Kinetic effect of zinc(II) and cadmium(II) ions on configurational inversion of deltaLLL-fac(S)-tris(L-cysteinato-N,S)cobalt(III) complex.

It has been confirmed from circular dichroism (CD) spectral changes of aqueous solutions of deltaLLL-fac(S)-[Co(L-cys-N,S)3]3- that the absolute configurational inversion to the ALLL isomer is remarkably accelerated by zinc(II), while it is retarded by cadmium(II). In the diluted solutions of these metal ions containing excess deltaLLL-fac(S)-[Co(L-cys-N,S)3]3-, the observed inversion rate constant linearly depends on the zinc(II) concentration with an intercept, while it is not affected by the cadmium(II) concentration. The kinetic behavior has been explained by difference between zinc(II)- and cadmium(II)-interactions with lone pairs on sulfur donor atoms of fac(S)-[Co(L-cys-N,S)3]3-. It has also been proposed that concentrations of zinc(II) and cadmium(II) can be simultaneously determined by the kinetic measurements.     

Large triplet pairing mixing in the FFLO state of spin fluctuation mediated superconductivity in Q1D systems

We study the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state of spin fluctuation mediated superconductivity and focus on the effect of coexisting charge fluctuations. We find that (i) consecutive transitions from singlet pairing to FFLO and further to S_z=1 triplet pairing can generally take place upon increasing the magnetic field when strong charge fluctuations coexist with spin fluctuations and (ii) the enhancement of the charge fluctuations lead to a significant increase of the parity mixing in the FFLO state, where the triplet/singlet component ratio in the gap function can be close to unity. We propose that such consecutive pairing state transition and strong parity mixing in the FFLO state may take place in a quasi-one-dimensional organic superconductor (TMTSF)₂X.     

Jordan tori for a torsion free abelian group

We classify Jordan G-tori, where G is any torsion-free abelian group. Using the Zelmanov prime structure theorem, such a class divides into three types, the Hermitian type, the Clifford type, and the Albert type. We concretely describe Jordan G-tori of each type.     

One-pot beta-substitution of enones with alkyl groups to beta-alkyl enones

Vinylic hydrogens at the beta-position of enones were effectively substituted with alkyl groups in a one-pot procedure to afford beta-alkyl enones in good to high isolated yields by conjugate addition of higher-order dialkyl cyanocuprates to enones, followed by a reaction with N-tert-butylbenzenesulfinimidoyl chloride at -78 degree C.     

Cascade radical reactions catalyzed by a Pd/light system: cyclizative multiple carbonylation of 4-alkenyl iodides

Cascade reactions of 4-alkenyl iodides, involving a carbonylation-cyclization-carbonylation sequence, were accomplished by a hnu/Pd system. The stereochemical outcomes suggest that radical carbonylation and subsequent acyl radical cyclization may be involved in this reaction.     

Octahedral-tetrahedral equilibrium and solvent exchange of cobalt(II) ions in primary alkylamines

The enthalpy differences (Delta H degrees ) of the equilibrium between the octahedral and tetrahedral solvated cobalt(II) complexes were obtained in some primary alkylamines such as propylamine (pa, 36.1 +/- 2.3 kJ mol(-1)), n-hexylamine (ha, 34.9 +/- 1.0 kJ mol(-1)), 2-methoxyethylamine (meea, 44.8 +/- 3.1 kJ mol(-1)), and benzylamine (ba, 50.1 +/- 3.6 kJ mol(-1)) by the spectrophotometric method. The differences in the energy levels between the two geometries of the cobalt(II) complexes in the spherically symmetric field (Delta E(spher)) were estimated from the values of Delta H degrees by offsetting the ligand field stabilization energies. It was indicated that the value of Delta E(spher) is the decisive factor in determining the value of Delta H degrees and is largely dependent on the electronic repulsion between the d-electrons and the donor atoms and the interelectronic repulsion in the d orbitals. The comparison between activation enthalpies (Delta H(++)) for the solvent exchange reactions of octahedral cobalt(II) ions in pa and meea revealed that the unexpectedly large rate constant and small Delta H(++) in pa are attributed to the strong electronic repulsion in the ground state and removal of the electronic repulsion in the dissociative transition state, which can give the small Delta E(spher) between the ground and transition states. Differences in the solvent exchange rates and the DeltaH(++) values of the octahedral metal(II) ions in some other solvents are discussed in connection with the electronic repulsive factors.     

