|
Ortho-carborane
Ortho-carborane is the organoboron compound with the formula C2B10H12. The prefix ''ortho'' is derived from ortho. It is the most prominent carborane. This derivative has been considered for a wide range of applications from heat-resistant polymers to medical applications. It is a colorless solid that melts, without decomposition, at 320 °C. Structure The cluster has C2v symmetry. Preparation Ortho-carborane is prepared by the addition of acetylenes to decaborane(14). Modern syntheses involve two stages, the first involving generation of an adduct of decaborane: :B10H14 + 2 SEt2 → B10H12(SEt2)2 + H2 In the second stage, the alkyne is installed as the source of two carbon vertices: :B10H12(SEt2)2 + C2H2 → C2B10H12 + 2 SEt2 + H2 Substituted acetylenes can be employed more conveniently than acetylene gas. For example bis(acetoxymethyl)acetylene adds to the decarborane readily. :B10H12(SEt2)2 + C2(CH2O2CCH3)2 → C2B10H10(CH2O2CCH3)2 + 2 SEt2 + H2 The organic subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoboron Compound
Organoborane or organoboron compounds are chemical compounds of boron and carbon that are Organic compound, organic derivatives of BH3, for example trialkyl boranes. Organoboron chemistry or organoborane chemistry is the chemistry of these compounds. Organoboron compounds are important reagents in organic chemistry enabling many chemical transformations, the most important one called hydroboration. Reactions of organoborates and boranes involve the transfer of a nucleophilic group attached to boron to an electrophilic center either inter- or intramolecularly. α,β-Unsaturated borates, as well as borates with a leaving group at the α position, are highly susceptible to intramolecular 1,2-migration of a group from boron to the electrophilic α position. Oxidation or protonolysis of the resulting organoboranes may generate a variety of organic products, including alcohols, carbonyl compounds, alkenes, and halides. Properties of the B-C bond The C-B bond has low polarity (the diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboryne
In organoboron chemistry, a carboryne is an unstable derivative of ortho-carborane with the formula B10C2H10. They are also called 1,2-dehydro-o-carboranes. The hydrogen atoms on the C2 unit in the parent ''o''-carborane are missing. The compound resembles and is isolobal with benzyne. A carboryne compound was first generated in 1990 starting from o-carborane. The hydrogen atoms connected to carbon are removed by ''n''-butyllithium in tetrahydrofuran and the resulting lithium dianion is reacted with bromine at 0 °C to form the bromo monoanion. : Heating the reaction mixture to 35 °C releases carboryne, which can subsequently be trapped with suitable dienes: : such as anthracene (to afford a triptycene-like molecule) and furan in 10 to 25% chemical yield. Carborynes react with alkynes to benzocarboranes in an adaptation of the above described procedure. O-carborane is deprotonated with ''n''-butyllithium as before and then reacted with dichloro-di(triphenylphosphi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platonic Hydrocarbon
In organic chemistry, a Platonic hydrocarbon is a hydrocarbon (molecule) whose structure matches one of the five Platonic solids, with carbon atoms replacing its vertices, carbon–carbon bonds replacing its edges, and hydrogen atoms as needed. Not all Platonic solids have molecular hydrocarbon counterparts; those that do are the tetrahedron (tetrahedrane), the cube (cubane), and the dodecahedron (dodecahedrane). Tetrahedrane Tetrahedrane (C4H4) is a hypothetical compound. It has not yet been synthesized without substituents, but it is predicted to be kinetically stable in spite of its angle strain. Some stable derivatives, including tetra( ''tert''-butyl)tetrahedrane (a hydrocarbon) and tetra(trimethylsilyl)tetrahedrane, have been produced. Cubane Cubane (C8H8) has been synthesized. Although it has high angle strain, cubane is kinetically stable, due to a lack of readily available decomposition paths. Octahedrane Angle strain would make an octahedron highly unstable due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organoboron Chemistry
Organoborane or organoboron compounds are chemical compounds of boron and carbon that are organic derivatives of BH3, for example trialkyl boranes. Organoboron chemistry or organoborane chemistry is the chemistry of these compounds. Organoboron compounds are important reagents in organic chemistry enabling many chemical transformations, the most important one called hydroboration. Reactions of organoborates and boranes involve the transfer of a nucleophilic group attached to boron to an electrophilic center either inter- or intramolecularly. α,β-Unsaturated borates, as well as borates with a leaving group at the α position, are highly susceptible to intramolecular 1,2-migration of a group from boron to the electrophilic α position. Oxidation or protonolysis of the resulting organoboranes may generate a variety of organic products, including alcohols, carbonyl compounds, alkenes, and halides. Properties of the B-C bond The C-B bond has low polarity (the difference in electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteroborane
Heteroboranes are classes of boranes, at least one boron atom is replaced by another element. Like many of the related boranes, these clusters are polyhedra and are similarly classified as ''closo-, nido-, arachno-, hypho-,'' according to the so-called electron count. ''Closo-'' represents a complete polyhedron, while ''nido-'', ''arachno-'' and ''hypho-'' stand for polyhedrons that are missing one, two and three vertices. Structurally, various heteroboranes can be derived from the icosahedral (''I''h) B12H122– via formal replacement of its BH fragments with isoelectronic CH+, P+ or S2+ fragments, e.g. ''closo''-1-CB11H12–, ''closo''-1,2-C2B10H12, ''closo''-1,2-P2B10H10 or ''closo''-1-SB11H11. See also * Carborane * Azaborane Azaborane usually refers a boranes, borane Cluster chemistry, cluster where BH vertices are replaced by N or NR (R = H, organic substituent). Like many of the related boranes, these clusters are polyhedra and can be classified as ''closo-'', ''nid . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morton Thiokol
