On Chirality and the Universal Asymmetry
On Chirality and the Universal Asymmetry

Author: Georges H. Wagnière

Publisher: John Wiley & Sons

Published: 2008-09-26

Total Pages: 256

ISBN-13: 3906390608

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Until half a century ago, it was assumed that the forces of nature were symmetric and that they did not distinguish between right and left, between image and mirror image. The discovery of the violation of parity in 1956 was more than a sensation, for some it was a shock. It implied that the universe displays handedness, or chirality, and that it is fundamentally asymmetric. Remarkably, a most striking asymmetry is encountered in the realm of biology. Living organisms contain proteins built almost exclusively from L-amino acids, and nucleic acids derived from D-sugars only. Yet a mirror-image biochemistry, based on D-amino acids and L-sugars is, from a purely chemical standpoint, entirely conceivable. Where, then, does this extraordinary natural selectivity come from? Is it directly, or indirectly, connected to the universal violation of parity? This book is meant as a brief review of the various manifestations of handedness, or chirality, in the universe. It does not attempt to present a solution to basic questions which perhaps will never be unambiguously and conclusively answered. Rather, it is an excursion through nature, to observe and recognize how the chirality manifests itself at different structural levels. The excursion starts in the chemistry and physics laboratory. Then a journey into outer space and back in time is undertaken. After a return to our planet Earth, the focus is on the development of living organisms. The text should be accessible to anyone having the equivalent of a first-year university instruction in physics and chemistry. It is also hoped that a layperson with a more modest scientific formation may gain a general impression of the basic asymmetry in nature and of the fundamental significance of chirality. Mathematical expressions, wherever they occur, may then be overlooked. Some more difficult sections may be skipped. A Glossary preceding the Subject Index should be helpful.

On Chirality and the Universal Asymmetry
On Chirality and the Universal Asymmetry

Author: Georges H. Wagnière

Publisher: John Wiley & Sons

Published: 2007-07-23

Total Pages: 264

ISBN-13: 9783906390383

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Until half a century ago, it was assumed that the forces of nature were symmetric and that they did not distinguish between right and left, between image and mirror image. The discovery of the violation of parity in 1956 was more than a sensation, for some it was a shock. It implied that the universe displays handedness, or chirality, and that it is fundamentally asymmetric. Remarkably, a most striking asymmetry is encountered in the realm of biology. Living organisms contain proteins built almost exclusively from L-amino acids, and nucleic acids derived from D-sugars only. Yet a mirror-image biochemistry, based on D-amino acids and L-sugars is, from a purely chemical standpoint, entirely conceivable. Where, then, does this extraordinary natural selectivity come from? Is it directly, or indirectly, connected to the universal violation of parity? This book is meant as a brief review of the various manifestations of handedness, or chirality, in the universe. It does not attempt to present a solution to basic questions which perhaps will never be unambiguously and conclusively answered. Rather, it is an excursion through nature, to observe and recognize how the chirality manifests itself at different structural levels. The excursion starts in the chemistry and physics laboratory. Then a journey into outer space and back in time is undertaken. After a return to our planet Earth, the focus is on the development of living organisms. The text should be accessible to anyone having the equivalent of a first-year university instruction in physics and chemistry. It is also hoped that a layperson with a more modest scientific formation may gain a general impression of the basic asymmetry in nature and of the fundamental significance of chirality. Mathematical expressions, wherever they occur, may then be overlooked. Some more difficult sections may be skipped. A Glossary preceding the Subject Index should be helpful.

Principles of Asymmetric Synthesis
Principles of Asymmetric Synthesis

Author: Robert E. Gawley

Publisher: Elsevier

Published: 2012-05-29

Total Pages: 569

ISBN-13: 0080914136

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The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. Using examples from the literature of asymmetric synthesis, this book presents a detailed analysis of the factors that govern stereoselectivity in organic reactions. After an explanation of the basic physical-organic principles governing stereoselective reactions, the authors provide a detailed, annotated glossary of stereochemical terms. A chapter on "Practical Aspects of Asymmetric Synthesis" provides a critical overview of the most common methods for the preparation of enantiomerically pure compounds, techniques for analysis of stereoisomers using chromatographic, spectroscopic, and chiroptical methods. The authors then present an overview of the most important methods in contemporary asymmetric synthesis organized by reaction type. Thus, there are four chapters on carbon-carbon bond forming reactions, one chapter on reductions, and one on oxidations (carbon-oxygen and carbon-nitrogen bond forming reactions). This organization allows the reader to compare the leading methods for asymmetric synthesis in an appropriate context. A highlight of the book is the presentation and discussion of transition states at the current level of understanding, for important reaction types. In addition, extensive tables of examples are used to give the reader an appreciation for the scope of each reaction. Finally, leading references are provided to natural product synthesis that has been accomplished using a given reaction as a key step. - Authoritative glossary to aid understanding of stereochemical terminology - Explanations of the key factors influencing stereoselectivity with numerous examples, organized by reaction type - A handy reference guide to the literature of asymmetric synthesis for practitioners in the field

