Magnetism and Transition Metal Complexes


Book Description

This text presents a detailed view of the calculation methods involved in the magnetic properties of transition metal complexes. Starting at an elementary level, it proceeds gradually through theory and calculations to offer sufficient background for original work in the field. No specialized knowledge of magnetism is assumed in the introductory chapters, which offer basic definitions and generalizations of magnetic behavior and briefly review both crystal field theory and perturbation theory. Succeeding chapters explore calculations of the magnetic properties of cubic and axially distorted complexes. Featuring the complete calculation for spin-orbit coupling and magnetic field perturbations for one d-configuration, the text also discusses derivations and results for other configurations. Other topics include the magnetism of polynuclear species, in which antiferromagnetic ordering occurs over small numbers of centers. Detailed calculations by the dipolar coupling approach are given, and the results are applied to a number of studies from the literature.




Magnetic Properties of Transition Metal Compounds


Book Description

This is a textbook of what is often called magnetochemistry. We take the point of view that magnetic phenomena are interesting because of what they tell us about chemical systems. Yet, we believe it is no longer tenable to write only about such subjects as distinguishing stereochemistry from the measurement of a magnetic susceptibility over a restricted temper ature region; that is, paramagnetism is so well-understood that little remains to explore which is of fundamental interest. The major purpose of this book is to direct chemists to some of the recent work of physicists, and in particular to a lengthy exposition of magnetic ordering phenomena. Chemists have long been interested in magnetic interactions in clusters, but many have shied away from long-range ordering phenomena. Now however more people are investigating magnetic behavior at temperatures in the liquid helium region, where ordering phenomena can scarcely be avoided. The emphasis is on complexes of the iron-series ions, for this is where most of the recent work, both experimental and theoretical, has been done. The discussion therefore is limited to insulating crystals; the nature of magnetism in metals and such materials as semiconductors is sufficiently different that a discussion of these substances is beyond our purposes. The book is directed more at the practical experimentalist than at the theoretician.




A Textbook of Inorganic Chemistry – Volume 1


Book Description

An advanced-level textbook of inorganic chemistry for the graduate (B.Sc) and postgraduate (M.Sc) students of Indian and foreign universities. This book is a part of four volume series, entitled "A Textbook of Inorganic Chemistry – Volume I, II, III, IV". CONTENTS: Chapter 1. Stereochemistry and Bonding in Main Group Compounds: VSEPR theory; dπ -pπ bonds; Bent rule and energetic of hybridization. Chapter 2. Metal-Ligand Equilibria in Solution: Stepwise and overall formation constants and their interactions; Trends in stepwise constants; Factors affecting stability of metal complexes with reference to the nature of metal ion and ligand; Chelate effect and its thermodynamic origin; Determination of binary formation constants by pH-metry and spectrophotometry. Chapter 3. Reaction Mechanism of Transition Metal Complexes – I: Inert and labile complexes; Mechanisms for ligand replacement reactions; Formation of complexes from aquo ions; Ligand displacement reactions in octahedral complexes- acid hydrolysis, base hydrolysis; Racemization of tris chelate complexes; Electrophilic attack on ligands. Chapter 4. Reaction Mechanism of Transition Metal Complexes – II: Mechanism of ligand displacement reactions in square planar complexes; The trans effect; Theories of trans effect; Mechanism of electron transfer reactions – types; outer sphere electron transfer mechanism and inner sphere electron transfer mechanism; Electron exchange. Chapter 5. Isopoly and Heteropoly Acids and Salts: Isopoly and Heteropoly acids and salts of Mo and W: structures of isopoly and heteropoly anions. Chapter 6. Crystal Structures: Structures of some binary and ternary compounds such as fluorite, antifluorite, rutile, antirutile, crystobalite, layer lattices- CdI2, BiI3; ReO3, Mn2O3, corundum, pervoskite, Ilmenite and Calcite. Chapter 7. Metal-Ligand Bonding: Limitation of crystal field theory; Molecular orbital theory: octahedral, tetrahedral or square planar complexes; π-bonding and molecular orbital theory. Chapter 8. Electronic Spectra of Transition Metal Complexes: Spectroscopic ground states, Correlation and spin-orbit coupling in free ions for Ist series of transition metals; Orgel and Tanabe-Sugano diagrams for transition metal complexes (d1 – d9 states); Calculation of Dq, B and β parameters; Effect of distortion on the d-orbital energy levels; Structural evidence from electronic spectrum; John-Tellar effect; Spectrochemical and nephalauxetic series; Charge transfer spectra; Electronic spectra of molecular addition compounds. Chapter 9. Magantic Properties of Transition Metal Complexes: Elementary theory of magneto - chemistry; Guoy’s method for determination of magnetic susceptibility; Calculation of magnetic moments; Magnetic properties of free ions; Orbital contribution, effect of ligand-field; Application of magneto-chemistry in structure determination; Magnetic exchange coupling and spin state cross over. Chapter 10. Metal Clusters: Structure and bonding in higher boranes; Wade’s rules; Carboranes; Metal carbonyl clusters - low nuclearity carbonyl clusters; Total electron count (TEC). Chapter 11. Metal-π Complexes: Metal carbonyls: structure and bonding; Vibrational spectra of metal carbonyls for bonding and structure elucidation; Important reactions of metal carbonyls; Preparation, bonding, structure and important reactions of transition metal nitrosyl, dinitrogen and dioxygen complexes; Tertiary phosphine as ligand.




