Prüfung der Marantastärke (Arrow-Root) auf Stärkemehl aus Kartoffeln und Weizen

Analytical and Bioanalytical Chemistry -     

Mikrochemische Apparate

Ohne Zusammenfassung     

A germaaluminocene

The reactions of dipotassium germacyclopentadienediide with two Group 13 dichlorides, Cp*BCl₂ and Cp*AlCl₂, yield two structurally different products. In the case of boron a borole complex of germanium(ii) is obtained. The aluminium halide gives an unprecedented neutral germaaluminocene. Both compounds were fully characterised by multinuclear NMR spectroscopy supported by DFT computations. The molecular structure of the germaaluminocene was determined by XRD.

Boron vs. aluminum: the synthesis of a borole complex of Ge(ii) is reported. Changing just the element from boron to aluminum unexpectedly yields an unprecedented neutral germaaluminocene.     

Determination of Olanzapine in rat brain using liquid chromatography with coulometric detection and a rapid solid-phase extraction procedure

A sensitive and selective method was developed for the determination of the antipsychotic drug Olanzapine levels in rat brain tissue, based on HPLC with electrochemical detection. The analyses were carried out on a C8 reversed phase column (150 mm x 4.6 mm, 5 microm), using a mobile phase composed of methanol and a phosphate buffer (44.0 mM, pH 3.5), containing triethylamine (21:79, v/v), flowing at 1.2 mL min(-1). A high sensitivity coulometric detection analytical cell containing two flow-through low volume working electrodes was used: electrode 1 was set at +0.350 V and electrode 2 at -0.200 V. Olanzapine, administered to rats in different doses or in different times, was extracted from tissue homogenate of either the whole brain or specific areas (cortex, hyppocampus, nucleus striatum) with a rapid solid phase extraction procedure (SPE) on Oasis HLB cartridges. The method provided a high extraction yield of Olanzapine and internal standard (2-methylolanzapine) from brain tissue homogenate with absolute recovery values higher than 90.0%. The detector response was linear over a concentration range of 0.2-100.0 ng mL(-1) of Olanzapine. The limit of quantification (LOQ) was 0.2 ng mL(-1). Precision results, expressed by the intra-day and the inter-day relative standard deviation values, were satisfactory, better than 4.6%. Accuracy was satisfactory as well. This method proved to be suitable for the analysis of Olanzapine in rat brain tissues and for the study of distribution and pharmacokinetics of Olanzapine in rat brain after a single treatment with the antipsychotic drug.     

The preparation and some reactions of chloro(η4-cycloocta-1,5-diene)(η5-cyclopentadienyl)ruthenium(II): A versatile,new synthetic precursor for cyclopentadienylruthenium(II) chemistry

Facile substitution of the cyclooctadiene and/or chloro ligands in [(η⁵-C₅H₅)Ru(C₈H₁₂Cl] (C₈H₁₂ = cycloocta-1,5-diene) under mild reaction conditions provides high yield synthetic routes to a range of new neutral and cationic cyclopentadienylruthenium(II) complexes.     

Metal dimers as catalysts : III. The reaction between Fe(CO)5, and group V donor ligands in the presence of [(η5-C5H4R)Fe(CO)222]2 (R  H,Me) and [(η5-C5Me5)Fe(CO)2]2 as catalyst

The reaction between Fe(CO)₅, and group V donor ligands L, (L  PPh₃, AsPh₃, SbPh₃, PMePh₂, PMe₂Ph, Asme₂Ph, P(C₆H₁₁)₃, P(n-Bu)₃, P(i-Bu)₃, P(OPh)₃, P(OEt)₃, P(OMe)₃) in the presence of [(η⁵-C₅Me₅Fe(CO)₂]₂ (R  H, Me) or [(η⁵-C₅Me₅)Fe(CO)₂]₂ as catalyst in refluxing toluene, rapidly gives the complexes Fe(CO)₄L in yields > 85%. The reaction rate is essentially independent of the nature of L for [(η₅-C₅Me₅)Fe(CO)₂]₂ as catalyst. For the other catalysts, the rate is influenced predominantly by the steric properties of L. These results are interpreted in terms of the interaction between the catalyst and the ligand L to give derivatives of the type (η⁵-C₅H₄R)₂Fe₂,(CO)₃,(L). These derivatives were also found to catalyse the reaction between Fe(CO)₅, and L. The complexes [(η-C₅H₄R)Fe(CO)₂]₂ (R  H, Me) and [(η⁵-C₅Me₅)Fe(CO)₂]₂ also catalyse the reaction between Mn₂(CO)₁₀ and PPh₃ to give Mn₂(CO)₈- PPh₃)₂ in > 80% yield.     

Influence of the bulk and surface morphology on adhesion of polystyrene-inter-poly-cross-2-ethylhexyl-methacrylate films and particles

The adhesion behavior of semi-interpenetrating polymer networks (semi-IPNs) of linear polystyrene (PS) in crosslinked poly-2-ethylhexylmethacrylate (EHMA) was studied by variation of the bulk and surface morphology, i.e., domain size, continuity, and concentration in the domains. Semi-IPNs were prepared by liquid-liquid demixing upon cooling of a homogeneous solution of PS in methacrylate monomer, followed by gelation of the PS-rich phase and UV polymerization of the methacrylate resin. Welding of films allowed the preparation of larger objects provided that (1) the samples were phase separated to a high degree and contained domains with a high PS concentration (>90%) and (2) polystyrene was present at the interface. For semi-IPN films, a linear dependence of the adhesion strength on the (crack healing time)^1/4 was obtained. Based on these considerations, a process was developed to obtain melt-processable semi-IPN particles, by quenching droplets of the polymer solution into a cold liquid. These particles obtained a PS-rich skin layer and showed good adhesion after blending with a thermoplast. © 1996 John Wiley & Sons, Inc.