Aromaticity And Antiaromaticity

Aromaticity and Antiaromaticity A comprehensive review of the science of aromaticity, as well as its evolution, from benzene to atomic clusters In Aromaticity and Antiaromaticity: Concepts and Applications, a team of accomplished chemists delivers a comprehensive exploration of the evolution and critical aspects of aromaticity. The book examines the new global criteria used to evaluate aromaticity, including the Nucleus Independent Chemical Shift (NICS) index and the electronic indices based on electronic properties. Additional discussions of inorganic aromatic compounds developed in this century, which give rise to new concepts like multifold aromaticity, are included. Three-dimensional aromaticity found in fullerenes and nanotubes, Möbius aromaticity present in some annulenes, and excited state aromaticity are explored as well. This volume explores the geometrical, electronic, magnetic, and thermodynamic characteristics of aromatic and antiaromatic compounds and their reactivity properties. It also provides: A thorough historical overview of aromaticity, as well as simple electronic and structural models Comprehensive explorations of organic and inorganic aromatic compounds, concepts of stability and reactivity, and geometric, energetic, magnetic, and electronic criteria of descriptors of aromaticity Practical discussions of heteroaromaticity, as well as Möbius aromaticity and excited state aromaticity In-depth examinations of sigma, pi, delta, and phi aromaticity Perfect for graduate students, researchers, and academics interested in aromaticity, organometallic chemistry, and computational chemistry, Aromaticity and Antiaromaticity: Concepts and Applications will also earn a place in the libraries of professionals and researchers working in organic, inorganic, and physical chemistry.

Designed to assist chemists in integrating the results of calculations on molecules and ions into their general body of chemical knowledge. Contains recent contributions from theoretical and computational chemistry to the development of the concept of aromaticity (antiaromaticity) and its expansion into new areas such as organometallic and cluster compounds and three-dimensional structures. Updates the modern status of aromaticity and covers basic principles and experimental applications.

Evaluating the aromaticity of a molecular system and the influence of this concept on its properties is a crucial step in the development of novel aromatic systems. Modern computational methods can provide researchers with a high level of insight into such aromaticity, but identifying the most appropriate method for assessing a specific system can prove difficult. Aromaticity: Modern Computational Methods and Applications reviews the latest state-of-the-art computational methods in this field and discusses their applicability for evaluating the aromaticity of a system. In addition to covering aromaticity for typical organic molecules, this volume also explores systems possessing transition metals in their structures, macrocycles and even transition structures. The influence of the aromaticity on the properties of these species (including the structure, magnetic properties and reactivity) is highlighted, along with potential applications in fields including materials science and medicinal chemistry. Finally, the controversial and fuzzy nature of aromaticity as a concept is discussed, providing the basis for an updated and more comprehensive definition of this concept. Drawing on the knowledge of an international team of experts, Aromaticity: Modern Computational Methods and Applications is a unique guide for anyone researching, studying or applying principles of aromaticity in their work, from computational and organic chemists to pharmaceutical and materials scientists. Reviews a range of computational methods to assess the aromatic nature of different compounds, helping readers select the most useful tool for the system they are studying Presents a complete guide to the key concepts and fundamental principles of aromaticity Provides guidance on identifying which variables should be modified to tune the properties of an aromatic system for different potential applications

Examines aromaticity through the historical and conceptual framework of simple molecular orbital theory. This approach is unique in that theoretical considerations are integrated with experimental observations. The criteria for aromatic, antiaromatic and nonaromatic compounds are discussed in with reference to benzene, cyclobutadiene and cyclooctatetraene. Also includes a chapter on the likely classes of aromatic compounds.

In additionto covering thoroughly the core areas of physical organic chemistry -structure and mechanism - this book will escortthe practitioner of organic chemistry into a field that has been thoroughlyupdated.

This is the perfect complement to "Chemical Bonding - Across the Periodic Table" by the same editors, who are two of the top scientists working on this topic, each with extensive experience and important connections within the community. The resulting book is a unique overview of the different approaches used for describing a chemical bond, including molecular-orbital based, valence-bond based, ELF, AIM and density-functional based methods. It takes into account the many developments that have taken place in the field over the past few decades due to the rapid advances in quantum chemical models and faster computers.

Metal clusters, an intermediate state between molecules and the extended solid, show peculiar bonding and reactivity patterns. Their significance is critical to many areas, including air pollution, interstellar matter, clay minerals, photography, catalysis, quantum dots, and virus crystals. In Aromaticity and Metal Clusters, dozens of international experts explore not only the basic aspects of aromaticity, but also the structures, properties, reactivity, stability, and other consequences of the aromaticity of a variety of metal clusters. Although the concept of aromaticity has been known for nearly two centuries, there is no way to measure it experimentally and no theoretical formula to calculate it. In order to gain insight into its exact nature, the authors of this volume examine various indirect characteristics such as geometrical, electronic, magnetic, thermodynamic, and reactivity considerations. The book begins by discussing the evolution of aromaticity from benzene to atomic clusters. Next, more specialized chapters focus on areas of significant interest. Topics discussed include: Computational studies on molecules with unusual aromaticity Electronic shells and magnetism in small metal clusters A density functional investigation on the structures, energetics, and properties of sodium clusters through electrostatic guidelines and molecular tailoring The correlation between electron delocalization and ring currents in all metallic aromatic compounds Phenomenological shell model and aromaticity in metal clusters Rationalizing the aromaticity indexes used to describe the aromatic behavior of metal clusters 5f orbital successive aromatic and antiaromatic zones in triangular uranium cluster chemistry This collection of diverse contributions, composed of the work of scientists worldwide, is destined to not only answer puzzling questions about the nature of aromaticity, but also to provoke further inquiry in the minds of researchers.

Explains the underlying structure that unites all disciplinesin chemistry Now in its second edition, this book explores organic,organometallic, inorganic, solid state, and materials chemistry,demonstrating how common molecular orbital situations arisethroughout the whole chemical spectrum. The authors explore therelationships that enable readers to grasp the theory thatunderlies and connects traditional fields of study withinchemistry, thereby providing a conceptual framework with which tothink about chemical structure and reactivity problems. Orbital Interactions in Chemistry begins by developingmodels and reviewing molecular orbital theory. Next, the bookexplores orbitals in the organic-main group as well as in solids.Lastly, the book examines orbital interaction patterns that occurin inorganic-organometallic fields as well as clusterchemistry, surface chemistry, and magnetism in solids. This Second Edition has been thoroughly revised andupdated with new discoveries and computational tools since thepublication of the first edition more than twenty-five years ago.Among the new content, readers will find: * Two new chapters dedicated to surface science and magneticproperties * Additional examples of quantum calculations, focusing oninorganic and organometallic chemistry * Expanded treatment of group theory * New results from photoelectron spectroscopy Each section ends with a set of problems, enabling readers totest their grasp of new concepts as they progress through the text.Solutions are available on the book's ftp site. Orbital Interactions in Chemistry is written for bothresearchers and students in organic, inorganic, solid state,materials, and computational chemistry. All readers will discoverthe underlying structure that unites all disciplines inchemistry.