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Aminophosphine
In organophosphorus chemistry, an aminophosphine is a compound with the formula R3−nP(NR2)n where R = H or an organic substituent, and n = 0, 1, 2. At one extreme, the parent H2PNH2 is lightly studied and fragile, but at the other extreme tris(dimethylamino)phosphine (P(NMe2)3) is commonly available. Intermediate members are known, such as Ph2PN(H)Ph. These compounds are typically colorless and reactive toward oxygen. They have pyramidal geometry at phosphorus. Parent members The fundamental aminophosphines have the formulae PH2−n(NH2)n (n = 1, 2, 3). These species cannot be isolated in a practical quantities, although they have been examined theoretically. H2NPH2 is predicted to be more stable than the P(V) tautomer HN=PH3. With secondary amines, the chemistry is more straightforward. Trisaminophosphines are prepared by treatment of phosphorus trichloride with secondary amines: :PCl3 + 6 HNMe2 → (Me2N)3P + 3 [H2NMe2]Cl Aminophosphine chlorides The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphenium
Phosphenium ions, not to be confused with phosphonium or Phosphirenium ion, phosphirenium, are divalent cations of phosphorus of the form [PR2]+. Phosphenium ions have long been proposed as reaction intermediates. Synthesis Legacy methods The first cyclic phosphenium compounds were reported in 1972 by Suzanne Fleming and coworkers. Acyclic phosphenium compounds were synthesized by Fleming's thesis advisor Robert W. Parry, Robert Parry in 1976. Methods Several methods exist for the preparation of two-coordinate phosphorus ions. A common method involves halide abstraction from halophosphines: :R2PCl + AlCl3 → [R2P+][] Protonolysis of tris(dimethylamino)phosphine affords the phosphenium salt: :P(NMe2)3 + 2 HOTf → [P(NMe2)2]OTf + [HNMe2]OTf Weakly coordinating anions are desirable. Triflic acid is often used. N-heterocyclic phosphenium (NHP) have also been reported. Reaction of PI3 with the α-diimine yields the NHP cation by Redox, reduction of the diimine a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tris(dimethylamino)phosphine
Tris(dimethylamino)phosphine is an organophosphorus compound with the formula P(NMe2)3 (Me = methyl). It is a colorless oil at room temperature, and is one of the most common aminophosphines. Its structure has been determined by X-ray crystallography. Tris(dimethylamino)phosphine acts as a base. It reacts with oxygen to give hexamethylphosphoramide, O=P(NMe2)3, and with sulfur to give the corresponding compound hexamethylthiophosphoramide, S=P(NMe2)3. It can also act as a ligand, forming complexes with a variety of metal centers. Its steric and electronic properties are similar to those of triisopropylphosphine. Because of its affinity for sulfur, tris(dimethylamino)phosphine is also effective as a desulfurization agent, e.g., in the conversion of dibenzyl disulfide into dibenzyl sulfide:{{cite journal, title= Sulfide Synthesis: Benzyl Sulfide, first1=David N. , last1=Harpp, first2= Roger A., last2=Smith , journal=Org. Synth., year=1978, volume=58, page=138, doi= 10.15227/org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphorus Chemistry
Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX (nerve agent), VX nerve agents. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds. Phosphorus, like nitrogen, is in pnictogen, group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties. The definition of organophosphorus compounds is variable, which can lead to confusion. In industrial and environmental chemistry, an organophosphorus compound need contain only an organic substituent, but need not have a direct phosphorus-carbon (P-C) bond. Thus a large proportion of pesticides (e.g., malathion), are often included in this class of compound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphonium
In polyatomic cations with the chemical formula (where R is a hydrogen or an alkyl, aryl, or halide group). These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions. Types of phosphonium cations Protonated phosphines The parent phosphonium is as found in the iodide salt, phosphonium iodide. Salts of the parent are rarely encountered, but this ion is an intermediate in the preparation of the industrially useful tetrakis(hydroxymethyl)phosphonium chloride: :PH3 + HCl + 4 CH2O → Many organophosphonium salts are produced by protonation of primary, secondary, and tertiary phosphines: :PR3 + H+ → The basicity of phosphines follows the usual trends, with R = alkyl being more basic than R = aryl. Tetraorganophosphonium cations The most common phosphonium compounds have four organic substituents attached to phosphorus. The quaternary phosphonium cations include tetraphenylphosphonium, (C6H5)4P+ and tetramethylphosphoni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Iodide
Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one hydrogen atom by an atom of iodine. It is naturally emitted by rice plantations in small amounts. It is also produced in vast quantities estimated to be greater than 214,000 tons annually by algae and kelp in the world's temperate oceans, and in lesser amounts on land by terrestrial fungi and bacteria. It is used in organic synthesis as a source of methyl groups. Preparation and handling Iodomethane is formed via the exothermic reaction that occurs when iodine is added to a mixture of methanol with red phosphorus. The iodinating reagent is phosphorus triiodide that is formed ''in situ:'' :3 CH3OH + PI3 → 3 CH3I + H2PO3H Alternatively, it is prepared from the reaction of dimethyl sulfate with potassium iodide in the presence of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethyl Group
