bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silver: Organometallic Chemistry
Authors: Fackler John P. 
Published: December 2011

Abstract

The organometallic chemistry of silver and copper are in many ways similar. Simple alkyls are not thermally stable but fluorination of the hydrocarbon imparts considerable stability to the silver(I) products. Except for the special anion, [Ag(CF
3
)
4
]
−
, and derivatives such as Ag(CF
3
)
3
L, L = phosphine, which are stable, the fluorocarbon products generally are light and air sensitive, but less so than the nonfluorinated alkyls. Organometallic stability is increased when the silver is bonded to alkenes, alkynes, and other unsaturated species. Alkynylsilver compounds are generally polymeric solids. Alkenes π‐bond to the silver in Ag(I) salts. This feature has led to the well‐established use of silver catalysts for olefin epoxidation.
Solids: Characterization by Powder DiffractionBased in part on the article Solids: Characterization by Powder Diffraction by Anthony K. Cheetham which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Vogt Tom 
Published: December 2011

AbstractThis review article covers recent developments in X‐ray and neutron powder diffraction with an emphasis on the complementary nature of these two condensed matter probes. After a short summary of the basics of X‐ray and neutron scattering, examples of ‘mesoscopic’ structure investigations (i.e. particle size, strain) are presented followed by state‐of‐the‐art combined neutron and X‐ray high‐resolution powder diffraction studies of ‘real’ catalysts. Neutron and X‐ray powder diffraction studies in magnetic fields are highlighted and the reemergence of the total scattering approach using pair‐distribution function (PDF) analysis within the context of ‘nanocrystallography’ is discussed. Modern examples of high‐pressure crystallography using X‐ray and neutrons are given. A short outlook considers future directions in light of nanoscience and new X‐ray and neutron sources.
Solids: Computer Modeling
Authors: Catlow Richard 
Published: December 2011

AbstractWe review the role of computer modeling techniques in solid state chemistry. The basic aims and objectives of the field are summarised. We then describe basic aspects of the methodologies both of techniques based on interatomic potentials and electronic structure methods. We consider the range of applicability of each technique. Later sections of the chapter describe recent topical examples including modeling and prediction of crystal structures, simulation of nano‐cluster structures and energies and modeling of reaction mechanisms in heterogeneously catalysed reactions.
Stability Constants & Their DeterminationBased in part on the article Stability Constants & Their Determination by Harry M. N. H. Irving which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Hutton Alan T. , Linder Peter W. 
Published: December 2011

AbstractThis article is concerned with quantitative aspects of reactions in solution between metal ions and ligands to form complexes. The equilibrium constants of these reactions are usually calledstability constantsorformation constants. Formal definitions are presented of stability constants and a distinction is made between thermodynamic constants (activity quotients) and stoichiometric constants (concentration quotients). The practical difficulties of determining thermodynamic constants are discussed and the general resort to measuring stoichiometric constants and its implications are rationalized. The important idea and usefulness of formation curves for a given metal–ligand system are described. Mention is made of old‐fashioned curve‐fitting procedures for processing the relevant experimental data and references are given to the currently more important computer programs that have been developed for the purpose. Brief descriptions, especially of the underlying principles, are given of a selection of the experimental methods that have been developed for determining stability constants, that is, potentiometry, voltammetric methods (polarography and anodic stripping voltammetry), pH‐metry, competitive equilibria, use of cation exchange resins, liquid–liquid partition, spectophotometric methods, and nuclear magnetic resonance spectroscopy. Mention is made of a few other methods. pH‐metry is by far the most widely used and arguably the most sensitive and accurate of all the methods that have been developed. Justification for the considerable effort that has been, and continues to be, put into determining stability constants is presented in a section that summarizes the uses of stability constants. In particular, applications considered are to extraction metallurgy, the nuclear energy industry, analytical methods, and to medical, environmental, and industrial research. These applications all require stability constant values of high reliability and sources of critically evaluated published constants are referenced. Finally, a summary is presented of contributions that have been made to some fundamental ideas of chemistry arising from consideration of stability constant values.
SuperconductivityBased in part on the article Superconductivity by Jeremy K. Burdett which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Poole Charles P. , Farach Horacio A. 
Published: December 2011

