bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper: Organometallic ChemistryBased in part on the article Copper: Organometallic Chemistry by Bruce H. Lipshutz & Michael R. Wood which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Lipshutz Bruce H. , Pfeiffer Steven S. 
Published: December 2011

AbstractMuch of copper chemistry over the past decade has transitioned toward catalysis, driven in large measure by environmental rather than economic concerns. Catalytic processes have appeared in large numbers, in particular due to the advances made in both the design of new ligands that effectively coordinate copper, but also due to their increased availability. Applications of copper‐catalyzed processes to bond formations have gone well‐beyond those of a CC nature, nowadays including CN, CO, CS, CP, and CH types. Asymmetric variants based on nonracemically ligated copper salts and copper hydride have led to highly valued entries to chiral products of great use in synthesis. Transmetalations from various metals (e.g. Zn, Zr, etc.) to copper also continue to play a vital role in organic synthesis, and are discussed herein as well.Considerable progress on many physical organic fronts relating to copper chemistry has been made. New advances in technologies that shed light on structural aspects of copper reagents are now available (extended X‐ray absorption fine structure, EXAFS, X‐ray absorption near edge structure, XANES) and are being used to accompany X‐ray analyses and highly sophisticated NMR techniques. High‐level computer calculations have led to theoretical ‘pictures’ illustrating the mechanistic pathways that may be followed by some of the most commonly used reactions in copper chemistry (e.g. 1,4‐additions). Taken in their entirety, these developments suggest that this past decade has been a most productive period in the continuing evolution of copper chemistry.
Copper Proteins: Oxidases
Authors: Stoj Christopher S. , Kosman Daniel J. 
Published: December 2011

AbstractOxidases are enzymes that use dioxygen as the electron acceptor in oxido‐reduction reactions. Many members of this enzyme class (EC 1.) rely on the Cu1+/Cu2+redox cycle of copper prosthetic group(s) in their catalysis of the electron transfer from reducing substrate to O2. Those copper oxidases that catalyze the four‐electron reduction of O2to 2H2O are known as multicopper oxidases (MCO) because each member of this group contains at least four copper atoms of three distinct electronic and spectral types. These three types are: type 1 or ‘blue’ Cu(II), so‐called because of its distinguishing strong absorbance at ∼600 nm; type 2 Cu(II), comparable in electronic structure to that found in square‐planar copper complexes; and type 3 Cu(II), a Cu(II)Cu(II) pair bridged by O(H) and thus diamagnetic. With four 1e−metal redox sites, MCOs are the all‐copper equivalent of the copper‐heme respiratory terminal oxidases. However, MCOs are true oxidases in that all members can use as electron acceptors common (di)phenolic, and aromatic (di)amine substrates, for example, hydroquinone, ascorbic acid, and phenylenediamine. The laccases and ascorbate oxidase are examples of these MCOs (EC 1.10.3). Members of a separate MCO class (EC 1.16.3) also use lower valent metal ions as substrates, for example, Fe2+, Cu1+, and/or Mn2+. These are thereby designated metallo‐oxidases; the most widely studied activity of this class has been towards Fe2+giving rise to the common enzyme name, ferroxidase. The typical MCO structure consists of three ‘cuprodoxin’ domains, a Greek‐key beta‐fold that characterizes a family of mononuclear copper electron‐transfer factors. Among MCOs are both soluble and type 1 membrane proteins. Functionally, MCOs are known to play essential roles in biodegradation and transformation, cell redox balance, and metal metabolism. This article summarizes current knowledge of this class of copper oxidase enzymes.
Cyanide Complexes of the Transition MetalsBased in part on the article Cyanide Complexes of the Transition Metals by Timothy P. Hanusa & David J. Burkey which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Hanusa Timothy P. 
Published: December 2011

