bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mercury: Organometallic ChemistryBased in part on the article Mercury: Organometallic Chemistry by Richard C. Larock which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Rais Daniela , Vilar Ramón 
Published: December 2011

Abstract
Over the past 10 years, a wide range of new organomercury compounds have been prepared and their reactivity extensively studied, leading to interesting applications in organic synthesis. The solvomercuration of alkenes is still the most widely employed organometallic reaction of mercury, although there have been important advances in the use of the mercury‐mediated ring opening of cyclopropanes. Several structural investigations of organomercurials have been recently carried out providing detailed information on the connectivity of a wide range of mono‐ and polymercuric complexes. In this article, an overview of the most important advances on the organometallic chemistry of mercury between 1993 and 2003 will be provided.
Metallic Materials Deposition: Metal‐Organic PrecursorsBased in part on the article Metallic Materials Deposition: Metal–Organic Precursors by Herbert D. Kaesz, Alfred Zinn, & Lutz Brandt which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Winter Charles H. , Zheng Wenjun , El‐Kaderi Hani M. 
Published: December 2011

AbstractThis review describes metal‐organic precursors for the growth of metal‐containing thin films by chemical vapor deposition methods. The major emphasis is on precursors that have been reported since 1994, and corresponds to a time of major growth in this field. Progress in the development of metal‐organic precursors is documented for the main group, lanthanide, and group 4–11 elements. In the main group elements, there has been considerable research activity directed toward the identification of strontium and barium precursors, due both to the technological importance of mixed oxide phases and the inherent difficulties in obtaining volatile, complexes of these large metal ions. Aluminum, gallium, and indium have also been the subject of intense investigation, owing to the importance of many phases containing these elements. The group 4 and 5 elements titanium, zirconium, hafnium, niobium, and tantalum have been the subject of considerable precursor development activity, owing to the importance of several mixed oxide phases and the importance of zirconium and hafnium oxide for high permittivity gate materials in microelectronics devices. Growth of metal nitride films of these elements has also been an active area of research for use as barrier materials in microelectronics devices. The deposition of copper metal films from metal‐organic precursors is driven by the urgent need for copper metallization procedures in microelectronics device manufacturing. The current state of metal‐organic precursor development is presented for each of the other metallic elements.
MetallothioneinsBased in part on the article Metallothioneins by Milan Vašák & Jeremias H. R. Kägi which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Vašák Milan , Romero‐Isart Núria 
Published: December 2011

AbstractMetallothionein (MT) is a generic name for a superfamily of ubiquitous low molecular weight cysteine‐ and metal‐rich proteins or polypeptides possessing sulfur‐based metal clusters. In these compounds, clusters are usually formed through the preferential coordination of d10metal ions by an array of closely spaced cysteine thiolate ligands. Their preservation in an increasing number of three‐dimensional structures of these proteins signifies the importance of this structural motif. The versatile and striking chemical reactivity of clusters in MTs and their unprecedented dynamics make this class of proteins highly unusual. A primary role of MTs has not been identified, and remains elusive, as further functions continue to be discovered.
Molybdenum: Organometallic ChemistryBased in part on the article Molybdenum: Organometallic Chemistry by M. David Curtis which appeared in the
Encyclopedia of Inorganic Chemistry, First Edition
.
Authors: Flower Kevin R. 
Published: December 2011

Abstract
This article considers only compounds that contain a direct molybdenum‐to‐carbon bond. Because of the size of the topic and the large number of publications each year, the article gives a general overview of major current areas of interest in molybdenum‐centered organometallic chemistry. The material is presented in three major sections: σ‐ligand‐containing complexes, which covers alkyl‐, carbonyl‐, halocarbonyl‐, alkylidenes‐, and alkylidyne complexes, heavier group 14 analogs of alkylidene and alkylidyne complexes; π‐ligand‐containing complexes, which covers alkene‐, polyene‐, alkyne‐, phosphaalkyne‐containing complexes, along with π‐bound cyclic organic systems such as cyclobutadiene, cyclopentadienyl, and arenes; polymetallic complexes and multiply bonded systems are also discussed. Each section considers the major methods of preparation of compounds containing that ligand class and surveys the major types of reaction they undergo, both metal‐ and ligand‐centered, along with the factors that influence the products that form. Where data is available, solid‐state structural data are presented to aid in the discussion of the material presented.
Nitrogenase: Metal Cluster Models
Authors: Barrière Frédéric 
Published: December 2011

