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Organoantimony Chemistry
Organoantimony chemistry is the chemistry of compounds containing a carbon to antimony (Sb) chemical bond. Relevant oxidation states are SbV and SbIII. The toxicity of antimony limits practical application in organic chemistry. Syntheses Stibines An organoantimony synthesis typically begins with tricoordinate antimony compounds, called stibines. Antimony trichloride reacts with organolithium or Grignard reagents to give compounds of the form R3Sb: : Stibines are weak Lewis acids and do not form ate complexes. As soft Lewis donors, they see wide use in coordination chemistry and typically react through oxidative addition: :R3Sb + Br2 → R3SbBr2 :R3Sb + O2 → R3SbO :R3Sb + B2H6 → R3Sb·BH3 This property also sensitizes them to air. If reduced instead, stibanes typically release substituents (ligands): : : The cyclic compound stibole, a structural analog of pyrrole, has not been isolated, but substituted derivatives have. Antimony metallocenes are k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during chemical reaction, reactions 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 prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Sensitivity
Air sensitivity is a term used, particularly in chemistry, to denote the reactivity of chemical compounds with some constituent of air. Most often, reactions occur with atmospheric oxygen (O2) or water vapor (H2O), although reactions with the other constituents of air such as carbon monoxide (CO), carbon dioxide (CO2), and nitrogen (N2) are also possible. Method A variety of air-free techniques have been developed to handle air-sensitive compounds. Two main types of equipment are gloveboxes and Schlenk lines. Glove boxes are sealed cabinets filled with an inert gas such as argon or nitrogen. Normal laboratory equipment can be set up in the glovebox, and manipulated by the use of gloves that penetrate its walls. The atmosphere can be regulated to approximately atmospheric pressure and set to be pure nitrogen or other gas with which the chemicals will not react. Chemicals and equipment can be transferred in and out via an airlock. A Schlenk line is a vacuum and inert-gas dual-mani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentamethylantimony
Pentamethylantimony or pentamethylstiborane is an organometalllic compound containing five methyl groups bound to an antimony atom with formula Sb(CH3)5. It is an example of a hypervalent compound. The molecular shape is trigonal bipyramid. Some other antimony(V) organometallic compounds include pentapropynylantimony (Sb(CCCH3)5) and pentaphenyl antimony (Sb(C6H5)5). Other known pentamethyl-pnictides include pentamethylbismuth and pentamethylarsenic. Production Pentamethylantimony can be made by reacting Sb(CH3)3Br2 with two equivalents of methyl lithium. Another production route is to convert trimethylstibine to the trimethyl antimony dichloride, and then replace the chlorine with methyl groups with methyl lithium. :Sb(CH3)3 + Cl2 → Sb(CH3)3Cl2 :Sb(CH3)3Cl2 + 2LiCH3 → Sb(CH3)5 + 2LiCl Properties Pentamethylantimony is colourless. At -143 °C it crystallizes in the orthorhombic system with space group ''Ccmm''. Unit cell dimensions are a=6.630 Å b=11.004&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biphenyl
Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one hydrogen (the site at which it is attached) may use the prefixes xenyl or diphenylyl. It has a distinctively pleasant smell. Biphenyl is an aromatic hydrocarbon with a molecular formula (C6H5)2. It is notable as a starting material for the production of polychlorinated biphenyls (PCBs), which were once widely used as dielectric fluids and heat transfer agents. Biphenyl is also an intermediate for the production of a host of other organic compounds such as emulsifiers, optical brighteners, crop protection products, and plastics. Biphenyl is insoluble in water, but soluble in typical organic solvents. The biphenyl molecule consists of two connected phenyl rings. Properties and occurrence Biphenyl is a solid at room temperature, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylstibine
Triphenylstibine is the chemical compound with the formula Sb(C6H5)3, which is often abbreviated SbPh3, This colourless solid is a common organoantimony(III) compound. It serves as a ligand in coordination chemistry and as a reagent in organic synthesis. Like the related molecules triphenylamine, triphenylphosphine and triphenylarsine, SbPh3 is pyramidal with a propeller-like arrangement of the phenyl groups. The Sb-C distances average 2.14-2.17 Å and the C-Sb-C angles are 95°. Synthesis and reactions Triphenylstibine was first reported in 1886, being prepared from antimony trichloride and chlorobenzene: :6 Na + 3 C6H5Cl + SbCl3 → (C6H5)3Sb + 6 NaCl In an alternative method, phenylmagnesium bromide is treated with SbCl3. Upon treatment with antimony trichloride, triphenylstibine undergoes a redistribution reaction: : Stiboranes can be synthesised from triphenylstibine by halogenation: : As confirmed by X-ray crystallography X-ray crystallography is the experiment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentaphenylantimony
Pentaphenylantimony is an organoantimony compound containing five phenyl groups attached to one antimony atom. It has formula Sb(C6H5)5 (or SbPh5). Structure The structure of pentaphenylantimony has been the subject of several studies, and a definite ground state remains uncertain. The molecule adopts a roughly square pyramidal shape in the unsolvated crystal. In crystals of the solvate with cyclohexane or tetrahydrofuran, the compound adopts a trigonal bipyramid shape. When dissolved, molecules are also trigonal bipyramidal. According to solution NMR measurements, the phenyl groups all appear to be equivalent, indicating fluxionality. Solid pure pentaphenylantimony forms triclinic crystals in the ''P'' space group. The unit cell has a=10.286 b=10.600 and c=13.594 Å, α=79.20° β=70.43° γ=119.52°. The basal Sb-C bond length is 2.216 Å whereas the apex Sb-C length is 2.115 Å. Reactions Pentaphenylantimony reacts with a variety of protic reagents (hydroge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onium Ion