Abstract

Cyano metal complexes contain one or more bound cyanide ligands, CN
−
, and constitute one of the largest and longest‐known classes of compounds in inorganic chemistry. Like carbon monoxide, the cyanide ion can function as a π‐acid ligand, but because of its negative charge, the cyanide ion can also form strong sigma bonds. This bifunctional behavior allows CN
−
to stabilize both high and low oxidation states of metals. The cyanide ion can bind to metals in both terminal and bridging (MCNM′) modes; the bridges are commonly linear, and are present in Prussian blue and many other polymeric metal cyanides. Framework solids with high degrees of void space can be formed with bridging cyanide ligands. Cyano metal complexes undergo a variety of oxidation‐reduction reactions, but owing to the strong σ‐donor properties of CN
−
, only a few ligands are capable of directly replacing metal‐bound cyanide. For most substitution reactions, photochemically induced dissociation of one or more of the CN
−
ligands is needed. Cyano complexes are used as pigments and dyes, and are being increasingly explored as electroactive, zeolitic, and chemical sensing materials.
Cytochrome OxidaseBased in part on the article Cytochrome Oxidase by Gerald T. Babcock which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Wikström Mårten 
Published: December 2011

AbstractHeme‐copper oxidase is the current generic name for the superfamily of respiratory enzymes that are responsible for cell respiration in the mitochondria of eukaryotic cells as well as in aerobic prokaryotes, and which shows substantial structural and functional homology among its members. This group of enzymes is responsible for more than 90% of the consumption of dioxygen by living organisms on this planet. Harnessing the high oxidizing power of the O2/H2O redox couple some 2.5–3 billion years ago made a revolutionary impact on evolution. The oxidation of foodstuffs by O2gave an approx. 15‐fold energetic advantage over previously predominant glycolytic oxidations, and was the prerequisite for the development and evolution of all higher multicellular organisms. Apart from mastering the O2reduction chemistry in a safe and economical fashion, these enzymes also function as remarkable energy transducers that convert much of the free energy released in the process into a proton gradient, which is subsequently used to drive virtually all energy‐requiring processes in the cell. This article reviews the major advances in the last 10 years of research on this group of enzymes. The major highlights are the elucidation of the crystal structures of several oxidases, major advances in the understanding of the mechanism of O2activation and reduction at the bimetallic heme iron‐copper active site, and recent progress in the ongoing research on the perhaps most intriguing but least known function, redox‐coupled proton translocation.
Decarbonylation Catalysis
Authors: Jardine Fred H. 
Published: December 2011

Abstract
Aldehydes or acid chlorides can be decarbonylated to alkanes or alkenes respectively by rhodium complexes. However, α,ω‐alkenals frequently isomerize to cyclic ketones. Palladium complexes decarbonylate aroyl cyanides. Stoichiometric reactions occur with many carbonyl compounds at low temperatures. Above 150°C, several of the reactions are catalytic. Aldehyde tautomers such as allylic alcohols or carbohydrates are also decarbonylated.
Defects in Solids
Authors: Tilley Richard J. D. 
Published: December 2011

Abstract
The chemical aspects of defects of relevance to inorganic crystalline solids are described, especially the close links with the composition of crystalline nonmetallic inorganic nonstoichiometric compounds. The discussion begins with a description of simple point defects in stoichiometric materials and the relationship between the population of these defects and the Gibbs energy of formation of the defects. This includes defects in monatomic structures and balanced populations of point defects, Frenkel and Schottky defects, in binary compounds. Superionic compounds that contain quasi‐liquid cation arrays are considered as extreme cases of these simpler defect populations. Nonstoichiometric compounds treated from the standpoint of small populations of point defect populations are considered, including color centers. Defect chemistry, the incorporation of point defects into chemical nomenclature, is described, including the Kroger–Vink notation and the construction of Brouwer diagrams. Grossly nonstoichiometric compounds, including those that can be considered to contain point defects or structurally organised defect clusters, such as the iron oxide wüstite, and the defect fluorite structures are illustrated. Extended defects portray a wider view of defect chemistry, in which planar faults and intergrowths are prominent structural features of many complex inorganic solids. To illustrate planar defects, examples are taken from crystallographic shear phases, twinned structures, intergrowth structures, and the niobium oxide block structures. Structures containing pentagonal columns linked by vertices provide an example of structures that contain columnar defects. Examples of inorganic solids that possess more than one defect type are taken from layered perovskite phases, tungsten bronzes, and high‐temperature ceramic superconductors. The final section is concerned with structures that were once described as containing defects but that have recently been found to be essentially defect free. These materials, in which defects are eliminated by the device of continuous structural modulation affecting one part of the structure, are widespread over many classes of inorganic solids. Examples drawn from oxides related to tantalum pentoxide, layer misfit phases, and anion‐excess fluorite‐related materials.
Diffraction Methods in Inorganic Chemistry
Authors: Howard Judith A. K. , Batsanov Andrei S. 
Published: December 2011

