- 1,2-addition of diphosphine monoxide to a double bond of a titanocene carbene complex
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A titanocene carbene complex reacted with diphosphine monoxide to give R2PCH2PR2.
- Ushio, Jun-Ichi,Murakami, Hiroaki,Mizuta, Tsutomu,Miyoshi, Katsuhiko
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- Manganese Diphosphine and Phosphinoamine Complexes Are Effective Catalysts for the Production of Biofuel Alcohols via the Guerbet Reaction
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We report a variety of manganese-based catalysts containing both chelating diphosphine (bis(diphenylphosphino)methane (dppm: 1, 2, and 7) or 1,2-bis(diphenylphosphino)ethane (dppe: 3)), and mixed-donor phosphinoamine (2-(diphenylphosphino)ethylamine (dppea: 4-6)) ligands for the upgrading of ethanol and methanol to the advanced biofuel isobutanol. These catalysts show moderate selectivity up to 74% along with turnover numbers greater than 100 over 90 h, with catalyst 2 supported by dppm demonstrating superior performance. The positive effect of substituting the ligand backbone was also displayed with a catalyst supported by C-phenyl-substituted dppm (8) having markedly improved performance compared to the parent dppm catalysts. Catalysts supported by the phosphinoamine ligand dppea are also active for the upgrading of ethanol to n-butanol. These results show that so-called PNP-pincer ligands are not a prerequisite for the use of manganese catalysts in Guerbet chemistry and that simple chelates can be used effectively.
- King, Ashley M.,Sparkes, Hazel A.,Wingad, Richard L.,Wass, Duncan F.
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- Photoreactions of Palladium Phosphine Complex with Chloroalkane. Production of Ethylene with 1,2-Dichloroethane and Novel Photochromic Behavior
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Photoirradiation on 02(dppm)3> (dppm = bis(diphenylphosphino)methane) in 1,2-dichloroethane solution with visible light yields I2Cl2(dppm)2> (2) and ethylene quantitatively.Irradiation of 2 in various solutions shows interesting photochromic behavior.
- Tsubomura, Taro,Itsuki, Atsushi,Homma, Masahiko,Sakai, Ken
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- Rearrangement and redistribution reaction of Ph2PCH2TMS with PhAsCl2 or AsCl3
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The attempted synthesis of bis(diphenylphosphinomethyl) phenylarsane and tris(diphenylphosphinomethyl) arsane through condensation of chloro arsanes and diphenyl (trimethylsilylmethyl) phosphane yielded a number of side products originating from migratory and redox-reactions in addition to the targeted ligands. An unexpected, 1,3,4-phosphadiarssolan-1-ium salt was obtained and crystallographically characterized as an A-shaped chlorido adduct.
- Gupta, Arvind Kumar,Green, Joshua P.,Orthaber, Andreas
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p. 967 - 971
(2019/07/03)
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- Ethylene oligomerization catalyst systems having enhanced selectivity
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Disclosed herein is a catalyst system for selective oligomerization of ethylene, which comprises a P—C—C—P frame-work ligand, which is (R1)(R2)P—(R5)CHCH(R6)—P(R3)(R4), and a chromium-based metal compound. Also disclosed is a method of greatly enhancing the activity and selectivity of oligomerization, such as trimerization or tetramerization, using a ligand having a specific steric arrangement structure.
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Page/Page column 45
(2013/02/27)
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- ETHYLENE TETRAMERIZATION CATALYST SYSTEMS AND METHOD FOR PREPARING 1-OCTENE USING THE SAME
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Disclosed herein is a method of preparing 1-octene at high activity and high selectivity while stably maintaining reaction activity by tetramerizing ethylene using a chromium-based catalyst system comprising a transition metal or a transition metal precursor, a cocatalyst, and a P—C—C—P backbone structure ligand represented by (R1)(R2)P—(R5)CHCH(R6)—P(R3)(R4).
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Page/Page column 8
(2010/06/16)
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- Catalyst-free alcoholysis of phosphane-boranes: a smooth, cheap, and efficient deprotection procedure
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Catalyst-free alcoholytic deprotection of borane-protected phosphorus compounds offers a smooth, efficient, and clean alternative to existing deprotection methods. In this paper we report our results on the general applicability of deprotecting phosphane-
- Van Overschelde, Michel,Vervecken, Elias,Modha, Sachin G.,Cogen, Simon,Van der Eycken, Erik,Van der Eycken, Johan
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experimental part
p. 6410 - 6415
(2009/12/09)
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- A mild and efficient CsOH-promoted synthesis of ditertiary phosphines
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A mild and efficient method for the synthesis of ditertiary phosphines has been developed. In the presence of cesium hydroxide, molecular sieves, and DMF, various dihalides were coupled with diphenylphosphine at room temperature, and the results have demonstrated that this methodology offers a general synthetic procedure producing a variety of ditertiary phosphines in high yields.
