Structure and dynamics of halogenoethanol-water mixtures studied by large-angle X-ray scattering, small-angle neutron scattering, and NMR relaxation

To clarify the structure of solvent clusters formed in halogenoethanol-water mixtures at the molecular level, large-angle X-ray scattering (LAXS) measurements have been made at 298 K on 2,2,2-trifluoroethanol (TFE), 2,2,2-trichloroethanol (TCE), and their aqueous mixtures in the TFE and TCE mole fraction ranges of 0.002 < or = x(TFE) < or = 0.9 and 0.5 < or = x(TCE) < or = 0.9, respectively. The radial distribution functions (RDFs) for TFE-water mixtures have shown that the structural transition from inherent TFE structure to the tetrahedral-like structure of water takes place at x(TFE) approximately 0.2. In the TCE-water mixtures inherent TCE structure remains in the range of 0.5 < or = x(TCE) < or = 1. Small-angle neutron scattering (SANS) experiments have been performed on CF(3)CH(2)OD- (TFE-d(1)-) D(2)O and CF(3)CD(2)OH- (TFE-d(2)-) H(2)O mixtures in the TFE mole fraction range of 0.05 < or = x(TFE) < or = 0.8. The SANS results in terms of the Ornstein-Zernike correlation length have revealed that TFE and water molecules are most heterogeneously mixed with each other in the TFE-water mixture at x(TFE) approximately 0.15, i.e., both TFE clusters and water clusters are most enhanced in the mixture. To evaluate the dynamics of TFE and ethanol (EtOH) molecules in TFE-water and ethanol-water mixtures, respectively, (1)H NMR relaxation rates for the methylene group within alcohol molecules have been measured by using an inversion-recovery method. The alcohol concentration dependence of the relaxation rates for the TFE-water and ethanol-water mixtures has shown a break point at x(TFE) approximately 0.15 and x(EtOH) approximately 0.2, respectively, where the structural transition from alcohol clusters to the tetrahedral-like structure of water takes place. On the basis of the present results, the most likely structure models of solvent clusters predominantly formed in TFE-water and TCE-water mixtures are proposed. In addition, effects of halogenation of the hydrophobic groups on clustering of alcohol molecules are discussed from the present results, together with the previous ones for ethanol-water and 1,1,1,3,3,3-hexafluoro-2-propanol- (HFIP-) water mixtures.     

Botrydienal,a new prytotoxin,and its related metabolites,dehydrobotrydienal and deacetyldihydrobotrydial produced by botryotiniasquamosa

A new phytotoxin, botrydienal, and its two related metabolites, dehydrobotrydienal and deacetyldihydrobotrydial, were isolated from $\text{Botryotinia}$$\text{squamosa}$, and their structures were elucidated as $\text{1}$, $\text{2}$ and $\text{3}$, respectively, on the basis of spectral analysis.     

Meta functionalization of anilines and phenol

Regioselective introduction of various functional groups on the meta-position of anilines and phenol was achieved by proton abstraction from the chromium tricarbonyl complexes $\text{3}$,$\text{5}$,$\text{7}$ with $\text{n}$-BuLi, followed by the addition of electrophiles and decomplexation.     

Separation of isotopic compounds by reversed-phase liquid chromatography. Effect of pressure gradient on isotope separation by ionization control

Isotope separation utilizing ionization control in reversed-phase liquid chromatography was studied. Several organic acids and bases labeled with oxygen-18 and nitrogen-15 were successfully separated from unlabeled compounds by using either 6-m microbore columns or recycle chromatography with short columns of conventional size. Differences in the separation factors for the same isotopic mixtures were observed between the two chromatographic systems, and attributed to the difference in the pressure gradient along the columns in the two systems. The steep pressure gradient existing in the short recycle columns resulted in an increase in the peak width and the separation factor for oxygen isotopic compounds, and a decrease in the peak width and the separation factor for nitrogen isotopic compounds.     

