链状三核异金属簇阴离子［Cl_2FeS_2M＇（PPh_3）_2］~－（M＝Mo

在５５０～９０ｃｍ~（－１）波数范围内，测量簇阴离子［Ｃｌ_２ＦｅＳ_２ＭＳ_２Ｍ′（ＰＰｈ_３）_２］~－（Ｍ＝Ｍｏ，Ｍ′＝Ａｇ；Ｍ＝Ｗ，Ｍ′＝Ｃｕ，Ａｇ）的付里叶变换红外光谱，并对标题簇阴离子［Ｃｌ_２ＦｅＳ_２ＷＳ_２Ｃｕ（ＰＰｈ_３）_２］~－，［Ｃｌ_２ＦｅＳ_２ＭｏＳ_２Ａｇ（ＰＰｈ_３）_２］~－和［Ｃｌ_２ＦｅＳ_２ＷＳ_２Ａｇ（ＰＰｈ_３）_２］~－骨架的振动光谱给予经验指认。同时采用＂诱导自洽方法计算振动力常数＂程序，对簇骨架［Ｃｌ_２ＦｅＳ_２ＭＳ_２Ｍ~′Ｐ_２］进行简正坐标分析。振动频率的计算值与观测值符合良好，两者平均偏差小于１．０％，计算结果支持了振动谱带的归属并表明计算力常数的合理性。文中还讨论了主要价键振动频率的变化规律。     

Polymerization using palladium (II) salts II: Polymerization of 2-ethynyl-5-bromothiophene

The title monomer was polymerized using a bis(triphenyl phosphine) palladium (II) chloride, cuprous iodide, triphenyl phosphine catalyst system. The products are low-molecular-weight materials with thermal stabilities somewhat inferior to corresponding phenylacetylene-based polymers.     

Triphenyl phosphine complex of cyclopentadienyl(manganese dicarbonyl triphenyl phosphine) gold

Conclusions The triphenyl phosphine complex of cyclopentadienyl (manganese dicarbonyl triphenyl phosphine) gold was obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2641–2642, November, 1973.     

Absolute configuration of tert-butyl-1-(2-methylnaphthyl)phosphine oxide

The enantiomers of tert-butyl-1-(2-methylnaphthyl)phosphine oxide 1 have been separated using a homemade HPLC column and an analytical gradient system. Vibrational absorption and circular dichroism spectra for both enantiomers have been measured in CD2Cl2 and CH2Cl2 solutions in the 2000-900 cm(-1) region. The fully relaxed potential energy surface of (S)-tert-butyl-1-(2-methylnaphthyl)phosphine oxide, obtained using the B3LYP functional with a 6-31G basis set, indicated two stable conformers with their populations in a approximately 2:1 ratio. The vibrational absorption and VCD spectra are predicted for these two conformers using the B3LYP functional with a 6-31G basis set. The comparison of predicted and experimental spectra indicated that (+)-tert-butyl-1-(2-methylnaphthyl)phosphine oxide is in the (S)-configuration. This assignment is supported by the ab initio prediction of positive optical rotation for the most stable conformer with an (S)-configuration and the nonequivalence sense of the tert-butyl group chemical shift observed in the 1H NMR spectrum of this enantiomer measured in the presence of (+)-(S)-mandelic acid as a chiral solvating agent.     

Complexation of phosphine ligands with peracetylated beta-cyclodextrin in supercritical carbon dioxide: spectroscopic determination of equilibrium constants

The interaction between peracetylated beta-cyclodextrin and several triphenyl phosphine derivatives was studied in supercritical carbon dioxide (scCO2) by UV-visible spectroscopy. The equilibrium constant for a 1:1 complexation reaction was obtained from titration spectra and calculated using two established mathematical models. The values of the equilibrium constants are 1-3 orders of magnitude smaller than those obtained in aqueous solution with analogous phosphines. This is likely due to the absence in scCO2 of the hydrophobic effect, which is replaced by a corresponding, but weaker, CO2-phobic effect. The largest value of Kf was found for complexes of diphenyl(4-adamantylphenyl)phosphine, which is rationalized on the basis of the excellent fit of the phosphine in the cyclodextrin cavity, leading to enhanced host-guest van der Waals interactions. This study can be considered the first step toward the comprehension of the complexation thermodynamics of modified cyclodextrins soluble in scCO2.     

