Symmetry and Topology in Chemical Reactivity


Book Description

This well-illustrated book develops, using only the ideas of basic quantum chemistry (e.g. perturbation and symmetry theory), a fundamental conceptual and theoretical framework for chemical reactivity. By feeding the role of symmetry and chemical group topology directly into the development, the analysis generates and explains the successful features of simpler reactivity theories (e.g. frontier orbital theory, the isolobal concept, PMO theory, the Woodward-Hoffmann rules), as well as defines their limitations. The unifying construct is that of a group-resolved correlation diagram, which is shown to represent the formal quantization of the electron arrow, replacing the concept of classical point electrons moving between groups with the concept of quantum electron matter waves which evolve with the evolving nuclear and chemical group structure. The use of the concept of chemical groups (functional group system, substituents, solvents) is central to the development, localising the evolutionary electrons within the functional groups and leading to an isolation and analytic definition of substituent and solvent (catalytic) effects as explicit functions of the reaction coordinate. Each archetypical reaction family is represented by fully-worked examples: viz. aliphatic nucleophilic substitution, aromatic electrophilic substitution, inorganic rearrangements, electrocyclic additions, Diels-Alder additions and addition stages in chiral reactions.







Distance, Symmetry, and Topology in Carbon Nanomaterials


Book Description

This contributed volume is inspired by the seminal discovery and identification of C60. Starting with a comprehensive discussion featuring graphene based nanostructures, subsequent chapters include topological descriptions of matrices, polynomials and indices, and an extended analysis of the symmetry and topology of nanostructures. Carbon allotropes such as diamond and its connection to higher-dimensional spaces is explored along with important mathematical and topological considerations. Further topics covered include spontaneous symmetry breaking in graphene, polyhedral carbon structures, nanotube junction energetics, and cyclic polyines as relatives of nanotubes and fullerenes. This book is aimed at researchers active in the study of carbon materials science and technology.




Chemical Topology


Book Description

Topology is becoming increasingly important in chemistry because of its rapidly growing number of applications. Here, its many uses are reviewed and the authors anticipate what future developments might bring. This work shows how significant new insights can be gained by representing molecular species as topological structures known as topographs. The text explores carbon structures, establishing how the stability of fullerene species can be accounted for and also predicting which fullerenes will be most stable. It is pointed out that molecular topology, rather than molecular geometry, characterizes molecular shape and various tools for shape characterization are described. Several of the fascinating ideas that arise from regarding topology as a unifying principle in chemical bonding theory are discussed, and in particular, the novel concept of the molecular topoid is shown to have numerous uses. The topological description of polymers is examined and the reader is gently guided through the realms of branched and tangled polymers. Overall, this work outlines the fact that topology is not only a theoretical discipline but also one that has practical applications and high relevance to the whole domain of chemistry.




Graph Theoretical Approaches to Chemical Reactivity


Book Description

The progress in computer technology during the last 10-15 years has enabled the performance of ever more precise quantum mechanical calculations related to structure and interactions of chemical compounds. However, the qualitative models relating electronic structure to molecular geometry have not progressed at the same pace. There is a continuing need in chemistry for simple concepts and qualitatively clear pictures that are also quantitatively comparable to ab initio quantum chemical calculations. Topological methods and, more specifically, graph theory as a fixed-point topology, provide in principle a chance to fill this gap. With its more than 100 years of applications to chemistry, graph theory has proven to be of vital importance as the most natural language of chemistry. The explosive development of chemical graph theory during the last 20 years has increasingly overlapped with quantum chemistry. Besides contributing to the solution of various problems in theoretical chemistry, this development indicates that topology is an underlying principle that explains the success of quantum mechanics and goes beyond it, thus promising to bear more fruit in the future.