Abstract

This article reviews the synthesis and properties of inorganic clusters that model the iron–sulfur centers found in the nitrogenase enzyme. These sites are of the Fe
4
S
4
, Fe
8
S
7
, and MoFe
7
S
9
stoichiometry. The enzyme [Fe
4
S
4
]
2+/1+
center is well modeled by synthetic clusters bearing thiolate ligands at iron. However, the [Fe
4
S
4
]
0
state is stabilized in the enzyme and has not been reproduced in the laboratory so far. Recent progress in synthetic models of the Fe
8
S
7
P‐cluster is reported. One of its known structures can be obtained by self‐assembly from basic constituents, or synthesized in a stepwise fashion from smaller clusters yielding topological analogues. The most challenging cluster to model is the FeMo‐cofactor. This MoFe
7
S
9
center is the site of dinitrogen reduction to ammonia. The cluster also exists with vanadium or iron in place of molybdenum in alternative nitrogenases. It was shown only recently that the FeMo‐cofactor is centered on a light atom that is probably a nitrogen atom. Structural modeling of this center is limited. Only its molybdenum or heterometal end has been accurately modeled. Functional chemistry of good structural models, those with sulfur ligands and metal–metal bonds, only concerns the reduction of already partially reduced diazo substrates such as diazene or hydrazine.
Nitrogenase Catalysis & AssemblyBased in part on the article Nitrogenases & the Iron–Molybdenum Cofactor by Paul W. Ludden which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Hu Yilin , Schmid Benedikt , Ribbe Markus W. 
Published: December 2011

AbstractNitrogenases are metalloenzymes that catalyze biological N2fixation, in which dinitrogen is reduced to ammonia. The best‐characterized molybdenum nitrogenase is composed of the iron (Fe) protein that contains a [4Fe–4S] cluster and the molybdenum–iron (MoFe) protein that contains an [8Fe–7S] cluster (P cluster) and a [Mo–7Fe–9S–homocitrate] cluster (FeMo cofactor).The catalysis of molybdenum nitrogenase occurs in a series of steps. First, the reduced Fe protein binds 2MgATP, undergoes a conformational change, and forms a complex with the MoFe protein. Then, coupled with the hydrolysis of 2MgATP, one electron is transferred from the Fe protein to the MoFe protein within the complex. This is followed by complex dissociation, which allows the enzyme to start the next cycle of electron transfer. Once a sufficient amount of electrons is accumulated on the MoFe protein, substrate reduction takes place.The assembly of the molybdenum nitrogenase Fe protein involves thenifHand at least thenifS, nifU, andnifMgene products that are implicated in the [4Fe–4S] cluster assembly, while the assembly of the MoFe protein requires at least 15nifgene products and involves the biosynthesis and insertion of the FeMo cofactor into the MoFe protein.
Nucleic Acid–Metal Ion Interactions
Authors: Kazakov Sergei A. , Hecht Sidney M. 
Published: December 2011

