π-Conjugated molecules with an even number of π-electrons usually have a closed-shell ground state. However, recent studies have demonstrated that a certain type of molecules could show open-shell singlet ground state and display diradical-like (diradicaloid) behavior. Their electronic structure can be understood in terms of the “diradical character” and “aromaticity” concepts. They display very different electronic properties from traditional closed-shell π-conjugated molecules and could be used as next-generation molecular materials. This book provides a comprehensive review on the chemistry, physics, and material applications of open-shell singlet diradicaloids. Particularly, it elaborates the fundamental structure–diradical character–electronic property relationships both theoretically and experimentally. The book has been written by leading scientists in the field from Japan, Germany, Spain, Italy, China, and Singapore.

Astrobiology, a new exciting interdisciplinary research field, seeks to unravel the origin and evolution of life wherever it might exist in the Universe. The current view of the origin of life on Earth is that it is strongly connected to the origin and evolution of our planet and, indeed, of the Universe as a whole. We are fortunate to be living in an era where centuries of speculation about the two ancient and fundamental problems: the origin of life and its prevalence in the Universe are being replaced by experimental science. The subject of Astrobiology can be approached from many different perspectives. This book is focused on abiogenic organic matter from the viewpoint of astronomy and planetary science and considers its potential relevance to the origins of life on Earth and elsewhere. Guided by the review papers in this book, the concluding chapter aims to identify key questions to motivate future research and stimulate astrobiological applications of current and future research facilities and space missions. Today’s rich array of new spacecraft, telescopes and dedicated scientists promises a steady flow of discoveries and insights that will ultimately lead us to the answers we seek.

Applications of EPR in Radiation Research is a multi-author contributed volume presented in eight themes: I. Elementary radiation processes (in situ and low temperature radiolysis, quantum solids); II: Solid state radiation chemistry (crystalline, amorphous and heterogeneous systems); III: Biochemistry, biophysics and biology applications (radicals in biomaterials, spin trapping, free-radical-induced DNA damage); IV: Materials science (polymeric and electronic materials, materials for treatment of nuclear waste, irradiated food); V: Radiation metrology (EPR-dosimetry, retrospective and medical applications); VI: Geological dating; VII: Advanced techniques (PELDOR, ESE and ENDOR spectroscopy, matrix isolation); VIII: Theoretical tools (density-functional calculations, spectrum simulations).

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

Advances in Physical Organic Chemistry, Volume 55, presents the latest reviews of recent work in physical organic chemistry. The book provides a valuable source of information that is ideal not only for physical organic chemists applying their expertise to both novel and traditional problems, but also for non-specialists across diverse areas who identify a physical organic component in their approach to research. The book's hallmark is its quantitative, molecular level understanding of phenomena across a diverse range of disciplines. Reviews the application of quantitative and mathematical methods to help readers understand chemical problems Provides the chemical community with authoritative and critical assessments of the many aspects of physical organic chemistry Covers organic, organometallic, bioorganic, enzymes and materials topics Presents the only regularly published resource for reviews in physical organic chemistry Written by authoritative experts who cover a wide range of topics that require a quantitative, molecular-level understanding of phenomena across a diverse range of disciplines

The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

The first book of its kind to focus on the chemistry of this promising class of molecules. Edited by an innovator in the field, who has gathered an international team of well-established experts, this is a comprehensive overview of the rapidly developing field of polycyclic (hetero)arenes, specifically highlighting on their molecular design and the latest synthetic procedures, as well as chemical and physical properties. Each chapter is dedicated to a specific compound class, the first eight covering polycyclic arenes, including both planar and non-planar conjugated molecules, while chapters nine to twelve deal with polycylic heteroarenes according to the heteroatoms, namely N, B, S and P. Important current and emergent applications in the field are also discussed, ranging from molecular sensors to electronic devices. The result is an essential reference for researchers in synthetic and physical organic chemistry, supramolecular chemistry, and materials science.

Kinetic Control in Synthesis and Self-Assembly provides a unique overview of the fundamental principles, novel methods and practical applications for researchers across organic synthesis, supramolecular chemistry and materials sciences. The book examines naturally occurring molecular systems in which kinetic processes are more ubiquitous than thermodynamic processes, also exploring the control of reactions and molecular self-assemblies, through kinetic processes, in artificial systems. These methods currently play a crucial role for tuning materials functions. From organic synthesis, to supramolecular assemblies, and from restricted spaces, to material synthesis for hierarchical structures, the book offers valuable coverage for researchers across disciplines. Interesting topics include how to regulate kinetic pathways more precisely, essential molecular design for kinetic traps, and how molecular environments surrounding molecules (i.e., solvent, temperature, and pressure effects) influence kinetic control in reactions and self-assemblies. - Describes the nature and potential applications of kinetic processes compared to thermodynamic processes - Presents information useful to researchers active in molecular synthesis and self-assembly toward materials - Collates coverage of kinetic control for synthesis and self-assembly, treated separately in literature

This brief investigates the diradical character, which is one of the ground-state chemical indices for "bond weakness" or "electron correlation" and which allows researchers to explore the origins of the electron-correlation-driven physico-chemical phenomena concerned with electronic, optical and magnetic properties as well as to control them in the broad fields of physics and chemistry. It then provides the theoretical fundamentals of ground and excited electronic structures of symmetric and asymmetric open-shell molecular systems by using model molecular systems. Moreover, it presents the theoretical design guidelines for a new class of open-shell singlet molecular systems for nonlinear optics (NLO) and singlet fission.