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Benzeneselenol
Benzeneselenol, also known as selenophenol, is the organoselenium compound with the formula C6H5SeH, often abbreviated PhSeH. It is the selenium analog of phenol. This colourless, malodorous compound is a reagent in organic synthesis. Synthesis Benzeneselenol is prepared by the reaction of phenylmagnesium bromide and selenium: :PhMgBr + Se → PhSeMgBr :PhSeMgBr + HCl → PhSeH + MgBrCl Since benzeneselenol does not have a long shelflife, it is often generated in situ. A common method is by reduction of diphenyldiselenide. A further reason for this conversion is that often, it is the anion that is sought. Reactions More so than thiophenol, benzeneselenol is easily oxidized by air. The facility of this reaction reflects the weakness of the Se-H bond, bond dissociation energy of which is estimated to be between 67 and 74 kcal/mol. In contrast, the S-H BDE for thiophenol is near 80 kcal/mol. The product is diphenyl diselenide as shown in this idealized equation: : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenyl Diselenide
Diphenyl diselenide is the chemical compound with the formula (C6H5)2Se2, abbreviated Ph2Se2. This orange-coloured solid is the oxidized derivative of benzeneselenol. It is used as a source of the PhSe unit in organic synthesis. Preparation and properties Ph2Se2 is prepared by the oxidation of benzeneselenoate, the conjugate base of benzeneselenol which is generated via the Grignard reagent: : PhMgBr + Se → PhSeMgBr :2 PhSeMgBr + Br2 → Ph2Se2 + 2 MgBr2 The molecule has idealized C2-symmetry, like hydrogen peroxide and related molecules. The Se-Se bond length of 2.29 Å the C-Se-Se-C dihedral angle is 82° and the C-Se-Se angles are near 110°. Antioxidant action "Dietary supplementation with Ph2Se2 prevented CH3HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph2Se2 may be a viable approach to prevention or reduction CH3HgCl-mediated neurotoxic effects." The protective effects of diphenyl diselenide against methy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenyl Diselenide
Diphenyl diselenide is the chemical compound with the formula (C6H5)2Se2, abbreviated Ph2Se2. This orange-coloured solid is the oxidized derivative of benzeneselenol. It is used as a source of the PhSe unit in organic synthesis. Preparation and properties Ph2Se2 is prepared by the oxidation of benzeneselenoate, the conjugate base of benzeneselenol which is generated via the Grignard reagent: : PhMgBr + Se → PhSeMgBr :2 PhSeMgBr + Br2 → Ph2Se2 + 2 MgBr2 The molecule has idealized C2-symmetry, like hydrogen peroxide and related molecules. The Se-Se bond length of 2.29 Å the C-Se-Se-C dihedral angle is 82° and the C-Se-Se angles are near 110°. Antioxidant action "Dietary supplementation with Ph2Se2 prevented CH3HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph2Se2 may be a viable approach to prevention or reduction CH3HgCl-mediated neurotoxic effects." The protective effects of diphenyl diselenide against methy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenyldiselenide
Diphenyl diselenide is the chemical compound with the formula (C6H5)2Se2, abbreviated Ph2Se2. This orange-coloured solid is the oxidized derivative of benzeneselenol. It is used as a source of the PhSe unit in organic synthesis. Preparation and properties Ph2Se2 is prepared by the oxidation of benzeneselenoate, the conjugate base of benzeneselenol which is generated via the Grignard reagent: : PhMgBr + Se → PhSeMgBr :2 PhSeMgBr + Br2 → Ph2Se2 + 2 MgBr2 The molecule has idealized C2-symmetry, like hydrogen peroxide and related molecules. The Se-Se bond length of 2.29 Å the C-Se-Se-C dihedral angle is 82° and the C-Se-Se angles are near 110°. Antioxidant action "Dietary supplementation with Ph2Se2 prevented CH3HgCl-induced locomotor impairment. This effect appeared to be mediated by antioxidant action. Ph2Se2 may be a viable approach to prevention or reduction CH3HgCl-mediated neurotoxic effects." The protective effects of diphenyl diselenide against met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It seldom occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium – from Greek ( 'Moon') – was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiophenol
Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols except the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom. Thiophenols also describes a class of compounds formally derived from thiophenol itself. All have a sulfhydryl group (-SH) covalently bonded to an aromatic ring. The organosulfur ligand in the medicine thiomersal is a thiophenol. Synthesis There are several methods of synthesis for thiophenol and related compounds, although thiophenol itself is usually purchased for laboratory operations. Methods a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoselenium Compounds