In organic chemistry, an ethyl group (abbr. Et) is an alkyl substituent with the formula , derived from ethane (). ''Ethyl'' is used in the International Union of Pure and Applied Chemistry's nomenclature of organic chemistry for a saturated two-carbon moiety in a molecule, while the prefix "''eth-''" is used to indicate the presence of two carbon atoms in the molecule. Ethylation Ethylation is the formation of a compound by introduction of the ethyl group. The most widely practiced example of this reaction is the ethylation of benzene with ethylene to yield ethylbenzene, a precursor to styrene, which is a precursor to polystyrene. Approximately 24.7 million tons of ethylbenzene were produced in 1999. :: Many ethyl-containing compounds are generated by electrophilic ethylation, i.e. treatment of nucleophiles with sources of Et+. Triethyloxonium tetrafluoroborate t3OF4 is such a reagent. For good nucleophiles, less electrophilic reagents are employed, such as ethyl h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(diethylamino)chlorophosphine
Bis(diethylamino)chlorophosphine is an organophosphorus compound with the formula (Et2N)2PCl (Et = ethyl). A colorless liquid, it serves as a masked source of PCl2+. Synthesis and reactions The compound is prepared by treatment of phosphorus trichloride with diethylamine: :4 Et2NH + PCl3 → (Et2N)2PCl + 2 Et2NH2Cl Illustrative of its utility is the synthesis of 1,2-bis(dichlorophosphino)benzene. The synthesis involves sequential lithiation of 1,2-dibromobenzene followed by treatment with (Et2N)2PCl:{{cite journal, doi=10.1021/ol010219y, pmid=11735590, title=BINOL-Based Diphosphonites as Ligands in the Asymmetric Rh-Catalyzed Conjugate Addition of Arylboronic Acids, journal=Organic Letters, volume=3, issue=25, pages=4083–4085, year=2001, last1=Reetz, first1=Manfred T., last2=Moulin, first2=Dominique, last3=Gosberg, first3=Andreas :C6H4Br2 + BuLi → C6H4(Br)Li + BuBr :C6H4(Br)Li + (Et2N)2PCl → C6H4(Br)(P(NEt2)2) + LiCl :C6H4(Br)(P(NEt2)2) + BuLi → C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphosphine
Diphosphane, or diphosphine, is an inorganic compound with the chemical formula P2H4. This colourless liquid is one of several binary phosphorus hydrides. It is the impurity that typically causes samples of phosphine to ignite in air. Properties, preparation, reactions Diphosphane adopts the gauche conformation (like hydrazine, less symmetrical than shown in the image) with a P−P distance of 2.219 angstroms. It is nonbasic, unstable at room temperature, and Pyrophoricity, spontaneously flammable in air. It is only poorly soluble in water but dissolves in organic solvents. Its 1H NMR spectrum consists of 32 lines resulting from an A2XX'A'2 splitting system. Diphosphane is produced by the hydrolysis of calcium monophosphide, which can be described as the Ca2+ derivative of . According to an optimized procedure, hydrolysis of 400 g of CaP at −30 °C gives about 20 g of product, slightly contaminated with phosphine. Reaction of diphosphane with butyllithium affords a varie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,2-Bis(dichlorophosphino)benzene
1,2-Bis(dichlorophosphino)benzene is an organophosphorus compound with the formula C6H4(PCl2)2. A viscous colorless liquid, it is a precursor to chelating diphosphines of the type C6H4(PR2)2. It is prepared from 1,2-dibromobenzene by sequential lithiation followed by treatment with (Et2N)2PCl (Et = ethyl), which affords C6H4 (NEt2)2sub>2. This species is finally cleaved with hydrogen chloride: :C6H4 (NEt2)2sub>2 + 8 HCl → C6H4(PCl2)2 + 4 Et2NH2Cl Related compounds *1,2-Bis(dichlorophosphino)ethane 1,2-Bis(dichlorophosphino)ethane is an organophosphorus compound with the formula (CH2PCl2)2. A colorless liquid, it is a precursor to chelating diphosphines. Synthesis and reactions It is prepared by the reaction of ethylene, white phosphorus, a ... References {{DEFAULTSORT:Bis(dichlorophosphino)benzene, 1,2- Phosphines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grignard Reagent
A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide . They are a subclass of the organomagnesium compounds. Grignard compounds are popular reagents in organic synthesis for creating new carbon-carbon bonds. For example, when reacted with another halogenated compound in the presence of a suitable catalyst, they typically yield and the magnesium halide as a byproduct; and the latter is insoluble in the solvents normally used. In this aspect, they are similar to organolithium reagents. Pure Grignard reagents are extremely reactive solids. They are normally handled as solutions in solvents such as diethyl ether or tetrahydrofuran; which are relatively stable as long as water is excluded. In such a medium, a Grignard reagent is invariably present as a complex with the magnesium atom conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl. Reactions Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a polar covalent bond. The chlorine atom is much more electronegative than the hydrogen atom, which makes this bond polar. Consequently, the molecule has a large dipole moment with a negative partial charge (δ−) at the chlorine atom and a positive partial charge (δ+) at the hydrogen atom. In part because of its high polarity, HCl is very soluble in water (and in other polar solvents). Upon contact, and HCl combine to form hydronium cations and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcoholysis
In chemistry, solvolysis is a type of nucleophilic substitution (S1/S2) or elimination reaction, elimination where the nucleophile is a solvent molecule. Characteristic of S1 reactions, solvolysis of a chirality (chemistry), chiral reactant affords the racemate. Sometimes however, the stereochemical course is complicated by intimate ion pairs, whereby the leaving anion remains close to the carbocation, effectively shielding it from an attack by the nucleophile. Particularly fast reactions can occur by neighbour group participation, with nonclassical ions as intermediates or transition states. Examples For certain nucleophiles, solvolysis reactions are classified. Solvolysis involving water (molecule), water is called hydrolysis. Related terms are alcoholysis (Alcohol (chemistry), alcohols) and specifically methanolysis (methanol), acetolysis, ammonolysis (ammonia), and aminolysis (alkyl amines). Glycolysis is however an older term for the multistep conversion of glucose to pyruvat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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