Substituent effect on the acetolysis of neophyl p-bromobenzenesulfonates

The substituent effect on the acetolysis of neophyl brosylates was analyzed successfully based on the analysis method of Yukawa-Tsuno. The basic concept of this method was strongly supported.     

Regioselective phenyl-substitution effects on the solvatochromism of 2-phenylimidazo[1,2-a]pyrazin-3(7H)-one derivatives: expansion of the color variation range of a visible indicator for the proton donor ability of solvents

Phenyl-substitution to the C8 position of an imidazopyrazinone ring resulted in the significant bathochromic shift of the lowest energy band, while the substitution to the C6 position does not produce such a shift. This provides evidence that a color variation range of the solvatochromism of 2-phenylimidazopyrazinone derivatives depends strongly on the position of phenyl-substitution. Results indicated that an imidazopyrazinone with the phenyl groups at the C2 and C8 positions acts as a potential indicator of the proton donor ability of solvents.     

Catalytic activity of β-cyclodextrin-histamine

We modified cyclodextrin (CD) by a histamine group to make a model of -chymotrypsin. Enzymatic turnover reaction was realized with CD-histamine at around neutral pH value. Compared with amino-CD, it is ascertained that this catalytic activity of CD-histamine is caused by an imidazole group. Using several substrates in the hydrolytic reactions, it shows that CD-histamine has a structural selectivity for substrates which are structurally different to each other.     

Synthesis and characterization of α-, β- and γ-cyclodextrin-nicotinamide

Abstract

α-, β- and γ-cyclodextrin-nicotinamide (α-, β- and γ-CDNA) were synthesized as NADH coenzyme models, and the binding abilities were investigated. CDNA binds a negatively charged guest stronger than unmodified cyclodextrin because of the electrostatic interaction between the nicotinamide residue and the guest molecule. Different binding abilities were measured and were dependent on cavity size.     

Structure-based discovery of glycolipids for CD1d-mediated NKT cell activation: tuning the adjuvant versus immunosuppression activity

Introduction of an aromatic group into the fatty acyl chain of alpha-GalCer modulates the activity and selectivity of IFN-gamma/IL-4 secretion through CD1d-mediated activation of NKT cells. Compound 14-16 are more potent than alpha-Galcer and biased for IFN-gamma than for IL-4. These new glycolipids may find use as adjuvants or as antimetastatic agents.     

Quantum sieving effect of modified activated carbon fibers on H2 and D2 adsorption at 20 K

Quantum sieving of activated carbon fibers (ACFs) and their fluorides was observed for H(2) and D(2) adsorption at 20 K. Fluorination reduced the slit-shaped pore width of ACFs by 0.2 nm. The activated carbon fibers can act as highly efficient quantum sieves for H(2) and D(2), because the effective size of an H(2) molecule is larger than that of a D(2) molecule due to the uncertainty principle and the molecular size difference between H(2) and D(2) is significant in the micropore space. The D(2)/H(2) selectivity of ACFs evaluated by ideal adsorption solution theory was larger than that of the fluorinated ACFs.     

Investigation of the Ion Storage/Transfer Behavior in an Electrical Double‐Layer Capacitor by Using Ordered Microporous Carbons as Model Materials

Ordered microporous carbon : The mechanism of an electrical double‐layer capacitor containing zeolite‐templated carbons as model microporous materials was investigated in detail (see figure). Its three‐dimensionally ordered and connected micropores were found to greatly reduce ion‐transfer resistance and, therefore, exhibited a high rate performance.

     

An atomic force microscope study of vanadium-benzene sandwich clusters soft-landed on self-assembled monolayers

Multiple-decker vanadium-benzene sandwich clusters V_n(benzene)_n+1 produced by a laser-vaporization synthesis method were soft-landed onto self-assembled monolayers of alkanethiol (C₁₈H-SAM) and fluorinated alkanethiol (C₁₀F-SAM) at 200 K. Noncontact atomic force microscopy has been used to examine the resulting adsorption states of the clusters landed on the SAMs at room temperature. For each SAM substrate, the aggregates of the deposited clusters were observed at the vacancy islands and near the steps of the SAM surface. The result indicates that, at room temperature, the clusters landed on the SAM substrate thermally diffuse on the surface to form columnar-shape islands around the defect sites of the SAM surface.