Abstract
Superconductivity occurs in a material below its characteristic transition temperature. It is defined in terms of its two significant properties, that is, zero electrical resistance, and perfect diamagnetism. There are two characteristic lengths, the penetration depth for magnetic field penetration, and the coherence length, which measures the size of the supercurrent carriers called Cooper pairs. Supercurrents or persistent currents can flow indefinitely without loss. Elements are Type I superconductors, which totally exclude magnetic fields from their interior, and compounds are Type II superconductors, which partially exclude these fields. The application of an applied magnetic field greater than a critical field, and an applied electric current density exceeding a critical density, converts a superconductor to the normal state. Superconducting elements, alloys, and compounds are discussed, including borocarbides, Chevrel compounds, Laves phases, heavy fermions, A‐15 compounds, organics, alkali doped fullerenes, and cuprates or high‐temperature superconductors.
Supported Organotransition Metal Compounds
Authors: Hanson Brian E. 
Published: December 2011

Abstract
Supported transition metal complexes were first prepared in the 1960s as a potential method for the immobilization of homogeneous catalysts. Although this goal is yet to be commercially realized, the chemistry of supported complexes has given insight to the preparation of heterogeneous catalysts as, for example, in the use of discrete metal complexes as precursors to heterogeneous polymerization catalysts. The purpose of this article is to review the general methods for the immobilization of transition metals with examples of each type of immobilization technique.
Technetium & Rhenium: Inorganic & Coordination Chemistry
Authors: Pombeiro Armando J. L. , Guedes da Silva M. Fátima C. , Crabtree Robert H. 
Published: December 2011

Abstract
The inorganic and coordination chemistry of both rhenium and technetium is described in a condensed way with presentation of significant and typical compounds and reactions and applications in nuclear medicine and catalysis. After an Introduction, with properties of those elements and their sources, a description of binary compounds (for example oxides, sulfides, halides, and nitrides), their syntheses, structures, and selected reactions are given. This is followed by a treatment of the coordination chemistry of those metals, comprising hydrides, metal–metal bonded species and complexes with ligands coordinated by donor‐atoms mainly of the following periodic groups: 15 (commonly nitrogen and phosphorus, including dinitrogen, nitrile, nitric oxide and related ligands, hydrazides, diazenides, nitride, imides, pyrazolylborates, and phosphine ligands), 16 (mainly oxo, thio, and other O‐ or S‐ligands), and 17 (halide ligands); the metal–carbon (group 14) bond complexes are usually not covered since they are dealt with separately. Preparative methods, structures, and reactivities are illustrated for those types of complexes.

Selected complexes of
99 m
Tc and
186
Re (or
188
Re) are described and their applications in nuclear medicine illustrated, as radiopharmaceuticals normally for clinical diagnosis. The application of inorganic rhenium complexes in catalysis constitutes a currently expanding area of high potential and their use as catalysts for the following reactions is reviewed: oxygen atom transfer (OAT) and related reactions; isomerization or etherification of allylic or propargylic alcohols; Beckmann rearrangement of oximes; dehydration of primary amides and aldoximes; dehydrogenation of alkanes, unconventional reduction of aldehydes and ketones; aldol‐type reactions; and photo‐ and electrocatalytic reduction of carbon dioxide. A few catalytic applications of technetium compounds are also indicated.
Tellurium: Organotellurium ChemistryBased in part on the article Tellurium: Organotellurium Chemistry by William R. McWhinnie which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Laitinen Risto S. , Oilunkaniemi Raija 
Published: December 2011

AbstractChemistry of organotellurium compounds has developed very rapidly during the recent decades. Tellurium reagents find uses in synthetic organic chemistry. Organometallic complexes with tellurolato or telluroether ligands show potential application in the fabrication of new materials for electronic devices. The present review emphasizes the preparation and structural characterization of some main classes of organic tellurium compounds and their organometallic complexes that are deemed of interest for inorganic chemists.
Thallium: Inorganic Chemistry
Authors: Tóth Imre , Győri Béla 
Published: December 2011

Abstract
Classical knowledge of thallium inorganic chemistry is summarized in the article. The introduction consists of the history, occurrence and distribution, production, and use of this trace element. The properties of thallium(I) and thallium(III) are discussed by the short description of the most important inorganic compounds: hydrides, halides and pseudohalides, oxides, hydroxides, ternary, and more complex oxides, chalcogenides, salts with oxoanions, complexes with multidentate organic ligands, metal–metal bonded Tl‐complexes. The toxicity and the analytical methods are also shortly discussed.
Tin: Inorganic Chemistry
Authors: Wardell James L. 
Published: December 2011

AbstractThe alloying of copper with tin to produce bronze led to the formation of tools and weapons in what was later called the ‘Bronze Age’ from ≈2600–1500 BC. Since that time tin, in both the +2 and +4 oxidation states has figured prominently in inorganic compounds. This article will provide a summary of the types of inorganic compounds that tin forms, their spectroscopic characterization, and industrial uses.
Titanium: Organometallic Chemistry
Authors: Mintz Eric A. 
Published: December 2011

