampling of celestial objects from beyond the solar system are projects currently underway. At the other end of the spectrum, there are experiments that study the elemental properties of matter, such as symmetry, and interactions with the fundamental forces. All these efforts will render their fruits soon. This volume unifies all the theories of the origin of biomolecular homochirality together in one source. The various chapters focus on chance mechanisms, physical forces such as the 'weakinteraction', fluid dynamics, amplification of chirality, the organic contents of meteorites and comets and, finally, the physical view of an intrinsically asymmetric universe. This complete, interdisciplinary review of an intriguing subject condenses a large and disparate range of contributions from journals in almost every scientific field. The various theories have been organized, interrelated and explained in a unified way. One of the book's strengths is its extensive use of graphic material to aid understanding the many subjects covered. It is fundamental, comprehensive and structured to be accessible for educational purposes.




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