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Organoplatinum Compounds
Organoplatinum chemistry is the chemistry of organometallic compounds containing a carbon to platinum chemical bond, and the study of platinum as a catalyst in organic reactions. Organoplatinum compounds exist in oxidation state 0 to IV, with oxidation state II most abundant. The general order in bond strength is Pt-C (sp) > Pt-O > Pt-N > Pt-C (sp3). Organoplatinum and organopalladium chemistry are similar, but organoplatinum compounds are more stable and therefore less useful as catalysts. Organoplatinum(0) Most organoplatinum(0) compounds contain alkene and alkyne ligands. Carbonyl complexes are rare, and the analogue of Ni(CO)4 is elusive. The alkene and alkyne ligands serve as two-electron donors, for example in the complexes (PPh3)2Pt(C2H4) and (PPh3)2Pt( C2Ph2). The ethylene ligand in (PPh3)2Pt(C2H4) is labile and exchanges with alkynes and electrophilic alkenes, even C60 a fullerene. A general synthetic route to (PPh3)2Pt(un) (un = alkene, alkyne) is reduction of potassium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a Chemical reaction, reaction with other Chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethylene
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene is widely used in the chemical industry, and its worldwide production (over 150 million tonnes in 2016) exceeds that of any other organic compound. Much of this production goes toward polyethylene, a widely used plastic containing polymer chains of ethylene units in various chain lengths. Ethylene is also an important natural plant hormone and is used in agriculture to force the ripening of fruits. The hydrate of ethylene is ethanol. Structure and properties This hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond. All six atoms that comprise ethylene are coplanar. The H-C-H angle is 117.4°, close to the 120° for ideal sp² hybridized carbon. The molecule is also relatively weak: rota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Gilman
Henry Gilman (May 9, 1893 – November 7, 1986) was an American organic chemist known as the father of organometallic chemistry, the field within which his most notable work was done. He discovered the Gilman reagent, which bears his name. Early life and education (1893-1918) Henry Gilman was born in Boston, Massachusetts, as the son of a tailor. He was the third of eight children. Gilman graduated from a Boston high school and later attended Harvard University where he graduated summa cum laude with a Bachelor of Science degree in 1915. During his final year as an undergraduate at Harvard, Gilman researched with Roger Adams. During this time, the two worked on the synthesis of substituted phenyl esters of oxalic acids. Gilman worked hard on his research describing it as 'a sheer delight' and often worked until midnight 'without any compulsion-just for the joy of it' and claimed this was an important step toward his interest in research. After undergraduate work Gilman was invit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Jackson Pope
Sir William Jackson Pope (31 March 1870 – 17 October 1939) was an English chemist. Biography William Jackson Pope was born on 31 March 1870 in Hoxton to William (a saddler) and Alice (née Hall). His parents were staunch and active Wesleyans who had eight children, of whom William was the eldest. In 1878 he entered the Central Foundation School, in London, where his ability to learn rapidly gave him leisure at the age of twelve to carry out simple chemical experiments in his bedroom. While at school he also developed great skill as a photographer—many of his early photographs were in perfect condition fifty years later. From there he moved to the Finsbury Technical College, where he learned much from H E Armstrong; the two later became close friends. Pope studied crystallography under H. A. Miers, and most of his earlier research focussed on measuring crystallographic data with a goniometer. These studies had an important influence on the development of his chemical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylmagnesium Iodide
Methylmagnesium chloride is an organometallic compound with the general formula CH3MgCl. This highly flammable, colorless, and moisture sensitive material is the simplest Grignard reagent and is commercially available, usually as a solution in tetrahydrofuran. Synthesis and reactions Relative to the more commonly encountered methylmagnesium bromide and methylmagnesium iodide, methylmagnesium chloride offers the advantages of low equivalent weight and low cost. It is prepared by the reaction of methyl chloride and magnesium in ethyl ether. left, Structure of CH3MgCl(thf)2, which is representative of the species in donor solvents. As with most Grignard reagents, methylmagnesium chloride is highly solvated by ether solvents via coordination from two oxygen atoms to give a tetrahedrally bonded magnesium center. Like methyllithium, it is the synthetic equivalent to the methyl carbanion synthon. It reacts with water and other protic reagents to give methane, e.g.,: :CH3MgCl + RO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platinum(IV) Chloride
Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl4. This brown solid features platinum in the 4+ oxidation state. Structure Typical of Pt(IV), the metal centers adopt an octahedral coordination geometry, . This geometry is achieved by forming a polymer wherein half of the chloride ligands bridge between the platinum centers. Because of its polymeric structure, PtCl4 dissolves only upon breaking the chloride bridging ligands. Thus, addition of HCl give H2PtCl6. Lewis base adducts of Pt(IV) of the type cis-PtCl4L2 are known, but most are prepared by oxidation of the Pt(II) derivatives. Formation and reactions PtCl4 is mainly encountered in the handling of chloroplatinic acid, obtained by dissolving of Pt metal in aqua regia. Heating H2PtCl6 gives PtCl4: :H2PtCl6 → PtCl4 + 2 HCl If excess acids are removed, PtCl4 crystallizes from aqueous solutions in large red crystals of pentahydrate PtCl4·5(H2O), which can be dehydrated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylplatinum Iodide
Trimethylplatinum iodide is the organoplatinum complex with the formula CH3)3PtIsub>4. It is a white, air-stable solid that was one of the first organometallic complexes reported. It arises from the reaction of potassium hexachloroplatinate with methylmagnesium iodide. The complex exists as a tetramer: a cubane-type cluster with four octahedral Pt(IV) centers linked by four iodides as triply bridging ligand In coordination chemistry, a bridging ligand is a ligand that connects two or more atoms, usually metal ions. The ligand may be atomic or polyatomic. Virtually all complex organic compounds can serve as bridging ligands, so the term is usually r ...s.{{cite journal, authors=Ebert, K. H.; Massa, W.; Donath, H.; Lorberth, J.; Seo, B. S.; Herdtweck, E., title=Organoplatinum Compounds: VI. Trimethylplatinum Thiomethylate and Trimethylplatinum Iodide. The Crystal Structures of CH3)3PtS(CH3)sub>4 and CH3)3PtIsub>4·0.5CH3I, journal=J. Organomet. Chem., year=1998, volume=559, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrakis(triphenylphosphine)platinum(0)
Tetrakis(triphenylphosphine)platinum(0) is the chemical compound with the formula Pt(P(C6H5)3)4, often abbreviated Pt(PPh3)4. The bright yellow compound is used as a precursor to other platinum complexes. Structure and behavior The molecule is tetrahedral, with point group symmetry of Td, as expected for a four-coordinate metal complex of a metal with the d10 configuration.Miessler, Gary L., and Donald A. Tarr. Inorganic Chemistry. 3rd ed. Upper Saddle River, NJ: Pearson Prentice Hall, 2004. Even though this complex follows the 18 electron rule, it dissociates triphenylphosphine in solution to give the 16e− derivative containing only three PPh3 ligands: :Pt(PPh3)4 → Pt(PPh3)3 + PPh3 Synthesis and reactions The complex is typically prepared in one-pot reaction from potassium tetrachloroplatinate(II). Reduction of this platinum(II) species with alkaline ethanol in the presence of excess triphenylphosphine affords the product as a precipitate. The reaction occurs in two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aryl Halide
In organic chemistry, an aryl halide (also known as haloarene) is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications. Preparation The two main preparatory routes to aryl halides are direct halogenation and via diazonium salts. Direct halogenation In the Friedel-Crafts halogenation, Lewis acids serve as catalysts. Many metal chlorides are used, examples include iron(III) chloride or aluminium chloride. The most important aryl halide, chlorobenzene is produced by this route. Monochlorination of benzene is always accompanied by formation of the dichlorobenzene derivatives. Arenes with electron donating groups react with halogens even in the absence of Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkyl Halide
The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidative Addition
Oxidative addition and reductive elimination are two important and related classes of reactions in organometallic chemistry. Oxidative addition is a process that increases both the oxidation state and coordination number of a metal centre. Oxidative addition is often a step in catalytic cycles, in conjunction with its reverse reaction, reductive elimination. Role in transition metal chemistry For transition metals, oxidative reaction results in the decrease in the d''n'' to a configuration with fewer electrons, often 2e fewer. Oxidative addition is favored for metals that are (i) basic and/or (ii) easily oxidized. Metals with a relatively low oxidation state often satisfy one of these requirements, but even high oxidation state metals undergo oxidative addition, as illustrated by the oxidation of Pt(II) with chlorine: : tCl4sup>2− + Cl2 → tCl6sup>2− In classical organometallic chemistry, the formal oxidation state of the metal and the electron count of the complex both in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopentadienyl
{{Chemistry index ...
Cyclopentadienyl can refer to *Cyclopentadienyl anion, or cyclopentadienide, **Cyclopentadienyl ligand *Cyclopentadienyl radical, • *Cyclopentadienyl cation, See also *Pentadienyl In organic chemistry, pentadienyl refers to the organic radical, anion, or cation with the formula , where ''z'' = 0, −1, +1, respectively. Organometallic chemistry In organometallic chemistry, the pentadienyl anion is a ligand, the acyclic ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
