Die Wirkung des reinen und des elektrolythaltigen destillierten Wassers auf Metalle

Ohne Zusammenfassung     

First chemical study of anaspidean Syphonota geographica: structure of degraded sterols aplykurodinone-1 and -2

Two unprecedented degraded sterols, aplykurodinone-1 (1) and -2 (2), have been isolated from the skin of the marine anaspidean Syphonota geographica, collected along the coasts of Greece. The structures and the relative stereochemistry were established by spectroscopic analysis and confirmed by chemical correlation with related known compounds.     

A Highly Luminescent Tetramer from a Weakly Emitting Monomer: Acid‐ and Redox‐Controlled Multiple Complexation by Cucurbit[7]uril

The tetrahedral, shape‐persistent molecule 1 ⁴⁺, containing four pyridylpyridinium units connected through a central carbon atom, exhibits unexpected photophysical properties including a substantially redshifted absorption (2350 cm^?1) and a very strong fluorescence (Φ_em=40 %), compared with the monomer 2 ⁺ (Φ_em=0.4 %). Density functional theory calculations on the structure and spectroscopic properties of 1 ⁴⁺ and 2 ⁺ show that exciton interactions, homoconjugation, and orbital nature account for the observed differences in their photophysical properties. The protonated tetramer binds four cucurbit[7]uril molecules and the host/guest interactions can be controlled by chemical (acid/base) as well as redox stimuli.     

Characterization of biosensors based on membranes containing a conducting polymer

A new type of biosensor based on the coupling of an enzyme to an ion-selective membrane containing a conducting polymer is evaluated. The results obtained with the enzyme field- effect transistor (ENFET) and the ion-selective electrode (ISE) for the determination of creatinine and urea are compared. The presence of the conducting polymer significantly lowers the detection limit for creatinine by one decade to 10^?7 and 10^?4 M for the ENFET and ISE, respectively. The determination of urea in urine and serum with the ENFET was carried out, and the results correlated well with those obtained by spectrophotometry.