Possible Scenarios for Homochirality on Earth
Possible Scenarios for Homochirality on Earth

Author: Michiya Fujiki

Publisher: Buy this from MDPI Books

Published: 2019-11-14

Total Pages: 318

ISBN-13: 3039217224

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In 1978, Fred Hoyle proposed that interstellar comets carrying several viruses landed on Earth as part of the panspermia hypotheses. With respect to life, the origin of homochirality on Earth has been the greatest mystery because life cannot exist without molecular asymmetry. Many scientists have proposed several possible hypotheses to answer this long-standing L-D question. Previously, Martin Gardner raised the question about mirror symmetry and broken mirror symmetry in terms of the homochirality question in his monographs (1964 and 1990). Possible scenarios for the L-D issue can be categorized into (i) Earth and exoterrestrial origins, (ii) by-chance and necessity mechanisms, and (iii) mirror-symmetrical and non-mirror-symmetrical forces as physical and chemical origins. These scenarios should involve further great amplification mechanisms, enabling a pure L- or D-world.

Fundamentals Of Supramolecular Chirality
Fundamentals Of Supramolecular Chirality

Author: Roberto Purrello

Publisher: World Scientific

Published: 2021-10-18

Total Pages: 225

ISBN-13: 1800610262

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Fundamentals of Supramolecular Chirality is a critical description of the start and advancement of supramolecular chirality. This book focuses on the noncovalent approach with some supplementary examples of covalent supramolecular chirality.This contribution to supramolecular chirality is not intended to be a mere catalogue and description of the work done. It also traces a philosophical path following the development and possible perspectives of this topic, providing not a review but a critical examination of the field.

Chirality in Supramolecular Assemblies
Chirality in Supramolecular Assemblies

Author: F. Richard Keene

Publisher: John Wiley & Sons

Published: 2016-12-20

Total Pages: 433

ISBN-13: 1118867327

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Supramolecular chemistry deals with the organisation of molecules into defined assemblies using non-covalent interactions, including weaker and reversible interactions such as hydrogen bonds, and metal-ligand interactions. The aspect of stereochemistry within such chemical architectures, and in particular chirality, is of special interest as it impacts on considerations of molecular recognition, the development of functional materials, the vexed question of homochirality, nanoscale effects of interactions at interfaces, biocatalysis and enzymatic catalysis, and applications in organic synthesis. Chirality in Supramolecular Assemblies addresses many of these aspects, presenting a broad overview of this important and rapidly developing interdisciplinary field. Topics covered include: Origins of molecular and topological chirality Homochirogenesis Chirality in crystallinity Host-guest behavior Chiral influences in functional materials Chirality in network solids and coordination solids Aspects of chirality at interfaces Chirality in organic assemblies Chirality related to biocatalysis and enzymes in organic synthesis. This book is a valuable reference for researchers in the molecular sciences, materials science and biological science working with chiral supramolecular systems. It provides summaries and special insights by acknowledged international experts in the various fields.

Organic Nanomaterials
Organic Nanomaterials

Author: Tomas Torres

Publisher: John Wiley & Sons

Published: 2013-08-05

Total Pages: 636

ISBN-13: 1118354362

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Discover a new generation of organic nanomaterials and their applications Recent developments in nanoscience and nanotechnology have given rise to a new generation of functional organic nanomaterials with controlled morphology and well-defined properties, which enable a broad range of useful applications. This book explores some of the most important of these organic nanomaterials, describing how they are synthesized and characterized. Moreover, the book explains how researchers have incorporated organic nanomaterials into devices for real-world applications. Featuring contributions from an international team of leading nanoscientists, Organic Nanomaterials is divided into five parts: Part One introduces the fundamentals of nanomaterials and self-assembled nanostructures Part Two examines carbon nanostructures from fullerenes to carbon nanotubes to graphene reporting on properties, theoretical studies, and applications Part Three investigates key aspects of some inorganic materials, self-assembled monolayers, organic field effect transistors, and molecular self-assembly at solid surfaces Part Four explores topics that involve both biological aspects and nanomaterials such as biofunctionalized surfaces Part Five offers detailed examples of how organic nanomaterials enhance sensors and molecular photovoltaics Most of the chapters end with a summary highlighting the key points. References at the end of each chapter guide readers to the growing body of original research reports and reviews in the field. Reflecting the interdisciplinary nature of organic nanomaterials, this book is recommended for researchers in chemistry, physics, materials science, polymer science, and chemical and materials engineering. All readers will learn the principles of synthesizing and characterizing new organic nanomaterials in order to support a broad range of exciting new applications.

