Structure of argentamine
ConclusionsOn the basis of chemical transformations and the UV, IR, and mass spectra of argentamine, isolated from the epigeal part ofAmmodendron argenteum O. Ktze, the structure of (—)-13-hydroxythermopsine has been proposed as the the most probable one for it. It has been shown that argentamine and baptifoline are epimeric at C11.
Schl?sselbruchst?cke in den Massenspektren von Alkaloiden, 3. Mitt.
Die wichtigsten massenspektrometrischen Abbaureaktionen, die zur Bildung von Schlusselbruchstucken in den Chinolizidinalkaloiden der Lupinin-, Cytisin- und Sparteinklasse fuhren, werden in der folgenden Arbeit erlautert. An Beispielen aus der Cytisinreihe wird demonstriert, wie durch Anderung der Basizitat** von Stickstoffatomen die Bruchstuckbildung so gelenkt werden kann, das einmal aus dem einen und einmal aus dem anderen Teil der Verbindung Schlusselbruchstucke entstehen.
Photoinduced spin-state transition of Co3+ in the layered perovskite manganite thin film
The photoinduced effect, at different temperatures, on layered perovskite manganite La1.2Sr1.8Mn1.8Co0.2O7 thin film deposited on a SrTiO3(100) substrate has been studied using a He–Ne laser (632.8 nm) with the power of output 25 mW at low temperatures. The electrical transport and magnetic properties of the film are investigated systematically in the temperature region from 20 to 300 K. The resistance shows a significant decrease at low temperatures (T<90 K) under laser irradiation, which can be interpreted in terms of the spin-state transition of Co3+ ions. The magnetic field combined with the laser is also used to detect the photoinduced effect of the spin-glass state. The time dependence of the metastable system under several applied fields was also discussed. The system has the ability to keep a persistent memory of the magnetic history imprinted in its zero-field resistance.