Control of release properties of guest molecules by the type of benzoheterocyclic ring in supramolecular host complexes

Three types of supramolecular benzoheterocyclic host complexes were successfully prepared using (1R,2S)-2-amino-1,2-diphenylethanol and three types of benzoheterocyclic (benzothiophene, benzofuran, and benzopyrrole) acid derivatives. The host complexes had one-dimensional (1D) channel-like cavities that were formed by the assembly of two-component 2₁-helical columnar network structures, which included guest alcohol molecules. The release behavior of the guest molecules could be tuned by the type of heterocyclic ring in the supramolecular host complex.     

Radiation-induced oxidation of polyethylene,ethylene–butene copolymer,and ethylene–propylene copolymer

Oxygen consumption and yield of oxidation products during γ-irradiation were studied on five types of polyethylene (PE), ethylene–butene copolymer (EB), and ethylene–propylene copolymer (EPR) using gas chromatography, mass spectrography, and high-resolution NMR. Samples were irradiated in oxygen under pressure from 0 to 500 torr by ⁶⁰Co γ-rays up to 20 Mrad at 22–25°C. In enough oxygen, oxygen consumption and yield of oxidation products are independent of oxygen pressure for low-density PE, EB, and EPR. The G values of oxygen consumption were 14–18.4 for PE, 11.6 for EB at 1 × 10⁶ rad/h, and 8.3 for EPR at 2 × 10⁵ rad/h. The oxidation products determined were carboxylic acid (? CH₂? CO? OH), H₂O, CO₂, and CO. The oxygen consumption and oxidation products for PE were found to increase with increasing crystallinity.     

Solubilization of a water-insoluble dye in aqueous NaBr solutions of alkylpyridinium bromides and its relation to micellar size and shape

In order to investigate the effect of added salt on micelle size, shape, and structure the solubilization of Orange OT in aqueous NaBr solutions of decylpyridinium bromide (DePB), dodecylpyridinium bromide (DPB), tetradecylpyridinium bromide (TPB), and hexadecylpyridinium bromide (CPB) has been examined. The solubilization powers of DePB and DPB micelles increase with increasing NaBr concentration up to 2.86 and 3.07 mol dm^–3, respectively, but above these concentrations remain unaltered. This suggests that spherical micelles of DePB and DPB can have a maximum and constant size at NaBr concentrations higher than these threshold concentrations. On the other hand, the solubilization powers of TPB and CPB micelles increase in the whole range of NaBr concentration studied. The dependencies of the solubilization powers of their micelles on the counterion concentration change at 0.10 and 0.03 mol dm^–3 NaBr, respectively, as suggests that TPB and CPB micelles undergo the sphere–rod transition at those concentrations. Orange OT is a more suitable probe for detecting the presence of the maximum- and constant-size spherical micelle than Sudan Red B.     

Reactivity of Highly Lewis‐Acidic Diborane(4) toward C≡N and N=N Bonds: Uncatalyzed Addition and N=N Bond‐Cleavage Reactions

The diboration of the C≡N bond in organic nitriles, and the N=N bond in azobenzene and pyridazine, by the highly Lewis‐acidic tetra(o‐tolyl)diborane(4) are reported. In the reactions with nitriles, azobenzene, and pyridazine, the addition of diborane(4) to the C≡N and N=N bonds was observed. Conversely, the N=N bond in phthalazine was cleaved by an addition/rearomatization sequence.     

Total Syntheses of (−)-Strictosidine and Related Indole Alkaloid Glycosides

A collective synthesis of glycosylated monoterpenoid indole alkaloids is reported. A highly diastereoselective Pictet–Spengler reaction with α-cyanotryptamine and secologanin tetraacetate as substrates, followed by a reductive decyanation reaction, was developed for the synthesis of (−)-strictosidine, which is an important intermediate in biosynthesis. This two-step chemical method was established as an alternative to the biosynthetically employed strictosidine synthase. Furthermore, after carrying out chemical and computational studies, a transition state for induction of diastereoselectivity in our newly discovered Pictet–Spengler reaction is proposed. Having achieved the first enantioselective total synthesis of (−)-strictosidine in just 10 steps, subsequent bioinspired transformations resulted in the concise total syntheses of (−)-strictosamide, (−)-neonaucleoside A, (−)-cymoside, and (−)-3α-dihydrocadambine.     

A new numerical method for quasi-particle spectroscopy around a pair of vortices in triplet superconductors

Triplet superconductors such as Sr₂RuO₄ and Na_xCoO₂·yH₂O are now found to be p-wave (p_x±ip_y) or f-wave ((p_x±ip_y)coscp_z) superconductors. In conventional singlet superconductors, vortices are quantized because phase of order parameter must rotate by 2π around a vortex. But triplet superconductors have a degree of freedom of spin, which is described by d-vector. The d-vector and phase can rotate by π around a vortex, separately. Therefore appearance of HQVs is predicted. Theoretically, it is found that a pair of HQVs is more stable than a singly quantized vortex, for several parameter regions.In this study, in order to investigate quasi-particle bound states around two vortices in s-wave superconductors, we have developed a new numerical method to solve the BdG equation for two vortices state, using Mathieu functions. We confirmed the validity of this method for two vortices state and applied it in case of a pair of vortices. And we solved it.     

Radiation-Induced Copolymerization of Thiophene with Maleic Anhydride

Radiation-induced copolymerization of thiophene with maleic anhydride has been studied. On the copolymerization in chloroform solution, the effects of dose rate, polymerization temperature, and, monomer composition and concentration on the yield and molecular weight of the copolymer were determined. The copolymerization proceeds via a radical mechanism with bimolecular termination of propagating polymer radicals, and the apparent activation energy is 5.3 kcal/mole. By NMR spectroscopy of copolymer, it was also found that these monomers copolymerize alternately to give a copolymer having structure I. In this copolymerization, the higher initial rates were obtained at an equimolar composition of monomers and by using solvents containing chlorine, such as CC1₄, CHC1₃, and C₆H₅C1.