Darstellung und Eigenschaften von Chlorozinksäuren

Contributions to the Chemistry of Hydrazine and its Derivatives. 53. Synthesis of P-, As-, and Sb-substituted Hydrazines by Addition of P? H, As? H, and Sb? H Groups to N?N Double Bonds Addition of diphenylphosphinous acid, diphenylthiophosphinous acid, methyl hydrogen phenylphosphonite, diethyl hydrogen phosphite, diphenylphosphane, dibutylphosphane, diphenylarsane, diethylarsane, and diphenylstibane to the N?N double bond of diethyl azodicarboxylate, dimethyl azodicarboxylate, ethyl phenylazocarboxylate, and azobenzene yields the P-, As-, and Sb- substituted hydrazines 1–23 . The spectroscopic data agree with the structural formulae. The course of the reactions suggests a polar reaction mechanism except in the case of the synthesis of 15 , which probably proceeds via radical intermediates. The azo systems employed show a distinct graduation in their ability to add to the element-hydrogen groups used.     

Spin-pattern recognition in high-resolution proton NMR spectroscopy

Techniques are introduced for the recognition of specific spin patterns in complex overlapping proton NMR spectra. They are based on the efficient and selective excitation of high-order multiple quantum coherence in systems of specified coupling network topology, and allow the suppression of undesired spin patterns.     

Zur Thermodynamik der Mischungen von n-Alkoholen mit Kohlenwasserstoffen

A method is presented which allows to describe the concentration dependence of the excessGibbs free energyG ^E as well as its variation with temperature in mixtures of n-alcohols with various hydrocarbons. The number of data required is reduced to one experimental point of the excessGibbs free energy for each system. The theoretical treatment is based on the work ofFlory ^{1, 2} and ofRenon andPrausnitz ³. The excess volume due to mixing and association is neglected, but differences in the size of the various species are taken into account. This procedure yields a thermodynamic correlation between the excessGibbs free energy and the enthalpy of mixingH ^E of alcohol-hydrocarbon solutions and results in a comprehensive formalism including nonassociated mixtures.     

Absorption of iodine laser pulses in potassium and cesium vapors

The absorption of ns iodine laser pulses at a wavelength of 1.315 μm in potassium and cesium vapors has been measured. At elevated temperature there is considerable absorption in both vapors. The absorption was not saturable at intensities up to 1 GW/cm², but increased with increasing intensity.