Hydrophilic polymer supported nanoparticles prepared from samarium trichloride and lanthanum trichloride in liquid-phase

Nanoparticles were obtained by the reaction of SmCl₃·6H₂O with sodium borohydride (NaBH₄) in the presence of sodium polyacrylate (PAA) with average molecular weight of 5,100 as a capping polymer. The resulting colloidal solution was placed on a Cu grid and characterized by transmission electron microscope (TEM) measurement, which clearly indicated the generation of nanoparticles. The reaction of LaCl₃ with NaBH₄ in the presence of PAA led to preparation of lanthanum nanoparticles, similarly as samarium nanoparticles.     

Frustration-induced eta inversion in the S=1/2 bond-alternating spin chain

We study the frustration-induced enhancement of the incommensurate correlation for a bond-alternating quantum spin chain in a magnetic field, which is associated with a quasi-one-dimensional organic compound F5PNN. We investigate the temperature dependence of the staggered susceptibilities by using the density matrix renormalization group, and then find that the incommensurate correlation becomes dominant in a certain range of the magnetic field. We also discuss the mechanism of this enhancement on the basis of the mapping to the effective S=1/2 XXZ chain and a possibility of the field-induced incommensurate long-range order.     

Ultrasonic effects on electroorganic processes. Part 25. Stereoselectivity control in cathodic debromination of stilbenedibromides

Ultrasonic effects on the cathodic debromination of stilbenedibromides on a platinum cathode was examined. Current efficiency and stereoselectivity for trans-stilbene, which was formed along with cis-stilbene in the cathodic debromination of stilbenedibromides, were significantly increased under ultrasonication with an intensity over the ultrasonic cavitation threshold. This ultrasonic effect is rationalized as due to mass transport promotion in the electrode-electrolytic solution interface. A mechanism for the ultrasonic effect is discussed in detail on the basis of the reaction pathway of the debromination of stilbenedibromides.     

Facile preparation of a new BINAP-based building block, 5,5'-diiodoBINAP, and its synthetic application

[reaction: see text] Bis(pyridine)iodonium tetrafluoroborate was successfully used for regioselective iodination of BINAP dioxide to give 5,5'-diiodoBINAP dioxide in an excellent yield of 92%, with no observed formation of 4,4'-diiodoBINAP dioxide. A Sonogashira cross-coupling reaction with 5,5'-diiodoBINAP dioxide gave the desired bis(trimethylsilylethynyl) product in 86% yield. The resulting 5,5'-disubstituted BINAP dioxides were reduced to the corresponding phosphines, which were used as chiral ligands for rhodium-catalyzed asymmetric 1,4-addition of phenylboronic acid to 2-cyclohexenone to give 3-phenylcyclohexanone in excellent yield with high enantioselectivity.     

Rh(I)-catalyzed CO gas-free cyclohydrocarbonylation of alkynes with formaldehyde to alpha,beta-butenolides

The rhodium(I)-catalyzed reaction of alkynes with formaldehyde proceeds via the double incorporation of a carbonyl moiety from formaldehyde, resulting in a CO gas-free cyclohydrocarbonylation leading to alpha,beta-butenolides.     

Composite bonded magnets with controlled anisotropy directions prepared by viscous deformation technique

When a radially anisotropic rare earth bonded magnet for a rotor with a high (BH)_max value is magnetized multi-polarly, its flux distributes rectangularly and increases a cogging torque. In order to overcome this difficulty, we newly developed highly dense Sm₂Fe₁₇N₃ and Nd₂Fe₁₄B-based composite bonded magnets with continuously controlled anisotropy directions by using a viscous deformation technique.     

Algebraic approach to chiral anomalies: General solution of the consistency condition

General form of nontrivial solutions of the Wess-Zumino consistency condition is derived, and the uniqueness of the chiral anomalies is discussed. Whole of the argument is based on the algebraic treatment of the problem in the extended Euclidean space-time of the dimension higher than six. Particularly crucial to the argument is a lemma, the proof of which is presented in detail.     

Oxidation of substrates having labile hydrogens by superoxide in the presence of phosgene dimer

Superoxide (O₂^?) oxidized substrates having labile hydrogens to ketones in the presence of phosgene dimer. Oxidations with similar treatment of alkynes were examined. The reaction mechanism was also discussed.