Facile iodination of the vinyl groups in protoporphyrin IX dimethyl ester and subsequent transformation of the iodinated moieties

Iodination of protoporphyrin IX dimethyl ester using phenyliodine bis(trifluoroacetate) (PIFA) and I₂ was studied. Iodine added to both the C3- and C8-vinyl groups equally to afford the iodohydrin or iodoether in the presence of water or alcohol, respectively. Any meso-hydrogen atom was not substituted by an iodine atom under these conditions, although both the vinyl group and one of the meso positions of methyl pyropheophorbide-a bearing a chlorin π-system, a chlorophyll-a derivative, was modified with PIFA and I₂. The reaction intermediates derived from the porphyrin were more reactive than those from the chlorin and liable to form intermolecular linkages. The obtained 2-iodo-1-hydroxyethyl group was transformed into a formyl group by a mild treatment. The corresponding iodoether moiety was readily converted into the acetyl group under basic conditions. These transformations were also applicable to smaller olefins such as styrene.     

Changing of the Crystal Structure of Nylon 6 Drawn under High Pressure

Nylon 6 filaments were drawn under high pressure. By means of wide-angle x-ray diffraction and differential scanning calorimetry, nylon 6 fibers were investigated after drawing at 80° C to a draw ratio of 3.75 and pressure in the range of atmospheric up to 2000 kg/cm² It was found that by increasing the pressure, structural conversion from the γ-pseudohexagonal to the α-monoclinic form occurs, and that crystallinity and orientation are also increased.     

Molecular Recognition of Medium-size Lactones by Enclathration of Cholic Acid

Abstract

Molecular recognitions of medium size lactones by enclathration of cholic acid (CA) are described. Size and location of the substituents on the lactone rings play an important role for enclathration. Lactones within the limited steric dimensions are included in CA, and larger or smaller ones are not included to give guest-free crystals of CA. Moreover, CA partially separates one enantiomer from racemic lactones by recystallization. X-ray crystallographic studies reveal that all included lactones form the β-trans type bilayer structure having a pentagonal void channel with a side pocket. The cross-sections illustrate that the lactone rings are incorporated in the center of the channel and that the substituents of the guests are fixed in the side pockets. The asymmetric channel enables CA to discriminate size and chirality of medium size lactones.     

Current transport property in GdBCO coated conductor with artificial pinning centers in a wide range of temperature,magnetic field up to 27 T,and field angle

We have investigated current transport property in Gd₁Ba₂Cu₃O_7−δ coated conductor with artificial pinning centers in a wide range of temperature, magnetic field, B up to 27 T, and field angle. Due to the additional c-axis correlated pins, critical current density, J_c in B//c was enhanced and the improvement was observed in wide range of B. On the other hand, around B⊥c below 65 K, the angular dependence of n-value showed a valley-like behavior, although the J_c was increasing. In addition, the temperature dependence of the pinning force density defined as J_c × B was not scaled on an expected master curve. These results indicate the pinning in B⊥c is governed by different mechanism below 65 K and high magnetic field.     

Construction of superhydrophobic surfaces by fibrous aggregation of perfluoroalkyl chain-containing organogelators

Superhydrophobic surfaces, characterized by water contact angles greater than 150 degrees, can be produced by means of intermediate organogels, which were formed by perfluoroalkyl chain-containing organogelators with volatile organic solvents.     

Metal oxides immobilized fabrics by radiation induced graft polymerization

Radiation induced graft polymerization is effective for adding a new functionality to various forms of existing polymers. Ion-exchange nonwoven fabrics by gamma radiation induced graft polymerization have been used as filters in air and liquid. However, these materials have no capability for removing non-ionic species, such as volatile organic compound and ozone. Manganese oxides immobilized fabrics were developed for removing ozone. In addition, these materials were capable of removing formaldehyde and arsenic. Fine particles of manganese oxides were observed on the fibers. New materials produced by radiation induced graft polymerization and metal immobilization were applicable for purification of contaminants in environment. Manufacturing process is applicable for immobilization of the other metal oxides.