Intramolecular Charge Transfer


Book Description

Bridging the gap between the multitude of advanced research articles and the knowledge newcomers to the field are looking for, this is a timely and comprehensive monograph covering the interdisciplinary topic of intramolecular charge transfer (ICT). The book not only covers the fundamentals and physico-chemical background of the ICT process, but also places a special emphasis on the latest experimental and theoretical studies that have been undertaken to understand this process and discusses key technological applications. After outlining the discovery of ICT molecules, the authors go on to discuss several important substance classes. They present the latest techniques for studying the underlying processes and show the interplay between charge transfer and the surrounding medium. Examples taken from nonlinear optics, viscosity and polarity sensors, and organic electronics testify to the vast range of applications. The result is a unique information source for experimentalists as well as theoreticians, from postgraduate students to researchers.




Photoinduced Intramolecular Charge Transfer in Donor-Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion


Book Description

This study is focused on the effects of photoinduced intramolecular charge transfer (CT) in three differently twisted donor-acceptor (D-A) biphenyls. Taking into account a further pair of differently twisted D-A biaryls new universal insights into the photoinduced electronic and conformation dynamics of D-A biaryls are obtained. Furthermore, possible applications in fields of solar energy conversion and fluorescence sensing of microenvironments are demonstrated. Experimental means of stationary and time-resolved (ps to s) luminescence, transient absorption (sub-ps), polarization spectroscopy, high pressure and low temperature techniques are employed in conjunction with quantum chemical calculations. Twist angle and solvent dependent electron transfer (ET) interactions between the D and A aryl moieties are responsible for the low lying and solvatochromic intramolecular CT electron band which gains unusually high intensity through strong electronic coupling of the pure 1ET with the ground (S0) and 1La state. As regards the class of biaryl compounds, for the first time, an excited state electron transfer from the D to the A could be monitored by dual spectrally separated stimulated fluorescence bands with precursor-successor relationship on a sub-ps timescale for the D-A biphenyls. It is concluded that, in additon to the electronic interaction of 1ET with S0 and 1La, the electronic interaction with a close lying 1Lb state plays a fundamental role in the ET dynamics and the 1CT-S0 transition probability in D-A biaryls. The initial photoinduced conformational relaxation occurs towards planarity in all biaryls investigated. However, various results evidence that the highly twisted D-A biphenyl additionally performs a slow "excited state intramolecular back twist rotation" leading to a solvent polarity dependent conformational equilibrium between a more planar (CT) and a more twisted (CTR) conformer in S1(1CT). Using global analysis of the biexponential fluorescence decays as a function of temperature and pressure in medium polar solvents, the kinetics, thermodynamics, viscosity control and decomposed emission spectra associated with this adiabatic photoreaction are determined. The twist angle dependent ability of the D-A biphenyls to serve as fluorescent probes of micropolarity, changes of microviscosity or matrix order, protic solvents and pH is investigated. In particular, fluorescence sensing of pH seems to be promising.







Handbook of Materials Modeling


Book Description

The first reference of its kind in the rapidly emerging field of computational approachs to materials research, this is a compendium of perspective-providing and topical articles written to inform students and non-specialists of the current status and capabilities of modelling and simulation. From the standpoint of methodology, the development follows a multiscale approach with emphasis on electronic-structure, atomistic, and mesoscale methods, as well as mathematical analysis and rate processes. Basic models are treated across traditional disciplines, not only in the discussion of methods but also in chapters on crystal defects, microstructure, fluids, polymers and soft matter. Written by authors who are actively participating in the current development, this collection of 150 articles has the breadth and depth to be a major contributor toward defining the field of computational materials. In addition, there are 40 commentaries by highly respected researchers, presenting various views that should interest the future generations of the community. Subject Editors: Martin Bazant, MIT; Bruce Boghosian, Tufts University; Richard Catlow, Royal Institution; Long-Qing Chen, Pennsylvania State University; William Curtin, Brown University; Tomas Diaz de la Rubia, Lawrence Livermore National Laboratory; Nicolas Hadjiconstantinou, MIT; Mark F. Horstemeyer, Mississippi State University; Efthimios Kaxiras, Harvard University; L. Mahadevan, Harvard University; Dimitrios Maroudas, University of Massachusetts; Nicola Marzari, MIT; Horia Metiu, University of California Santa Barbara; Gregory C. Rutledge, MIT; David J. Srolovitz, Princeton University; Bernhardt L. Trout, MIT; Dieter Wolf, Argonne National Laboratory.




Advances in Electron Transfer Chemistry


Book Description

Advances in Electron Transfer Chemistry, Volume 3 presents studies that discuss findings in the various aspects of electron chemistry. The book is comprised of four chapters; each chapter reviews a work that tackles an issue in electron transfer chemistry. Chapter 1 discusses the photoinduced electron transfer in flexible biaryl donor-acceptor molecules. Chapter 2 tackles light-induced electron transfer in inorganic systems in homogeneous and heterogeneous phases. The book also covers internal geometry relaxation effects on electron transfer rates of amino-centered systems. The sequential electron transfer reactions catalyzed by cytochrome p-450 enzymes are also dealt with. The text will be of great use to researchers interested in the field of electron transfer chemistry.