- Honaker, Matthew T.,Salvatore, Ralph Nicholas
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p. 277 - 283
(2007/10/03)
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- CsOH-promoted P-alkylation: A convenient and highly efficient synthesis of tertiary phosphines
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A mild and efficient method for the synthesis of tertiary phosphines and ditertiary phosphines has been developed. In the presence of cesium hydroxide, molecular sieves and DMF at room temperature, various secondary phosphines and alkyl bromides were examined, and the results have demonstrated that this methodology offers a general synthetic procedure to produce tertiary phosphines in moderate to high yields. Optically active tertiary phosphine synthesis is also described.
- Honaker, Matthew T.,Sandefur, Benjamin J.,Hargett, James L.,McDaniel, Alicia L.,Salvatore, Ralph Nicholas
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p. 8373 - 7377
(2007/10/03)
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- Preparation of organohalosilanes
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When oganohalosilanes are prepared by charging a reactor with a contact mass containing a metallic silicon powder and a copper catalyst, and introducing an organohalide-containing gas into the reactor to effect the direct reaction, a poly(organo)phosphino compound is added to the contact mass. The invention is successful in producing organohalosilanes at a significantly improved production rate without reducing the selectivity of useful silane.
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- General route to halide-bridged organopalladium A-frame complexes and studies of reductive elimination from these bimetallic systems
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Reactions of [Pd2Cl2(μ-dppm)2] with RMgX (R = Me, Et, Bu, Ph, C6H4Me-4) at low temperature, followed by addition of CBr4 and excess NH4PF6 or 1 equiv of TIPF6, provided halide-bridged organopalladium A-frame complexes of the form [Pd2R2(μ-X)(μ-dppm)2]PF6. Mixed metal complexes were obtained similarly starting from [PdCtCl2(μ-dppm)2]. Unsymmetrical A-frames of the type [Pd2(C6H2Me3-2,4,6)R(μ-Cl)(μ-d ppm)2]+ were generated reaction of [Pd(C6H2Me3-2,4,6) (dppm)2]+ (obtained by treatment of [PdCl2 (cod)] w mesitylmagnesium bromide at low temperature, followed by 2 equiv of dppm) with [Pd2R2(μ-Cl)2 (AsPh3)2]. The organopalladium A-frames did not react readily with CO, but the corresponding acyl derivatives [Pd2(COR)2(μ-Cl)(μ-dppm)2]PF6 were produced by carbonylation of [Pd2R2(μ-Cl)2(AsPh3)2] followed by addition of dppm (R = Me, Et, Bn). Thermal decomposition of [Pd2(CH2Ph)2(μ-Cl)(μ-dppm)2]Cl was found to be first order in A-frame and resulted in quantitative formation of [Pd2Cl2(μ-dppm)2] and 1,2-diphenylethane. The methyl and aryl complexes underwent both reductive elimination and hydrogen abstraction reactions. [Pd2Et2(μ-Br)(μ-ddpm)2]PF6 decomposed by β-hydride elimination and subsequent reductive elimination to yield ethene and ethane, whereas the butyl derivative gave both 1- and 2-butene. Acetic acid was formed when [Pd2(COMe)2(μ-Cl)(μ-dppm)2]PF6 was heated in dmso-d6 solution, but decarbonylation was the predominant process in dioxane. The molecular structures of [Pd2(CH2Ph)2(μ-Br)(μ-dppm)2] PF6·H2O, 2C6H6 and [Pd2Cl2(μ-Cl)(μ-dppm)2]OH· 0.5(CH3)2CO are also described.
- Stockland Jr., Robert A.,Janka, Mesfin,Hoel, Gretchen R.,Rath, Nigam P.,Anderson, Gordon K.
