FIR.-Spektren von Übergangsmetallkomplexen mit orthogonalem Ligandensystem. I. Halogeno-Kupfer(II)-Komplexe methylsubstituierter Pyridine

Far-infrared spectra (400–40 cm^?1) have been studied for orthogonal systems CuL₂X₂ (L = pyridine, mono-, di-, tri-methylsubstituted pyridine and X = Cl, Br). Assignements are suggested for the four bands of the molecular vibrations which form a stable region within the spectra of the complex series. Relations between number and position of bands and structural data are discussed.     

Ion-Selective Sensors

Numerous advances have recently been made in the development of ion-selective (glass, solid, liquid) membrane electrode systems. The theoretical principles and practical requirements of such “sensors” are outlined in this article, and an attempt is made to review their possible applications.     

Cyclosporin A,ein immunsuppressiv wirksamer Peptidmetabolit aus Trichoderma polysporum (LINK ex PERS.) Rifai

Cyclosporin A, a Peptide Metabolite from Trichoderma polysporum (LINK ex PERS .) Rifai, with a remarkable immunosuppressive activity Two antifungal metabolites, cyclosporins A and C, were isolated from a strain of Trichoderma polysporum (LINK ex PERS .) Rifai. Cyclosporin A, the main component, has the molecular formula C₆₂H₁₁₁N₁₁O₁₂ as deduced by NMR. and mass spectra. Hydrolytic cleavage of cyclosporin A furnished 11 amino acids as fragments, among them an artefact of a new C₉-amino acid. The amino acid sequence was determined by Edman degradation of iso-cyclosporin A, a basic rearrangement product formed from cyclosporin A by N, O-acyl migration. In an independent investigation an X-ray analysis of the iodo derivative 10 was performed (see the following paper). On the basis of the chemical, spectroscopic and crystallographic evidence the complete structure of cyclosporin A was elucidated as the neutral cyclic oligopeptide 1 . Cyclosporin A and C show remarkable immunosuppressive and antiphlogistic activities in several pharmacological models.     

Ein Verfahren zur Stabilitätsfrage bei Matrizen-Eigenwertproblemen

Summary Given the eigenvalue problem (A–E) x=0 for real or complex matricesA the number of eigenvalues with positive real parts is determined without evaluating the caracteristical polynomial. A proceeding is developed here to transform the given matrixA into a reduced form by applying a finite series of elementary transformations upon the matrix. The elements of the reduced matrix allow immediately to solve the problem.     

ICP–MS trace-element analysis as a forensic tool

Careful tracing of evidence at the site of a crime must be performed before suspects can be convicted of a crime or homicide. Fingerprints and ballistic control samples are important evidence. A common method used to examine lead bullets is comparison of physical properties such as weight, dimensions, shape, and distinctive markings. However ballistic investigations, for example comparison of characteristic scratches and marks left on fired bullets, do not always give sufficient information. Ballistic abrasion patterns can change for a variety of reasons, e.g. deformation or mechanical strain. Sometimes only particles remain in a victims body. In such cases trace-element composition and lead-isotope ratios can be compared with those of controls. Elemental composition of particles and deformed bullets have been compared with the elemental fingerprints and isotope ratios of potential bullet types found on suspects. The applicability of the method was studied for two different cases. Data interpretation and several limitations of the technique are also discussed in this paper.     

Transient processes in photogalvanic cells: Part III. The alternating current photogalvanic cell

An alternating current photogalvanic cell, having a symmetrical electrode configuration, is described. It uses the Ru(bipy)₃²⁺/Fe³⁺ system. The light beam alternately illuminates the two electrodes, yielding almost rectangular current/time and voltage/time responses. The main advantage of this type of a cell is a very stable power output. Unlike other cells, mass transport from one electrode to the other is not necessary, eliminating the disadvantage of slow diffusion processes. A computer simulation of this behaviour is presented. The long-term characteristics depend on the Fe³⁺/Fe²⁺ concentration ratio.     

Charge-Transfer-Übergänge im Pentacyano-benzonitril-ferrat (II)

Charge Transfer Transitions of Pentacyano-Benzonitrile-Ferrate(II) Pentacyano-benzontrile-ferrate(II) shows two charge transfer transitions, which are interpreted as central atom to benzonitrile transitions d-1π* and d-2π*. Selective excitation to the d-1π* state leads to a completely reversible photoreaction. An isosbestic point is observed at 398 nm in aqueous solution.