AbstractX‐ray diffraction is by far the largest source of information on crystal and molecular structures and (at high precision) can reveal fine details of the electron density distribution. Neutron diffraction is indispensable for special tasks, for example, locating hydrogen atoms and studying crystal dynamics and magnetic properties. After a brief introduction on crystal symmetry and diffraction physics, the article surveys the currently available instrumentation and practical techniques of diffraction experiments, of interpreting the structural data and assessing their quality, with an emphasis on recent progress in technology (synchrotron radiation, area detectors, low‐ and high‐temperature, and high‐pressure experiments), software (direct phasing, dealing with twinning and incommensurate phases), and data storage (crystallographic databases).
Dioxygen & Related LigandsBased in part on the article Dioxygen & Related Ligands by Rebecca R. Conry & Kenneth D. Karlin which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Conry Rebecca R. 
Published: December 2011

AbstractMetal–dioxygen interactions are important in the activation of dioxygen by aerobic organisms and in other processes that utilize dioxygen, for instance, in catalytic oxygenation reactions. Most d‐block metals have been found to interact with dioxygen and many dioxygen‐containing complexes have been isolated. A number of binding modes have been found in these complexes, including the simple binding of one O2molecule to one metal center and systems where the O2moiety bridges two or more metal ions. Some reduction of dioxygen occurs upon binding; thus, these complexes are generally regarded as containing superoxide (one‐electron reduced) or peroxide (two‐electron reduced) ligands, which are typically spectroscopically distinguished. In general, superoxo complexes exhibit υ(OO) in their infrared or Raman spectra between about 960 and 1200 cm−1and usually contain planar metal2–O2units for dinuclear complexes, whereas peroxide complexes result in υ(OO) between about 650 and 950 cm−1and the dinuclear complexes typically have nonplanar metal2–O2units. Examples of superoxo and peroxo complexes for the different binding modes are discussed, including the discovery that some dinuclear metal–dioxygen complexes [M(O2)M; M = metal] are in equilibrium with bis‐μ‐oxo complexes [M(O)2M; i.e. the OO bond is no longer present].
Electronic Structure of Solids
Authors: Canadell Enric 
Published: December 2011

AbstractThe basic language needed to understand the electronic structure of solids is introduced. The approach is chemically oriented and the notion of orbital interaction, so useful to understand the electronic structure of molecules, is used as much as possible. A step‐by‐step approach to the electronic structure of several solids is discussed. Notions like Density of states (DOS), Fermi surface (and nesting), Peierls distortions, charge and spin density waves (CDW/SDW), and COOP (crystal orbital overlap population) curves are presented and analyzed with reference to selected examples. The role of electron repulsions is also considered. The relationship between the electronic structure and the structural and transport properties of solids is discussed. A brief account of the more commonly used computational approaches for solids is also presented.
Fluorides: Solid‐State Chemistry
Authors: Massa Werner 
Published: December 2011

