Phenylmagnesium bromide , with the simplified formula C 6 H 5 MgBr , is a magnesium -containing organometallic compound . It is commercially available as a solution in diethyl ether or tetrahydrofuran (THF). Phenylmagnesium bromide is a Grignard reagent . It is often used as a synthetic equivalent for the phenyl "Ph " synthon .
18-430: PMB can stand for: Phenylmagnesium bromide , a reagent p-Methoxybenzyl, in the benzyl group Nickname of Pietermaritzburg , KwaZulu-Natal, South Africa Picture Motion Browser , Sony software PMB (software) , a library system Postmenopausal bleeding , a menstrual condition Print Measurement Bureau , a Canadian media surveying company Private Mail Bag ,
36-628: A of conjugate acid, aqueous scale) Triphenylphosphine (IUPAC name: triphenylphosphane ) is a common organophosphorus compound with the formula P(C 6 H 5 ) 3 and often abbreviated to P Ph 3 or Ph 3 P. 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 . PPh 3 exists as relatively air stable, colorless crystals at room temperature. It dissolves in non-polar organic solvents such as benzene and diethyl ether . Triphenylphosphine can be prepared in
54-463: A service provided by some postal authorities Private mailbox at a commercial mail receiving agency Pro-Música Brasil , record label body Brazilian Woman's Party , brazilian right-wing party Pierre-Marc Bouchard (born 1984), Canadian ice hockey player Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title PMB . If an internal link led you here, you may wish to change
72-430: Is a strong nucleophile as well as a strong base . It can abstract even mildly acidic protons, thus the substrate must be protected where necessary. It often adds to carbonyls , such as ketones, aldehydes. With carbon dioxide, it reacts to give benzoic acid after an acidic workup. If three equivalents are reacted with phosphorus trichloride , triphenylphosphine can be made. Triphenylphosphine 2.73 (p K
90-424: Is exploited in its use to deoxygenate organic peroxides, which generally occurs with retention of configuration: It is also used for the decomposition of organic ozonides to ketones and aldehydes, although dimethyl sulfide is more popular for the reaction as the side product, dimethyl sulfoxide is more readily separated from the reaction mixture than triphenylphosphine oxide. Aromatic N -oxides are reduced to
108-526: Is indicated by its reactivity toward electrophilic alkenes, such as Michael-acceptors, and alkyl halides. It is also used in the synthesis of biaryl compounds, such as the Suzuki reaction . PPh 3 combines with alkyl halides to give phosphonium salts . This quaternization reaction is particularly fast for benzylic and allylic halides: These salts, which can often be isolated as crystalline solids, react with strong bases to form ylides , which are reagents in
126-481: Is prepared from triphenylphosphine dichloride: PPh 3 is a weak base (aqueous p K aH = 2.73, determined electrochemically), although it is a considerably stronger base than NPh 3 (estimated aqueous p K aH < –3). It forms isolable triphenylphosphonium salts with strong acids such as HBr: PPh 3 is widely used in organic synthesis . The properties that guide its usage are its nucleophilicity and its reducing character. The nucleophilicity of PPh 3
144-583: The Staudinger reaction . Illustrative is the preparation of triphenylphosphine phenylimide : The phosphanimine can be hydrolyzed to the amine. Typically the intermediate phosphanimine is not isolated. Cl 2 adds to PPh 3 to give triphenylphosphine dichloride ([PPh 3 Cl]Cl), which exists as the moisture-sensitive phosphonium halide . This reagent is used to convert alcohols to alkyl chlorides in organic synthesis . Bis(triphenylphosphine)iminium chloride (PPN Cl , formula [(C 6 H 5 ) 3 P) 2 N]Cl
162-507: The Wittig reactions . Aryl halides will quaternize PPh 3 to give tetraphenylphosphonium salts: The reaction however requires elevated temperatures and metal catalysts. In the Mitsunobu reaction , a mixture of triphenylphosphine and diisopropyl azodicarboxylate ("DIAD", or its diethyl analogue, DEAD ) converts an alcohol and a carboxylic acid to an ester. DIAD is reduced as it serves as
