Synthesis of hydrolytically stable phosphorus-containing polymers via polycondensation and their utilization in polymer blends

Amorphous polyarylene ether homo- and copolymers were synthesized which were based upon bisphenol A and either 4, 4'-dichlorodiphenylsulfone, 4, 4'-difluorobenzophenone or 4, 4'-difluorodiphenyl phenylphosphine oxide. Solution blends were prepared from these homo- and copolymers with linear bisphenol A based polyhydroxyether, which was used as a model for the epoxy or vinyl ester thermosetting matrix resins for composite materials. It was observed that transparent, single Tg blends could be prepared from the phosphine oxide containing homopolymer and a 50/50 phosphine oxide/dichlorodiphenylsulfone copolymer. The other homopolymers produced materials with two Tg's, implying that they were definitely phase separated systems. Thermogravimetric analysis was also conducted and the phosphine oxide blends produced high char yields suggesting utilization in fire-resistant applications. The miscibility of the phosphine oxide material has been attributed to specific hydrogen bonding interactions observed between the phosphine oxide bond and the secondary hydroxyl group in the polyhydroxy ether. This hydroxyl functionality is also present in the epoxy and vinylester precursors and it is suggested that these materials could be utilized as interface sizings for carbon fibers, which would produce a graded microstructure between the fiber and the polymer matrix systems.     

醚功能化的膦配体的合成、负载及其在钯催化的Suzuki-Miyaura反应中的应用

合成了一种新的醚功能化的二茂铁膦3,连到Merrifield树脂上形成负载型的膦配体4;分别开展了膦配体3及其负载型的4在钯催化的Suzuki-Miyaura偶联反应中催化研究;发现相应形成的均相和多相钯催化剂可高产率地催化一系列的溴代芳烃与芳基硼酸偶联形成相应的联芳烃,以及负载型催化剂在不补加钯时具有一定的循环性能.     

Evaluation of bifunctional chiral phosphine oxide catalysts for the asymmetric hydrosilylation of ketimines

A series of bifunctional phosphine oxides have been prepared and evaluated as catalysts for the trichlorosilane mediated asymmetric hydrosilylation of ketimines. bis-Phosphine oxides, hydroxy-phosphine oxides, and biaryl phosphine oxides all demonstrated good catalytic activity, but poor to moderate enantioselectivity. A bis-P-chiral phosphine oxide displayed the highest enantioselectivity of 60%.     

Modular synthesis of ChiraClick ligands: a library of P-chirogenic phosphines

A library of novel and diverse P-chirogenic phosphine ligands containing a triazole moiety (ChiraClick ligands) were prepared in high yield in a modular fashion that allows for variation of both the phosphine and the triazole structure, as well as giving access to the two enantiomers of the ligand.     

A very simple, highly stereoselective and modular synthesis of ferrocene-based P-chiral phosphine ligands

A very simple, highly stereoselective and modular synthesis of ferrocene-based P-chiral phosphine ligands has been developed. On the basis of this new methodology, several new families of ferrocene-based phosphine ligands have been prepared coupling chirality at phosphorus with other, more standard stereogenic features. The introduction of P-chirality into ferrocene-based phosphine ligands enhances the enantioselective discrimination produced by the corresponding Rh catalyst when a matching among the planar chirality, carbon chirality, and the chirality of phosphorus is achieved.     

Preparation of microcapsule-supported palladium catalyst using SPG (Shirasu Porous Glass) emulsification technique

<正>A new method for the preparation of microcapsule-supported palladium catalyst was described.The highly monodisperse crosslinked polystyrene microcapsules containing phosphine ligand were synthesized by the self-assembling of phase separated polymer (SaPSeP) method using diphenyl(4-vinylphenyl) phosphine and divinylbenzene as a monomer and crosslinking agent,respectively, and 2,2'-azobisisobutyronitrile(AIBN) as an initiator within the droplets of oil-in-water(O/W) emulsions,which were prepared by using the Shirasu Porous Glass(SPG) membrane emulsification technique.The prepared microcapsule-supported palladium catalyst exhibited high catalytic activity for Heck reaction and can be reused several times without loss of activity.     

Synthesis of chiral thiourea–phosphine organocatalysts derived from l-proline

A novel class of thiourea–phosphine was prepared from l-proline as a chiral renewable resource. The original structure of the chiral framework offers an interesting potential to the construction of bifunctional organocatalysts for asymmetric transformations.     

溴化钯或乙酰丙酮羰基铑/手性配体催化醛与乙酰胺的不对称酰胺羰化反应研究

采用溴化钯为催化剂前体,与非螯合型双齿膦配体L1(DPPFF)、联吡啶型双齿膦配体L2(P-PHOS)和二茂铁基手性双膦配体L3((S,Rp)-BPPF)制备络合物催化剂,以乙酰丙酮羰基铑为催化剂前体,与手性亚磷酸酯配体L4-L6制备络合物催化剂,将其分别应用于底物环己基甲醛或苯乙醛的不对称酰胺羰化反应中,研究结果表明...     