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p. 5212 - 5219
(2008/10/08)
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- Structure of diiodine adducts of some di- and tri-tertiaryphosphines in the solid state and in solution
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A series of ditertiaryphosphine-tetraiodine adducts R2P(I2)(CH2)nP(I2)R 2 (R = Ph, n = 1-4; R = PhCH2 or o-CH3C6H4, n = 2) and two tritertiaryphosphine-hexaiodine adducts, PhP(CH2CH2PPh2)2I6 and CH3C(CH2-PPh2)3I6 have been prepared and characterised by 31P-{H} solution NMR and Raman spectroscopy. In the case of Ph2P(I2)(CH2)nP(I 2)Ph2 (n = 2 or 4), 31P-{H} NMR magic angle spinning NMR spectroscopy has been used to investigate the nature of the compounds in the solid state. In agreement with our previous extensive studies on the monophosphine derivatives, R3PI2, the tetraiododiphosphine compounds Ph2P(I2)(CH2)nP(I 2)Ph2 (n = 2 or 4) isolated from diethyl ether contain molecular four-co-ordinate phosphorus centres onto which the diiodine is bound as a linear spoke, as indicated by their 3IP-{H} NMR shifts obtained in CDCl3 solution. Again, in agreement with our previous solution studies of the monophosphine derivatives R3PI2, the diphosphine-tetraiodine adducts completely ionise in CDCl3 solution to produce the ionic compounds [R2P(I)(CH2)nP(I)R2]2I; the solution 31P-{H} NMR shifts are very similar to analogous solution shifts previously assigned to [R3PI]I. The Raman band assignable to v(P-I) has been identified for the compounds and a further band at lower frequency has been observed and assigned to v(I-I). Although the solid-state NMR spectra of the triphosphine-hexaiodine adducts were not recorded, a band assignable, to v(I-I) was observed in the Raman spectrum, suggesting the molecular four-co-ordinate spoke structure also prevails for these hexaiodotritertiaryphosphine compounds in the solid state. From solution 31P-{H} NMR shifts these adducts also appear to ionise in CDCl3 solution.
- Bricklebank, Neil,Godfrey, Stephen M.,McAuliffe, Charles A.,Deplano, Paula,Mercuri, Marie L.,Sheffield, Joanne M.
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p. 2379 - 2382
(2007/10/03)
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- ZUR REAKTION VON PHOSPHORVERBINDUNGEN MIT SCHWESINGER BASEN-I P-C-BINDUNGKNUEPFUNG AN P-H-FUNKTIONELLEN PHOSPHORVERBINDUNGEN
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Secondary and tertiary phosphines (RR'PH; R2R'P) may be synthesized by alkylation of primary or secondary phosphines with organo halides (R' = Et, n-C7H15, Bz, Me3Si; X = Cl, Br) in the presence of Schwesinger bases as auxillary bases in high yields.Alkylation of diphenylphosphine with alkylene dihalides and Schwesinger bases affords alkylendiphosphines. Key words: Alkylation; secondary and tertiary phosphines; Schwesinger bases.
- Uhlig, Frank,Puschner, Beatrix,Herrmann, Eckhard,Zobel, Bernhard,Bernhardt, Henry,Uhlig, Wolfram
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p. 155 - 164
(2007/10/02)
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- Radical Cations of Bis(diphenylphosphino) Derivatives (Ph2P-R-PPh2): The Formation of Localized, Cyclic, and Dimeric Configurations. An ESR and Quantum Chemical Study
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A matrix ESR study on radiogenic radical cations of Ph2P-R-PPh2 derivatives with various linkers (R) is presented.The experiments show that in a frozen dichloromethane solution the radical cations can adopt localized (Ph2PR*+), cyclic , and dimeric (Ph2RP*-PRPh2+) configurations, depending on the nature of the linker.The cyclic and dimeric products are formed in the reaction of a localized cation with a second free-electron pair, resulting in an intra- or intermolecular three-electron P-P ?* bond, respectively.The formation of the cyclic structure, with a strongly bent P-P ?* bond, requires a specific proximate position of the two phosphine moieties in the precursor molecule.The mutual orientation of the two free-electron pairs of the precursors is assessed by NMR via the nJPP spin-spin coupling constant.Ab initio UHF quantum chemical calculations at the 3-21G*/SCF level support the assignments.
- Janssen, Rene A. J.,Aagaard, Olav M.,Cabbolet, Marcoen J. T. F.,Waal, Bas F. M. de
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p. 9256 - 9263
(2007/10/02)
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- Catalytic (co)dimerization of alkyl acrylates
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The alkyl acrylates, e.g., methyl or ethyl acrylate, are improvedly dimerized, or codimerized with a conjugated diene, by contacting same with a catalytically effective amount of (a) at least one palladium source, (b) at least one organophosphorus(III) compound, and (c) at least one hydracid HY, the anion Y- of which does not coordinate with palladium ions.