180-505: The "labile" S content of a sample, say vulcanized rubber. Triphenylphosphine selenide, Ph 3 PSe, may be easily prepared via treatment of PPh 3 with red (alpha-monoclinic) Se . Salts of selenocyanate , SeCN , are used as the Se source. PPh 3 can also form an adduct with Te, although this adduct primarily exists as (Ph 3 P) 2 Te rather than PPh 3 Te. Aryl azides react with PPh 3 to give phosphanimines, analogues of OPPh 3 , via
198-873: The corresponding amine in high yield at room temperature with irradiation: Sulfonation of PPh 3 gives tris(3-sulfophenyl)phosphine, P(C 6 H 4 -3-SO 3 ) 3 ( TPPTS ), usually isolated as the trisodium salt. In contrast to PPh 3 , TPPTS is water-soluble, as are its metal derivatives. Rhodium complexes of TPPTS are used in certain industrial hydroformylation reactions. Lithium in THF as well as Na or K react with PPh 3 to give Ph 2 PM (M = Li, Na, K). These salts are versatile precursors to tertiary phosphines. For example, 1,2-dibromoethane and Ph 2 PM react to give Ph 2 PCH 2 CH 2 PPh 2 . Weak acids such ammonium chloride , convert Ph 2 PM (M = Li, Na, K) into diphenylphosphine : Triphenylphosphine binds well to most transition metals , especially those in
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#1732855961701216-407: The fact that OPPh 3 is more polar and hence more soluble in polar solvents than PPh 3 . Triphenylphosphine abstracts sulfur from polysulfide compounds, episulfides, and elemental sulfur . Simple organosulfur compounds such as thiols and thioethers are unreactive, however. The phosphorus-containing product is triphenylphosphine sulfide , Ph 3 PS. This reaction can be employed to assay
234-463: The form of turnings. A small amount of iodine may be used to activate the magnesium to initiate the reaction. Coordinating solvents such as ether or THF, are required to solvate (complex) the magnesium(II) center. The solvent must be aprotic since alcohols and water contain an acidic proton and thus react with phenylmagnesium bromide to give benzene . Carbonyl-containing solvents, such as acetone and ethyl acetate , are also incompatible with
252-503: The hydrogen acceptor, and the PPh 3 is oxidized to OPPh 3 . In the Appel reaction , a mixture of PPh 3 and CX 4 (X = Cl, Br) is used to convert alcohols to alkyl halides. Triphenylphosphine oxide (OPPh 3 ) is a byproduct. This reaction commences with nucleophilic attack of PPh 3 on CBr 4 , an extension of the quaternization reaction listed above. The easy oxygenation of PPh 3
270-651: The laboratory by treatment of phosphorus trichloride with phenylmagnesium bromide or phenyllithium . The industrial synthesis involves the reaction between phosphorus trichloride , chlorobenzene , and sodium: Triphenylphosphine crystallizes in triclinic and monoclinic modification. In both cases, the molecule adopts a pyramidal structure with propeller-like arrangement of the three phenyl groups. Triphenylphosphine undergoes slow oxidation by air to give triphenylphosphine oxide , Ph 3 PO: This impurity can be removed by recrystallisation of PPh 3 from either hot ethanol or isopropanol . This method capitalizes on
288-551: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=PMB&oldid=1253901666 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Phenylmagnesium bromide Phenylmagnesium bromide is commercially available as solutions of diethyl ether or THF . Laboratory preparation involves treating bromobenzene with magnesium metal, usually in
306-436: The middle and late transition metals of groups 7–10. In terms of steric bulk, PPh 3 has a Tolman cone angle of 145°, which is intermediate between those of P(C 6 H 11 ) 3 (170°) and P(CH 3 ) 3 (115°). In an early application in homogeneous catalysis , NiBr 2 (PPh 3 ) 2 was used by Walter Reppe for the synthesis of acrylate esters from alkynes , carbon monoxide , and alcohols . The use of PPh 3
324-524: The reagent. Although phenylmagnesium bromide is routinely represented as C 6 H 5 MgBr , the molecule is more complex. The compound invariably forms an adduct with two OR 2 ligands from the ether or THF solvent. Thus, the Mg is tetrahedral and obeys the octet rule . The Mg–O distances are 201 and 206 pm whereas the Mg–C and Mg–Br distances are 220 pm and 244 pm, respectively. Phenylmagnesium bromide
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