AbstractInorganic solid fluorides and fluorometalates play a unique role in inorganic chemistry. The preparation, mostly using aqueous or anhydrous HF or even elemental F2, requires special conditions: no glass or silicate containing vessels can be used. Their structural chemistry is governed by the outsider role of the fluoride anion. It is the smallest and least polarizable anion and its mainly ionic compounds follow the rules of hard spheres packing better than any other class of substances. Nearly all metal ions except those with the largest ionic radii form fluoride structures with octahedral [Mn+F6](6−n)–units. If the metal:fluorine ratio is less than 6, these octahedra share common vertices or, in rare cases, edges or even faces to account for electroneutrality, the more the lower the oxidation state of the metal. In this way, a variety of 1D chain, 2D net, and 3D framework structures is formed that can be classified into a few large structure families. In binary fluorides, for example, VF5has an octahedral cis‐chain structure, VF4a layer structure based on a square net of corner‐connected octahedra, VF3has a ReO3‐related 3D structure with all corners of octahedra connected, and VF2has the rutile‐type structure with partial edge‐sharing of octahedra. In ternary or quaternary compounds, for example, alkali or alkaline earth fluorometalates, the same principles are valid for the anionic substructure while the counter cations fill interstices and stabilize at the same time the structure. The main structure families are grouped according to the basic principles of octahedral nets. These are the ReO3‐related trifluorides, the fluoride perovskites AMF3, their relatives elpasolites A2A′MF6, and cryolites A3MF6, as well as some layer structures with square nets. A second large family is based on mixed octahedral nets including triple units: it includes for example, the pyrochlores, the weberites, the hexagonal and tetragonal tungsten bronze structures, and some derivable layer structures. Recent developments deal with ‘tailoring’ of low‐dimensional or framework structures using ‘soft‐chemistry’ methods. The relatively simple structural chemistry of fluorides invoked their use as model systems, for instance, for the investigation of electronic effects like Jahn–Teller ordering, or for magnetic investigations. Besides the cryolite Na3AlF6used in Al production, some fluorides are of technical interest owing to their special optical properties (e.g. laser optics, fluoride glasses), their ability for fluoride ion conductivity, or their role as catalysts for fluorinations or halogene exchange in organic systems.
Fluorine: Inorganic ChemistryBased in part on the article Fluorine: Inorganic Chemistry by Darryl D. DesMarteau, Charles W. Bauknight, Jr., & Todd E. Mlsna which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Atwood David A. 
Published: December 2011

AbstractThis article provides an overview of the extensive and diverse inorganic chemistry of fluorine. Key topics are covered, such as the methods used for the formation of element–fluorine bonds with hydrogen fluoride and elemental fluorine. The article includes a general description of the structure and bonding of common fluorine compounds and the various spectroscopic techniques for their characterization. More specific details are provided for the fluoride compounds of boron, and the groups 14–17 elements. New topics such as the means by which carbon–fluorine bonds may be broken and the fluorination of carbon‐based materials such as fullerenes and nanotubes are included in the appropriate sections.
Gold: Organometallic Chemistry
Authors: Schier Annette , Schmidbaur Hubert 
Published: December 2011

AbstractOrganogold chemistry reaches back to the beginning of the twentieth century, when Grignard compounds were first reacted with chloroauric acid. Since then, the number of organogold compounds has grown rapidly and now includes species with gold in various oxidation states (0, +1, +2, and +3) and with virtually all classes of organic substituents and ligands (alkyl, alkenyl, alkynyl, ylide, heteroaryl, ylide, carbonyl, isocyanide, carbenes, alkenes, alkynes, etc.). This development was possible owing to the discovery of many new synthetic pathways that reflect the general upsurge of organometallic chemistry in the last century and to the introduction of new physical and analytical methods as routine tools for the determination of composition and structure. Incentive and motivation for organogold research were also triggered by the emerging applications of gold and its compounds in medicine and pharmacology, as well as in many areas of modern technology, with material science and homogeneous and heterogeneous catalysis as the most prominent examples. The discovery of a novel type of bonding interactions, most common between low‐valent gold atoms with a closed‐shell electronic configuration (aurophilicity), has led to a rapid growth of the supramolecular chemistry of gold. The aggregation of mononuclear compounds to give dimers, oligomers, polymers, and clusters was found to induce novel photophysical properties (luminescence etc.), which attract widespread interest. In polynuclear compounds, aurophilic bonding is responsible for unique configurations and conformations of molecules, including clustering of gold atoms around hypercoordinate carbon atoms as one of the most curious phenomena.
Heterogeneous Catalysis by Metals
Authors: Ma Zhen , Zaera Francisco 
Published: December 2011

