Spin-Crossover Materials


Book Description

The phenomenon of spin-crossover has a large impact on the physical properties of a solid material, including its colour, magnetic moment, and electrical resistance. Some materials also show a structural phase change during the transition. Several practical applications of spin-crossover materials have been demonstrated including display and memory devices, electrical and electroluminescent devices, and MRI contrast agents. Switchable liquid crystals, nanoparticles, and thin films of spin-crossover materials have also been achieved. Spin-Crossover Materials: Properties and Applications presents a comprehensivesurvey of recent developments in spin-crossover research, highlighting the multidisciplinary nature of this rapidly expanding field. Following an introductory chapter which describes the spin-crossover phenomenon and historical development of the field, the book goes on to cover a wide range of topics including Spin-crossover in mononuclear, polynuclear and polymeric complexes Structure: function relationships in molecular spin-crossover materials Charge-transfer-induced spin-transitions Reversible spin-pairing in crystalline organic radicals Spin-state switching in solution Spin-crossover compounds in multifunctional switchable materials and nanotechnology Physical and theoretical methods for studying spin-crossover materials Spin-Crossover Materials: Properties and Applications is a valuable resource for academic researchers working in the field of spin-crossover materials and topics related to crystal engineering, solid state chemistry and physics, and molecular materials. Postgraduate students will also find this book useful as a comprehensive introduction to the field.




Spin Crossover in Transition Metal Compounds I


Book Description

With contributions by numerous experts







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.




Functional Molecular Materials


Book Description

The field of molecular materials represents an exciting playground for the design, tailoring, and combination of chemical building blocks as carriers of physical properties and aims at the understanding and development of novel functional molecular devices. Within this extraordinarily widespread framework, the realization of materials with the desired functionalities can only be achieved through a rational design strategy based on a solid understanding of the chemical and physical features of each constituting building block. This book provides a general overview of molecular materials, discussing their key features in a simple and organic way by focusing more on basic concepts rather than on specialized descriptions, in order to supply the non-expert reader with the immediate fundamental tools and hints to understand and develop research in this field. With this view, it is a step-by-step guide toward the preparation of functional molecular materials, where the knowledge and understanding so far attained by the scientific community through the investigation of significant archetypical examples is deconstructed down to the fundamental basis and then presented in reverse, from the base to the top.




Spin States in Biochemistry and Inorganic Chemistry


Book Description

It has long been recognized that metal spin states play a central role in the reactivity of important biomolecules, in industrial catalysis and in spin crossover compounds. As the fields of inorganic chemistry and catalysis move towards the use of cheap, non-toxic first row transition metals, it is essential to understand the important role of spin states in influencing molecular structure, bonding and reactivity. Spin States in Biochemistry and Inorganic Chemistry provides a complete picture on the importance of spin states for reactivity in biochemistry and inorganic chemistry, presenting both theoretical and experimental perspectives. The successes and pitfalls of theoretical methods such as DFT, ligand-field theory and coupled cluster theory are discussed, and these methods are applied in studies throughout the book. Important spectroscopic techniques to determine spin states in transition metal complexes and proteins are explained, and the use of NMR for the analysis of spin densities is described. Topics covered include: DFT and ab initio wavefunction approaches to spin states Experimental techniques for determining spin states Molecular discovery in spin crossover Multiple spin state scenarios in organometallic reactivity and gas phase reactions Transition-metal complexes involving redox non-innocent ligands Polynuclear iron sulfur clusters Molecular magnetism NMR analysis of spin densities This book is a valuable reference for researchers working in bioinorganic and inorganic chemistry, computational chemistry, organometallic chemistry, catalysis, spin-crossover materials, materials science, biophysics and pharmaceutical chemistry.




Transition Metals in Coordination Environments


Book Description

This book focuses on the electronic properties of transition metals in coordination environments. These properties are responsible for the unique and intricate activity of transition metal sites in bio- and inorganic catalysis, but also pose challenges for both theoretical and experimental studies. Written by an international group of recognized experts, the book reviews recent advances in computational modeling and discusses their interplay using experiments. It covers a broad range of topics, including advanced computational methods for transition metal systems; spectroscopic, electrochemical and catalytic properties of transition metals in coordination environments; metalloenzymes and biomimetic compounds; and spin-related phenomena. As such, the book offers an invaluable resource for all researchers and postgraduate students interested in both fundamental and application-oriented research in the field of transition metal systems.




Synthesis and Applications of New Spin Crossover Compounds


Book Description

The crystal chemistry of spin crossover (SCO) behavior in coordination compounds can potentially be in association with smart materials—promising materials for applications as components of memory devices, displays, sensors and mechanical devices and, especially, actuators, such as artificial muscles. This Special Issue is devoted to various aspects of SCO and related research, comprising 18 interesting original papers on valuable and important SCO topics. Significant and fundamental scientific attention has been focused on the SCO phenomena in a wide research range of fields of fundamental chemical and physical and related sciences, containing the interdisciplinary regions of chemical and physical sciences related to the SCO phenomena. Coordination materials with bistable systems between the LS and the HS states are usually triggered by external stimuli, such as temperature, light, pressure, guest molecule inclusion, soft X-ray, and nuclear decay. Since the first Hofmann-like spin crossover (SCO) behavior in {Fe(py)2[Ni(CN)4]}n (py = pyridine) was demonstrated, this crystal chemistry motif has been frequently used to design Fe(II) SCO materials to enable determination of the correlations between structural features and magnetic properties.




Multifunctional Molecular Materials


Book Description

This book provides a comprehensive overview on multifunctional molecular materials that involve coexistence or interplay or synergy between multiple physical properties focusing on electrical conductivity, magnetism, single-molecule magnets behavior, chirality, spin crossover, and luminescence. The book's coverage ranges from transition metals and




Machine Learning in Chemistry


Book Description

Recent advances in machine learning or artificial intelligence for vision and natural language processing that have enabled the development of new technologies such as personal assistants or self-driving cars have brought machine learning and artificial intelligence to the forefront of popular culture. The accumulation of these algorithmic advances along with the increasing availability of large data sets and readily available high performance computing has played an important role in bringing machine learning applications to such a wide range of disciplines. Given the emphasis in the chemical sciences on the relationship between structure and function, whether in biochemistry or in materials chemistry, adoption of machine learning by chemistsderivations where they are important