Direct meso-alkynylation of porphyrins doubly assisted by pyridyl coordination

Direct meso-alkynylation of β,β'-dipyridylporphyrin with various alkynyllithium reagents has been achieved, in which the β,β'-dipyridyl groups play an important role in facilitating the nucleophilic addition of the reagents through double coordination. This method enabled the synthesis of a meso-ethynylene-bridged diporphyrin.     

N,N-Dilauryl Chitosan：Synthesis and Surface Pressure-area Isotherm

With sodium dodecyl sulfonate(SDS) as the phase transferring catalyst, N,N-Dilauryl chitosans with a high degree of alkyl group substitution were prepared and characterized by means of FTIR, ^1H NMR and elemental analyses. The results indicate that the average degree of alkyl group substitution on the chitosan increases with decreasing the molecular weight of the chitosan. The fully N,N-dilaurylated chitosan was found to be dissolvable in chloroform. The collapsed pressures of the samples derived from chitosan with 3000,5000 and 10000 dalton are 47.6, 48. 2 and 51.0 mN/m, respectively. The surface area occupied by the monomer unit(glucosamine) of all. those samples is 0:6 nm^2.     

Onset of pi(0) suppression studied in Cu+Cu collisions at sqrt S NN=22.4, 62.4, and 200 GeV

Neutral pion transverse momentum (p(T)) spectra at midrapidity (|y| less than or approximately 0.35) were measured in Cu+Cu collisions at sqrt[s(NN)]=22.4, 62.4, and 200 GeV. Relative to pi_(0) yields in p+p collisions scaled by the number of inelastic nucleon-nucleon collisions (N(coll) the pi_(0) yields for p(T) more than or approximately 2 GeV/c in central Cu+Cu collisions are suppressed at 62.4 and 200 GeV whereas an enhancement is observed at 22.4 GeV. A comparison with a jet-quenching model suggests that final state parton energy loss dominates in central Cu+Cu collisions at 62.4 and 200 GeV, while the enhancement at 22.4 GeV is consistent with nuclear modifications in the initial state alone.     

Particle-species dependent modification of jet-induced correlations in Au+Au collisions at sqrt[s_{NN}]=200 GeV

Measurements in Au+Au collisions at sqrt[s_{NN}]=200 GeV of jet correlations for a trigger hadron at intermediate transverse momentum (p_{T,trig}) with associated mesons or baryons at lower p_{T,assoc} indicate strong modification of the away-side jet. The ratio of jet-associated baryons to mesons increases with centrality and p_{T,assoc}. For the most central collisions, the ratio is similar to that for inclusive measurements. This trend is incompatible with in-vacuum fragmentation but could be due to jetlike contributions from correlated soft partons, which recombine upon hadronization.     

Debromination of phenacyl and benzylic bromides with tertiary stibine and the mechanistic consideration

Tributylstibine is an efficient reagent for debromination of phenacyl and arylmethyl bromides. The mechanistic difference between stibine and phosphine is discussed briefly.     

Highly active supported catalysts for olefin polymerization. Supports from a grignard reagent for preparation of highly active catalysts

Supports were obtained by the interaction of C₄H₉MgCl with the reaction mixture of AlCl₃ and CH₃Si(OC₂H₅)₃ or Si(OC₂H₅)₄ (Mg/Al/Si = 2/1/1). With the combination of Al(C₂H₅)₃ and methyl-p-toluate, immobilized titanium catalysts prepared by the treatment of the supports with TiCl₄ and ethylbenzoate showed extraordinary high activity and stereoregularity in the polymerization of propylene.¹ By the study of the reaction of AlCl₃ with CH₃Si(OC₂H₅)₃, the elemental analysis and powder x-ray diffractometric measurements of the supports, it was found that the supports comprised of Cl, Mg, Al, and Si atoms, OC₂H₅ groups, C₄H₉ groups, and ethers, and that they were amorphous solids to the extent that the x-ray diffraction peak assigned to the 003 plane in MgCl₂ crystals completely disappeared.     

Asymptotic constraint for chiral condensation of Coulomb gauge QCD

We study the³ P ₀ quark-antiquark pair condensation in QCD, representing the gluon-interaction approximately by instantaneous Coulomb plus Breit potential. Particular attention is paid to non-uniqueness of the solution of the gap equation. The genuine dynamical solution can be characterized by a rapidly convergent behavior at large momentum, as was recognized in covariant formulations of Landau gauge. We impose the required behavior and make a numerical study of the chiral condensation.     

A New Method of Photopatterning with LB Films Based on a Chemically Amplified Mechanism

IntroductionDeep-UV lithography is generally recognized asthe most promising lithographic technology, for the pro-duction of high-resolution devices. However, lithogra-phy requires high sensitivity, high resolution, and highresistance. To make this techno…     

Wittig-horner reaction of a phosphonate of reissert analogue a new method for introduction of alkyl groups into isoquinoline

Dimethyl 2-isopropoxycarbonyl-1, 2-dihydroisoquinoline-1-phosphonate ($\text{1}$) was prepared from isoquinoline, isopropyl chloroformate, and trimethyl phosphite. Wittig-Horner reaction of $\text{1}$ with various aldehydes afforded the corresponding exo-methylene compounds, which were converted to 1-substituted isoquinolines with hydrogen chloride.     

Liquid membrane transport of lanthanoid elements using organophosphinic acid

Transport of La, Nd, Eu, Tb, Tm and Lu through a supported liquid membrane (SLM) was investigated by using di(2,4,4-trimethylpentyl)phosphinic acid (DTMPPA) as a mobile carrier. Lanthanoid elements in the feed solution were quantitatively transported and concentrated into the product solution of mild acidity. The transport rates increased with increasing atomic number of lanthanoids in the low pH region of the feed solution. Separation factors evaluated from the transport rates for lanthanoids were close to those from the distribution ratios in liquid-liquid extraction.