Application and Modification of Cyclometalated Ruthenium(II) Complex [Ru(o-C6H4-2-C5H4N)- (MeCN)4]PF6 for Atom Transfer Radical Polymerization

Polymerizations of n-butyl acrylate (BA), methyl methacrylate (MMA) and styrene (St) were promoted by the Ru(II) cyclometalated complex with labile MeCN ligand in the presence of Al(OiPr)₃. The polymerization proceeds via radical mechanism and requires the loss of MeCN ligand. The poor control over the polymerizations can be explained in terms of the traditional ATRP scheme. However, the controllability may be significantly improved by addition of reducing SnCl₂. Mechanism of the process is proposed.     

Carboxylphosphanes and Carboxyphosphane Chalcogenides

Abstract

Low temperature reactions of organo chloro phosphanes with carboxylic acids and their salts allow the preparation of carboxyphosphanes - mixed anhydrides of carboxylic acids with phosphinic acids. These are subject to thermal rearrangement reaction of the Michaelis-Arbusov type. Molecular oxygen converts them into carboxy-phosphorane oxides. These compounds are also obtainable by reacting organochlorophosphane oxides with carboxylates. Their thermal stability is higher than that of the P(III)compounds. Analoguous reactions of P-sulfides and selenides give the corresponding thio and seleno phosphoranes with higher thermal stability. At elevated temperatures a number of rearrangement reactions occur, thus producing phosphane oxides and phosphinic acid phosphinyl alkaryl ester. The reaction products of the following reaction sequences are discusses with regard to their NMR-, IR-, MS-spectra and hydrolytic and thermal properties:     

Validation of a high-performance liquid chromatographic-radioimmunoassay method for the determination of lacidipine in plasma.

A sensitive and reproducible method for the determination of lacidipine, a new potent antihypertensive dihydropyridine, is reported. The method involves solid-phase extraction, reversed-phase high-performance liquid chromatography and radioimmunoassay of the collected fraction. The assay provides a limit of detection of 20 pg/ml of plasma, allowing the determination of trough (24 h) plasma concentrations. The method is suitable for pharmacokinetic studies in man.     

Approximation and regular perturbation of optimal control problems via Hamilton-Jacobi theory

We present two convergence theorems for Hamilton-Jacobi equations and we apply them to the convergence of approximations and perturbations of optimal control problems and of two-players zero-sum differential games. One of our results is, for instance, the following. LetT andT _h be the minimal time functions to reach the origin of two control systemsy = f(y, a) andy = f _h (y, a), both locally controllable in the origin, and letK be any compact set of points controllable to the origin. If f _h –f Ch, then |T(x) – T _h (x)| C _K h , for all x K, where is the exponent of Hölder continuity ofT(x).     

Darstellung einiger perfluorbenzol-di-, tri- und tetrasulfonsäuren

1,2,3,4-Tetrafluorbenzenesulfonic acid, 1,2,4,5-tetrafluorobenzenesulfonic acid, 1,2,3,5-tetrafluorobenzenedisulfonic acid, 1,3,5-trifluorobenzene-2,4-disulfonic acid and 1,3,5-trifluorobenzenetrisulfonic acid are obtained by sulfonation of the three isomeric tetrafluorobenzenes, and of 1,3,5-trifluorobenzene, with stabilized SO₃ at normal pressure. Starting from dilithium 1,2,3,4-tetrafluorobenzenedisulphinate 1,2,3,4-tetrafluorobenzenedisulfonic acid can be prepared via oxidation with hydrogen peroxide. Fluorine displacement reactions lead to 1-thiol-2,3,5-trifluorobenzenedisulfonic acid, 1-thiol-2,3,6-trifluorobenzenedisulfonic acid, 1-thiol-2,4,5-trifluorobenzenedisulfonic acid, 1-thiol-2,5-difluorobenzenetrisulfonic acid and 1-thiol-3,5-difluorobenzenetrisulfonic acid, which can be converted into 1,2,4-trifluorobenzenetrisulfonic acid, 1,3-difluorobenzenetetrasulfonic acid and 1,4-difluorobenzenetetrasulfonic acid by oxidation procedures. N.m.r. parameters of the new compounds are described.     

Perfluordicarbonsäuren,VI [1] Darstellung der perfluorpyridin-2,3-dicarbonsäure durch oxidation von perfluorchinolin

The oxidation of perfluoroquinoline with nitric acid (98%) yields perfluoropyridine-2.3-dicarboxylic acid (V) besides 2.3.4.6.7-pentafluoro-5.8-dioxo-5.8-dihydro-quinoline (IV) and 3.4.5.6.7.8-Hexafluoro-2-oxo-1.2-dihydro-quinoline (VIa).