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Trimethylphosphine
Trimethylphosphine is an organophosphorus compound with the formula P(CH3)3, commonly abbreviated as PMe3. This colorless liquid has a strongly unpleasant odor, characteristic of alkylphosphines. The compound is a common ligand in coordination chemistry. Structure and bonding It is a pyramidal molecule with approximate ''C''3''v'' point group, symmetry. The C–P–C bond angles are approximately 98.6°. The C–P–C bond angles are consistent with the notion that phosphorus predominantly uses the 3p orbitals for forming bonds and that there is little sp hybridization of the phosphorus atom. The latter is a common feature of the chemistry of phosphorus. As a result, the lone pair of trimethylphosphine has predominantly s-character as is the case for phosphine, PH3. PMe3 can be prepared by the treatment of triphenyl phosphite with methylmagnesium chloride: : 3 CH3MgCl + P(OC6H5)3 → P(CH3)3 + 3 C6H5OMgCl The synthesis is conducted in dibutyl ether, from which the more volatil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylphosphine
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry. PPh3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether. Preparation and structure Triphenylphosphine can be prepared in the laboratory by treatment of phosphorus trichloride with phenylmagnesium bromide or phenyllithium. The industrial synthesis involves the reaction between phosphorus trichloride, chlorobenzene, and sodium: :PCl3 + 3 PhCl + 6 Na → PPh3 + 6 NaCl Triphenylphosphine crystallizes in triclinic and monoclinic modification. In both cases, the molecule adopts a pyramidal structure with propeller-like arrangement of the thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triethylphosphine
Triethylphosphine is the organophosphorus compound with the formula P(CH2CH3)3, commonly abbreviated as PEt3. It is a colorless liquid with an unpleasant odor characteristic of alkylphosphines. The compound is a common ligand in organometallic chemistry, such as in auranofin. Structure and simple reactions It is a pyramidal molecule with approximate ''C''3''v'' symmetry. PEt3 is usually prepared using Grignard reagents: : 3 CH3CH2MgCl + P(OC6H5)3 → P(CH2CH3)3 + 3 C6H5OMgCl PEt3 reacts with strong acids to give salts PEt3.Annette Schier and Hubert Schmidbaur "P-Donor Ligands" in Encyclopedia of Inorganic Chemistry 2006, Wiley-VCH, Weinheim. This reaction is reversible. Similarly, it is also easily alkylated to give phosphonium derivatives. PEt3 is easily oxidised to the phosphine oxide with oxygen. Coordination chemistry Triethylphosphine is a highly basic ligand that forms coordination complexes with many metals. As a ligand, triethylphosphine's Tolman cone angle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphine
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (). With traces of present, is spontaneously flammable in air ( pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm. Phosphine has a trigonal pyramidal structure. Phosphines are compounds that include and the organophosphines, which are derived from by substituting one or more hydrogen atoms with organic groups. They have the general formula . Phosphanes are saturated phosphorus hydrides of the form , such as triphosphane. Phosphine () is the smallest of the phosphines and the smallest of the phosphanes. History Philippe Gengembre (1764–1838), a student of Lavoisi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis acids and bases, Lewis bases. The nature of metal–ligand bonding can range from covalent bond, covalent to ionic bond, ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acids and bases, Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity (chemistry), reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenyl Phosphite
Triphenyl phosphite is the organophosphorus compound with the formula P(OC6H5)3. It is a colourless viscous liquid. Preparation Triphenylphosphite is prepared from phosphorus trichloride and phenol in the presence of a catalytic amount of base: :PCl3 + 3 HOC6H5 → P(OC6H5)3 + 3 HCl Reactions Triphenylphosphite is a precursor to trimethylphosphine, it serves as a source of P3+ that is less electrophilic than phosphorus trichloride: : (C6H5O)3P + 3CH3MgBr → P(CH3)3 + 3"MgBrOC6H5" Triphenylphosphite is quaternized by methyl iodide: : (C6H5O)3P + CH3I → H3(C6H5O)3Psup>+I− Coordination complexes Triphenylphosphite is a common ligand in coordination chemistry. It forms zero-valent complexes of the type M (OC6H5)3sub>4 (M = Ni, Pd, Pt). The nickel complex can be prepared by displacement of the diene from bis(cyclooctadiene)nickel: : Ni(COD)2 + 4 P(OC6H5)3 → Ni (OC6H5)3sub>4 + 2 COD Related complexes are homogeneous catalysts for the hydrocyanation of alkenes. It also form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand Cone Angle
In coordination chemistry, the ligand cone angle (θ) is a measure of the steric bulk of a ligand in a transition metal coordination complex. It is defined as the solid angle formed with the metal at the vertex of a cone and the outermost edge of the van der Waals spheres of the ligand atoms at the perimeter of the base of the cone. Tertiary phosphine ligands are commonly classified using this parameter, but the method can be applied to any ligand. The term ''cone angle'' was first introduced by Chadwick A. Tolman, a research chemist at DuPont. Tolman originally developed the method for phosphine ligands in nickel complexes, determining them from measurements of accurate physical models. Asymmetric cases The concept of cone angle is most easily visualized with symmetrical ligands, e.g. PR3. But the approach has been refined to include less symmetrical ligands of the type PRR′R″ as well as diphosphines. In such asymmetric cases, the substituent angles' half angles, , are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Bromide