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- Synthesis and reactivity of Ph2PCH2PPh2- (dppm-) stabilized Pd-Co and Pd-Pt-Co clusters. Effect of platinum versus Palladium on the neighboring palladium center
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The quantitative and regioselective synthesis of the mixed-metal cluster [PdPtCo2(CO)7(dppm)2] (1b) was achieved by the reaction of the bimetallic complex [PdPtCl2(dppm)2] (dppm = μ-Ph2PCH2PPh2) with [Co(CO)4]-. As a result of phosphorus migration from palladium to cobalt, formal insertion of the Co(CO)3 fragment into a metal-phosphorus bond of the precursor exclusively occurs into the more labile P→Pd bond. The presence of numerous potential reaction centers (e.g., metal(s), metal-metal bonds, and CO and dppm ligands) in these clusters led to an investigation of the site selectivity toward attack by nucleophiles. The lability of the exocyclic Co(CO)4 fragment was evidenced and compared between 1b and [Pd2Co2(CO)7(dppm)2] (1a). Although a Pd-Co bond is involved, this lability is very sensitive to the neighboring metal center (Pd or Pt). Transmission of electronic effects from one metal center to another was evidenced, and a platinum effect was observed in dissociating solvents, where 1a is partly dissociated but 1b is completely dissociated into [PdPtCo(CO)3(S)(dppm)2][Co(CO)4] (S = solvent), This is a reversible process, as is the equilibrium between 1 and halide anions. Solvento clusters were prepared that possess a labile coordination site on Pd leading to completely regioselective reactions with donor molecules, e.g., phosphines, CO, or C2Ph2. These ligands are labile (PR3 2Ph2 a platinum effect on the reactive Pd center. The tris[bis(diphenylphosphino)methane] cationic cluster [Pd2Co(CO)2(dppm)3]+ was isolated, in which all the metal-metal bonds are bridged by dppm ligands. Spectroscopic IR and 1H, 31P{1H}, and, sometimes, 195Pt{1H} NMR data are discussed and confirm that in all these reactions the basic PdMCo(dppm)2 (M = Pd, Pt) framework is maintained, thus showing a certain robustness and that the reactions investigated all take place in the plane of this framework. The Co(CO)3P fragment in the triangulo clusters reported in this work behaves as a neutral 3-electron donor organometallic bridging group vs the Pd-Pd or Pt-Pd unit.
- Braunstein, Pierre,De Méric De Bellefon, Claude,Ries, Michel
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p. 1338 - 1346
(2008/10/08)
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- Synthesis and reactivity of cobalt dimers of the type Co2(CO)3(L-L)2I2. Crystal structure of [Co2(CO)2(μ-CO) (μ-I) (Me2PCH2PMe2) (Ph2PCH2PPh2)]I
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The cobalt dimers Co2(CO)3(L-L)2, L-L = Ph2PCH2PPh2 (dppm) and Me2PCH2PMe2 (dmpm), are oxidized by iodine in the presence of bis(diphenylphosphino)methane to yield the ionic complexes [Co2(CO)3(L-L)(L-L)′]I. In a similar fashion, Co2(CO)6(dppm) reacts with elemental sulfur to yield Co2(CO)3(dppm)2S. The complex [Co2(CO)3(dmpm)(dppm)I]I crystallizes in the P21/n space group with dimensions a = 10.956 (3) A, b = 15.881 (6) ?, c = 21.393 (5) ?, and β = 97.20 (2)° with four molecules per unit cell. Of a total of 4796 unique reflections collected, 2965 reflections with Fo2 > 3σ(Fo2) were used to refine the structure. The structure converged at R = 0.051 and Rw = 0.065. The geometry around the cobalt atoms is very similar to that reported for [Rh2(CO)3(dppm)2Cl]+, [Rh2(CO)3(dppm)2H]+, and Ir2(CO)3(dppm)2S. The molecule may be described as an A-frame structure with a neutral ligand, CO, occupying the additional bridging site. The observed Co-Co bond distance is 2.555 (2) ? consistent with a single bond between the metal atoms. Reduction of the ionic complex with zinc yields a pyrophoric green solid that analyzes approximately for Co2(CO)3(dppm)2.
- Lisic, Edward C.,Hanson, Brian E.
