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Phosphine Oxide (phosphine + oxide)
Kinds of Phosphine Oxide Selected AbstractsAir-Stable and Highly Active Dendritic Phosphine Oxide- Stabilized Palladium Nanoparticles: Preparation, Characterization and Applications in the Carbon-Carbon Bond Formation and Hydrogenation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2008Lei Wu Abstract Dendrimer-stabilized palladium nanoparticles were formed in the reduction of palldium bis(acetylacetonate) [Pd(acac)2] in the presence of phosphine dendrimer ligands using hydrogen in tetrahydrofuran. The resulting Pd nanoparticles were characterized by TEM, 31P,NMR and 31P MAS NMR. The results indicated that the dendritic phosphine ligands were oxidized to phosphine oxides. These dendrimer-stabilized Pd nanoparticles were demonstrated to be efficient catalysts for Suzuki and Stille coupling reactions and hydrogenations. The dendritic wedges served as a stabilizer for keeping the nanoparticles from aggregating, and as a vehicle for facilitating the separation and/or the recycling of the Pd catalyst. In the case of the Suzuki coupling reaction, these Pd nanoparticles exhibited high catalytic efficiency (TON up to 65,000) and air stability as compared with the commonly used homogeneous catalyst tetrakis(triphenylphosphine)palladium [Pd(PPh3)4]. In addition, the results obtained from the bulky dendritic substrate suggest that the Pd nanoparticles might act as reservoir of catalytically active species, and that the reaction is actually catalyzed by the soluble Pd(0) and/or Pd(II) species leached from the nanoparticle surface. [source] Stereospecific Deoxygenation of Phosphine Oxides with Retention of Configuration Using Triphenylphosphine or Triethyl Phosphite as an Oxygen Acceptor.CHEMINFORM, Issue 12 2005Hai-Chen Wu Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Highly Efficient Universal Bipolar Host for Blue, Green, and Red Phosphorescent OLEDsADVANCED MATERIALS, Issue 22 2010Ho-Hsiu Chou The bipolar host material BCPO (bis-4- (N-carbazolyl)phenylphosphine oxide) containing a phosphine oxide and two carbazole groups, synthesized in three steps, shows a high triplet energy gap of 3.01,eV. The material can be used as a universal host for blue, green, and red phosphorescent devices, all giving extremely high efficiencies with turn-on voltages within 3 V. [source] Synthesis and characterization of soluble copolyimides containing chalcone and phosphine oxide moieties in the main chainJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Wei Wang Abstract The functional diamines 3,3,-diaminochalcone and bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide were successfully prepared by simple and convenient procedures with short reaction times, and the overall yields were 78 and 70%, respectively. Copolyimides prepared from 3,3,-diaminochalcone, bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide, and 4,4,-(hexafluoroisopropylidene)diphthalic anhydride exhibited excellent solubility in several organic solvents, such as dimethyl sulfoxide, N,N -dimethylformamide, N -methyl pyrrolidone, tetrahydrofuran, and acetone. They also showed very good thermal stability even up to 450°C for 5% weight loss (by thermogravimetric analysis) in nitrogen and a high glass-transition temperature up to 274°C (by differential scanning calorimetry) in nitrogen. The copolymers' adhesive and photoreactive properties were also investigated, and it was confirmed that the copolyimide containing chalcone and phosphine oxide moieties in the main chain had good adhesiveness and photoreactivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Advanced flame-retardant epoxy resins from phosphorus-containing diolJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2005M. José Alcón Abstract Phosphorus-containing epoxy systems were prepared from isobutylbis(hydroxypropyl)phosphine oxide (IHPO) and diglycidyl ether of bisphenol A (DGEBA). Diethyl- N,N -bis(2-hydroxyethyl) aminomethyl phosphonate (Fyrol 6) could not be incorporated into the epoxy backbone by a reaction with either epichlorohydrin or DGEBA because intramolecular cyclization took place. The curing behavior of the IHPO,DGEBA prepolymer with two primary amines was studied, and materials with moderate glass-transition temperatures were obtained. V-0 materials were obtained when the resins were tested for ignition resistance with the UL-94 test. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3510,3515, 2005 [source] Development of an efficient route to hyperbranched poly(arylene ether sulfone)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2005Patrick Himmelberg Abstract A two-step route to an AB2 monomer that underwent polymerization via nucleophilic aromatic substitution to afford hyperbranched poly(arylene ether sulfone)s (HB PAES) was developed. The synthesis of 3,5-difluoro-4,-hydroxydiphenyl sulfone (4) was accomplished by the reaction of 3,5-difluorophenylmagnesium bromide with 4-methoxyphenylsulfonyl chloride, followed by deprotection of the phenol group with HBr in acetic acid. The polymerization of 4 in the presence of 3,4,5-trifluorophenylsulfonyl benzene or tris(3,4,5-trifluorophenyl)phosphine oxide as a core molecule afforded HB PAES with number-average molecular weights ranging from 3400 to 8400 Da and polydispersity index values ranging from 1.5 to 4.8. The presence of cyclic oligomeric species, formed by an intramolecular cyclization process, was a contributing factor to the relatively low molecular weights. The degree of branching (DB) of the HB PAES samples was estimated by a comparison of the 19F NMR spectra of the polymer samples with those of a series of model compounds, and DB values ranging from 0.51 to 0.70 were determined. The glass-transition temperatures for the HB PAES samples were in the range of 205,222 °C, as determined by differential scanning calorimetry. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:3178,3187, 2005 [source] Synthesis and optical properties of fluorinated poly(arylene ether phosphine oxide)sJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2003Jae-Pil Kim Abstract Fluorinated dihydroxy phosphine oxide monomers were synthesized via chlorination, Grignard, and demethylation techniques. The prepared monomer was successfully polymerized with each of the three perfluorinated monomers (decafluorobiphenyl, decafluorobenzophenone, and pentafluorophenylsulfide) by nucleophilic aromatic substitution. The average molecular weight ranged between 7800 and 14,900 g/mol. The glass-transition temperatures of the polymers were registered in the range of 185,235 °C, and all the polymers exhibited high thermal stability up to 326,408 °C. The results of the refractive-index measurements indicated control of the refractive index between 1.5181 and 1.5536 and an optical loss of 0.53 dB/cm at 1550 nm. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1497,1503, 2003 [source] Ultraviolet curing of acrylic systems: Real-time Fourier transform infrared, mechanical, and fluorescence studiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2002Carmen Peinado Abstract The photopolymerization of acrylic-based adhesives has been studied by Fourier transform infrared and fluorescence analysis in real time. Real-time infrared spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics of the reaction. Furthermore, the incident light intensity dependence of the polymerization rate shows that primary radical termination is the predominant mechanism during the initial stages of the curing of the acrylic system with bis(2,4,6-trimethylbenzoyl) phenyl phosphine oxide (TMBAPO) as a photoinitiator. The fluorescence intensity of selected probes increases during the ultraviolet curing of the adhesive, sensing microenvironmental viscosity changes. Depending on the nature of the photoinitiator, different fluorescence,conversion curves are observed. For TMBAPO, the fluorescence increases more slowly during the initial stage because of the delay in the gel effect induced by primary radical termination. Mechanical tests have been carried out to determine the shear modulus over the course of the acrylic adhesive ultraviolet curing. In an attempt to extend the applications of the fluorescence probe method, we have undertaken comparisons between the fluorescence changes and shear modulus. Similar features in both curves confirm the feasibility of the fluorescence method for providing information about microstructural changes during network formation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4236,4244, 2002 [source] Synthesis and characterization of novel polyimide from bis-(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxideJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2001Kwang Un Jeong Abstract A novel diamine, bis-(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxide (mDA3FPPO), containing phosphine oxide and fluorine moieties was prepared via the Grignard reaction from an intermediate, 4-(trifluoromethyl)phenyl diphenyl phosphine oxide, that was synthesized from diphenylphosphinic chloride and 4-(trifluoromethyl)bromobenzene, followed by nitration and reduction. The monomer was characterized by Fourier transform infrared (FTIR), 1H NMR, 31P NMR, 19F NMR spectroscopies; elemental analysis; melting point measurements; and titration and was used to prepare polyimides with a number of dianhydrides such as pyromellitic dianhydride (PMDA), 5,5,-[2,2,2-trifluoro-1-(trifluoromethyl)ethyliden]-bis-1,3-isobenzofuranedione (6FDA), 3,3,,4,4,-benzophenone tetracarboxylic dianhydride (BTDA), and 4,4,-oxydiphthalic dianhydride (ODPA). Polyimides were synthesized via a conventional two-step route; preparation of polyamic acids, followed by solution imidization, and the molecular weight were controlled to 20,000 g/mol. Resulting polyimides were characterized by FTIR, NMR, DSC, and intrinsic viscosity measurements. Refractive-index, dielectric constant, and adhesive properties were also determined. The properties of polyimides were compared with those of polyimides prepared from 1,1-bis-(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (3FDAm) and bis-(3-aminophenyl) phenyl phosphine oxide (mDAPPO). The polyimides prepared from mDA3FPPO provided high glass-transition temperatures (248,311 °C), good thermal stability, excellent solubility, low birefringence (0.0030,0.0036), low dielectric constants (2.9,3.1), and excellent adhesive properties with Cu foils (107 g/mm). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3335,3347, 2001 [source] Novel Phosphorus-Containing Poly(ether sulfone)s and Their Blends with an Epoxy Resin: Thermal Decomposition and Fire RetardancyMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2006Ulrike Braun Abstract Summary: The decomposition of novel phosphorus-containing poly(oxyphenylene-sulfonyl-phenylene-oxy-diphenyl phenylene phosphine oxide) (PSU_I), 2,5-dihydroxy-1-biphenylene-phosphine oxide based polysulfone (PSU_II), poly(sulfonyl-diphenylphenylene phosphonate) (PSU_P) and bisphenol A-based polysulfone (PSU) is studied. The influence of the chemical structure, charring and phosphorus release is discussed based on the mass loss, kinetics and products. The pyrolysis and fire behaviour of blends with epoxy resin (EP) are studied. For EP-PSU_II, phosphorus initiates water elimination and changes the decomposition pathway of EP. The fire behaviour of EP-PSU shows some improvements, whereas the heat release rate is crucially reduced for EP-PSU_II due to simultaneous char formation and flame inhibition. Decomposition model of PSU_II. [source] Mechanistic Investigation of the Oxygen-Atom-Transfer Reactivity of Dioxo-molybdenum(VI) ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 28 2006Brian W. Kail Abstract The oxygen-atom-transfer (OAT) reactivity of [LiPrMoO2(OPh)] (1, LiPr=hydrotris(3-isopropylpyrazol-1-yl)borate) with the tertiary phosphines PEt3 and PPh2Me in acetonitrile was investigated. The first step, [LiPrMoO2(OPh)]+PR3,[LiPrMoO(OPh)(OPR3)], follows a second-order rate law with an associative transition state (PEt3, ,H,,=48.4 (±1.9) kJ,mol,1, ,S,,=,149.2 (±6.4) J,mol,1,K,1, ,G,,=92.9 kJ,mol,1; PPh2Me, ,H,,=73.4 (±3.7) kJ,mol,1, ,S,,=,71.9 (±2.3) J,mol,1,K,1, ,G,,=94.8 kJ,mol,1). With PMe3 as a model substrate, the geometry and the free energy of the transition state (TS) for the formation of the phosphine oxide-coordinated intermediate were calculated. The latter, 95 kJ,mol,1, is in good agreement with the experimental values. An unexpectedly large O-P-C angle calculated for the TS suggests that there is significant O-nucleophilic attack on the PC ,* in addition to the expected nucleophilic attack of the P on the MoO ,*. The second step of the reaction, that is, the exchange of the coordinated phosphine oxide with acetonitrile, [LiPrMoO(OPh)(OPR3)] + MeCN , [LiPrMoO(OPh)(MeCN)] + OPR3, follows a first-order rate law in MeCN. A dissociative interchange (Id) mechanism, with activation parameters of ,H,,=93.5 (±0.9) kJ,mol,1, ,S,,=18.2 (±3.3) J,mol,1,K,1, ,G,,=88.1 kJ,mol,1 and ,H,,=97.9 (±3.4) kJ,mol,1, ,S,,=47.3 (±11.8) J,mol,1,K,1, ,G,,=83.8 kJ,mol,1, for [LiPrMoO(OPh)(OPEt3)] (2,a) and [LiPrMoO(OPh)(OPPh2Me)] (2,b), respectively, is consistent with the experimental data. Although gas-phase calculations indicate that the MoOPMe3 bond is stronger than the MoNCMe bond, solvation provides the driving force for the release of the phosphine oxide and formation of [LiPrMoO(OPh)(MeCN)] (3). [source] Ruthenium-Catalyzed Propargylic Substitution Reactions of Propargylic Alcohols with Oxygen-, Nitrogen-, and Phosphorus-Centered NucleophilesCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2005Yoshiaki Nishibayashi Dr. Abstract The scope and limitations of the ruthenium-catalyzed propargylic substitution reaction of propargylic alcohols with heteroatom-centered nucleophiles are presented. Oxygen-, nitrogen-, and phosphorus-centered nucleophiles such as alcohols, amines, amides, and phosphine oxide are available for this catalytic reaction. Only the thiolate-bridged diruthenium complexes can work as catalysts for this reaction. Results of some stoichiometric and catalytic reactions indicate that the catalytic propargylic substitution reaction proceeds via an allenylidene complex formed in situ, whereby the attack of nucleophiles to the allenylidene C, atom is a key step. Investigation of the relative rate constants for the reaction of propargylic alcohols with several para -substituted anilines reveals that the attack of anilines on the allenylidene C, atom is not involved in the rate-determining step and rather the acidity of conjugated anilines of an alkynyl complex, which is formed after the attack of aniline on the C, atom, is considered to be the most important factor to determine the rate of this catalytic reaction. The key point to promote this catalytic reaction by using the thiolate-bridged diruthenium complexes is considered to be the ease of the ligand exchange step between a vinylidene ligand on the diruthenium complexes and another propargylic alcohol in the catalytic cycle. The reason why only the thiolate-bridged diruthenium complexes promote the ligand exchange step more easily with respect to