AbstractThe majority of titanium organometallic chemistry involves complexes in which the titanium is in its highest oxidation state (+4) with cyclopentadienyl derivatives as ancillary ligands. However, considerable chemistry has also been developed for complexes with titanium in the +3 and +2 oxidation state, with lesser amounts of chemistry developed for titanium in lower oxidation states (+1, 0). Since the early 1980s, chemists have placed considerable emphasis on the fine‐tuning of the structure and reactivity of titanium organometallic complexes. Particular emphasis has been devoted to tailoring the structure and reactivity of bis(cyclopentadienyl)titanium derivatives by incorporating electron‐donating, electron‐withdrawing, sterically demanding, or chiral substituents on the cyclopentadienyl ring. Considerable effort has gone into preparing ansa‐metallocenes with a wide variety of bridging groups and substituents to fine‐tune the reactivity catalysts prepared from them. In a similar manner, considerable effort has gone into the development of constrained geometry complexes. Several types of chiral substituted cyclopentadienyl, annulated cyclopentadienyl,ansa‐metallocenes, and constrained geometry complexes have been prepared and applied to olefin polymerization and organic synthesis. Additional efforts at modifying the structure and reactivity by focusing on varying the oxidation state or coordination geometry at the titanium center have expanded over the past decade.
Tungsten: Inorganic & Coordination Chemistry
Authors: McCleverty Jon A. 
Published: December 2011

Abstract
The inorganic and coordination chemistry of tungsten is described, being presented according to ligands and/or donor atom sets (halides, cyanides, and other ligands containing group IV atoms, ligands containing O, S, Se, Te, N, P, Sb, Bi, or, As donor atoms, hydrides, and borohydrido ligands) and are discussed in relation to the oxidation state. Special mention is made of metal–metal bonded dinuclear species, a brief description of polyoxoanionic species is given, and tri‐ and tetranuclear cluster compounds and some species of higher nuclearity, containing chalcogenide atoms, are described.
Tungsten Proteins
Authors: Adams Michael W. W. , Roy Roopali 
Published: December 2011

AbstractTungsten (W, atomic number 74) and molybdenum (Mo, atomic number 42) are very similar metals chemically, and are equally abundant elements on this planet. Molybdenum has been known for decades to play an essential role in biology, and molybdenum‐containing enzymes are ubiquitous in both prokaryotes and eukaryotes. In contrast, tungsten appears to play a much more limited role in biological systems, and one that was established relatively recently. So far, tungsten‐containing enzymes have been found only in prokaryotes. The best‐characterized organisms with regard to their metabolism of tungsten are certain species of anaerobic archaea that grow at extreme temperatures (the hyperthermophiles) or produce methane gas (the methanogens), and anaerobic bacteria that produce acetate (the acetogens) or utilize acetylene. Of these, only the hyperthermophilic archaea appear to be obligately tungsten‐dependent. That is, they do not synthesize molybdenum‐containing homologs of key tungstoenzymes when grown on molybdenum rather than tungsten. Three fundamentally different types of tungstoenzyme have been characterized so far. The best characterized is the Aldehyde ferredoxin oxidoreductase (AOR) family, represented by aldehyde ferredoxin oxidoreductase. Hyperthermophilic archaea such asPyrococcus furiosuscontain at least four members of the AOR family of tungstoenzymes. These appear to play key roles in the metabolism of sugar and peptides. The second family, termed F(M)DH, contains two types of tungstoenzyme, formate dehydrogenase and formyl methanofuran dehydrogenase. These are involved in CO2metabolism in acetogens and methanogens, respectively. The F(M)DH members are much more complex enzymes than the AOR family and show no amino acid sequence similarity to them. The third family is represented by the enzyme acetylene hydratase (AH). It catalyzes the hydration of acetylene and is found in acetylene‐utilizing bacteria. Members of the AOR and F(M)DH family catalyze redox reactions of very low potential (≤−420 mV), in which tungsten undergoes a two‐electron redox reaction [W(IV) to W(VI)]. Crystal structures are available for two members of the AOR family and reveal that each subunit of the proteins contains a single W atom coordinated to two organic pterin molecules, which are bridged by a magnesium ion. An iron–sulfur cluster is situated near the W atom and is thought to be involved in electron transfer to it. The geochemical, ecological, and biochemical basis for tungsten‐ rather than molybdenum‐dependent organisms is discussed.
ZeolitesBased in part on the article Zeolites by Alan Dyer which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Williams Craig D. 
Published: December 2011

