A comparison of the ultraslow relaxation processes at the ionic liquid|water interface for three hydrophobic ionic liquids

The ultraslow relaxation, on the order of a few seconds or longer, of the structure of the electrical double layer in response to the change in the phase-boundary potential across the ionic liquid (IL)|water(W) interface, which was recently reported for trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide, has been confirmed in two new hydrophobic ionic liquids, trihexyltetradecylphosphonium bis(nonafluorobutanesulfonyl)amide and trihexyltetradecylphosphonium tetrakis(pentafluorophenyl)borate. A comparison of the degree of the hysteresis in electrocapillary curves for these ILs with those for trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide demonstrates that the degree of the hysteresis is not correlated with the viscosity of these ILs. The ultraslow relaxation of the electrical double layer seems to be a general feature of ILs at electrified interfaces.     

Hypernuclear fine structure in (16)(Lambda)O and the LambdaN tensor interaction

We have observed two gamma-ray transitions in (16)(Lambda)O from the 6.6 MeV excited 1(-)(2) state to both ground-state spin-doublet members (1(-)(1),0(-)) by the (K-,pi(-)gamma) reaction. We have obtained the ground-state doublet spacing to be 26.4+/-1.6(stat)+/-0.5(syst) keV and the excitation energy of the 1(-)(2) state to be 6561.7+/-1.1(stat)+/-1.7(syst) keV. The ground-state doublet spacing provides a small but nonzero strength of the tensor interaction between a Lambda and a nucleon. This is the first experimental result on the LambdaN tensor interaction.     

Direct benzyne-C60 addition does not generate a [5,6] open fulleroid

Recent reports describe the different products resulting from the reaction of C₆₀ with benzyne generated from anthranilic acid derivatives and isoamyl nitrate in the presence and absence of triethylamine. Reinvestigation here via ¹H, ¹³C, HMBC NMR and Mass spectroscopy elucidates that these products are the [6,6] closed C₆₀-fused δ lactones, and not the [5,6] open fulleroids which would result from benzyne addition. Furthermore, theoretical calculations show that the open isomer [5,6] benzyne addition is less stable than the [5,6] closed isomer as an isolable product.     

Effects of solvent on the free-radical copolymerizabilities of pyridazinones with styrene

Free-radical copolymerizations of N-methylpyridazinone (I) and N-phenylpyridazinone (II) with styrene (M₁) were carried out in various solvents. The copolymerization rates were found to increase linearly with increasing viscosities of the reaction mixtures. Monomer reactivity ratios were strongly affected by the reaction media. This might be due to solvation of the carbonyl group of the pyridazinone ring, because linear relationships between log 1/r1 and vc=o of the pyridazinones were obtained. It was also found that monomer concentration influences these copolymerizabilities.     

5-Exo versus 6-endo cyclization of nucleoside 2-sila-5-hexenyl radicals: reaction of 6-(bromomethyl)dimethylsilyl 1',2'-unsaturated uridines

The mode of cyclization of 2-sila-5-hexen-1-yl radicals generated from 6-(bromomethyl)dimethylsilyl-1',2'-unsaturated uridines was investigated. In contrast to the case of the 2'-unsubstituted 6-silicon-tethered substrate (4), which undergoes exclusive 6-endo-cyclization, reactions of the 2'-substituted (Me, CO2Me, OBz, and Cl) derivatives (14, 20, 22, and 24) uniformly proceeded in preferential or exclusive 5-exo-mode. The Tamao oxidation of the resulting cyclized products was also carried out to synthesize the corresponding 1'-C-hydroxymethyl derivatives.     

A mycelium with polyelectrolyte complex-bunched hyphae: several important factors affecting on the fermentation performance at a very high cell density

We have reported in the previous paper (Colloids Surf. B (2006) in press) a marked increase in the rate of gluconic acid production at a very high cell concentration (40 g/l) of filamentous fungus (Aspergillus niger IFO 31012) which was immobilized with polyelectrolyte complex consisting of potassium poly(vinyl alcohol) sulfate and trimethylammonium glycol chitosan iodide [6-O-(2-hydroxyethyl)-2-(trimethylammonio)-chitosan iodide]. The present study was carried out to look at what factors play a crucial role in this enhancement. We measured viscosity of broth, mass-transfer coefficient (k(L)a) for oxygen and diffusion coefficient of glucose (substrate). It has become apparent that there is only a difference in the diffusion coefficient of glucose between the free and immobilized cells. Therefore, we believe that the diffusion limitation by substrates as a problem in submerged mycelial processes is improved by immobilization based on polyelectrolyte complexes.