Haupt-Abbau-Prozesse bei der Sonnenbestrahlung von Cellulose: ESR-Untersuchungen.

Ohne Zusammenfassung     

Cyclopolymerisation. 3. Mitt. ESR-Untersuchungen von Diallylaminen mit Redox-Systemen

Ohne Zusammenfassung     

ESR-Untersuchungen an bestrahlten Phosphatgläsern

ESR Studies of Radiation Processes in Phosphate Glasses Radiation processes in phosphate glasses are investigated by ESR and optical measurements. ESR shows a hole-centre in the systems K₂O/P₂O₅ and K₂O/MGO/P₂O₅ which depends on manner and concentration of the cations. Its nature is explained in somewhat a different way than given by BEEKENKAMP or by MIURA and HASEGAWA . Another hole-centre which is independent of cations is discussed in agreement with optical investigations. The electrons set free by radiation react with O₂ solved in the glass or with cations. The particels Ag⁰, Ag²⁺, Ag⁺₂ have been found and Agⁿ⁺₄ may be present too in the system K₂O/MgO/Ag₂O/P₂O₅. The system K₂O/MgO/Tl₂O/P₂O₅ shows analogous reactions, but full explanation of the lines could not yet be given.     

ESR-Untersuchungen am Bis(N-Thiobenzoyl-K-phenylhydroxylamin)-kupfer(II)

ESR Studies on Bis(N-Thiobenzoyl-N-phenylhydroxylamine)copper(II) The e.s.r. spectra of liquid and frozen solutions and diamagnetically diluted polycrystalline samples of bis(N-thiobenzoyl-N-phenylhydroxylamine)copper(II) are reported. This compound was found to exist as both cis- and trans-isomer. Strong covalent out-of-plane π-bonds effects a relative order of molecular orbitals b_1g < e_g < b_2g, which is different from the order of normal planar copper(II) complexes.     

ESR-Untersuchungen an Silber(II)-bis-(di-n-butyl-diselenocarbamat)-Einkristallen

A single crystal EPR study of Ag(II)-bis-(di-n-butyl-diselenocarbamate) is reported. The symmetry of the g-tensor and the silver hyperfinestructure tensor A is rhombically; the principal values of the tensors are given. The degree of covalency of the ground state σ-bond was determined by use of the observed ⁷⁷Se ligand hyperfine interaction. The maximum component of the g-tensor does not coincide with the A_z value of the silver hfs. This indicates, that there are significant deviations in the electronic structure to what is expected for a square planar silver(II) complex: the over-all symmetry of the coordination sphere is C_2h. In addition, the structure has been found as being similar to the analogous copper(II) dialkyl-diselenocarbamates.     

ESR-Untersuchungen zum oxidativen Strahlungsabbau: Reaktionen der Peroxidradikale in bestrahlten Vinylpolymeren

Zusammenfassung Die Rekombination der strahlungserzeugten Radikale in Polypropylen folgt unter der Einwirkung von Sauerstoff entsprechend einer früheren Arbeit der Autoren einem Kreisproze?, in dessen Verlauf das Polymere Sauerstoff aufnimmt. Diese Sauerstoffaufnahme wird berechnet und ihr theoretischer Verlauf mit Messungen an Polypropylen verglichen. Für Poly?thylen und Polyvinylchlorid wird der Kreisproze? ebenfalls nachgewiesen, und zwar durch Messung der Abh?ngigkeit der Rekombination der Radikale vom Sauerstoffdruck, der Sauerstoffaufnahme w?hrend der Rekombination und der Umwandlung der Peroxidradikale in Kohlenstoffradikale. Anhand von Gelmessungen wird der Zusammenhang zwischen den Reaktionen des Kreisprozesses und dem oxidativen Strahlungsabbau der behandelten Polymere dargestellt.

---

Summary According to an earlier paper of the authors the recombination of the radicals produced in polypropylen by irradiation is determined by a chain reaction mechanism under the influence of oxygen, in the course of which the polymer consumes oxygen. This consumption of oxygen is calculated and the calculated curve is compared with the results of measurements on polypropylen. The validity of the chain reaction mechanism is proved for polyethylen and Polyvinylchlorid, too, by means of measuring the dependence of the radical decay from the oxygen pressure, the oxygen consumption during the recombination of the radicals and the transmutation of the peroxide radicals into carbon radicals. The connexion of the chain reaction mechanism and the radiation induced oxidative degradation of the polymers dealt with is demonstrated by gel measurements.