电荷转移聚合研究——三苯基磷引发丙烯腈光聚合

研究了三苯基磷(TPP)引发丙烯腈(AN)光聚合。测定了光聚合速率 R_p与单体浓度、引发剂浓度的关系为:R_p=K[AN]~(1.49)[TPP]~(0.47)以及光聚合反应活化能E_α=6.16千卡/摩尔,从激发态电荷转移机制,讨论了引发聚合机理。     

Nucleophilic addition of azoles to triphenyl-(phenylethynyl)phosphonium bromide and base hydrolysis of the addition products

Reactions of pyrazole, 3,5-dimethylpyrazole, imidazole, and 1,2,4-triazole with triphenyl(phenylethynyl)phosphonium bromide gave the corresponding 2-azolyl-2-phenylethenyl(triphenyl)phosphonium salts. Base hydrolysis of the addition products led to the formation of 2-azolyl-1,2-diphenylethyl(diphenyl)phosphine oxides.     

Establishing the mechanism of Rh-catalysed activation of O2 by H2

Reductive activation of O(2) by H(2) with rhodium terpyridine complexes in H(2)O and CH(3)CN is described and the mechanism is fully elucidated. The rhodium complex extracts electrons from H(2) and reductively activates O(2) to form a peroxo active intermediate. This intermediate is able to oxidise triphenyl phosphine to triphenyl phosphine oxide. A model system constructed in CH(3)CN provides isolable analogues of catalytic intermediates in H(2)O, allowing a detailed look at each step in the catalytic cycle.     

Preparation of carbodiimides by the reaction of thioureas with diethyl azodicarboxylate

A new synthesis of disubstituted carbodiimides from N.N′-disubstituted thioureas, diethyl azodicarboxylate and triphenyl phosphine has been achieved. The intermediates of the reaction have been isolated and found to be 1:1 adducts of the thioureas and diethyl azodicarboxylate, N¹,N²-disubstituted—S—(N³,N⁴-biscarboethoxy)hydrazinoisothioureas which, on treatment with triphenyl phosphine at room temperature, afford the corresponding carbodiimides. Alternatively, the intermediates on heating under reflux in benzene or toluene, decompose to the carbodiimides, diethyl hydrazodicarboxylate and sulphur.     

Mechanism of the sulfurisation of phosphines and phosphites using 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride)

Contrary to a previous report, the sulfurisation of phosphorus(III) derivatives by 3-amino-1,2,4-dithiazole-5-thione (xanthane hydride) does not yield carbon disulfide and cyanamide as the additional reaction products. The reaction of xanthane hydride with triphenyl phosphine or trimethyl phosphite yields triphenyl phosphine sulfide or trimethyl thiophosphate, respectively, and thiocarbamoyl isothiocyanate which has been trapped with nucleophiles. The reaction pathway involves initial nucleophilic attack of the phosphorus at sulfur next to the thiocarbonyl group of xanthane hydride followed by decomposition of the phosphonium intermediate formed to products. The Hammett rho-values for the sulfurisation of substituted triphenyl phosphines and triphenyl phosphites in acetonitrile are approximately -1.0. The entropies of activation are very negative (-114+/-15 J mol-1 K-1) with little dependence on solvent which is consistent with a bimolecular association step leading to the transition state. The negative values of DeltaS(not equal) and rho values indicate that the rate limiting step of the sulfurisation reaction is formation of the phosphonium ion intermediate which has an early transition state with little covalent bond formation. The site of nucleophilic attack has been also confirmed using computational calculations.     

Bis(phosphine imide)s: easily tunable organic electron donors

[graph: see text] The electrochemical, structural, and spectroscopic properties of bis(phosphine imide)s have been investigated. p-Phenylenebis(phosphine imide)s Ar3PNC6H4NPAr3 (1a-d) have two reversible single-electron oxidations. The first oxidation potentials can be varied from -0.05 to 0.15 V (versus SCE) by modification of the substituents on phosphorus (Ar). Electron-donating substituents lower the oxidation potential, while electron-withdrawing substituents increase the oxidation potential. The difference between the first and second oxidation potential (deltaE, 0.41-0.50) and the electronic coupling (Hab, 1.1 eV) are similar for 1a-d. Computational (DFT) and UV-visible-NIR spectroscopic investigations of 1a-d suggest that the first oxidation leads to a delocalized radical cation 1a*+ while the second oxidation leads to a quinonoidal dicationic state 1a2+. The aromatic linker between phosphine imides has also been modified. Upon oxidation, N,N'-4,4'-biphenylene(bis(triphenyl)phosphine imide) (3) forms radical cationic and a dicationic species similar to 1a-d. While deltaE (0.18 V) and Hab (0.63 eV) are smaller, suggesting weaker electronic communication between the two P=N units in the radical cationic state, the presence of NIR absorptions with vibrational fine structure (768, 861, and 983 nm) supports the formation of delocalized radical cation for 3*+.     