Organoselenium compounds (or seleno-organic) are chemical compounds containing carbon-to-selenium chemical bonds. Organoselenium chemistry is the corresponding science exploring their properties and reactivity. Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected. Organoselenium compounds are found at trace levels in ambient waters, soils and sediments. Selenium can exist with oxidation state −2, +2, +4, +6. Se(II) is the dominant form in organoselenium chemistry. Down the group 16 column, the bond strength becomes increasingly weaker (234 kilojoule, kJ/mole (unit), mol for the C−Se bond and 272 kJ/mol for the C−S bond) and the bond lengths longer (C−Se 198 pm, C−S 181 pm and C−O 141 pm). Selenium compounds are more nucleophilic than the corresponding sulfur compounds and also more acidic. The pKa, p''K''a values of XH2 are 16 for oxygen, 7 for sulfur and 3.8 for selenium. In contrast to sulfoxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annales De Chimie Et De Physique
__NOTOC__ ''Annales de chimie et de physique'' ( French for ''Annals of Chemistry and Physics'') is a scientific journal founded in Paris, France, in 1789 under the title ''Annales de chimie''. One of the early editors was the French chemist Antoine Lavoisier. Lavoisier, an aristocrat, was guillotined in May 1794, ostensibly for tax fraud: and the journal was not published from 1794 to 1796 while the Reign of Terror was at its height under the French Directory. In 1815, it became the ''Annales de chimie et de physique'', and was published under that name for the next 100 years. In 1914, it split into two successor journals. The first one, '' Annales de physique'', was latterly published by EDP Sciences under the same name up to 2009, when it became integrated in the ''European Physical Journal'' series as the '' European Physical Journal H – Historical Perspectives on Contemporary Physics''. The second successor, ''Annales de chimie'', later became '' Annales de chimie: Scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin De La Société Chimique De Paris
Bulletin or The Bulletin may refer to: Periodicals (newspapers, magazines, journals) * Bulletin (online newspaper), a Swedish online newspaper * ''The Bulletin'' (Australian periodical), an Australian magazine (1880–2008) ** Bulletin Debate, a famous dispute from 1892 to 1893 between Henry Lawson and Banjo Paterson * ''The Bulletin'' (alternative weekly), an alternative weekly published in Montgomery County, Texas, U.S. * ''The Bulletin'' (Bend), a daily newspaper in Bend, Oregon, U.S. * ''The Bulletin'' (Belgian magazine), a weekly English-language magazine published in Brussels, Belgium * ''The Bulletin'' (Philadelphia newspaper), a newspaper in Philadelphia, Pennsylvania, U.S. (2004–2009) * ''The Bulletin'' (Norwich) * ''The Bulletin'' (Pittsburgh), a monthly community newspaper in Pittsburgh, Pennsylvania, U.S. * ''London Bulletin'', surrealist monthly magazine (1938–1940) * ''The Morning Bulletin'', a daily newspaper published in Rockhampton, Queensland, Austral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Trichloride
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms hexahydrate with the formula , containing six water molecules of hydration. Both are colourless crystals, but samples are often contaminated with iron(III) chloride, giving a yellow color. The anhydrous material is important commercially. It has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large amounts are also used in other areas of the chemical industry. The compound is often cited as a Lewis acid. It is an example of an inorganic compound that reversibly changes from a polymer to a monomer at mild temperature. Structure Anhydrous adopts three structures, depending on the temperature and the state (solid, liquid, gas). Solid has a sheet-like layered structure with cubic close-packed chloride ions. In this framework, the Al centres exhibit octahedral coordination geometry. In contrast, has a more mole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium Tetrachloride
Selenium tetrachloride is the inorganic compound composed with the formula SeCl4. This compound exists as yellow to white volatile solid. It is one of two commonly available selenium chlorides, the other example being selenium monochloride, Se2Cl2. SeCl4 is used in the synthesis of other selenium compounds. Synthesis and structure The compound is prepared by treating selenium with chlorine. When the reacting selenium is heated, the product sublimes from the reaction flask. The volatility of selenium tetrachloride can be exploited to purification of selenium. Solid SeCl4 is actually a tetrameric cubane-type cluster, for which the Se atom of an SeCl6 octahedron sits on four corners of the cube and the bridging Cl atoms sit on the other four corners. The bridging Se-Cl distances are longer than the terminal Se-Cl distances, but all Cl-Se-Cl angles are approximately 90°. SeCl4 has often been used as an example for teaching VSEPR rules of hypervalent molecules. As such, one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Due to the cyclic continuous pi bonds between the carbon atoms, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. History Discovery The word "''benzene''" derives from "''gum benzoin''" (benzoin res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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