Kobalt und Nickel

Ohne Zusammenfassung     

Palladium‐Catalyzed Direct Cross‐Coupling of Carboranyllithium with (Hetero)Aryl Halides

A palladium‐catalyzed direct C‐arylation reaction of readily available cage carboranyllithium reagents with aryl halides has been developed for the first time. This method is applicable to a wide range of aryl halide substrates including aryl iodides, aryl bromides, and heteroaromatic halides.     

Determination of limonin in dog plasma by liquid chromatography–tandem mass spectrometry and its application to a pharmacokinetic study

A highly sensitive liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 mm ammonium acetate buffer–methanol (26:74, v/v) on a C₁₈ column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 469.4 → 229.3 and m/z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625–100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter‐ and intra‐day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs. Copyright © 2012 John Wiley & Sons, Ltd.     

Validated LC‐MS method for simultaneous quantitation of catalpol and harpagide in rat plasma: application to a comparative pharmacokinetic study in normal and diabetic rats after oral administration of Zeng‐Ye‐Decoction

A simple and efficient liquid chromatography‐mass spectrometry (LC‐MS) method was developed and validated for simultaneous quantitation of catalpol and harpagide in normal and diabetic rat plasma. Protein precipitation extraction with acetonitrile was carried out using salidroside as the internal standard (IS). The LC separation was performed on an Elite C₁₈ column (150 × 4.6 mm, 5 µm) with the mobile phase consisting of acetonitrile and water within a runtime of 12.0 min. The analytes were detected without endogenous interference in the selected ion monitoring mode with positive electrospray ionization. Calibration curves offered satisfactory linearity (r > 0.99) at linear range of 0.05–50.0 µg/mL for catalpol and 0.025–5.0 µg/mL for harpagide with the lower limits of quantitation of 0.05 and 0.025 µg/mL, respectively. Intra‐ and inter‐day precisions (RSD) were <9.4%, and accuracy (RE) was in the ?6.6 to 4.9% range. The extraction efficiencies of catalpol, harpagide and IS were all >76.5% and the matrix effects of the analytes ranged from 86.5 to 106.0%. The method was successfully applied to the pharmacokinetic study of catalpol and harpagide after oral administration of Zeng‐Ye‐Decoction to normal and diabetic rats, respectively. Copyright © 2013 John Wiley & Sons, Ltd.     

MODEL SIMULATION OF WATER-IN-OIL XANTHAN FERMENTATION

The W/O xanthan fermentation is simulated by integrating the microbial kinetic behaviors and the multiple-phase process characteristics. Model 1 assumes uniform redistribution of cells, substrates and product by frequent droplet breakup and coalescence. Model 2 simulates the system of viscous aqueous phase with minimal droplet breakup and component redistribution. The real fermentation should proceed within the bounds set by the two models. Effects of various parameters are evaluated. The aqueous-phase xanthan concentration (X_n) and volumetric productivity (Q_P) achieved at 200 h are used as the indicators. X_n and Q_P increase with nitrogen-source concentration (S_NO) initially but plateau (Model 1) or decrease slightly (Model 2) at high S_NO. X_n (at 200 h) decreases with increasing aqueous-phase volume fraction (f). Q_P, however, increases with f reflecting its basing on the total dispersion volume. Increasing agitation and aeration result in higher X_n and Q_P. The higher agitation enhances the G/O interfacial oxygen transfer and reduces the droplet size. Increasing aeration improves the G/O interfacial transfer but increases the droplet size. Its net positive effect implies a rate-limiting step at G/O interface. The W/O fermentation can produce far higher X_n (> 200 kg/m3) and Q_P( > 0.8 kg/m3-h) than the conventional fermentation (X_n ～ 50 kg/m3, Q_P ～ 0.5 kg/m3-h).     

A Facile and Versatile Synthesis of Energetic Furazan-Functionalized 5-Nitroimino-1,2,4-Triazoles

An analogue-oriented synthetic route for the formulation of furazan-functionalized 5-nitroimino-1,2,4-triazoles has been explored. The process was found to be straightforward, high yielding, and highly efficient, and scalable. Nine compounds were synthesized and the physicochemical and energetic properties, including density, thermal stability, and sensitivity, were investigated, as well as the energetic performance (e.g., detonation velocities and detonation pressures) as evaluated by using EXPLO5 code. Among the new materials, compounds 4 – 6 and 11 possess high densities, acceptable sensitivities, and good detonation performances, and thereby demonstrate the potential applications as new secondary explosives.     

Solution‐processable and thermally cross‐linkable fluorene‐cored triple‐triphenylamines with terminal vinyl groups to enhance electroluminescence of MEH‐PPV: Synthesis,curing, and optoelectronic properties

This study reports the synthesis, curing, and optoelectronic properties of a solution‐processable, thermally cross‐linkable electron‐ and hole‐blocking material containing fluorene‐core and three periphery N‐phenyl‐N‐(4‐vinylphenyl)benzeneamine ( FTV ). The FTV exhibited good thermal stability with T_d above 478 °C in nitrogen atmosphere. The FTV is readily cross‐linked via terminal vinyl groups by heating at 160 °C for 30 min to obtain homogeneous film with excellent solvent resistance. Multilayer PLED device [ITO/PEDOT:PSS/cured‐ FTV /MEH‐PPV/Ca (50 nm)/Al (100 nm)] was successfully fabricated using solution processed. Inserting cured‐ FTV is between PEDOT:PSS and MEH‐PPV results in simultaneous reduction in hole injection from PEDOT:PSS to MEH‐PPV and blocking in electron transport from MEH‐PPV to anode. The maximum luminance and maximum current efficiency were enhanced from 1810 and 0.27 to 4640 cd/m² and 1.08 cd/A, respectively, after inserting cured‐ FTV layer. Current results demonstrate that the thermally cross‐linkable FTV enhances not only device efficiency but also film homogeneity after thermal curing. FTV is a promising electron‐ and hole‐blocking material applicable for the fabrication of multilayer PLEDs based on PPV derivatives. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 000: 000–000, 2012