Crystal structure of cobalt molybdate hydrate CoMoO4·nH2O

We have determined the crystal structure of the title compound, which has a triclinic cell with cell parameters of , , , α=76.617°, β=84.188°, γ=74.510° and space group . The crystal structure suggests the chemical formula CoMoO₄·3/4H₂O. The structure consists of MoO₄ tetrahedra and CoO₆ octahedra, confirming the earlier X-ray absorption near-edge spectroscopic (XANES) investigation on the hydrate. The comparison of the crystal structures of the hydrate and the α-,β-, and hp-phases shows that the hydrate exhibits metal cation coordinations similar to those of the β-phase, but had arrangements of CoO₆ and MoO_n polyhedra similar to those of the hp-phase.     

Cyclopalladation of the indole ring in palladium(II) complexes of 2N1O-donor ligands and its dependence on the O-donor properties

Synthetic, structural, spectroscopic, and kinetic studies have been carried out on the Pd(II) complexes of new 2N1O-donor ligands containing a pendent indole, 3-(N-2-pyridylmethyl-N-2-hydroxy-5-methoxybenzylamino)ethylindole (HMeO-iepp), 3-(N-2-pyridylmethyl-N-2-hydroxy-5-nitrobenzylamino)ethylindole (HNO2-iepp), and (N-2-pyridylmethyl-3-indolylethylamino)acetic acid (Hiepc) (H denotes a dissociable proton). [Pd(MeO-iepp)Cl] (2), [Pd(NO2-iepp)Cl] (3), and [Pd(iepc)Cl] (4) were prepared and revealed by X-ray analysis to have a pyridine nitrogen, an amine nitrogen, a phenolate or carboxylate oxygen, and a chloride ion in the coordination plane. UV absorption and 1H NMR spectral changes indicated that all the complexes could be converted to the indole-binding complexes where the O donor was replaced by the indole C2 atom by cyclopalladation in DMSO or DMF in the temperature range of 40-60 degrees C. Formation of the indole-binding complex species obeyed the first-order kinetics, from which the activation parameters were estimated. The formation rate was dependent on the properties of the O-donor group, a lower pKa value of its conjugate acid causing faster conversion to the indole-binding species in the order 2 (methoxyphenolate) < 3 (nitrophenolate) < 4 (carboxylate). On the other hand, the ratio of the indole-binding complex to the O-donor complex as a result of the conversion was greater for the complexes with a higher pKa value of the ligand OH group, the order being 2 > 3 > 4.     

Optimal laser control of ultrafast photodissociation of I2- in water: mixed quantum/classical molecular dynamics simulation

A linearized optimal control method in combination with mixed quantum/classical molecular dynamics simulation is used for numerically investigating the possibility of controlling photodissociation wave packets of I(2)(-) in water. Optimal pulses are designed using an ensemble of photodissociation samples, aiming at the creation of localized dissociation wave packets. Numerical results clearly show the effectiveness of the control although the control achievement is reduced with an increase in the internuclear distance associated with a target region. We introduce effective optimal pulses that are designed using a statistically averaged effective dissociation potential, and show that they semiquantitatively reproduce the control achievements calculated by using optimal pulses. The control mechanisms are interpreted from the time- and frequency-resolved spectra of the effective optimal pulses.     

An intramolecular diels-alder approach to quassinoids—a stereoselective construction of a-aromatic klaineanone

Thermolysis of a benzocyclobutene derivative ($\text{20}$) prepared from norcamphor produced stereoselectively a tetracyclic compound ($\text{2}$), which was converted to a lactone ($\text{21}$) having correct stereochemistry at C₇, C₈, C₉, C₁₁, C₁₃, and C₁₄ positions of (±)-klaineanone.     

Comparison of total fluorine, extractable organic fluorine and perfluorinated compounds in the blood of wild and pefluorooctanoate (PFOA)-exposed rats: Evidence for the presence of other organofluorine compounds

The widespread occurrence and environmental persistence of perfluorinated compounds (PFCs) received worldwide attention recently. Exhaustive analysis of all fluorinated compounds in an environmental sample can be daunting because of the constraints in the availability of analytical standards and extraction methods. Combustion ion chromatographic technique for trace fluorine analysis was used to assess the concentrations of known PFCs (e.g., PFOS, PFOA) and total fluorine (TF) in the blood of wild rats collected from Japan. The technique was further validated using tissues from PFOA-exposed rats. Six PFCs (PFOS, PFOSA, PFUnDA, PFDA, PFNA, and PFOA) were detected in all of the wild rat blood samples. Concentrations of extractable organic fluorine (EOF) in fraction 1 (Fr1; MTBE extraction) of wild rats ranged 60.9-134 ng F mL⁻¹, while those in fraction 2 (Fr2; hexane) were below LOQ (32 ng F mL⁻¹); TF concentrations in the blood of wild rats ranged from 59.9-192 ng F mL⁻¹. The contribution of known PFCs in EOF-Fr1 (MTBE) varied from 9% to 89% (56% on average), and known PFC concentrations in TF content were less than 25%. In contrast, TF concentrations in the blood of PFOA-exposed rats ranged from 46900 to 111000 ng F mL⁻¹, with PFOA contributing over 90% of TF. A comparison of results from the samples analyzed in this study and the literature revealed three distinct groups with PFOA/known PFC and TF levels (i.e., wild rats and general population, occupationally exposed workers, and PFOA-exposed laboratory rats). The mass balance analysis of the different forms of fluorine in blood suggested the presence of other forms of organic fluorine in addition to known PFCs.     

