The effect of divinylsulfone on the irradiation crosslinking of polypropylene

Polypropylene films were irradiated with ⁶⁰Co γ-rays in divinylsulfone (DVS) or butadiene (BD) gases. The variations of the intrinsic viscosities of the samples irradiated in vacuum or in DVS with dose showed usual patterns but the variation of the latter was somewhat more rapid. The intrinsic viscosity of the sample irradiated in BD could not be measured due to the early appearance of gel. The gel fraction of the sample irradiated in DVS appeared at lower dose than that irradiated in vacuum, but the former did not increase as much as the latter. The gel fraction of the sample irradiated in BD increased remarkably. The concentrations of the two kinds of double bonds increased in the sample irradiated in BD but levelled off gradually with dose. ESR study showed that the polypropylene radical reacted with DVS to form anisotropic radicals. The mechanisms of the effects of both reagents on irradiation of polypropylene were discussed.     

Quadruple Decker [3.3][3.3][3.3]Orthocyclophane Acetal—An Orthocyclophane Ladder

Through clever bridging of orthocyclophanes (in this case by acetalization), molecules such as 1 can be formed with four benzene rings in a stacked face-to-face arrangement. UV/Vis spectroscopic and electrochemical properties of 1 are governed by π–π through-space interactions within the molecule.     

Vinyl Polymerization by Metal Complexes. XXIII. UV and Kinetic Studies on the Photopolymerization with Iron(III)-Amine-Carbon Tetrachloride Systems

Abstract

In order to elucidate the initiation reaction of the photopolymerization with iron(III)-amine-carbon tetrachloride systems, the photochemical reaction process among iron(III), amine, and carbon tetrachloride in methanol solution was followed at 0°C by UV spectroscopy as for iron(III) ion. The rate constants of both the reduction of iron (III) under irradiation with light and the oxidation of iron(II) in the dark were measured, and were related to the rates of photopolymerization of methyl methacrylate. Kinetic study on the photopolymerization of methyl methacrylate with iron(III)-triethylenetetramine-carbon tetrachloride system was made in parallel in methanol solution at 0°C. The initiation mechanism of the photopolymerization was postulated.     

Use of tube radial distribution of ternary mixed carrier solvents for introduction of absorption reagent for metal ion separation and online detection into capillary

When ternary mixed solvents consisting of water-hydrophilic/hydrophobic organic solvents are fed into a micro-space under laminar flow conditions, the solvent molecules are radially distributed in the micro-space. The specific fluidic behavior of the solvents is called the "tube radial distribution phenomenon (TRDP)". A novel capillary chromatography method was developed based on the TRDP that creates the inner major and outer minor phases in a tube, where the outer phase acts as a pseudo-stationary phase. This is called "tube radial distribution chromatography (TRDC)". In this study, Chrome Azurol S as an absorption reagent was introduced into the TRDC system for metal ion separation and online detection. The fused-silica capillary tube (75 μm id and 110 cm length) and water-acetonitrile-ethyl acetate mixture (3:8:4 volume ratio) including 20 mM Chrome Azurol S as a carrier solution were used. Metal ions, i.e. Co(II), Cu(II), Ni(II), Al(III), and Fe(III), as models were injected into the present TRDC system. Characteristic individual absorption characteristics and elution times were obtained as the result of complex formation between the metal ions and Chrome Azurol S in the water-acetonitrile-ethyl acetate mixture solution. The elution times of the metal ions were examined based on their absorption behavior; Co(II), Ni(II), Al(III), Fe(III), and Cu(II) were eluted in this order over the elution times of 4.7-6.8 min. The elution orders were determined from the molar ratios of metal ion to Chrome Azurol S and Irving-Williams series for bivalent metal ions.     

Star-shaped pyrrole-fused tetrathiafulvalene oligomers: synthesis and redox, self-assembling, and conductive properties

A series of star-shaped pyrrole-fused tetrathiafulvalene (TTF) oligomers 1-3 was synthesized via an S(N)Ar reaction of fluorinated benzenes with the pyrrolyl sodium salts. Electrochemical and chemical oxidations of 1-3 revealed that a radical cation moiety on each TTF unit was successfully accumulated in all oligomers. Self-assembled structures of neutral and oxidized species were characterized by SEM and XRD, and their conductive properties of the iodine-doped 1-3 as well as an intermolecular mixed-valence ion radical salt were investigated.     

