Crystal and molecular structure of diphenylphosphinylacetic acid

Diphenylphosphinylacetic acid crystallizes in the monoclinic space groupP2_l/n with unit cell dimensionsa=5.6875(7),b=17.049(4),c=13.471(2) Å, =93.36(1)° and Z=4. The molecular packing consists of hydrogen bonded chains arising from intermolecular interactions between a carboxylic acid hydroxyl group and an oxygen of an adjacent phosphine oxide moiety.     

(iPr3P)6Rh6H12]2+: a high-hydride content octahedron that bridges the gap between late and early transition metal clusters

Treatment of [(iPr3P)2Rh(nbd)][Y] {nbd = norbornadiene, Y = B{3,5-(CF3)2C6H3}4- [B(ArF)4] or 1-H-closo-CB11Me11-} with H2 (ca. 4 atm) results in the isolation, in moderate yield, of the octahedral cluster complex [(iPr3P)6Rh6H12][Y]2 1. The cluster (for both anions) has been characterized by NMR, mass spectroscopy, and X-ray crystallography. These show 1 to have 12 edge-bridging hydrogen atoms, and the structure bears more resemblance to clusters of the early transition metals with pi-donor ligands than those of the late transition metals with pi-acceptor ligands. Intermediate complexes on the route to 1, namely, the nonclassical dihydrogen complexes [(iPr3P)2Rh(H)2(eta2-H2)x][B(ArF)4] (x = 1 or 2), have been observed spectroscopically. The high hydride content of 1 makes it a possible model for nanocluster colloidal Rh(0) catalysts that are used in olefin and arene hydrogenation.     

High-throughput approaches to the quantitative analysis of ketoconazole, a potent inhibitor of cytochrome P450 3A4, in human plasma

Ketoconazole, an imidazole-piperazine compound, is an orally active antimycotic agent. In addition, ketoconazole is a specific inhibitor of cytochrome P450 3A4. As about 60% of oxidized drugs are biotransformed by this isoform, the potential effect of a concomitant administration of ketoconazole on drug disposition may be of interest during drug development. The present paper describes three different approaches (methods A, B, and C) to attain high-throughput sample preparation and analysis in the quantification of ketoconazole in human plasma. Method A consisted of acetonitrile precipitation in a 96-well plate, transfer of the supernatant via a Tomtec Quadra 96 Model 320, and subsequent injection onto a 50 x 4.6 mm (i.d.) Develosil Combi-RP-5 column (packed with C30 bonded silica particles). Method B consisted of an identical sample preparation to method A with the exception that a Michrom Magic Bullet(trade mark) column, 2.0 --> 0.50 mm (i.d., tapered bore) x25 mm length, was used. Lastly, in method C, a turbulent-flow chromatography (TurboFlow LC/APCI-MS/MS) module was used for the direct analysis of ketoconazole in human plasma. A Sciex API 3000 was used in methods A and B, while a Micromass Quattro LC was employed in method C. Based on the values obtained for the calibrator (standard) and quality control samples, all three protocols yielded satisfactory accuracy, precision, and reduced manual sample preparation time.     

Ion separation on a thread

Summary Preliminary trials indicate that the sensitivity of separation by solvent extraction may be improved by concentrating the extracts upon a thread. Chromatographic separation may be added to simplify the identification of the metals.

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Zusammenfassung Vorläufige Ergebnisse zeigen, daß die Möglichkeit besteht, die Empfindlichkeit der Kationentrennung durch stufenweise Extraktion zu steigern, indem man die Extrakte auf einem Nähfaden konzentriert. Chromatographische Trennung auf dem Faden kann dazu benutzt werden, den Nachweis der einzelnen Metalle zu vereinfachen.

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Résumé Des essais préliminaires indiquent que la sensibilité de la séparation par extraction avec un solvant peut être améliorée en concentrant les extraits sur un fil. La séparation chromatographique peut être ajoutée pour simplifier l'identification des métaux.

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On the occasion of the hundredth return ofFriedrich Emich's birthday.