Synthesis of phellanphos,an efficient chiral 1,2-diphosphine for asymmetric catalysis

A chiral 1,2-diphosphine was prepared in two steps from ()-α-phellandrene. This phosphine phellanphos gives a cationic rhodium complex (phellanphos-cyclooctadienerhodium hexafluorophosphate) which catalyses asymmetric reductions. N-Acetylphenylalanine and N-acetylalanine have been prepared in 94–95% enantiomeric excess.     

Facile synthesis of bisphosphine monoxides from Morita–Baylis–Hillman carbonates

A facile two-step synthesis of bisphosphine monoxides (BPMOs, with both the phosphine and phosphine oxide moieties within one molecule) from readily available Morita–Baylis–Hillman (MBH) carbonates was realized. Under the catalysis of DABCO, the MBH carbonates undergo allylic phosphorylation reaction with diphenylphosphine oxide or diethyl phosphonate to give monophosphine oxides bearing an activated alkene moiety; subsequent base-catalyzed hydrophosphination of the prepared monophosphine oxide with HPPh₂ readily affords the BPMOs.     

Preparation of polymer-supported phosphine from ferrocene for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions

Polymer-supported phosphine ligand 3b derived from ferrocene was prepared,and applied in palladium-catalyzed Suzuki- Miyaura reactions.A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields. The recycling of the polymer-bound catalyst was tested without adding palladium.     

Perfluoroalkylphosphine coordination chemistry of platinum: synthesis of (C2F5)2PPh and (C2F5)PPh2 complexes of platinum(II)

A 1:1 addition of Ph2PCl to an ethereal solution of C2F5Li (formed from the reaction of BuLi with C2F5Cl) yields Ph2P(C2F5)(abbreviated pfepp) (1). The introduction of a fluoroethyl group results in a phosphine with electronic characteristics that approximate phosphites, bridging the electronic gap between traditional donor phosphine ligands and more electrophilic phosphine ligands like PhP(C2F5)2 (2). The pfepp ligand 1 is isolated as a high boiling liquid, which crystallizes upon standing at room temperature in an inert atmosphere. A series of Pt(II) complexes of the type trans-L2PtCl2 (L = pfepp 3; PhP(C2F5)2 4) have been prepared and structurally characterized by multinuclear NMR, IR and X-ray crystallography. The crystal structure of is the first example of a structurally characterized monodentate phosphine with a pentafluoroethyl pendant group.     

Synthesis of thiazole aminophosphine oxides, aminophosphonic and aminophosphinic acids and Cu(II) binding abilities of thiazole aminophosphonic acids

A series of new aminophosphine oxides, aminophosphonic and aminophosphinic acids derived from thiazole was synthesized by addition of phosphine oxides or silylated phosphorus esters to the corresponding thiazole aldimines. The thiazole aldimines were obtained from 2-thiazole aldehyde and primary amines by a standard procedure. The corresponding phosphine oxides were obtained by alkylation of diethyl phosphite or ethyl phenylphosphinate with the appropriate Grignard reagents. The silylated phosphorus esters were prepared from trimethyl phosphite and from methyl- or phenylphosphinic ethyl ester by treatment with bromotrimethylsilane. The coordination ability towards Cu(II) ions are described for two obtained aminophosphonate ligands.     

Sterically hindered and robust pnictogen ligands derived from carboranes: synthesis and X-ray structure determination of tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))phosphine, tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))arsine and chloro(tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))phosphine)gold(I)

Sterically hindered phosphine and arsine ligands derived from ortho-carborane were synthesized and characterized by X-ray crystallography. Tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))phosphine, 2 (crystal data, hexagonal, space group P6(3), a = b = 12.251(3) A, c = 11.514(4) A, alpha = beta = 90 degrees, gamma = 120 degrees, V = 1496.6(7) A(3), Z = 2, R(1) = 0.0568) and tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))arsine, 3 (crystal data, hexagonal, space group P6(3), a = b = 12.330(3) A, c = 11.474(4) A, alpha = beta = 90 degrees, gamma = 120 degrees, V = 1510.7(7) A(3), Z = 2, R(1) = 0.0930) were prepared in 82% and 68% yield, respectively. The phosphine ligand is resistant to air-oxidation but was converted to corresponding oxide when heated with hydrogen peroxide. The tertiary carboranyl phosphine reacted with (Tht)AuCl to yield chloro(tris(1'-methyl(1,2-dicarba-closo-dodecaboran-1-yl))phosphine)gold(I), 4 (crystal data, monoclinic, space group P2(1)/c, a = 19.101(4) A, b = 12.167(2) A, c = 13.846(3) A, alpha = gamma = 90 degrees, beta = 91.13(3) degrees, V = 3217.2(11) A(3), Z = 4, R(1) = 0.0396) in 82% yield. From the X-ray structure of the gold complex, the cone angle of the phosphine was determined to be 213(2) degrees, which is among the largest values reported to date.     