Abstract
Approximately 80% of the processes in the chemical industries require the use of catalysts. Because of that, catalysis generates annual global sales of about $1.5 trillion, and contributes directly or indirectly to approximately 35% of the world's GDP. Most catalytic processes are heterogeneous in nature, and often rely on the use of transition metal particles dispersed on high surface area supports. In this chapter, the basic chemical concepts behind heterogeneous metal catalysis are introduced. Examples are then provided for typical practical catalytic systems used in the generation of energy, the production of chemicals, the preparation of materials, and the cleaning of the environment. Finally, several promising new research directions related to the future development of heterogeneous metal catalysis are highlighted, in particular those associated with the designing and characterization of novel catalytic materials, the surface science of catalysis, high throughput catalyst testing, improved selectivities, and green chemistry.
Hydrides: Solid State Transition Metal Complexes
Authors: Yvon Klaus , Renaudin Guillaume 
Published: December 2011

AbstractAt present, some 50 different homoleptic transition (T) metal hydride complexes are known to occur in over 127 compounds that cover 47 structure types. The complexes form with T elements from group seven (Mn) to closed d‐shell elements of group twelve (Zn). While the great majority are centred by one T‐metal atom and display up to nine terminal hydrogen ligands, some are centred by two (Ru, Pt), four (Rh, Ni), or more (Ru, Rh) and display both terminal and bridging hydrogen ligands, and/or TT metal bonds. The structural and electronic configurations are consistent with those usually found in coordination compounds. The complexes are stabilized by charge transfer from the surrounding cation matrix, are often 18‐electron, and less often 16‐ or 14‐electron. Some hydride structures show evidence for metal–metal interactions as in typically interstitial metal hydrides while others contain additional hydride anions (H−) bonded to electropositive metals only, such as in saline hydrides. No HH bond formation is observed. Most hydrides are nonmetallic and many are colored. Some, however, show hydrogenation induced complex formation and metal‐to‐insulator transitions. The systems generally display very high volume efficiencies for hydrogen storage but are thermally too stable and/or too expensive for practical applications. Thermodynamic data suggest that their enthalpy of formation scales with the thermal stability of the binary hydrides of the electropositive metal constituents.
Hydrocyanation by Homogeneous Catalysis
Authors: Casalnuovo Albert L. , McKinney Ronald J. , Tolman Chadwick A. 
Published: December 2011

Abstract
The homogeneous catalysis of hydrocyanation is discussed with particular reference to the hydrocyanation of butadiene to adiponitrile, as employed in the commercial synthesis of nylon. Nickel complexes with bulky phosphite ligands are most effective and the mechanism is discussed. Asymmetric versions of the reaction are also discussed.
Hydrosilation CatalysisBased in part on the article Hydrosilation Catalysis by John F. Harrod which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Marschner Christoph 
Published: December 2011

Abstract
The addition of a hydrosilane across an unsaturated molecule is called hydrosilation. This can be catalyzed by a number of reagents among which transition metal compounds are most important. The reaction of a variety of different silanes with alkyl, alkoxy, and halogen substituents is well established. The unsaturated molecules involve alkenes, alkynes, and a huge number of different carbonyl compounds as well as combinations thereof. While hydrosilation of alkenes and alkynes can mainly be seen as a silylation method, the reaction with carbonyl compounds constitutes a formal reduction. Among the used catalyst systems hexachloroplatinic acid in isopropanol (Speier's catalyst) is most frequently used.
Mechanistically the transition metal catalyzed reaction of an alkene can be seen as an oxidative addition of the silicon hydrogen bond, followed by the migratory insertion of the coordinated alkene into the metal hydrogen or silicon bond and a final reductive elimination of the alkylsilane. The formation of vinylsilanes through the dehydrogenating silation reaction is a frequently occurring side reaction. Such by‐products are thought to be formed by β‐hydride elimination of an intermediate β‐silylalkyl metal complex.
The hydrosilation reaction can promote the transformation of a prochiral (alkene, ketone) to a potentially chiral molecule. It bears potential for asymmetric synthesis, which is currently heavily investigated. The reaction is equally popular for classical organic synthesis as well as for material science tasks such as the chemical bonding of a polymer to a surface.