Photosensitized NADH formation system with multilayer TiO2 film

A TiO(2)/polymer film on a quartz plate fabricated by a layer-by-layer method was employed for NADH production from NAD(+) with lipoamide dehydrogenase and methyl viologen in Tris-HCl buffer on irradiation with UV light, and the ultra thin film prevented from enzyme deactivating effectively.     

Nanostructured liquid-crystalline Li-ion conductors with high oxidation resistance: molecular design strategy towards safe and high-voltage-operation Li-ion batteries

Nanostructured, uncharged liquid-crystalline (LC) electrolyte molecules having bicyclohexyl and cyclic carbonate moieties have been developed for application in Li-ion batteries as quasi-solid electrolytes, which suppress leakage and combustion. Towards the development of safe and high performance Li-ion batteries, we have designed Li-ion conductive LC materials with high oxidation resistance using density functional theory (DFT) calculation. The DFT calculation suggests that a mesogen with a bicyclohexyl moiety is suitable for the high-oxidation-resistance LC electrolytes compared to a mesogen containing phenylene moieties. A tri(oxyethylene) chain introduced between the cyclic carbonate and the bicyclohexyl moiety in the core part tunes the viscosity and the miscibility with Li salts. The designed Li-ion conductive LC molecules exhibit smectic LC phases over a wide temperature range, and they are miscible with added lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt up to 5 : 5 in molar ratio in their smectic phases. The resulting LC mixtures with LiTFSI show oxidation resistance above 4.0 V vs. Li/Li⁺ in cyclic voltammetry measurements. The enhanced oxidation resistance improves the performance of Li half-cells containing LC electrolytes.

Ion-conductive liquid-crystalline molecules with high-oxidation resistance, which were designed with density functional theory calculation, improved charge–discharge reactions in Li-ion batteries.     

Interactions of cyclodextrins with dipalmitoyl, distearoyl, and dimyristoyl phosphatidyl choline liposomes. A study by leakage of carboxyfluorescein in inner aqueous phase of unilamellar liposomes

The interaction of cyclodextrins (CDs) with L-alpha-dipalmitoyl phopsatidyl choline (DPPC), L-alpha-distearoyl phosphatidyl choline (DSPC), and L-alpha-dimyristoyl phosphatidyl choline (DMPC) unilamellar liposomes was investigated by the leakage of carboxylfluorescein (CF) entrapped in the inner aqueous phase of liposomes, at 25 degrees C (DPPC and DSPC liposomes) and at 5 degrees C (DMPC liposomes). The efficiency of CDs for CF leakage was remarkable in the order of heptakis (2,6-di-O-methyl)-beta-CD (DOM-beta-CD) > alpha-CD > heptakis (2,3,6-tri-O-methy)-beta-CD (TOM-beta-CD) from DPPC liposomes, in the order of DOM-beta-CD > TOM-beta-CD > alpha-CD from DSPC liposomes and in the order of alpha-CD > DOM-beta-CD > TOM-beta-CD from DMPC liposomes. The other CDs used in the present studies, beta-CD, 2-hydroxylpropyl beta-CD, and gamma-CD scarcely induced the CF leakage from above the three liposomes. From the profiles of % CF leakage, together with measurements of differential scanning calorimetry, it was found that hydrophobic DOM-beta-CD penetrates the matrix of the liposomes to interact with them as well as TOM-beta-CD, and that less hydrophobic alpha-CD exists at the surface of the membrane to interact with the liposomes. Further, it was found that the interaction of CDs with liposomes changes depending not only on the length of fatty acid chain of phospholipid (condensation force and hydrophobicity) but also the hydrophobicity and the cavity size of CD.     