AbstractNucleic acids (DNA and RNA) are actually salts (or complexes) of metal ions from a chemical point of view. It is impossible to separate the behavior of DNA and RNA from their interactions with metal ions. Metal ions are usually required to promote and stabilize functionally active or native conformations of nucleic acids, as well as to mediate nucleic acid‐protein interactions. However, certain metal ions can also cause structural transformation of nucleic acids, and induce their chemical modification and cleavage. Metal‐nucleic acid interactions are involved in nucleotide biochemistry; genetic information storage and transfer, and control of gene expression, as well as in mutagenesis and carcinogenesis. However, in most cases, it is not currently clear whether the observed effects actually result from direct metal ion‐nucleic acid interaction, since other species, such as specific proteins, may be mediators between the metal ion and the nucleic acid in these processesin vivo. Interest in metal‐nucleic acid interactions is also enhanced by studies of the mechanisms of antitumor activity of certain platinum metal compounds, finding metal ions in crystal structure of natural RNA molecules, studies of the mechanism of RNA catalysis and possible involvement of metal ions in origin of life, as well as by the use of metal ions as structural probes of nucleic acids and as biotechnology tools. This article does not attempt to be comprehensive, but rather presents selected examples to illustrate key facets of metal ion‐nucleic acid interaction. The focus is on the chemical and structural properties of both nucleic acids and metal ions relevant to their interactions. Nucleic acid‐metal interactions can be either nonspecific or dependent on the chemical nature, sequence, and structure of nucleic acids. However, the specificity of these interactions is dependent on structural and chemical properties of both the nucleic acids and the metal ions. Both nucleic acids and metal ions exhibit considerable complexity in their interactions, and such interactions could affect the chemical and biochemical properties of both species.
Osmium: Organometallic Chemistry
Authors: Shapley Patricia A. 
Published: December 2011

Abstract
Organometallic complexes of osmium include those with sigma bonds between the metal and the organic moiety, such as metal–alkyl complexes, or π bonds, such as metal–alkene complexes. The osmium alkyl complexes include homoleptic alkyls and complexes with ancillary carbonyl, cyclopentadienyl, arene, or alkene ligands. Because osmium complexes are stable in higher oxidation states than either ruthenium or iron, oxidative addition of CH bonds to form alkylidene and alkylidyne complexes is very common. Metal–ligand bonds also tend to be stronger in osmium complexes than in complexes of the lighter elements of this group. Because of the stability of OsOs bonds, there are many bimetallic and cluster complexes of osmium and these species have an extensive reaction chemistry. Selective oxidation reactions of unsaturated organic molecules dominates the catalytic chemistry of this metal. Mechanistic studies on the activation of molecular oxygen and oxygen transfer reactions by organoosmium complexes have provided insights into catalytic oxidation chemistry.
Oxides: Solid‐State Chemistry
Authors: McCarroll William H. , Ramanujachary Kandalam V. 
Published: December 2011

AbstractThis article is an overview of the solid‐state chemistry of oxides. It starts with a brief description of the periodic trends associated with compounds of oxygen and is followed by a discussion of the principle of the closest packing of spheres that can be used to describe ionic structures. An in depth description of several structure types, important in solid‐state oxide chemistry, follows, and covers the important binary structures as well as several ternary structures including the Perovskite, Spinel, Garnet, Pyrochlore, and Scheelite structures.Selected special topics in solid‐state oxide chemistry include a discussion of crystallographic shear structures, defect oxides, and tungsten and molybdenum bronzes, intergrowth structures of which the high‐temperature superconductor YBa2Cu3O7is an example. The importance of structure‐property relations in oxides is illustrated by a discussion of metal–metal bonds in oxides, electronic conduction in a variety of oxides, and the catalytic properties of defect scheelites.A lengthy discussion is devoted to the various means used by solid‐state chemists to synthesize oxides not only as bulk polycrystalline phases but as single crystals and thin films as well that are so important to electronic applications. The article concludes with a discussion of several important practical applications of oxides including magnetic oxides, oxide sensors, luminescent materials, ferroelectrics, CMR oxides, optical materials, ceramics, and refractory materials as well as a brief overview of other important uses.Because this is a survey article, in depth discussion of many properties of oxides is not possible. However, many of these topics are covered in depth in other parts of the Encyclopedia and the reader will find the cross references helpful. A substantial list of references also provides a gateway to the solid‐state literature.
Palladium: Inorganic & Coordination Chemistry
Authors: Albéniz Ana C. , Espinet Pablo 
Published: December 2011