Thiokol (variously Thiokol Chemical Corporation(/Company), Morton Thiokol Inc., Cordant Technologies Inc., Thiokol Propulsion, AIC Group, ATK Thiokol, ATK Launch Systems Group; finally Orbital ATK before becoming part of Northrop Grumman) was an American corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems. Its name is a portmanteau of the Greek words for sulfur (θεῖον ''"theion"'') and glue (κόλλα ''"kolla"''), an allusion to the company's initial product, Thiokol polymer. The Thiokol Chemical Company was founded in 1929. Its initial business was a range of synthetic rubber and polymer sealants. Thiokol was a major supplier of liquid polymer sealants during World War II. When scientists at the Jet Propulsion Laboratory discovered that Thiokol's polymers made ideal binders for solid rocket fuels, Thiokol moved into the new field, opening laboratories at Elkton, Maryland, and later production facilities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olin Corporation
Olin Corporation is an American manufacturer of ammunition, chlorine, and sodium hydroxide. The company traces its roots to two companies, both founded in 1892: Franklin W. Olin's Equitable Powder Company and the Mathieson Alkali Works. Olin chemical plants frequently malfunction and pose a Chemical hazard, hazard to employees and nearby residents. History Founding and expansion (1890s-1900s) The company was started by Franklin W. Olin, Franklin Walter Olin in Niagara Falls, New York as the Equitable Powder Company. Olin created the company for the purpose of supplying the area's coal mines and limestone quarries with explosives. Olin's blasting and gunpowder company expanded into the production of cartridge (firearms), cartridges in 1898. The company bought a paper manufacturer (the Ecusta Paper Company in Pisgah Forest, North Carolina), [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboryne Synthesis
In organoboron chemistry, a carboryne is an unstable derivative of ortho-carborane with the formula B10C2H10. They are also called 1,2-dehydro-o-carboranes. The hydrogen atoms on the C2 unit in the parent ''o''-carborane are missing. The compound resembles and is isolobal with benzyne. A carboryne compound was first generated in 1990 starting from o-carborane. The hydrogen atoms connected to carbon are removed by ''n''-butyllithium in tetrahydrofuran and the resulting lithium dianion is reacted with bromine at 0 °C to form the bromo monoanion. : Heating the reaction mixture to 35 °C releases carboryne, which can subsequently be trapped with suitable dienes: : such as anthracene (to afford a triptycene-like molecule) and furan in 10 to 25% chemical yield. Carborynes react with alkynes to benzocarboranes in an adaptation of the above described procedure. O-carborane is deprotonated with ''n''-butyllithium as before and then reacted with dichloro-di(triphenylphosphi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandwich Compound
In organometallic chemistry, a sandwich compound is a chemical compound featuring a metal bound by haptic, covalent bonds to two arene (ring) ligands. The arenes have the formula , substituted derivatives (for example ) and heterocyclic derivatives (for example ). Because the metal is usually situated between the two rings, it is said to be "sandwiched". A special class of sandwich complexes are the metallocenes. The term ''sandwich compound'' was introduced in organometallic nomenclature in 1956 in a report by J. D. Dunitz, L. E. Orgel and R. A. Rich, who confirmed the structure of ferrocene by X-ray crystallography. The correct structure, in which the molecule features an iron atom ''sandwiched'' between two parallel cyclopentadienyl rings, had been proposed several years previously by Robert Burns Woodward and, separately, by Ernst Otto Fischer. The structure helped explain puzzles about ferrocene's conformers. This result further demonstrated the power o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arene Substitution Patterns
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. ''Ortho'', ''meta'', and ''para'' substitution * In ''ortho''-substitution, two substituents occupy positions next to each other, which may be numbered 1 and 2. In the diagram, these positions are marked R and ''ortho''. * In ''meta''-substitution the substituents occupy positions 1 and 3 (corresponding to R and ''meta'' in the diagram). * In ''para''-substitution, the substituents occupy the opposite ends (positions 1 and 4, corresponding to R and ''para'' in the diagram). The toluidines serve as an example for these three types of substitution. Synthesis Electron donating groups, for example amino, hydroxyl, alkyl, and phenyl groups tend to be ''ortho''/''para''-directors, and electron withdrawing groups such as nitro, nitrile, and ketone groups, tend to be ''meta''-directors. Propert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicarbollide
In organometallic chemistry, a dicarbollide is an anion of the formula 2B9H11sup>2-. Various isomers exist, but most common is 1,2-dicarbollide derived from ortho-carborane. These dianions function as ligands, related to the cyclopentadienyl anion. Substituted dicarbollides are also known such as 2B9H10(pyridine)sup>− (pyridine bonded to B) and 2R2B9H9sup>2- (R groups bonded to carbon). Synthesis of dicarbollides Dicarbollides are obtained by base-degradation of 12-vertex dicarboranes. This degradation of the ortho derivative has been most heavily studied. The conversion is conducted in two-steps, first "deboronation" and second deprotonation: :C2B10H12 + NaOEt + 2 EtOH → Na+C2B9H12− + H2 + B(OEt)3 :Na+C2B9H12− + NaH → Na2C2B9H11 + H2 The dianion derived from ortho-carborane, 2B9H11sup>2- is a nido cluster. The nomenclature rules call the high coordination number vertex as 1. Thus the nido cluster with two adjacent carbon centers on the rim is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organolithium
In organometallic chemistry Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ..., organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) Chemical bond, bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry. Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C−Li bond is highly ionization, ionic. Owing to the polar nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
