Crystal growth of cyclodextrin‐based metal‐organic framework with inclusion of ferulic acid

The crystallization of γ‐cyclodextrin‐based metal‐organic framework (CD‐MOF) with inclusion of ferulic acid (FA) was carried out through vapor diffusion of methanol to the aqueous solution of γ‐cyclodextrin (γ‐CD), KOH and FA. Although the crystallization of pure CD was limited in highly basic solution of KOH (pH>13.0), the CD‐MOF with inclusion of FA (FA/CD‐MOF) was able to be formed at pH 6.8 after the neutralization of KOH by FA. The inclusion behavior of FA in CD‐MOF was studied by using differential scanning calorimetry. The data indicate the formation of the stable association between FA and γ‐CD in FA/CD‐MOF.     

Supramolecular polymer gels from polystyrene bearing cyclic amidine Group and acrylic acid/n‐butyl acrylate copolymers

We have prepared supramolecular polymer gels by mixing solutions of a polystyrene bearing cyclic amidine pendant groups (Poly‐A) and copolymers of acrylic acid and n‐butyl acrylate (Poly‐C), followed by evaporation. FT‐IR analysis indicated that the gels were formed through three‐dimensional network of the amidinium‐carboxylate salt bridge. DSC study showed that the Poly‐A and the Poly‐C were miscible when the salt bridge content was high. On the other hand, the mixtures with small salt bridge content showed phase separation. Dynamic shear measurements showed that the gel prepared from Poly‐A and Poly‐C with acrylic acid unit content of 15% had G' higher than G″ over a temperature range of ?22 °C to 32 °C, in which the G' value reached almost 1 MPa. The gel had a crossover point of G' and G″ at 32 °C, very close to room temperature, which suggested facile processability. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 765–770     

Deformations of canonical singularities

We prove that small deformations of canonical singularities are canonical.

     

Tensor interactions and polarization phenomena in heavy-ion scattering

Elastic and inelastic scattering of ⁷Li by ⁵⁸Ni at E_lab = 14.2 and 20.3 MeV is investigated theoretically, special emphasis being laid on polarization phenomena. A parameter-independent study shows second-rank tensor interactions to be the main origin of tensor analyzing powers for both elastic and inelastic scattering. Coupled-channel (CC) calculations using cluster-folding interactions which include the tensor terms are found to be successful in reproducing the data for cross sections and vector and tensor analyzing powers, when projectile excitation effects are sufficiently taken into account. Scattering of ⁶Li by ⁵⁸Ni at E_lab = 20.0 MeV is also investigated by the CC calculation, where successes similar to the ⁷Li case are obtained in understanding experimental data.     

Application of high pressure induced by water-freezing to the direct catalytic asymmetric three-component List-Barbas-Mannich reaction

High pressure induced by water-freezing has been successfully applied to the direct catalytic asymmetric-three component List-Barbas-Mannich reaction, in which higher yield and better enantioselectivity can be realized than those from the reaction at room temperature under 0.1 MPa.     

Characterization of resulting network polymer precursors in stepwise crosslinking diepoxide/diamine polymerization

Our previous mechanistic discussion of network formation in chainwise crosslinking multiallyl polymerization was extended to stepwise crosslinking diepoxide/diamine polymerization, typically including bisphenol‐A diglycidyl ether (BADGE) and 4,4′‐diaminodiphenylmethane (DDM). In allyl polymerization a monomer chain transfer is an essential termination reaction, providing only oligomeric primary polymer chains. Therefore, crosslinking multiallyl polymerization could be in the category of a classical gelation theory. Thus, the gelation behavior was discussed by comparing the actual gel point with the theoretical one. Then the resulting network polymer precursors (NPPs) were characterized by size‐exclusion chromatography‐multiangle laser light scattering‐viscometry to clarify the stepwise crosslinking BADGE/DDM polymerization mechanism. Notably, the intrinsic viscosity ratio [η]_NPP/[η]_Linear tended to decrease with the progress of crosslinking and finally, it reached less than 0.2. This suggests that the structure of resulting NPP becomes dendritic at a conversion close to the gel point. These dendritic NPPs can collide with each other to form crosslinks between NPPs, eventually leading to gelation as a reflection of the high concentration of NPP. The dilution effect on gelation was marked in polar solvent; no gelation was observed at a dilution of 1/5. However, in nonpolar solvent the gelation was promoted by dilution; this is ascribed to enhanced crosslink formation between NPPs through hydrogen bonding due to abundant hydroxyl groups in the NPP generated by the polyaddition reaction. Finally, the subject of “Is cured epoxy resin inhomogeneous?” is briefly discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011