Gold nanoparticle-templated assembly of oligothiophenes: preparation and film properties

Terthiophene-appended gold nanoparticles were prepared by the reduction of AuCl₄⁻(C₈H₁₇)₄N⁺ with NaBH₄ in the presence of bis[2,5-di(3-hexylthiophen-2-yl)thiophene-3-carboxyloxyhexanyl]disulfide. A hexagonal self-assembly of particles with gold core diameters (1.9±0.1 nm) was detected by high-angle annular dark-field scanning transmission electron microscopy. The electric conductivity of the iodine-doped film was 9.1×10⁻⁶ S cm⁻¹, which was ascribable to the terthiophene-based inter-ligand π-π interactions. The Au/terthiophene hybrid spin-coated film consisted of a highly three-dimensional assembled structure of terthiophenes, as inferred from grazing-incidence small-angle X-ray scattering, indicating that such monodispersed and small-sized gold nanoparticles can serve as a template for this organization. In this study, a gold nanoparticle-templated assembly of oligothiophenes has been fabricated for proposing a method to develop tailor-made organizations of π-conjugated oligomers.     

Relativistic and electron‐correlation effects on magnetizabilities investigated by the Douglas‐Kroll‐Hess method and the second‐order Møller‐Plesset perturbation theory

Isotropic and anisotropic magnetizabilities for noble gas atoms and a series of singlet and triplet molecules were calculated using the second‐order Douglas‐Kroll‐Hess (DKH2) Hamiltonian containing the vector potential A and in part using second‐order generalized unrestricted Møller‐Plesset (GUMP2) theory. The DKH2 Hamiltonian was resolved into three parts (spin‐free terms, spin‐dependent terms, and magnetic perturbation terms), and the magnetizabilities were decomposed into diamagnetic and paramagnetic terms to investigate the relativistic and electron‐correlation effects in detail. For Ne, Kr, and Xe, the calculated magnetizabilities approached the experimental values, once relativistic and electron‐correlation effects were included. For the IF molecule, the magnetizability was strongly affected by the spin‐orbit interaction, and the total relativistic contribution amounted to 22%. For group 17, 16, 15, and 14 hydrides, the calculated relativistic effects were small (less than 3%), and trends were observed in relativistic and electron‐correlation effects across groups and periods. The magnetizability anisotropies of triplet molecules were generally larger than those of similar singlet molecules. The so‐called relativistic‐correlation interference for the magnetizabilities computed using the relativistic GUMP2 method can be neglected for the molecules evaluated, with exception of triplet SbH. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009     

Vesicle formation in oleyldimethylamine oxide/sodium oleate mixtures

Vesicle formation in a mixture of oleyldimethylamine oxide (OleylDMAO) and sodium oleate (NaOl) was investigated by viscoelastic measurements and cryoscopic transmission electron micrograph (cryo-TEM) observations. The viscoelastic properties changed with increasing mole fraction of NaOl (X _NaOl) from the Maxwell behavior of OleylDMAO solutions (X _NaOl=0) suggesting a transient network of long flexible chains. For X _NaOl=0.2 and 0.4 mixtures, both the shear storage modulus G and the shear loss modulus G showed weak dependences on angular frequency with a relation G>G. From cryo-TEM observations, vesicles coexisted with threadlike micelles in mixtures of X _NaOl=0.2 and 0.3. As X _NaOl increased further (X _NaOl=0.5 and 0.6), threadlike micelles disappeared and the coexistence of vesicles and globular micelles was observed. At X _NaOl=0.5, the viscosity decreased remarkably, which was consistent with the disappearance of threadlike micelles. The results indicated that vesicles were formed by the addition of NaOl to OleylDMAO solutions, contrary to the expectation of a decrease of the packing parameter with the introduction of electric charges.     

Formation of Supramolecular Polymers Constructed by Cyclodextrins with Cinnamamide

-Cyclodextrin having cinnamamide at 6- or 3-positions (6-CiNH--CD, 3-CiNH--CD) and -cyclodextrin with cinnamamide on 6-position (6-CiNH--CD) have been prepared. Supramolecular structures were formed in the solid state or aqueous solutions and characterized by measurements of NMR and vapor pressure osmometry (VPO). The results indicate that 6-CiNH--CD formed insoluble supramolecular polymers in the solid state, while 6-CiNH--CD and 3-CiNH--CD formed supramolecular complexes in aqueous solutions. 6-CiNH--CD was found to form a dimer in an aqueous solution. 3-CiNH--CD formed intermolecular complexes to give supramolecular polymers. The differences of the position of guest part on cyclodextrins caused to give a variety of supramolecular structures in aqueous solutions.