Cross section and analyzing powers for the reaction pd→3He + γ at intermediate energies

We report the results of measurements of the differential cross section and analyzing power for the reaction pd → γ³He at six energies in the range 200 < E_p < 500 MeV. The cross-section data are in good agreement with the most recent results for the inverse process assuming detailed balance; thus no evidence for time-reversal violation is inferred. In addition, the shapes of the measured angular distributions are in general overall accord with those measured in the photodisintegration reaction. The data are compared with several theoretical calculations showing inclusion of meson-exchange current contributions to be important in reproducing the measured cross section. The analyzing powers measured at E_p = 500 MeV are not yet explained by microscopic models.     

Application of P-stereogenic aminophosphine phosphinite ligands in asymmetric hydroformylation

New chiral aminophosphine phosphinite ligands with a stereogenic center at the aminophosphine phosphorus atom were prepared based on (R,S)-ephedrine as the chiral auxiliary and backbone. Substituents at the chiral aminophosphine as well as at the phosphinite phosphorus atom were varied. These new ligands were applied to the rhodium-catalyzed asymmetric hydroformylation of vinyl arenes. The enantiomeric excess reached up to 77%. 1H and 31P NMR studies of the Rh complexes under syngas pressure reveal that [HRh(CO)2(PP)] complexes with the NP* moiety in an axial position are responsible for enantioselectivity.     

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