Electron Transfer


Book Description

an integrated approach to electron transfer phenomena This two-part stand-alone volume in the prestigious Advances in Chemical Physics series provides the most comprehensive overview of electron transfer science today. It draws on cutting-edge research from diverse areas of chemistry, physics, and biology-covering the most recent developments in the field, and pointing to important future trends. This initial volume includes: * A historical perspective spanning five decades * A review of concepts, problems, and ideas in current research * Electron transfer in isolated molecules and in clusters * General theory, including useful algorithms * Spectra and electron transfer kinetics in bridged compounds The second volume covers solvent control, ultrafast electron transfer and coherence effects, molecular electronics, electron transfer and chemistry, and biomolecules. Electron transfer science has seen tremendous progress in recent years. Technological innovations, most notably the advent of femtosecond lasers, now permit the real-time investigation of intramolecular and intermolecular electron transfer processes on a time scale of nuclear motion. New scientific information abounds, illuminating the processes of energy acquisition, storage, and disposal in large molecules, clusters, condensed phase, and biophysical systems. Electron Transfer: From Isolated Molecules to Biomolecules is the first book devoted to the exciting work being done in nonradiative electron transfer dynamics today. This two-part edited volume emphasizes the interdisciplinary nature of the field, bringing together the contributions of pioneers in chemistry, physics, and biology. Both theoretical and experimental topics are featured. The authors describe modern approaches to the exploration of different systems, including supersonic beam techniques, femtosecond laser spectroscopy, chemical syntheses, and methods in genetic and chemical engineering. They examine applications in such areas as supersonic jets, solvents, electrodes, semi- conductors, respiratory and enzymatic protein systems, photosynthesis, and more. They also relate electron transfer and radiationless transitions theory to pertinent physical phenomena, and provide a conceptual framework for the different processes. Complete with over two hundred illustrations, Part One reviews developments in the field since its inception fifty years ago, and discusses electron transfer phenomena in both isolated molecules and in clusters. It outlines the general theory, exploring areas of the control of kinetics, structure-function relationships, fluctuations, coherence, and coupling to solvents with complex spectral density in different types of electron transfer processes. Timely, comprehensive, and authoritative, Electron Transfer: From Isolated Molecules to Biomolecules is an essential resource for physical chemists, molecular physicists, and researchers working in nonradiative dynamics today.




Organic Redox Systems


Book Description

Providing a thorough overview of leading research from internationally-recognized contributing authors, this book describes methods for the preparation and application of redox systems for organic electronic materials like transistors, photovoltaics, and batteries. Covers bond formation and cleavage, supramolecular systems, molecular design, and synthesis and properties Addresses preparative methods, unique structural features, physical properties, and material applications of redox active p-conjugated systems Offers a useful guide for both academic and industrial chemists involved with organic electronic materials Focuses on the transition-metal-free redox systems composed of organic and organo main group compounds




Electronic Materials: The Oligomer Approach


Book Description

Electroactive oligomers form an important class of advanced materials for the development of new devices such as thin-film, flexible batteries; semiconductors; large-area optical displays; and sensors. In addition, the study of oligomeric model compounds is an essential prerequisite for understanding and developing polymers for electronics and optoelectronics applications. Written and edited by leading scientists in the field, this applications-oriented handbook represents the first comprehensive, systematic study of electroactive oligomeric materials. Special emphasis is placed on a critical review of the literature; relevant materials and technical data are collected in tables throughout. Includes - materials synthesis - structure--property relationship as a function of chain-length - applications in optics and electronics - oligomers as models for polymers - the role of oligomers in tomorrow's technology? Electronic Materials - The Oligomer Approach offers a stimulating combination of basic concepts and practical applications. It is sure to become a standard reference source that no-one working in the field can do without.




Density Functional Theory


Book Description

Density Functional Theory (DFT) is a powerful technique for calculating and comprehending the molecular and electrical structure of atoms, molecules, clusters, and solids. Its use is based not only on the capacity to calculate the molecular characteristics of the species of interest but also on the provision of interesting concepts that aid in a better understanding of the chemical reactivity of the systems under study. This book presents examples of recent advances, new perspectives, and applications of DFT for the understanding of chemical reactivity through descriptors forming the basis of Conceptual DFT as well as the application of the theory and its related computational procedures in the determination of the molecular properties of different systems of academic, social, and industrial interest.




Cyclopolymerization and Cyclocopolymerization


Book Description

This broadly-based work gathers the vast bulk of information published on cyclopolymerization since its discovery - including the symmetrical diene counterparts of all classical monomers that can undergo addition polymerization, all unsymmetrical dienes, and cyclopolymerizable monomers such as dialdehydes, diynes, diisocyanates, diepoxides, dinitriles, and some organometallic monomers.;Providing access to contemporary knowledge in the field and offering discussions of interest to a wide variety of polymer scientists, Cyclopolymerization and Cyclocopolymerization: delineates theory; summarizes polymerization procedures; furnishes theoretical justification for mechanistic proposals; details commercial applications; and describes new monomer syntheses. Supplying over 2700 references as well as chemical abstract citations, Cyclopolymerization and Cyclocopolymerization is a resource which should be of practical value to polymer, academic, theoretical and industrial chemists; chemical and plastics engineers; research and development directors in chemistry and chemical engineering programmes; and graduate-level students in these disciplines