Mirror-Image Asymmetry
Mirror-Image Asymmetry

Author: James P. Riehl

Publisher: John Wiley & Sons

Published: 2011-04-22

Total Pages: 272

ISBN-13: 047058887X

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An overview of the importance and consequences of asymmetry from molecules to the macroscopic world As scientists have become more capable of probing the structure of three-dimensional objects at the molecular level, the need to understand the concept and the consequences of mirror-image asymmetry—chirality—has increased enormously. Written at an introductory level, Mirror-Image Asymmetry provides an overview of the importance and effects of asymmetry from the atomic and molecular world of physics and chemistry to the organisms and structures that we see and use in our everyday life. The reader will develop a broad appreciation of three-dimensional asymmetry from the microscopic molecular world to the macroscopic world of handedness, automobile driving, windmills, sports, and similar phenomena. The book features: An introduction to basic definitions and the nomenclature of asymmetric and dissymmetric molecules Up-to-date examples of the importance and consequences of asymmetry in modern drug applications, current theories of the origin of asymmetry in nature, and examples of molecular asymmetry in smell, taste, and insect communication Many illustrations, chemical structures, and photographs that enable the reader to connect the actual asymmetrical structures to the different phenomena that depend on structural asymmetry In the 150 years since Louis Pasteur discovered asymmetry in molecular structures, scientists have made great progress in understanding how interactions between chiral molecules influence biochemical processes. This knowledge is leading to very sophisticated asymmetric synthetic techniques that have greatly benefitted many research groups especially those in the pharmaceutical industry. This guide to the role of molecular and macroscopic chirality will inspire students and scientists in chemistry, biology, physics, and drug discovery.

Chirality at the Nanoscale
Chirality at the Nanoscale

Author: David B. Amabilino

Publisher: John Wiley & Sons

Published: 2009-02-11

Total Pages: 442

ISBN-13: 3527625356

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The only standard reference in this exciting new field combines the physical, chemical and material science perspectives in a synergic way. This monograph traces the development of the preparative methods employed to create nanostructures, in addition to the experimental techniques used to characterize them, as well as some of the surprising physical effects. The chapters cover every category of material, from organic to coordination compounds, metals and composites, in zero, one, two and three dimensions. The book also reviews structural, chemical, optical, and other physical properties, finishing with a look at the future for chiral nanosystems.

Revelation, Rationality, Knowledge & Truth
Revelation, Rationality, Knowledge & Truth

Author: Hazrat Mirza Tahir Ahmad

Publisher: Islam International Publications Ltd

Published: 1998-06-30

Total Pages: 787

ISBN-13: 1853726400

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Any divide between revelation and rationality, religion and logic has to be irrational. If religion and rationality cannot proceed hand in hand, there has to be something deeply wrong with either of the two. Does revelation play any vital role in human affairs? Is not rationality sufficient to guide man in all the problems which confront him? Numerous questions such as these are examined with minute attention. All major issues which intrigue the modern mind are attempted to be incorporated in this fascinatingly comprehensive statute. Whatever the intellectual or educational background of the reader, this book is bound to offer him something of his interest. It examines a very diverse and wide range of subjects including the concept of revelation in different religions, history of philosophy, cosmology, extraterrestrial life, the future of life on earth, natural selection and its role in evolution. It also elaborately discusses the advent of the Messiah, or other universal reformers, awaited by different religions. Likewise, many other topical issues which have been agitating the human mind since time immemorial are also incorporated. The main emphasis is on the ability of the Quran to correctly discuss all important events of the past, present and future from the beginning of the universe to its ultimate end. Aided by strong incontrovertible logic and scientific evidence, the Quran does not shy away from presenting itself to the merciless scrutiny of rationality. It will be hard to find a reader whose queries are not satisfactorily answered. We hope that most readers will testify that this will always stand out as a book among books – perhaps the greatest literary achievement of this century.