In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen (group 15 of the periodic table), chalcogen (group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is ammonium, , the protonated derivative of ammonia, . The name onium is also used for cations that would result from the substitution of hydrogen atoms in those ions by other groups, such as organic groups, or halogens; such as tetraphenylphosphonium, . The substituent groups may be divalent or trivalent, yielding ions such as iminium and nitrilium. A simple onium ion has a charge of +1. A larger ion that has two onium ion subgroups is called a double onium ion, and has a charge of +2. A triple onium ion has a charge of +3, and so on. Compounds of an onium cation and some other anion are known as onium compounds or onium salts. Onium ions and onium compounds are inversely analogous to ions and ate complexe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organobismuth
Organobismuth chemistry is the chemistry of organometallic compounds containing a carbon to bismuth chemical bond. Applications are few. The main bismuth oxidation states are Bi(III) and Bi(V) as in all higher group 15 elements. The energy of a bond to carbon in this group decreases in the order P > As > Sb > Bi. The first reported use of bismuth in organic chemistry was in oxidation of alcohols by Frederick Challenger in 1934 (using Ph3Bi(OH)2). Knowledge about methylated species of bismuth in environmental and biological media is limited. Discovery Triethylbismuth, the first known organobismuth compound, was prepared in 1850 by Löwig and Schweizer from iodoethane and a potassium–bismuth alloy. As with most trialkylbismuth compounds, BiEt3 has an extremely pungent and unpleasant odor, and is spontaneously oxidized in air. The chemistry of these complexes first began receiving significant attention when Grignard reagents and organolithium compounds became available. Organo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentaphenylantimony
Pentaphenylantimony is an organoantimony compound containing five phenyl groups attached to one antimony atom. It has formula Sb(C6H5)5 (or SbPh5). Structure The structure of pentaphenylantimony has been the subject of several studies, and a definite ground state remains uncertain. The molecule adopts a roughly square pyramidal shape in the unsolvated crystal. In crystals of the solvate with cyclohexane or tetrahydrofuran, the compound adopts a trigonal bipyramid shape. When dissolved, molecules are also trigonal bipyramidal. According to solution NMR measurements, the phenyl groups all appear to be equivalent, indicating fluxionality. Solid pure pentaphenylantimony forms triclinic crystals in the ''P'' space group. The unit cell has a=10.286 b=10.600 and c=13.594 Å, α=79.20° β=70.43° γ=119.52°. The basal Sb-C bond length is 2.216 Å whereas the apex Sb-C length is 2.115 Å. Reactions Pentaphenylantimony reacts with a variety of protic reagents (hydroge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenyl Lithium
Phenyllithium is an organometallic agent with the empirical formula . It is most commonly used as a metalating agent in organic syntheses and a substitute for Grignard reagents for introducing phenyl groups in organic syntheses. Crystalline phenyllithium is colorless; however, solutions of phenyllithium are various shades of brown or red depending on the solvent used and the impurities present in the solute. Preparation Phenyllithium was first produced by the reaction of lithium metal with diphenylmercury: : Reaction of a phenyl halide with lithium metal produces phenyllithium: : Phenyllithium can also be synthesized with a metal-halogen exchange reaction: : The predominant method of producing phenyllithium today are the latter two syntheses. Reactions The primary use of PhLi is to facilitate formation of carbon-carbon bonds by nucleophilic addition and substitution reactions: : 2-Phenylpyridine is prepared by the reaction of phenyl lithium with pyridine, a process that enta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-ray Crystallography
X-ray crystallography is the experimental science of determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to Diffraction, diffract in specific directions. By measuring the angles and intensities of the X-ray diffraction, a crystallography, crystallographer can produce a three-dimensional picture of the density of electrons within the crystal and the positions of the atoms, as well as their chemical bonds, crystallographic disorder, and other information. X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences between various materials, especially minerals and alloys. The method has also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins and nucleic acids such as DNA. X-ray crystall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallocene
A metallocene is a compound typically consisting of two cyclopentadienyl anions (, abbreviated Cp) bound to a metallic element, metal center (M) in the oxidation state II, with the resulting general formula Closely related to the metallocenes are the metallocene derivatives, e.g. titanocene dichloride or vanadocene dichloride. Certain metallocenes and their derivatives exhibit catalysis, catalytic properties, although metallocenes are rarely used industrially. Cationic group 4 metallocene derivatives related to [Cp2ZrCH3]+ catalyze Ziegler–Natta catalyst, olefin polymerization. Some metallocenes consist of metal plus two cyclooctatetraenide anions (, abbreviated cot2−), namely the lanthanocenes and the actinocenes (uranocene and others). Metallocenes are a subset of a broader class of compounds called sandwich compounds. In the structure shown at right, the two pentagons are the cyclopentadienyl anions with circles inside them indicating they are aromaticity, aromatically ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