     

ESR-Untersuchungen zur Struktur der 1,2-Thiazet-yle,einer Neuen Klasse Stabiler Radikale

The structures of benzo[c] and naphtho [2,1-c]-1,2-thiazet- yl have been elucidated by ESR spectroscopy (including simulation of the spectra and investigation of the corresponding ¹⁵N- and N-D-compounds) and by mass spectroscopic studies. This new class of stable S,N-radicals, available from different starting materials, belongs to an oxygen-free type of N-radical.     

Cyclopolymerisation. 2. Mitt. ESR-Untersuchungen der Reaktionen freier Radikale einiger Diolefine

Ohne Zusammenfassung     

Cyclopolymerisation. 2. Mitt. ESR-Untersuchungen der Reaktionen freier Radikale einiger Diolefine

Ohne Zusammenfassung     

Chelate von β-Dicarbonylverbindungen und ihren Derivaten. XXX. ESR-Untersuchungen an Kupferchelaten des Typs Cu [N2S2]

Chelates of β-Dicarbonyl Compounds and their Derivatives. XXX. EPR Studies on Copper Chelates of Cu[N₂S₂] Type Two copper(II) chelates with ligands containing sulphur and nitrogen in 1,3-positions were investigated by the EPR method. The Cu? S bond was found to be more covalent than the Cu? N bond.     

ESR-Untersuchungen zum Substituenteneinfluß an Kupfer(II)-β-Thioxoketonaten

The ESR spectra of some copper chelates of β-thioxoketones are reported. Using a simple MO-model the MO-parameters are calculated. The influence of the substituents with respect to the degree of covalency of the metal ligand bonds is discussed.     

ESR-Untersuchungen an Tetramesitylmolybdän(V) – einem homoleptischen σ-Arylübergangsmetallkation

ESR Investigations on Tetramesityl Molybdenum(V) – a Homoleptic σ-Aryl Transition Metal Cation An ESR investigation on the homoleptic σ-aryl transition metal cation tetramesityl molybdenum(V) is reported. The ESR parameters can be interpreted by means of a D_2d ligandfield model (distorted tetrahedral symmetry, B₁ ground state). Analyzing the ^95,97Mo hyperfine splitting the hyperfine parameters P and K are derived. They indicate a very low value for the effective nuclear charge on the molybdenum: ≈ +0.4. The covalency degree of the Mo? C σ bonds is considerably larger than that observed for tetramesityl vanadium(IV). The small anisotropy of the g tensor indicates the presence of remarkable charge-transfer interactions.     

ESR-Untersuchungen an Kupfer(II)- und Vanadyl(IV)-bis-(1,1-dicyanoäthylen-2,2-dithiolat)-Chelaten

EPR Investigations on Copper(II) and Vanadyl(IV) Bis(1,1-dicyanoethylene-2,2-dithiolate) Chelates EPR investigations on [Cu(i-MNT)₂][NBu]₂ and on [VO(i-MNT)₂][NBu]₂ in solutions and polycristalline matrices (diamagnetically diluted) are reported. The EPR spectra can be described by an axial-symmetric spin-Hamiltonain. Using MO models of the symmetry D_4h (for[Cu(i-MNT)₂]^2?) and C_4v (for[VO(i-MNT)₂]^2?) the bonding parameters of the first coordination sphere of the chelates were calculated taking into account the influence of the ligand-spin-orbit interaction. The Cu? S σ bond has been found to be pure covalent, the inplane and out-of-plane π bonds are different with respect to the degree of covalency. Contrary to this the V? S bonds are less covalent. The results obtained are compared with those of other sulfur-containing chelates. Preparation and properties of the new compound [VO(i-MNT)₂][NBu]₂ are reported.     

Adsorptions-kinetik von Einzelschichten von Eieralbumin

Ohne Zusammenfassung