AbstractPalladium is a group 10 metal used in the manufacture of exhaust autocatalysts in the automobile industry, in dental palladium alloys, in the electronics industry, in jewelry alloys, and in the manufacture of industrial catalysts. Although the latter represents only about 5% of Pd use, it is extremely important. A remarkable property of metallic palladium is its ability to absorb considerable amounts of hydrogen. The inorganic and coordination chemistry of palladium is mostly that of their oxidation states 0 and +2, but the oxidation states +1 and +4 are also well represented. Only in a few examples Pd can be guaranteed as Pd +3, while in others the ligands of Pd are noninnocent and the apparent oxidation state assigned to Pd can be deceptive. Only one Pd(V) and one Pd(VI) compound have been reported but not confirmed by independent research groups. The Pd(0) complexes reported include compounds with many possible ligands, which are known in [PdL4], [PdL3], and [PdL2] stoichiometries. The former are formed with conventional ligands and have the tendency to dissociate at least one ligand in solution, while the latter are formed with bulky ligands and are more reactive toward oxidative addition. In addition to Pd on carbon, colloids and polymer‐stabilized forms of Pd are catalytically important. All Pd(I) compounds reported feature PdPd or PdM bonds, with or without supporting bridges, displaying quite a large range of distances. Pd(II) compounds are commonly four‐coordinated square planar, but there are a considerable number of five‐coordinated compounds. Three‐coordinated Pd(II) compounds are not known. One doubtless case of a four‐coordinated tetrahedral (and accordingly paramagnetic) complex has been reported. Pdf2is a rare example of six‐coordinated Pd(II). Square‐planar Pd(II) fragments are building blocks in the construction of extended self‐assembled structures. Coordination tocis‐‘PdL2’ fragments can be used to define corners, whiletrans‐‘PdL2’ moieties can help build linear edges. Mononuclear complexes of Pd(III) can be stabilized by some tridentate macrocyclic ligands containing S and N as donors. A binuclear Pd(III) compound, displaying the shortest PdPd bond is also known. In both cases, the coordination number for Pd is six. Pd(IV) is not an uncommon oxidation state, although it is quite oxidant. Complexes with many different ligands, which show octahedral coordination are known.
Phosphorus: Inorganic ChemistryBased in part on the article Phosphorus: Inorganic Chemistry by Josef Novosad which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Kelly Paul F. 
Published: December 2011

AbstractThe element phosphorus was first discovered in 1669, and some measure of the growth of its uses and importance since then is evident from the fact that approximately half a million tons of the element are now produced annually; in addition, phosphorus‐based materials may be generated from naturally occurring phosphates, and for this reason over 130 million tons of such material are utilized per annum. Its importance to life means that natural phosphorus cycles occur; in addition, utilization of the element and its compounds is key to many industrial processes (producing products varying from pesticides to oil additives). In the laboratory, work has shown that many ‘naked’ phosphide anions can be prepared – these can even mimic organic systems, as in the case of the cyclo [P5]−ligand, which binds face on to metals in the manner of the cylcopentadienyl ligand. In addition, there are many examples of transition metal complexes of ligands containing only phosphorus; these range in size from just a single phosphorus atom to complex structures containing up to 14 atoms. Away from transition metal chemistry, phosphorus forms compounds with elements from all groups of the periodic table barring the noble gases; this article provides an overview of such compounds, with special interest in compounds that have an industrial use, that stabilize unusual bonding arrangements, or that are of current interest. In the process, it highlights the ability of the element to become involved in catenation and to form small cluster units, often with many PP bonds present. Thus, group 13 compounds of the element include the industrially important phosphides and a recently prepared new class of boron–phosphorus polymer. Silicon compounds of the element often exhibit unusual structures and some of these are illustrated and reference is made to multiple‐bonded systems, including the first example of a phosphabismuthene. Sulfides such as P4S10and halides such as PCl3and POCl3are of immense industrial importance and details of such processes and the consumption levels are provided. References to recent reviews on a range of pertinent topics are provided, including PSi chemistry, phosphides, phosphorus‐based polymers, phosphorus complexes of transition metals, phosphorus‐borane chemistry, phosphane ligands, organophosphorus chemistry, and phosphorus hydrides.
Photosynthesis
Authors: Staples Christopher R. , Blankenship Robert E. 
Published: December 2011