Introduction to Molecular Magnetism


Book Description

This first introduction to the rapidly growing field of molecular magnetism is written with Masters and PhD students in mind, while postdocs and other newcomers will also find it an extremely useful guide. Adopting a clear didactic approach, the authors cover the fundamental concepts, providing many examples and give an overview of the most important techniques and key applications. Although the focus is one lanthanide ions, thus reflecting the current research in the field, the principles and the methods equally apply to other systems. The result is an excellent textbook from both a scientific and pedagogic point of view.




Physical Inorganic Chemistry


Book Description

GEORGE CHRISTOU Indiana University, Bloomington I am no doubt representative of a large number of current inorganic chemists in having obtained my undergraduate and postgraduate degrees in the 1970s. It was during this period that I began my continuing love affair with this subject, and the fact that it happened while I was a student in an organic laboratory is beside the point. I was always enchanted by the more physical aspects of inorganic chemistry; while being captivated from an early stage by the synthetic side, and the measure of creation with a small c that it entails, I nevertheless found the application of various theoretical, spectroscopic and physicochemical techniques to inorganic compounds to be fascinating, stimulating, educational and downright exciting. The various bonding theories, for example, and their use to explain or interpret spectroscopic observations were more or less universally accepted as belonging within the realm of inorganic chemistry, and textbooks of the day had whole sections on bonding theories, magnetism, kinetics, electron-transfer mechanisms and so on. However, things changed, and subsequent inorganic chemistry teaching texts tended to emphasize the more synthetic and descriptive side of the field. There are a number of reasons for this, and they no doubt include the rise of diamagnetic organometallic chemistry as the dominant subdiscipline within inorganic chemistry and its relative narrowness vis-d-vis physical methods required for its prosecution.




Ligand Field Theory and Its Applications


Book Description

A complete, up-to-date treatment of ligand field theory and its applications Ligand Field Theory and Its Applications presents an up-to-date account of ligand field theory, the model currently used to describe the metal-ligand interactions in transition metal compounds, and the way it is used to interpret the physical properties of the complexes. It examines the traditional electrostatic crystal field model, still widely used by physicists, as well as covalent approaches such as the angular overlap model, which interprets the metal ligand interactions using parameters relating directly to chemical behavior. Written by internationally recognized experts in the field, this book provides a comparison between ligand field theory and more sophisticated treatments as well as an account of the methods used to calculate the energy levels in compounds of the transition metals. It also covers physical properties such as stereochemistry, light absorption, and magnetic behavior. An emphasis on the interpretation of experimental results broadens the book's field of interest beyond transition metal chemistry into the many other areas where these metal ions play an important role. As clear and accessible as Brian Figgis's 1966 classic Introduction to Ligand Fields, this new book provides inorganic and bioinorganic chemists as well as physical chemists, chemical physicists, and spectroscopists with a much-needed overview of the many significant changes that have taken place in ligand field theory over the past 30 years.




Introduction to Magnetochemistry


Book Description

Introduction to Magnetochemistry provides an introduction to the more important aspects of magnetochemistry. The measurement of magnetic moment has been one of the most consistently useful to coordination chemists. For teaching purposes it provides a simple method of illustrating the ideas of electronic structure, and in research it can provide fundamental information about the bonding and stereochemistry of complexes. The book contains six chapters covering topics such as free atoms and ions, transition metal complexes, crystal field theory, second and third row transition metal complexes, antiferromagnetism, and spin-pairing of electrons. The final chapter describes important experimental methods and then to shows briefly the way in which the problems of interpretation may be tackled.







Lanthanide Single Molecule Magnets


Book Description

This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures – an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and explore new directions. Jinkui Tang is a professor at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. Peng Zhang is currently pursuing his PhD at Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, with a specific focus on the molecular magnetism of lanthanide compounds under the supervision of Prof. Jinkui Tang.




Spin Crossover in Transition Metal Compounds I


Book Description

With contributions by numerous experts