Preparation of palladium film by coating photolysis process using KrF or ArF excimer laser

The preparation of palladium (Pd) films has been investigated using KrF or ArF laser irradiation on a Pd acetate (PdAc) coated substrate. A crystalline Pd film could be obtained by KrF laser irradiation (fluence = 15-40 mJ/cm²) but PdAc was found to remain in the film. An increase in the substrate temperature to 423 K decreased the inclusion of the unreacted precursor and produced a better crystallinity. An amorphous and uniform Pd film composed of very fine particles was found to be formed by this process under reduced pressure, which is probably due to the preferential ablation of the crystalline nuclei. ArF laser irradiation is more effective for decomposing the PdAc and for producing a Pd film with a better crystallinity and no (or smaller) organic inclusion.     

Adsorption states of NO on the Pt(1 1 1) step surface

Using infrared reflection absorption spectroscopy (IRAS) and scanning tunneling microscopy (STM), we investigated the adsorption states of NO on the Pt(9 9 7) step surface. At 90 K, we observe three N-O stretching modes at 1490 cm⁻¹, 1631 cm⁻¹ and 1700 cm⁻¹ at 0.2 ML. The 1490 cm⁻¹ and 1700 cm⁻¹ peaks are assigned to NO molecules at fcc-hollow and on-top sites of the terrace, respectively. The 1631 cm⁻¹ peak is assigned to the step NO species. In the present STM results, we observed that NO molecules were adsorbed at the bridge sites of the step as well as fcc-hollow and on-top sites of the terrace. To help with our assignments, density functional theory calculations were also performed. The calculated results indicate that a bridge site of the step is the most stable adsorption site for NO, and its stretching frequency is 1607 cm⁻¹. The interactions between NO species at different sites on Pt(9 9 7) are also discussed.     

Simultaneous analytical method for the determination of TCH346 and its four metabolites in human plasma by liquid chromatography/tandem mass spectrometry

TCH346 (dibenzo[b,f]oxepin-10-ylmethyl-prop-2-ynylamine) is a novel propargylamine compound under investigation as a putative agent in the treatment of chronic neurodegenerative illnesses. To support clinical studies an analytical method was developed for TCH346 plus its three amine metabolites and a carboxylic acid metabolite in human plasma. Using a two-step liquid-liquid extraction, one under acidic and one under basic conditions, by pH-switching both the basic and acidic analytes were extracted from 0.5 mL of plasma. All these basic and acidic compounds could be analyzed simultaneously using gradient high-performance liquid chromatographic (HPLC) separation with positive/negative selected reaction monitoring mass spectrometry. As a result of the validation study, the analytical method was shown to be appropriate for the determination of TCH346 and its metabolites CGP70861, GP42120, CGP71090, and GP54840 in plasma for forthcoming clinical studies. The LLOQs were set to 2, 200, 20, 20, and 200 pg/mL for TCH346, CGP70861, GP42120, CGP71090, and GP54840, respectively, and the ULOQ for all analytes was 20 000 pg/mL. All analytes were stable in 50% MeOH at 4 degrees C for at least one year, in human plasma stored below -70 degrees C for at least 7 months, in human plasma below -18 degrees C for at least 6 months, in human plasma at room temperature for at least 1 day, and in the final extract solution at 4 degrees C for at least 3 days.     

Superconductivity in the graphite-potassium intercalation compound C8K

Superconducting properties of pseudo-single crystals of C₈K were investigated by low frequency a.c. magnetic susceptibility and electrical resistivity measurements. The measured values of T_c were between 128 and 198 mK for 13 samples. Measurements of the superconducting transition in a magnetic field revealed a remarkable anisotropy, such that if θ is defined as the angle between the applied magnetic field and the layer plane, type II superconductivity was observed for 0° ≦ ∣ θ ∣ ? 25° and type I superconductivity for 25° ? ∣ θ ∣≦ 90°. The angular dependences of H_c2 and H_c3 were fairly well-explained by the effective mass model.