The phase diagram of the Ga–S system in the concentration range of 48.0–60.7 mol% S

Journal of Thermal Analysis and Calorimetry - A novel flame-retarded epoxy resins system is prepared by copolymerizing diglycidyl ether of bisphenol A (EP) with tris(3-nitrophenyl) phosphine...     

Synthesis,structure, and activity of enhanced initiators for olefin metathesis

A series of ruthenium olefin metathesis catalysts of the general structure (H(2)IMes)(PR(3))(Cl)(2)Ru=CHPh (H(2)IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) have been prepared; these complexes are readily accessible in two steps from commercially available (H(2)IMes)(PCy(3))(Cl)(2)Ru=CHPh. Their phosphine dissociation rate constants (k(1)), relative rates of phosphine reassociation, and relative reaction rates in ring-opening metathesis polymerization (ROMP) and ring-closing metathesis (RCM) have been investigated. The rates of phosphine dissociation (initiation) from these complexes increase with decreasing phosphine donor strength. Complexes containing a triarylphosphine exhibit dramatically improved initiation relative to (H(2)IMes)(PCy(3))(Cl)(2)Ru=CHPh. Conversely, phosphine reassociation shows no direct correlation with phosphine electronics. In general, increased phosphine dissociation leads to faster olefin metathesis reaction rates, which is of direct significance to both organic and polymer metathesis processes.     

Bisphosphine‐Functionalized Cyclic Decapeptides Based on the Natural Product Gramicidin S: A Potential Scaffold for Transition‐Metal Coordination

The natural product Gramicidin S is a promising scaffold for novel oligopeptide‐based bisphosphine ligands, combining the advantageous rigid chiral backbone with the close proximity of phosphine substituents. The required unnatural, phosphine‐containing, amino acid building blocks were synthesized by means of a novel protocol that involves the enantioselective alkylation of a chiral nickel Schiff base template. Three Ni complexes were prepared with different alkyl chains between the phosphine group and the α‐carbon atom of the incorporated glycine; the absolute stereochemistry of two of them was determined by single‐crystal X‐ray structure analysis. By detaching the template, enantiopure L ‐phosphine amino acids resulted enabling the solid‐phase, stepwise construction of a linear sequence of the phosphine‐modified oligopeptides. On cyclization three bisphosphine‐substituted Gramicidin S analogues resulted, differing only in the size and shape of the linkage between the phosphine groups and the oligopeptides backbone. Their crystal structures suggest these species to have potential as chelating ligands.     

Mild and efficient copper-catalyzed N-arylation of alkylamines and N-H heterocycles using an oxime-phosphine oxide ligand

A mild and efficient copper-catalyzed system for N-arylation of alkylamines and N-H heterocycles with aryl iodides using a novel, readily prepared and highly stable oxime-functionalized phosphine oxide ligand was developed. The coupling reactions could even be performed in solvent-free conditions with moderate to good yields.     

Stereospecific Synthesis of α‐ and β‐Hydroxyalkyl P‐Stereogenic Phosphine–Boranes and Functionalized Derivatives: Evidence of the PO Activation in the BH3‐Mediated Reduction

Access to hydroxy‐functionalized P‐chiral phosphine–boranes has become an important field in the synthesis of P‐stereogenic compounds used as ligands in asymmetric catalysis. A family of optically pure α and β‐hydroxyalkyl tertiary phosphine–boranes has been prepared by using a three‐step procedure from readily accessible enantiopure adamantylphosphinate, obtained by semi‐preparative HPLC on multigram scale. Firstly, a two‐step one‐pot transformation affords the enantiopure hydroxyalkyl tertiary phosphine oxides in good yields and enantioselectivities. The third step, BH₃‐mediated reduction, allows the formation of the desired phosphine–boranes with excellent stereospecifity. The mechanistic study of this reduction provides new evidence to elucidate the crucial role of the pendant hydroxy group and the subsequent activation of the P?O bond by the boron atom.     

1,2,3]Triazolo[1,5-a]pyridyl phosphines reflecting the influence of phosphorus lone pair orientation on spectroscopic properties

A series of new triazolopyridine-based phosphines has been prepared. These compounds revealed unexpected spectroscopic patterns. In particular, the NMR spectra are highly dependent on the relative conformational preference of the phosphine substituent at C7. Here, we report on their complete NMR analysis, X-ray structures and DFT calculations that confirm the particular arrangement of the phosphorus lone pair orbital related to the substituent pattern of the chosen phosphine.