other monoruthenium complexes in this catalytic reaction should be that one Ru moiety, which is not involved in the allenylidene formation, works as an electron pool or a mobile ligand to another Ru site. The catalytic procedure presented here provides a versatile, direct, and one-step method for propargylic substitution of propargylic alcohols in contrast to the so far well-known stoichiometric and stepwise Nicholas reaction. [source] A new family of platinum(II) complexes incorporating five- and six-membered cyclic phosphine ligandsHETEROATOM CHEMISTRY, Issue 2 2010Andrea Kerényi New platinum complexes of the type cis -Pt(L)2Cl2 have been synthesized from five- and six-membered cyclic phosphines, which were prepared after deoxygenating a series of phosphine oxides (3-phospholene oxides, phospholane oxides, a 1,4-dihydrophosphinine oxide, and a 1,2,3,6-tetrahydrophosphinine oxide). The complexes were characterized by NMR and mass spectral data, and their stereostructures were elucidated by B3LYP/6-31G(d)-LANL2DZ ECP calculations. The phosphine intermediates were characterized as the corresponding phosphine-boranes. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:63,70, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20579 [source] Direct conversion of secondary phosphine oxides and H -phosphinates with [Di(acyloxy)iodo]benzenes to phosphinic and phosphonic amidesHETEROATOM CHEMISTRY, Issue 2 2009Anna Hubacz The reaction of [di(acyloxy)iodo]benzene with secondary phosphine oxides or H -phosphinates in the presence of primary or secondary amines allows one to obtain phosphinic or phosphonic acids amides in the one-pot process. We take advantage of the strong acylating system DAIB/R2P(O)H to phosphinylation of amines. However, the reaction mechanism is multipathway and causes yields of phosphinic or phosphonic acids amides to be moderate. When the concentration of amines is low, the intermolecular process plays a main role leading to the formation of carboxylic amides through mixed phosphoric,carboxylic anhydride, and also in the low concentration of amines, tetrahydrofuran effectively competes with the amines in the nucleophilic attack on the acylating intermediates. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:81,86, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20514 [source] Synthesis and Reactions of Enantiopure Substituted Benzene cis -Hexahydro-1,2-diolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2010R. Boyd Abstract Enantiopure cis -dihydro-1,2-diol metabolites, obtained from toluene dioxygenase-catalysed cis -dihydroxylation of six monosubstituted benzene substrates, have been converted to their corresponding cis -hexahydro-1,2-diol derivatives by catalytic hydrogenation via their cis -tetrahydro-1,2-diol intermediates. Optimal reaction conditions for total catalytic hydrogenation of the cis -dihydro-1,2-diols have been established using six heterogeneous catalysts. The relative and absolute configurations of the resulting benzene cis -hexahydro-1,2-diol products have been unequivocally established by X-ray crystallography and NMR spectroscopy. Methods have been developed to obtain enantiopure cis -hexahydro-1,2-diol diastereoisomers, to desymmetrise a meso - cis -hexahydro-1,2-diol and to synthesise 2-substituted cyclohexanols. The potential of these enantiopure cyclohexanols as chiral reagents was briefly evaluated through their application in the synthesis of two enantiomerically enriched phosphine oxides from the corresponding racemic phosphine precursors. [source] Air-Stable and Highly Active Dendritic Phosphine Oxide- Stabilized Palladium Nanoparticles: Preparation, Characterization and Applications in the Carbon-Carbon Bond Formation and Hydrogenation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2008Lei Wu Abstract Dendrimer-stabilized palladium nanoparticles were formed in the reduction of palldium bis(acetylacetonate) [Pd(acac)2] in the presence of phosphine dendrimer ligands using hydrogen in tetrahydrofuran. The resulting Pd nanoparticles were characterized by TEM, 31P,NMR and 31P MAS NMR. The results indicated that the dendritic phosphine ligands were oxidized to phosphine oxides. These dendrimer-stabilized Pd nanoparticles were demonstrated to be efficient catalysts for Suzuki and Stille coupling reactions and hydrogenations. The dendritic wedges served as a stabilizer for keeping the nanoparticles from aggregating, and as a vehicle for facilitating the separation and/or the recycling of the Pd catalyst. In the case of the Suzuki coupling reaction, these Pd nanoparticles exhibited high catalytic efficiency (TON up to 65,000) and air stability as compared with the commonly used homogeneous catalyst tetrakis(triphenylphosphine)palladium [Pd(PPh3)4]. In addition, the results obtained from the bulky dendritic substrate suggest that the Pd nanoparticles might act as reservoir of catalytically active species, and that the reaction is actually catalyzed by the soluble Pd(0) and/or Pd(II) species leached from the nanoparticle surface. [source] | |||||||||||||