AbstractPhotosynthesis is a biological process in which light energy is captured and stored as chemical energy by organisms such as plants, algae and certain bacteria. The stored energy is then used to power cellular processes. Most organisms that perform photosynthesis utilize chlorophylls or bacteriochlorophylls, in conjunction with other pigments such as carotenoids, pheophytins, and bilins. The emphasis in this article will be on the aspects of photosynthesis that relate most directly to the subject of inorganic chemistry. The aspects presented include excited states, photochemical reactions, the role of metal ions in photosynthesis, the structures of pigments, electron transfer pathways, reduction potentials of components, chromophore absorption and fluorescence spectra, energetics, and kinetics. Recent crystal structures of photosystems I and II, the important enzyme cytochromeb6f, and antenna complexes and supercomplexes are presented and discussed.
Platinum‐Based Anticancer DrugsBased in part on the article Platinum‐Based Anticancer Drugs by Steven J. Brown, Christine S. Chow & Stephen J. Lippard which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Robillard Marc S. , Reedijk Jan 
Published: December 2011

AbstractThe chemotherapeutic agent cisplatin enjoys the status of one of the world's best‐selling anticancer drugs. As is the case with other chemotherapeutic drugs, however, cisplatin has its drawbacks, including intrinsic or acquired resistance and toxicity. Efforts to mitigate cisplatin's drawbacks have inspired the synthesis of myriad analogs, but with only a handful that have been shown to be acceptable for clinical application. Increased understanding of the mechanism of the action of cisplatin, as a result of decades of research, is leading to a more rational design of new platinum drugs. However, the incomplete puzzle of cisplatin's ways and the lack of a single decisive biological target for anticancer treatment still complicate the search for improved platinum drugs. This article gives a brief introduction to cisplatin, and subsequently summarizes and evaluates the development of cisplatin derivatives and possible new approaches.
Rhodium: Organometallic Chemistry
Authors: Mague Joel T. 
Published: December 2011

AbstractA review of the major advances in the organometallic chemistry of rhodium covering the period 1993–2003 is presented. Highlighted are complexes containing N‐donor ligands such as triazacyclononanes and tris‐(pyrazolyl)borates, those containing vinylidene and allenylidene ligands, and the formation of metallamacrocyclic complexes. Also featured are results of detailed computational studies on the activation of CH bonds and the course of olefin hydroformylation and hydrogenation processes. Classes of organorhodium compounds covered include alkyl, aryl, vinylidene, allenylidene, alkynyl, and carbene complexes. Also reviewed are alkene, alkyne, isocyanide, and arene complexes, as well as carbonyl cluster compounds together with significant coverage of dinuclear complexes stabilized by bis(diphenylphosphino)methane ligands.
S
‐Donor Ligands
Authors: Collinson Simon R. , Schröder Martin 
Published: December 2011

Abstract
The chemistry of S‐donor ligands with metal centres is reviewed with emphasis placed on the structures and redox activity of the resultant complexes. Sulfides and thiolates bind to a wide range of metal ions. The oxidation of thiolates to sulfones and sulfoxides and the structures and chemistry of metal‐thiolene complexes are detailed. Thioethers are generally poor ligands for transition metal ions but macrocylic ligands afford stable complexes. Many metalloproteins contain metal–sulfur bonds and the structures of many of these have now been elucidated. This has sparked a renaissance in the synthesis of low‐molecular weight metal complex mimics.
Selenium: Inorganic ChemistryBased in part on the article Selenium: Inorganic Chemistry by Bernt Krebs, Stefan Bonmann, & Illenora Eidenschink which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.
Authors: Atwood David A. 
Published: December 2011

AbstractSelenium is the first member of the group 16 elements O, S, Se, Te, and Po that shows some metallic character. The increasing metallic character in the series O, S, Se, Te, Po is reflected also in the lower electronegativity, in the less acid character of the oxides, and in the lower stability of the oxidation number +VI for selenium compared to sulfur. There is a large variety of compounds of SeII, SeIV, and SeVI with the electronegative elements N, O, F, Cl, and Br. Thus, there are six general types of compounds, and these will comprise the main sections in the article. They are cations, halides, oxides, haloselenates, oxohaloselenates, and the related compounds that form when both selenium and nitrogen are present in the molecule.