AbstractThis work looks at the natural formation of zeolites in our environment. It details the steps required in the laboratory to successfully manufacture zeolites, producing both novel and nature identical crystal forms. The classification of zeolites based on their aluminium content, pore/channel size is also covered in some detail. Finally the various physical and chemical properties that make zeolites so useful to everyday life are examined. These include their absorptive properties, ion‐exchange properties, desiccant properties, and catalytic properties.
Zintl Compounds
Authors: Kauzlarich Susan M. 
Published: December 2011

AbstractThe term Zintl phases was originally used to recognize contributions to the field of solid‐state inorganic compounds by Eduard Zintl. They were defined as a subgroup of intermetallic phases where the anions or anionic network could be considered formally to be valence satisfied. These compounds are made up of electropositive elements from groups 1, 2 that, in a formal sense, donate their electrons to the electronegative elements from groups 13, 14, and 15, which use them to form the correct number of bonds such that each element has a filled shell. The historical definition has been expanded from binary to ternary phases and enlarged to include transition metals and rare earth elements in some cases. The compounds that make up this class are described along with the corresponding Zintl anions arising from solution chemistry. Recent results in the field such as the use of Zintl phases for novel materials is also described.
Luminescence Behavior & Photochemistry of Organotransition Metal Compounds
Authors: Yam Vivian Wing‐Wah , Lo Kenneth Kam‐Wing 
Published: December 2011

AbstractIn this article, the luminescence and photochemical properties of a selection of organotransition metal compounds are reviewed and discussed. The examples are classified according to the identity of the carbon‐containing ligands, which include the carbonyl, isocyanide, cyanide, alkynyl, alkenyl, arene, aryl, alkylidene, alkylidyne, cyclometalating, and alkyl ligands. The luminescence and photochemistry of selected tungsten, molybdenum, and rhenium carbonyl compounds are described in this article, followed by some examples with the analogous isocyanide and cyanide ligands. The luminescence properties and potential applications of these systems are discussed. Transition metal complexes containing alkynyl ligands display a very wide structural diversity and catalytic properties, and many systems also show intriguing photoluminescence properties, especially those of rhenium(I), platinum(II), palladium(II), and the coinage metals. Studies focused on the photophysical studies and the excited‐state chemistry of selected alkynyl systems and related alkenyl, arene, and aryl complexes are outlined and discussed. Luminescent metal–carbon multiple bonded systems including the alkylidene and alkylidyne compounds have received relatively little attention, and examples have been confined to the complexes of molybdenum and tungsten. However, much effort has recently been devoted to exploring the interesting emission properties of alkylidene and alkylidyne systems with other metal centers such as rhenium, ruthenium, osmium, platinum, and coinage metals, which are outlined in this article. Some recent examples in the areas of cyclometalated complexes, especially those of rhodium(III), iridium(III), platinum(II), and gold(III) centers are highlighted in this article as many examples display impressive photophysical and photochemical behavior. Metal alkyl systems represent a special class of luminescent organometallic system due to their strong σ‐donating properties of the alkyl ligands, and the photophysical and excited‐state properties of some selected examples are described. Finally, luminescent organotransition metal compounds with application potentials in the development of new materials, photodevices, and sensory systems are summarized in various parts of this article.
Metallochaperones & Metal Ion Homeostasis
Authors: Culotta Valeria C. 
Published: December 2011

Abstract
There exists a large array of proteins that rely on metal ions such as copper and manganese for function and these so‐called metalloproteins are housed in diverse locations throughout the cell. It is imperative that each metalloprotein connects with the proper metal ion and also at the right time. How does this meeting of protein and metal occur in a specific and regulated fashion? The problem seems paramount when one considers the potentially toxic nature of metals. With the harm that metals can impose on biomolecules, these ions are never allowed to roam freely in the reactive form and, as such, the bioavailability of metals within cells is very limited. To overcome this problem, eukaryote cells have evolved with specific ‘metal trafficking pathways’ or designated routes a metal ion can follow once inside the cell. On one hand, the bulk of the metal may be subject to a dead fate involving sequestration by metal detoxification systems. On the other hand, a fraction of the metal destined for metalloproteins enters a trafficking pathway that involves both membrane transporters and ‘metal chaperones’ that directly insert the metal into the target metalloprotein. The bulk of current knowledge on metal chaperones and metal trafficking pathways has emerged from studies on copper and to a lesser degree on manganese. The work described herein focuses on paradigms developed for copper and manganese, with possible implications for other essential metals as well.