Structural investigation of high-valent manganese-salen complexes by UV/Vis, Raman, XANES, and EXAFS spectroscopy.

XANES and EXAFS spectroscopic studies at the Mn-K- and Br-K-edge of reaction products of (S,S)-(+)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III) chloride ([(salen)Mn(III)Cl], 1) and (S,S)-(+)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III) bromide ([(salen)Mn(III)Br], 2) with 4-phenylpyridine N-oxide (4-PPNO) and 3-chloroperoxybenzoic acid (MCPBA) are reported. The reaction of the Mn(III) complexes with two equivalents of 4-PPNO leads to a hexacoordinated compound, in which the manganese atom is octahedrally coordinated by four oxygen/nitrogen atoms of the salen ligand at an average distance of approximately 1.90 A and two additional, axially bonded oxygen atoms of the 4-PPNO at 2.

Zirconium-mediated asymmetric baeyer-villiger oxidation.

Combinations of axially chiral C2-symmetric diols were used as ligands in zirconium-mediated Baeyer-Villiger reactions. The in situ preformed Zr-diol species proved effective in the asymmetric oxidation of bicyclic and monosubstituted cyclobutanones when a hydroperoxide was employed as oxidant. Asymmetric induction could be preserved upon replacement of one out of two enantiopure BINOL ligands by conformationally flexible 2,2'-biphenol.

The Search for New Environmentally Friendly Chemical Processes.

Minimization of the hazards in chemical industry processes and the avoidance of the production of toxic substances-these are the goals of environmentally friendly processes. These technologies can also be economically advantageous. This approach is exemplified by a new, almost ideal atom-efficient oxidative route to adipic acid (1, see scheme), which offers several environmentally improved features compared to the traditional manufacture.

[Anesthesiologic problems in endoscopic interventions of the respiratory organs].

In 28 patients--16 normotensive and 12 hypertensive patients--anaesthetized with hexobarbitone, halothane, nitrous oxide/oxygen and intermittent doses of suxamethonium we examined the influence of diagnostic bronchoscopy on arterial blood pressure, heart frequency, rate pressure product as well as acid-base balance and arterial oxygen partial pressure. Both groups of patients showed a remarkable and highly significant increase in these hemodynamic parameters during intubation, extubation and bronchial lavage. Clinically relevant changes of acid-base balance and arterial oxygen partial pressure which could be responsible for these hemodynamic reactions did not occur.