Non-Basic Solution Routes to Prepare ZnO Nanoparticles

Nanocrystalline ZnO particles were prepared from alcoholic solutions of zinc acetate dihydrate without using base such as NaOH or LiOH through a colloid process carried out at a low temperature of 60°C. A comparative study of chemical reactions from zinc acetate dihydrate to ZnO was made using different types of monool solvents, i.e. methanol, ethanol, and 2-methoxyethanol. It was revealed that layered hydroxide zinc acetate was formed as an intermediate and its transformation into ZnO was a key reaction step in any of the solutions. Reaction time necessary for the precipitation of ZnO was greatly influenced by the solvents used. Methanol was useful for the preparation of the ZnO nanoparticles, which were chemically pure in terms of cation impurities and exhibited green photoluminescence by the ultraviolet excitation.     

Synthese von derivaten der cinchona-alkaloide—XXXII Synthese von dihydrocorynanthean und 3-epidihydrocorynanthean aus cinchonin

Starting from cinchonine, 3-epidihydrocorynantheane was synthesized through 2′-oxohexahydrocinchonine. Quinine was transformed into 10-methoxydihydrocorynantheane by the same reaction steps. In both cases, it was found that Oppenauer oxidation of the secondary hydroxyl group at quinine-numbering C-9 was accompanied with no configurational change at the neighboring C-atom, which originated from C-8 in quinuclidine moiety. 3-Epidihydrocorynantheane was converted to dihydrocorynantheane by oxidation with mercuric acetate and then sodium borohydride reduction.     

Photoinduced DNA end capping via N3-methyl-5-cyanovinyl-2'-deoxyuridine

A modified oligodeoxynucleotide (ODN) containing N(3)-methyl-5-cyanovinyl-2'-deoxyuridine reacts by photoirradiation at 366 nm with an adenine residue of a complementary template ODN to yield an end-capped ODN in 87% yield.     

Synthesis of pyridine N-oxide-SbCl5 complexes and their intramolecular and oxygen-transfer reaction

Mixing with equimolar solutions of pyridine N-oxide or its homologs and SbCl₅ in CCl₄ deposited 1:1 complexes as colorless crystals in high yield. On thermolysis, these complexes underwent intramolecular oxygen transfer to give selectively the corresponding 2-pyridone derivatives. N,N-Dimethylaniline N-oxide and SbCl₅ also gave a crystalline 1:1 complex which on thermolysis yield o-dimethylaminophenol in good yield.     

Synthesis, structure and physical properties of layered semiconductors MCuFCh (M=Sr, Eu, Ch=S, Se)

Effects of open shell cations on magnetic, optical and carrier transport properties were examined for layered wide bandgap semiconductors MCuFCh (M=Sr, Eu, Ch=S, Se). Single-phase MCuFCh powder and ceramic samples were synthesized by solid-state reactions. The crystal structures refined by the Rietveld analyzes revealed that all the materials have the space group P4/nmm, indicating that the samples have the same crystal structure as that of layered oxychalcogenides LaCuOCh, and cation vacancies of several percent were present for Cu⁺ and Eu²⁺ sites in EuCuFCh. Thermopower measurements revealed that both SrCuFCh and EuCuFCh were p-type semiconductors. Degenerate conduction was observed for EuCuFCh with conductivities >1 S cm⁻¹, whereas SrCuFCh exhibited thermally activated behavior. The optical band gaps of SrCuFS and SrCuFSe estimated were approximately 3.0 and 2.7 eV, respectively, and those of EuCuFCh were ∼2 eV. Temperature dependence of magnetic susceptibilities of EuCuFCh followed the Curie-Weiss law down to 5 K and the samples did not show any transition to a magnetic ordering phase.     

The intersection of three spheres in a sphere and a new application of the Sato-Levine invariant

Take transverse immersions such that (1) is an embedding, (2) and is connected, and (3) . Then we obtain three surface-links = (, ) in , where =(1,2,3), (2,3,1), (3,1,2). We prove that, we have the equality where is the Sato-Levine invariant of , if all are semi-boundary links.

     

Preparation of samples for gas chromatography/mass spectrometry analysis of phthalate and adipate esters in plasma and beverages by steam distillation and extraction

Phthalate and adipate esters are present in relatively large amounts in the environment, resulting in their large blank values at analysis and making precise analysis difficult. We developed a highly sensitive analytical method for phthalate and adipate esters in plasma and beverages by lowering the blank values that interfere with analysis. The method uses a closed distillation cleanup system in which steam distillation and extraction are performed simultaneously. The recoveries from beverages and plasma were both satisfactory, ranging from 90.2 to 118.3%, relative standard deviation (RSD) = 2.8-5.3%, and 96.2-134.4%, RSD = 2.2-6.5%, respectively. The detection limits of dibutyl phthalate and di-2-ethyl hexyl phthalate were 5 ng/mL, and those of diethyl phthalate, butyl benzyl phthalate, and di-2-ethyl hexyl adipate were 10 ng/mL in rabbit plasma and beverages.     

Catalytic C-C bond cleavage and C-Si bond formation in the reaction of RCN with Et3SiH promoted by an iron complex

Catalytic C-C bond cleavage of acetonitrile and C-Si bond formation have been attained in the photoreaction of MeCN with Et3SiH in the presence of an iron complex, Cp(CO)2FeMe. This catalytic system can be applied for arylnitrile C-C bond cleavage.     

C2-hydroxyglycosylation with glycal donors. Probing the mechanism of sulfonium-mediated oxygen transfer to glycal enol ethers

The C2-hydroxyglycosylation reaction employing the reagent combination of a diaryl sulfoxide and triflic anhydride offers a novel method for glycal assembly whereby a hydroxyl functionality is stereoselectively installed at the C2-position of a glycal donor with concomitant glycosylation of a nucleophilic acceptor. Mechanistic investigations into this reaction revealed a novel process for sulfonium-mediated oxidation of glycal enol ethers in which the sulfoxide oxygen atom is stereoselectively transferred to the C2-position of the glycal. (18)O-labeling studies revealed that the S-to-C2 oxygen-transfer process involves initial formation of a C1[bond]O linkage followed by O-migration to C2, leading to the generation of an intermediate glycosyl 1,2-anhydropyranoside that serves as an in situ glycosylating agent. These findings are consistent with the initial formation of a C2-sulfonium[bond]C1-oxosulfonium pyranosyl species upon activation of the glycal donor with Aryl(2)SO x Tf(2)O.