Functionalization of the 4(5)methyl group of imidazoles: A novel synthesis of substituted imidazoles

Acyl vinyl phosphonium salts react with amidines to form imidazolyl phosphonium salts. These imidazolyl salts can be readily converted to multifunctional imidazoles with quantitative recovery of triphenyl phosphine.     

A highly efficient azide-based protecting group for amines and alcohols

The azide-based carbamate or carbonate protecting group (Azoc) shown above can be removed in less than 2 min under neutral conditions using trimethyl or tributyl phosphine as well as polymer-bound triphenyl phosphine. It was shown to be orthogonal to Fmoc and Mtt for peptide synthesis and to afford beta-glycoside with a 2-aminoglucosyl donor by virtue of the neighboring group participation.     

Synthesis of 2-substituted oxazoloquinazolinones

Chemistry of Heterocyclic Compounds - The reaction of methyl 2-isothiocyanatobenzoate and 1-azido-3-(4-substituted phenyl)propan-2-ones in the presence of triphenyl phosphine in dioxane by heating...     

Electron-donating properties of p-phenylene phosphine imides: an electrochemical and spectroscopic investigation

[reaction: see text] Electronic properties of phosphine imide based organic electron donors have been investigated. N,N'-p-Phenylenebis(triphenyl)phosphine imide (Ph(3)P=NC(6)H(4)N=PPh(3), 1) has two reversible single-electron oxidations (0.04 and 0.53 V vs SCE). Spectroscopic investigations of poly(p-phenylene phosphine imide)s (2) are similar to those of polymer model compounds, suggesting formation of localized radical cations on the polymer chains and electronically insulating phosphorus atoms.     

NMR spectrometric study of molecular complex formation of [60]- and [70]fullerenes with a number of phosphine oxides

Molecular complex formation between [60]- and [70]fullerenes with a series of phosphine oxides, namely, tri-n-octyl phosphine oxide, triphenyl phosphine oxide and tri-n-butyl phosphine oxide has been studied in CCl4 medium by NMR spectrometric method. Both [60]- and [70]fullerenes have been shown to form 1:1 adducts with the above series of phosphine oxides. Formation constants (K) for all the complexes have been determined from the systematic variation of NMR chemical shifts of specific protons of the donors in presence of [60]- and [70]fullerenes. Trends in the values of K suggest that [70]fullerene binds stronger with the phosphine oxides relative to [60]fullerene.     

Synergic extraction of uranium(VI) by combination of tri-iso-octylamine and neutral donors

Synergistic effect of neutral donors like tri-butyl phosphate (TBP), triphenyl phosphine oxide (TPPO), trioctyl phosphine oxide (TOPO), and dimethyl sulphoxide (DMSO) on the extraction of uranium(VI) by tri-isooctyl amine into CCl₄ is reported. Synergistic coefficients and adduct formation constants are calculated from distribution data and correlated with relative donor abilities of added bases.     

Esterification of allylic alcohols with benzoic acid in the presence of diethyl azodicarboxylate and triphenylphosphine

Stereoselectivity of esterification reaction of some allylic alcohols, mainly unsaturated pyranosides, with benzoic acid in the presence of diethyl azodicarboxylate and triphenyl phosphine was investigated. The reaction was found to proceed with inversion, without allylic rearrangement.     

α-Addition of activated methylenes to alkynoates. A straightforward synthesis of multifunctional compounds

The present work describes a simple one pot access to α-(gem-difunctional) acrylic esters and to polysubstituted dihydrothiophenes exploiting the addition of activated methylenes to alkynoates rerouted by triphenyl phosphine.     

Atom Transfer Radical Polymerization of Butadiene Initiated by Benzyl Chloride/MoCl5 Substituted by 1-octanol/PPh3

A novel initiator system, benzyl chloride/MoCl₅ substituted by 1-octanol/triphenyl phosphine (PPh₃), was applied to the atom transfer radical polymerization (ATRP) of butadiene. The characterization revealed the linear increase of the number average molecular weight with the monomer conversion and the rather wide molecular weight distributions of the polymerization products. The microstructure of the butadiene was detected by IR and ¹H-NMR. The chlorine atom at ω –end group of the polymer and the change of valence states of molybdenum detected by UV–Vis spectra revealed that the polymerization accorded primarily with the mechanism of ATRP.