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p. 512 - 516
(2008/10/08)
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- Pentafluorophenyl Complexes of Palladium and Platinum containing Chelating, Unidentate, or Bridging Ph2PCH2PPh2 Ligands
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The reactions of cis-, trans-, and (M=Pd or Pt, thf=tetrahydrofuran, tht=tetrahydrothiophene) with dppm (Ph2PCH2PPh2) in molar ratios M:dppm=1:1 and 1:2 have been studied.Pentafluorophenyl complexes containing dppm acting as endobidentate (chelate), unidentate, or exobidentate (bridging homo- or heterometal centres) have been obtained and characterized by i.r. and 31P n.m.r. spectroscopy.
- Uson, Rafael,Fornies, Juan,Espinet, Pablo,Navarro, Rafael,Fortuno, Consuelo
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p. 2077 - 2082
(2007/10/02)
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- A Simple Synthesis and Some Synthetic Applications of Substituted Phosphide and Phosphinite Anions
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Based on data for the acidity relationship of phosphines and phosphinous acids and water in dimethyl sulfoxide and water, a simple method is reported for the generation of phosphide and phosphinite anions by the action of concentrated aqueous alkali on primary and secondary phosphines as well as phosphinous acids in dimethyl sulfoxide or other dipolar aprotic solvents.Alkylation of the anion yields secondary and tertiary phosphines, polyphosphines, functionally substituted phosphines as well as similarly substituted phosphine oxides.Phosphinous acids have beenalkylated in various solvents in two-phase systems containing concentrated aqueous alkali and tetrabutylammonium iodide as phase transfer catalyst.
- Tsvetkov, E. N.,Bondarenko, N. A.,Malakhova, I. G.,Kabachnik, M. I.
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p. 198 - 208
(2007/10/02)
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- Dicyanophosphide Reactions
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31P (and, as applicably, 77Se) NMR spectra show P(CN)2(-) to take up one or two atoms of sulfur or selenium and to react with a variety of anionic phosphorus nucleophiles.Displacement of the first cyanide gives cyanodiphosphides, cyanophosphinidene-phosphates, -phosphinates, -thiophosphinates and -iminophosphinates, respectively.Displacement of the second cyanide gives triphosphates and triphosphinates which are otherwise known as products from the nucleophilic P4 degradation. - Key words: Nucleophilic Displacement at Two-coordinate Phosphorus, Sulfuration and Selenation, 77Se NMR Spectra, 31P NMR Spectra
- Schmidpeter, Alfred,Burget, Guenther
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p. 1306 - 1313
(2007/10/02)
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- Carbon Acidity. 63. Equilibrium Ion Pair Acidities of Some Phosphorus-Substituted Carbon Acids
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Ion-pair C-H acidities are reported as pKCsCHA for bis(diphenylphosphino)methane (1, 31.1), (p-phenylbenzyl)diphenylphosphine (3, 31.0), p-tolyldiphenylphosphine (4, 37.9), and several of the corresponding phosphine oxides.The diphenylphosphine group is about as anion stabilizing as p-biphenyl.The Ph2P(O) group is additionally stabilizing because of enhanced ion-pair interaction.The pKCsCHA of benzyldiphenylphosphine (2) can be estimated to be about 32.
- Streitwieser, Andrew,Juaristi, Eusebio
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p. 768 - 770
(2007/10/02)
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- Rapid Transfer of Selenium from Tertiary Phosphine Selenides to Tertiary Phosphines
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Selenium transfer between PR3Se and PR3 in solution is rapid on the n.m.r. time scale, and a bimolecular process is indicated.Mixtures of Ph2P(Se)C2H4(Se)PPh2, Ph2(Se)C2H4PPh2, and Ph2PC2H4PPh2 display similar variable-temperature 1H n.m.r. characteristics and their methylene-proton signals coalesce at elevated temperatures.The compound Ph2P(Se)CH2(Se)PPh2 reacts immediately on mixing with Ph2PCH2PPh2 to give exclusively Ph2P(Se)CH2PPh2, whereas solutions of Ph2P(Se)C2H4(Se)PPh2 and Ph2PC2H4PPh2 equilibrate with Ph2P(Se)C2H4PPh2 in 1:1:2 proportions, respectively.The sulphur analogues behave similarly, but react much more slowly.Selenium reacts at ambient temperature with Ph2P(S)CH2PPh2 to form only Ph2P(S)CH2(Se)PPh2, but the action of sulphur on Ph2P(Se)CH2PPh2 leads to a mixture of Ph2P(Se)CH2(Se)PPh2, Ph2P(Se)CH2(S)PPh2, and Ph2P(S)CH2(S)PPh2.Controlling influences and synthetic implications of these reactions are discussed.
- Brown, Douglas H.,Cross, Ronald J.,Keat, Rodney
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p. 871 - 874
(2007/10/02)
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