Untersuchung der physikalischen Eigenschaften der Kompositionen auf der Basis des Polyvinylchlorids und der Kautschuke unterschiedlicher Struktur

Ohne Zusammenfassung     

A tetra-substituted chrysene: orientation of multiple electrophilic substitution and use of a tetra-substituted chrysene as a blue emitter for OLEDs

The first tetra-substituted non-fused chrysene, 3,6,9,12-tetrakis(4-tert-butylphenyl)chrysene with blue electroluminescence at 450 nm, and with a radiance of 500 cd m(-2), was synthesized by a two-step procedure: direct bromination of chrysene in trimethyl phosphate, followed by palladium-catalyzed cross-coupling of tetrabromochrysene and tert-butylphenylboronic acid .     

Effect of high-frequency modes and hot transitions on free energy gap dependence of charge recombination rate

The charge recombination (CR) dynamics of geminate ion pairs formed by excitation of the ground-state donor-acceptor complexes in polar solvent have been investigated within the framework of stochastic approach. It is shown that for low exergonic reactions these dynamics critically depend on the reorganization energy of intramolecular high-frequency mode. Even moderate reorganization energies (0.1-0.2 eV) significantly accelerate the excited-state population decay making it nearly exponential. In the solvent-controlled regime, the majority of the excited donor-acceptor complexes recombine at nonthermal (hot) stage when the nonequilibrium initial wave packet passes through a number of term crossings corresponding to the transitions with creation of several vibrational quanta. Analysis of this mechanism allows to conclude (i) the CR in viscous solvents proceeds much faster than the diffusive relaxation of solvent, (ii) under certain conditions, the CR rate becomes practically independent of the diffusive component of solvent relaxation which is determined by solvent viscosity, (iii) in contrast to predictions of Marcus theory, the CR rate decreases monotonically with the rise of reaction exergonicity even at small free energy gaps, in accordance with experimental results. Two semiquantitative approaches providing rather simple analytical expressions for the hot charge recombination dynamics are suggested. These approximations give a good reproduction of the excited-state decay in the wide area of model parameters.     

2,2″‐Dimethoxy‐1,1′:3′,1″‐terphenyl as a novel protective group for low‐coordinated phosphorus compounds: The case of diphosphenes

A synthetic approach to meta‐terphenyls iodides bearing methoxy groups in the 2 and 2′′′ positions has been described. 2,2″‐Dimethoxy‐1,1′:3′,1″‐terphenyl groups have been shown to stabilize diphosphenes in solution. The existence of conformers of the diphosphene 7 has also been recorded. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:360–360, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10162     

Attempted 1,3-trimethylsilyl migration in Me3Si?PSN?R system

A dimer of thioxo-N-t-butylimino(trimethylsiloxy)-phosphorane 5 has been prepared by reaction of tris(trimethylsilyl) phosphine with N-sulfinyl-N-tert-butylamine. The structure of 5 has been confimed by X-ray analysis data. 1-Aza-2-thia-3-phosphaallene 1 , thiaphosphaziridine 3 , iminophosphine P-sulfide 4 are postulated as intermediates of the reaction studied.