Synthesis of 1-(5,6-dihydro-2H-thiopyran-2-yl)uracil by a Pummerer-type thioglycosylation reaction: the regioselectivity of allylic substitution

1-(5,6-Dihydro-2H-thiopyran-2-yl)uracil derivatives, a new 4′-thio-D4-nucleoside analogue, were synthesized by reacting 5,6-dihydro-2H-thiopyran sulfoxide and persilylated uracil in a Pummerer-type thioglycosylation reaction. The reaction of 5-alkyl substituted dihydrothiopyran sulfoxide 7 only gave 1-(dihydrothiopyran-2-yl)uracil 9. On the other hand, the reaction with a 5-siloxy substituted derivative of 7 resulted in a mixture of products with the uracil moiety at either the α- or the γ-position. The use of a prolonged reaction time resulted in the exclusive formation of the 4-substituted dihydrothiopyran derivative 10. The result suggests that an equilibrium is operative in the formation of the α- and γ-adducts and that the latter should be more thermodynamically stable than the former. This conclusion was also supported by theoretical calculations.     

High-performance liquid chromatography of coenzyme Q-related compounds and its application to biological materials

A convenient and precise method for the separation and determination of coenzyme Q (CoQ)-related compounds (CoQ homologues, plastoquinone-9, ubichromenol-9, etc.) was developed using high-performance liquid chromatography (HPLC). All compounds tested were separated using a reverse-phase column with a suitable mobile phase and detected at a wavelength of 275 nm. CoQ extracts in plasma and erythrocytes were purified by thin-layer chromatography prior to HPLC analysis, but such purification was not necessary when determining CoQ in urine and tissues. Hydroquinone forms of CoQ existing in animal tissues were oxidized to the corresponding quinone forms with potassium hexacyanoferrate(III). This HPLC method was applied satisfactorily to the determination of the contents of CoQ homologues in human and animal samples. CoQ10 was the only homologue detected in human samples, and CoQ8, CoQ9 and CoQ10 were native homologues of CoQ in rat tissues. Ubichromenol-9 and plastoquinone-9 were not detected in these samples.     

Spontaneous self-assembly process for threadlike micelles

More than 100 micros dissipative particle dynamics simulations were carried out to investigate the spontaneous formation process of threadlike micelles from the random configuration for surfactant molecules. Stable spherical micelles were formed during the earlier stage. These spherical micelles fused to each other and grew into rodlike and threadlike micelles during the later stage. The length and radius of a micelle were estimated by tracing the backbone positions and the distance between the head group particles and the backbone of the micelles, respectively. The ratio of the largest to the smallest principal moments of inertia for each micelle was calculated as the micelle shape.     

Synthesis and pharmacological evaluation of 1-isopropyl-1,2,3,4-tetrahydroisoquinoline derivatives as novel antihypertensive agents

A series of 1-isopropyl-1,2,3,4-tetrahydroisoquinoline derivatives were synthesized and their bradycardic activities were evaluated in isolated guinea pig right atria. Structure-activity relationship studies revealed that the introduction of an appropriate substituent and its position on the 1,2,3,4-tetrahydroisoquinoline ring are essential for potent in vitro activity. Furthermore, the tether between the piperidyl moiety and the terminal aromatic ring is important for potent antihypertensive activity. Oral administration of 6-fluoro-1-isopropyl-2-{[1-(2-phenylethyl)piperidin-4-yl]carbonyl}-1,2,3,4-tetrahydroisoquinoline (3b) to spontaneously hypertensive rats (SHR) elicited antihypertensive effects without inducing reflex tachycardia, which is often caused by traditional L-type Ca2? channel blockers.     

Enantioselective desymmetrization of meso-N-(heteroarenesulfonyl)aziridines with TMSN3 catalyzed by chiral Lewis acids

A catalytic enantioselective desymmetrization of meso-N-(heteroarenesulfonyl)aziridines with TMSN₃ using chiral Lewis acids afforded products with high enantioselectivity. As proof of the utility of this procedure, the precursor of selective κ-opioid agonist (1S,2S)-(−)-U-50,488 was synthesized.