Das Atomgewicht des Palladiums

Ohne Zusammenfassung     

Diastereoselective formation and optical activity of an M4L6 cage complex

A chiral bridging ligand affords a single diastereoisomer of tetrahedral M4L6 cage complex in which the optical rotation of each ligand is increased by a factor of 5 on coordination.     

Anion control of ligand self-recognition in a triple helical array

Self-assembly of the ligand L(1) with Co(2+) into a dinuclear triple helicate [Co(2)(L(1))(3)](4+) produces an anion binding pocket which encapsulates perchlorate anions. Furthermore we demonstrate how this ability to bind anions can control ligand self-recognition properties.     

Quantitative analysis using gas chromatography/combustion/isotope ratio mass spectrometry and standard addition of intrinsically labelled standards (SAIL)--application to isoflavones in foods

We have investigated a novel application of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) for the quantitative analysis of the isoflavones in food matrices. Previous methods have been hampered by the lack of analytical standards to introduce early enough in the extraction procedure to allow compensations for losses at all stages of the procedure. In this work we have produced standard materials that can be added at the initial extraction, by intrinsically labelling soya plants by growing them in an atmosphere enriched in the stable isotope of carbon in CO(2). On analysis these plants were shown to contain phytoestrogens at a high (up to 20%) level of enrichment. The dried plant material has been used to estimate the isoflavone concentrations of a set of spiked flours. For daidzein the methodology was shown to produce results comparable to those achieved by GC/MS techniques. The method was less successful for genistein, possibly due to the greater fragility of this compound under the conditions required for the analysis.     

Cycloartanes, protolimonoids, a pregnane and a new ergostane from Trichilia reticulata

The new ergostane steroid ergosta-5,24(24')-diene-3beta,4beta,22R-triol (1), a pregnane, (E)-volkendusin, characterised as the diacetate (3), cycloartanes 4-6 and protolimonoids 7-9 were obtained from the leaves and twigs of Trichilia reticulata.     

Defect parameters in the alkali halides

Abstract

Methods are available which calculate the free energies of defects in ionic systems within the quasi-harmonic approximation. The Harwell SHEOL code is used to calculate the defect enthaplies and entropies for a number of alkali halides where reliable diffusion data are known. We discuss the trends in the calculations and the comparison with experiment.     

A Boolean topological orthomodular poset

Wilce introduced the notion of a topological orthomodular poset and proved any compact topological orthomodular poset whose underlying orthomodular poset is a Boolean algebra is a topological Boolean algebra in the usual sense. Wilce asked whether the compactness assumption was necessary for this result. We provide an example to show the compactness assumption is necessary.