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Silatrane
Atranes are a class of tricyclic molecules with three five-membered rings. It is a heterocyclic structure similar to the propellanes. It has a transannular dative bond from a nitrogen at one bridgehead to a Lewis acidic atom such as silicon or boron at the other bridgehead.Voronkov, Mikhail G.; Baryshok, Viktor P. "Atranes - a new generation of biologically active substances" (in Russian) Vestnik Rossiiskoi Akademii Nauk 2010, volume 80, 985-992. The name "atrane" was first proposed by . Nomenclature Various atranes are named depending on the central element, e.g. "silatrane" (E = silicon); "boratrane" (E = boron); "phosphatrane" (E = phosphorus), etc. It is also proposed that when Y = nitrogen, the prefix "aza" be inserted before ''element'' + "atrane" (azasilatrane, for example) because atranes wherein E = silicon and Y = oxygen have been referred to as just "silatranes". Structure and properties Silatranes exhibit unusual properties as well as biological activity in w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrane
Atranes are a class of tricyclic molecules with three five-membered rings. It is a heterocyclic structure similar to the propellanes. It has a transannular dative bond from a nitrogen at one bridgehead to a Lewis acidic atom such as silicon or boron at the other bridgehead.Voronkov, Mikhail G.; Baryshok, Viktor P. "Atranes - a new generation of biologically active substances" (in Russian) Vestnik Rossiiskoi Akademii Nauk 2010, volume 80, 985-992. The name "atrane" was first proposed by . Nomenclature Various atranes are named depending on the central element, e.g. "silatrane" (E = silicon); "boratrane" (E = boron); "phosphatrane" (E = phosphorus), etc. It is also proposed that when Y = nitrogen, the prefix "aza" be inserted before ''element'' + "atrane" (azasilatrane, for example) because atranes wherein E = silicon and Y = oxygen have been referred to as just "silatranes". Structure and properties Silatranes exhibit unusual properties as well as biological activity in w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylsilatrane
Phenylsilatrane is a convulsant chemical which has been used as a rodenticide. Phenylsilatrane and some of its analogs with 4-substituents of H, CH3, Cl, Br, and CSi(CH3)3 are highly toxic to mice. They have been observed in the laboratory to inhibit the 35S-''tert''-butylbicyclophosphorothionate ( TBPS) binding site ( GABA-gated chloride channel) of mouse brain membranes. See also * Atrane Atranes are a class of tricyclic molecules with three five-membered rings. It is a heterocyclic structure similar to the propellanes. It has a transannular dative bond from a nitrogen at one bridgehead to a Lewis acidic atom such as silicon or bor ... * GABAA receptor negative allosteric modulator * GABAA receptor § Ligands * Chlorophenylsilatrane References Convulsants Nitrogen heterocycles Organosilicon compounds Oxygen heterocycles Rodenticides Silicon heterocycles GABAA receptor negative allosteric modulators Phenyl compounds Atranes {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silane
Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Silane with alkyl groups are effective water repellents for mineral surfaces such as concrete and masonry. Silanes with both organic and inorganic attachments are used as coupling agents. Production Commercial-scale routes Silane can be produced by several routes. Typically, it arises from the reaction of hydrogen chloride with magnesium silicide: : Mg2Si + 4 HCl -> 2 MgCl2 + SiH4 It is also prepared from metallurgical-grade silicon in a two-step process. First, silicon is treated with hydrogen chloride at about 300 °C to produce trichlorosilane, HSiCl3, along with hydrogen gas, according to the chemical equation : Si + 3 HCl -> HSiCl3 + H2 The trichlorosilane is then converted to a mixture of silane and silicon tetrachloride: : 4 HS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypervalent Molecule
In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride (), sulfur hexafluoride (), chlorine trifluoride (), the chlorite () ion, and the triiodide () ion are examples of hypervalent molecules. Definitions and nomenclature Hypervalent molecules were first formally defined by Jeremy I. Musher in 1969 as molecules having central atoms of group 15–18 in any valence other than the lowest (i.e. 3, 2, 1, 0 for Groups 15, 16, 17, 18 respectively, based on the octet rule). Several specific classes of hypervalent molecules exist: * Hypervalent iodine compounds are useful reagents in organic chemistry (e.g. Dess–Martin periodinane) * Tetra-, penta- and hexavalent phosphorus, silicon, and sulfur compounds (e.g. PCl5, PF5, SF6, sulfuranes and persulfuranes) * Noble gas compounds (ex. xe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stannatrane
A stannatrane (IUPAC: 1-aza-5-stannabicyclo .3.3ndecane) is a tin-based atrane belonging to the larger class of organostannanes. Though the term stannatrane is often used to refer to the more commonly employed carbastannatrane, azastannatranes have also been synthesized (prefix refers to the identity of the atom bound directly to tin center). Stannatrane reagents offer highly selective methods for the incorporation of "R" substituents in complex molecules for late-stage diversification. These reagents differ from their tetraalkyl organostannane analogues in that there is no participation of dummy ligands in the transmetalation step, offering selective alkyl transfer in Stille Coupling reactions. These transmetalating agents are known to be air- and moisture-stable, as well as generally less toxic than their tetraalkyl counterparts. History and structural properties The first carbastannatrane was reported in 1984 by Jurkschat and Tzschach. By reaction of an amino-tri Grignar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation when subjected to certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the ''reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base (chemistry)
In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form Hydroxide ions OH−. These ions can react with hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their applica .... A base was therefore a metal hydroxide such as Sodium hydroxide, NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proazaphosphatrane
In chemistry, a Verkade base (or Verkade superbase) is a superbase with the formula P(MeNCH2CH2)3N. A colorless oil, it is an aminophosphine although its inventor John Verkade called it proazaphosphatrane. The trimethyl derivative or 2,5,8,9-tetraza-1-phosphabicyclo .3.3ndecane is the simplest. Diverse analogues of the Verkade base are known, e.g. with isopropyl groups in place of methyl. Synthesis and reactions The Verkade base is generated by the reaction of N,N,N-trimethyl tren with tris(dimethylamino)phosphine: :P(NMe2)3 + (MeNHCH2CH2)3N → P(MeNCH2CH2)3N + 3 Me2NH The principal reaction of the Verkade base is protonation. The proton is attacked by the Verkade base at phosphorus, which induces the formation of a transannular P-N bond. The product exemplifies the structure of an atrane. 290 px, left, Protonation of Verkade base. The conjugate acid P(MeNCH2CH2)3Nsup>+ has a pKa of 32.9 in acetonitrile. For comparison, the conjugate acid of triethylamine has a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