Electrochemical synthesis, crystal structure, and photomagnetic properties of a three-dimensional cyano-bridged copper-molybdenum complex

A single crystal of Cs(I)2Cu(II)7[Mo(IV)CN8]4.6H2O was electrochemically prepared on a Pt wire electrode with a constant potential of +500 mV vs Ag/AgCl electrode. X-ray single-crystal structural analysis showed that this compound consists of a three-dimensional cyano-bridged Cu-Mo bimetallic assembly with a tetragonal structure of I4/mmm. The coordination geometry of Mo(IV) is bicapped trigonal prism, and that of Cu(II) is five-coordinate of square pyramidal or four-coordinate of square planar. This compound was also prepared as a 0.2-3.0 microm thick film on a SnO2-coated glass in the same electrochemical manner. When the sample, which shows paramagnetism due to Cu(II) (S = 1/2), was irradiated with 450-500 nm light at 5 K, spontaneous magnetization with a Curie temperature of 23 K was observed. This photoinduced change was recovered by a thermal treatment. In the infrared (IR) and electron spin resonance (ESR) spectra after light irradiation, variations in the stretching IR peak of CN bridged to Mo(IV) and the paramagnetic ESR peak of Cu(II) were observed, respectively. The data indicate that this photomagnetism is caused by the electron transfer from Mo(IV) to Cu(II) and the ferromagnetic ordering between Cu(II) (S = 1/2) and Mo(V) (S = 1/2).     

Generalized diffusion equation of interacting brownian particles

Macroscopic behavior of a system of brownian particles interacting with each other through potential forces is described by a generalized diffusion equation (GDE) for the density of particles. The diffusion coefficient in the GDE is given by the generalized Stokes—Einstein relation and generally depends on the density. In the presence of long-range interactions, the GDE becomes non-local in space. When a Coulomb interaction exists, the GDE corresponds to an improvement of the Poisson—Boltzmann equation.     

Wettability control of a solid surface by utilizing photocatalysis

This paper describes a strategic approach utilizing a photocatalyst to obtain a solid surface with a high level of sustainable wettability (hydrophilicity or hydrophobicity). We clarified that the substances adsorbed on the surface could be successfully removed by photocatalytic oxidation resulting in sustainable high hydrophilic and high hydrophobic states. In addition to the conventional redox reaction, photoinduced wettability conversion plays an inevitable role in obtaining a superhydrophilic state. Both of the aforementioned photoinduced properties can be applied to sustain a high level of hydrophilicity. A superhydrophobic surface can be designed based on the Cassie theory. However, a combination with the usual TiO₂ photocatalyst leads to a decrease in hydrophobicity because the photocatalyst becomes hydrophilic itself as a result of the photoinduced hydrophilic reaction. Utilizing the newly developed hydroxyapatite doped with Ti(IV) ions (TiHAP) photocatalyst, which has a considerably reduced hydrophilic effect, a superhydrophobic surface can be sustained after exposing it to outdoor conditions for a long period. As for sustaining the hydrophobic state, the introduction of a material design based on dynamic wettability leads to the possibility of novel functional materials with a high dynamic hydrophobicity. Our study shows that a high level of wettability (hydrophilic or hydrophobic) of a solid surface as that sustained by biologic action is possible by utilizing photocatalysis. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 279–290; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20154     

Bulk-type all-solid-state batteries with mechanically prepared LiCoPO4 composite cathodes

Journal of Solid State Electrochemistry - All-solid-state Li batteries are suitable for the application of 5 V-class cathode materials that can provide high energy densities. However, it is hard to...     

Efficiency of porous hydrophilic polymer-based packing materials in chromatographic analysis of drugs existing with polypeptide

Summary A size monodispersed restricted-access polymeric packing material has been prepared through a simple and easy one-step method of co-polymerization of glycerol monomethacrylate and glycerol dimethacrylate with cyclohexanol as prorogen. A typical seeded polymerization (two step swelling and polymerization method) in an aqueous medium gave a 90 % yield of porous beads which could be utilized as a packing material in high performance liquid chromatography (HPLC) without any size classification due to the excellent size monodispersity. A BET measurement and size exclusion chromatography in either tetrahydrofuran or water revealed that the prepared material had only small pores (around 100 Å in diameter). It showed ample hydrophobicity for the separation of hydrophilic drug molecules in 10% aqueous acetonitrile buffer, while polypeptides such as bovine serum albumin were excluded and eluted before the void volume of the column with quantitative recovery.     

Stereoselective total synthesis of bazzanene

3azzanene, the stereoisomer of trichodiene, isolated from a liverwort was synthesized with complete stereoselectivity in 8 steps (12% yield) starting from a known bicyclo[2.2.2]octane derivative.