Structural Chemistry


Book Description

This book explains key concepts in theoretical chemistry and explores practical applications in structural chemistry. For experimentalists, it highlights concepts that explain the underlying mechanisms of observed phenomena, and at the same time provides theoreticians with explanations of the principles and techniques that are important in property design. Themes covered include conceptual and applied wave functions and density functional theory (DFT) methods, electronegativity and hard and soft (Lewis) acid and base (HSAB) concepts, hybridization and aromaticity, molecular magnetism, spin transition and thermochromism. Offering insights into designing new properties in advanced functional materials, it is a valuable resource for undergraduates of physical chemistry, cluster chemistry and structure/reactivity courses as well as graduates and researchers in the fields of physical chemistry, chemical modeling and functional materials.




Chemical Reaction Networks


Book Description

Over the last decade, increased attention to reaction dynamics, combined with the intensive application of computers in chemical studies, mathematical modeling of chemical processes, and mechanistic studies has brought graph theory to the forefront of research. It offers an advanced and powerful formalism for the description of chemical reactions and their intrinsic reaction mechanisms. Chemical Reaction Networks: A Graph-Theoretical Approach elegantly reviews and expands upon graph theory as applied to mechanistic theory, chemical kinetics, and catalysis. The authors explore various graph-theoretical approaches to canonical representation, numbering, and coding of elementary steps and chemical reaction mechanisms, the analysis of their topological structure, the complexity estimation, and classification of reaction mechanisms. They discuss topologically distinctive features of multiroute catalytic and noncatalytic and chain reactions involving metal complexes. With it's careful balance of clear language and mathematical rigor, the presentation of the authors' significant original work, and emphasis on practical applications and examples, Chemical Reaction Networks: A Graph Theoretical Approach is both an outstanding reference and valuable tool for chemical research.




Symmetry


Book Description

International Series in Modern Applied Mathematics and Computer Science, Volume 10: Symmetry: Unifying Human Understanding provides a tremendous scope of "symmetry, covering subjects from fractals through court dances to crystallography and literature. This book discusses the limits of perfection, symmetry as an aesthetic factor, extension of the Neumann-Minnigerode-Curie principle, and symmetry of point imperfections in solids. The symmetry rules for chemical reactions, matching and symmetry of graphs, mosaic patterns of H. J. Woods, and bilateral symmetry in insects are also elaborated. This text likewise covers the crystallographic patterns, Milton's mathematical symbol of theodicy, symmetries of soap films, and gapon formalism. This volume is a good source for researchers and specialists concerned with symmetry.




Modern Charge-Density Analysis


Book Description

Focusing on developments from the past 10-15 years, this volume presents an objective overview of the research in charge density analysis. The most promising methodologies are included, in addition to powerful interpretative tools and a survey of important areas of research.




Chemical Reactivity


Book Description

The growth of technology for chemical assessment has led to great developments in the investigation of chemical reactivity in recent years, but key information is often dispersed across many different research fields. Combining both original principles and the cutting-edge theories used in chemical reactivity analysis, Chemical Reactivity, Volume 1 present the latest developments in theoretical chemistry and its application for the assessment of chemical processes.Beginning with an exploration of different theories and principles relating to electronic structure and reactivity of confined electronic systems, the book goes on to highlight key information on such topics as Dyson orbitals, target-ion overlaps, reaction fragility, magnetizability principles and the Fuki function. Density Functional Theory is discussed in relation to numerous different principles and approaches, with further information on constrained methods and diabatic models, bonding evolution theory, orbital-based population analysis models and charge transfer models, and Quantum chemistry and QTAIM.Consolidating the knowledge of a global team of experts in the field, Chemical Reactivity, Volume 1: Theories and Principles is a useful resource for both students and researchers interested in gaining greater understanding of the principles and theories underpinning chemical reactivity analysis. - Provides readers with the key information needed to gain a good overview of contemporary chemical reactivity studies and a clear understanding of the theory behind state-of-the-art methods in the field - Highlights advances in the computational descriptions of reactivity, including reactivity in confined environments, conceptual density functional theory, and multi-reference quantum chemistry - Provides comprehensive coverage by consolidating the knowledge of many well-known researchers in the field from around the world




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