Effects of crosslinker density on the polymer network structure in poly‐N,N‐dimethylacrylamide hydrogels

To investigate the effects of crosslinker density on the properties of hydrogels, compression tests, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Raman measurements were performed on poly‐N,N‐dimethylacrylamide hydrogels. The results of the compression tests showed that the Young's modulus increases as the crosslinker density increases. To understand the mechanism of the change in the mechanical properties, the structures of the polymer networks and water and the molecular vibrations were analyzed using SEM, DSC, and Raman methods. From the SEM images, it was found that the porosity estimated from the mesh size and cell density increases with increasing crosslinker density. In addition, the DSC and Raman results show that the thickness of the bound water increases as the porosity increases, although the density of the polymer chains in the porous wall remains nearly constant. The increase in the number density of polymer chains can be one of the mechanisms contributing to the increase in the mechanical strength of the hydrogels at lower crosslinker density below 5 mol %, as proposed by previous studies. At higher crosslinker density, however, the number density of polymer chains does not increase with increasing crosslinker density. The present results suggest that the bound water plays an important role in strengthening the hydrogel. The water structure may be one of the dominant factors governing the chemical and physical properties of hydrogels. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1017–1027     

Twelve new compounds from Ligularia melanothyrsa; isolation of melanothyrsins A–E,normelanothyrsin A,and other eremophilane sesquiterpenoids

Twelve new compounds, namely, five melanothyrsins A–E (1α-angeloyloxyeremophilenolides), normelanothyrsin A (1α-angeloyloxynoreremophilenone), and six other eremophilane-type compounds, have been isolated from Ligularia melanothyrsa Hand.-Mazz. (Asteraceae), collected in the Sichuan Province of China. Six of the compounds have a 1α-angeloyloxy moiety, while the other six have no functional group at the C-1 position. The absolute configuration was also determined using CD spectra. This is the first chemical study of compounds isolated from this species.     

Unique Structural Properties of 2,4,6‐Tri‐tert‐butylanilide: Isomerization and Switching between Separable Amide Rotamers through the Reaction of Anilide Enolates

Herein, we report a unique structural property of 2,4,6‐tri‐tert‐butylanilide, which can be separated into its amide rotamers at room temperature. Interconversion between the rotamers of anilide enolates occurs readily at room temperature and their reaction with electrophiles gives mixtures of the rotamers in a ratio that depends on the reactivity of the corresponding electrophile. That is, the reaction of the 2,4,6‐tri‐tert‐butylacetanilide enolate with reactive electrophiles, such as allyl bromide or protic acids, gives mixtures of the anilide rotamers in which the E rotamer is the major component, whereas less‐reactive electrophiles, such as 1‐bromopropane and 2‐iodopropane, yield mixtures of the rotamers in which the Z rotamer is the major component. The rotameric ratio of the product is also strongly dependent on the reactivity of the anilide enolate. Switching between the anilide rotamers can be achieved through protonation of a less‐reactive enolate by a less‐reactive protic acid and thermal isomerization of the anilide.     

Novel thermal curing reaction of oxetane resins with polyfunctional phenols

The thermal curing reaction of polyfunctional oxetanes (oxetane resins) such as tris[4‐(3‐ethyloxetane‐3‐yl)methoxyphenyl]methane (TEOMP) and 1,3,5‐tris(3‐ethyl‐3‐oxetanylmethoxy)benzene with certain polyfunctional phenols was performed in bulk with quaternary onium salts as catalysts. The reaction proceeded smoothly at 180–220 °C and produced insoluble gel products, and the rate of gel production increased with the reaction temperature. The rate of the addition reaction of TEOMP with 3,3′,5,5′‐tetrachlorobisphenol A was also measured by IR spectroscopy, and the rate of reaction was proportional to the product of the oxetane concentration and the catalyst concentration in the film state. Furthermore, the glass‐transition temperatures and 5 and 10 wt % weight‐loss temperatures of the resulting gel products were confirmed with differential scanning calorimetry and thermogravimetric analysis, and the glass‐transition temperatures and 5 wt % weight‐loss temperatures were 127–162 °C and 323–351 °C, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2028–2037, 2005     

Asymmetric Induction at Remote Quaternary Centers of Cyclohexadienones by Rhodium‐Catalyzed Conjugate Hydrosilylation

The enantioselective desymmetrizing conjugate hydrosilylation of prochiral differently γ,γ‐disubstituted cyclohexadienone derivatives 2 to furnish the corresponding cyclohexenones 4 with a remote chiral all‐carbon quaternary center at the γ position is described. Chiral rhodium–bis(oxazolinyl)phenyl complexes 1 were effective catalysts for this transformation. This catalytic system was extended to the asymmetric transformation of spirocarbocyclic cyclohexadienones 5 to give the corresponding products 6 with high enantiomeric ratios.