Bromomethane, commonly known as methyl bromide, is an organobromine compound with chemical formula, formula Carbon, CHydrogen, H3Bromine, Br. This colorless, odorless, nonflammable gas is Bromine cycle, produced both industrially and biologically. It is a recognized ozone depletion, ozone-depleting chemical. According to the IPCC Fifth Assessment Report, it has a Global warming potential, global warming potential of 2. The compound was used extensively as a pesticide until being phased out by most countries in the early 2000s. From a chemistry perspective, it is one of the halomethanes. Occurrence and manufacture Marine organisms are estimated to produce 56,000 tonnes annually. It is also produced in small quantities by certain terrestrial plants, such as members of the family Brassicaceae. In 2009, an estimated 24,000 tonnes of methyl bromide were produced. Its production was curtailed by the Montreal Protocol, such that in 1983, production was nearly twice that of 2009 level ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tertiary Phosphines
Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to: * Tertiary period, an obsolete geologic period spanning from 66 to 2.6 million years ago * Tertiary (chemistry), a term describing bonding patterns in organic chemistry * Tertiary care, specialized consultative healthcare * Tertiary color, a color made up by mixing one primary color with one secondary color, in a given color space * Tertiary consumer, in ecology * Tertiary education, educational levels following the completion of secondary education such as university or trade school * Tertiary feathers or tertials, feathers attached to humerus or inner portion of the wings of birds * Tertiary sector of the economy, or the service sector * Tertiary source, in research * Tertiary stress, a proposed level of stress in phonetics * In biochemistry, the tertiary structure of a protein is its overall shape, also known as its fold * Tertiary, a member of a third order religious group See also * Tern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry. Hydrogen peroxide is a reactive oxygen species and the simplest peroxide, a compound having an oxygen–oxygen single bond. It decomposes slowly into water and elemental oxygen when exposed to light, and rapidly in the presence of organic or reactive compounds. It is typically stored with a Stabilizer (chemistry), stabilizer in a weakly acidic solution in an opaque bottle. Hydrogen peroxide is found in biological systems including the human body. Enzymes that u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Hypochlorite
Sodium hypochlorite is an alkaline inorganic chemical compound with the formula (also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach. It is the sodium salt of hypochlorous acid, consisting of sodium cations () and hypochlorite anions (, also written as and ). The anhydrous compound is unstable and may decompose explosively. It can be crystallized as a pentahydrate , a pale greenish-yellow solid which is not explosive and is stable if kept refrigerated. Sodium hypochlorite is most often encountered as a pale greenish-yellow dilute solution referred to as chlorine bleach, which is a household chemical widely used (since the 18th century) as a disinfectant and bleaching agent. In solution, the compound is unstable and easily decomposes, liberating chlorine, which is the active principle of such products. Sodium hypochlorite is still the most important chlorine-based bleach. Its corrosive properties, common availability, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphine Oxide
Phosphine oxide is the inorganic compound with the formula H3PO. Although stable as a dilute gas, liquid or solid samples are unstable. Unlike many other compounds of the type POxHy, H3PO is rarely discussed and is not even mentioned in major sources on main group chemistry. H3PO has been detected by mass spectrometry as a reaction product of oxygen and phosphine, by means of FT-IR in a phosphine-ozone reaction Generation Phosphine oxide has been claimed as the product of a reaction of phosphine with vanadium oxytrichloride as well as with chromyl chloride. The product was obtained by matrix isolation. It has also been reported relatively stable in a water-ethanol solution by electrochemical oxidation of white phosphorus, where it slowly disproportionates into phosphine and hypophosphorous acid. Phosphine oxide is reported as an intermediate in the room-temperature polymerization of phosphine and nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrophoricity
A substance is pyrophoric (from , , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolithium compounds and triethylborane. Pyrophoric materials are often water-reactive as well and will ignite when they contact water or humid air. They can be handled safely in atmospheres of argon or (with a few exceptions) nitrogen. Fire classification fire extinguishers are designated for use in fires involving metals but not pyrophoric materials in general. A related concept is hypergolicity, in which two compounds spontaneously ignite when mixed. Uses The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose. Practical applications include the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
