Synthesis of Chiral Bisphosphines with Tunable Bite Angles and Their Applications in Asymmetric Hydrogenation of β-Ketoesters.-The chiral bisphosphine shown in entry C) is found to be an efficient ligand for the asymmetric hydrogenation of β-ketoesters. The enantioselectivity is affected by the bridge length.

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Organic chemistry Z 0200 Palladium-Catalyzed Alkenylation by the Negishi Coupling -[225 refs.]. -(NEGISHI, E.-I.; HU, Q.; HUANG, Z.; QIAN, M.; WANG, G.; Aldrichimica Acta 38 (2005) 3, 71-88; Brown and Wetherill Lab. Chem., Purdue Univ., West Lafayette, IN 47907, USA; Eng.) -Lindner 38-271

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A stable magnetic carbon was synthesized using activated sludge as the carbon precursor. The ultrasonic pretreatment was used to destroy the cells in the activated sludge and to release the soluble carbon source, which was responsible for the improved stability of the synthesized magnetic carbon. 800 W was demonstrated as the optimized ultrasonication power for the pretreatment of activated sludge. Then, the carbonization parameters, such as pyrolysis temperature, heating rate, and dwell time were optimized as 800 °C, 10 °C/min, and 60 min, respectively. To be more specific, this activated sludge derived magnetic carbon can reduce almost all the hexavalent chromium (Cr(VI)) (2.0 mg/L) in 10 min and has a maximum capacity as high as 203 mg/g. The iron release rate of the synthesized activated sludge derived magnetic carbon was decreased, which improved the electron utilization of zerovalent iron (ZVI). This composite was demonstrated to have a good stability and recyclability as well. Finally, the Cr(VI) removal mechanisms were clarified under the acidic and the natural conditions.

The Pd-catalyzed cross-coupling reaction of 2-bromo-1,3-dienes derived from alkyl aldehydes, especially with Cl2Pd(DPEphos) as a catalyst, proceeds with clean stereoinversion of the Br-bearing C=C bond to produce in high yields and in high stereoselectivity (>/=97-98%) conjugated Z,E dienes of potentially high utility in the synthesis of complex natural products. The observed stereoinversion cannot be readily accommodated by the widely accepted pi-sigma-pi rearrangement mechanism for isomerization of ordinary allylpalladium derivatives.

A facile template-free and one-pot thermal decomposition approach was used for the mass preparation of submicrometer-sized NiO octahedra. Ni octahedra with tailored crystallization and texture characteristics are easily achieved through H 2 -annealing of NiO octahedra at various temperatures. The good morphology retention of Ni octahedra is due to the principle of minimum surface free energy as well as the similar crystallographic system to that of NiO. Studies on static magnetic and microwave electromagnetic properties reveal the relationships among the reactivity, shape, and resultant properties of the nanomaterials. Because of their high BET specific surface area and favorable crystal size, porous Ni octahedra produced at 300 C exhibit excellent matching and absorbing properties with a minimum R L value of À37.93 dB at 12.80 GHz and 11.60 GHz bandwidth (below À20 dB). Thus the Ni octahedra described here are believed to have a wide range of applications, including catalysis, electromagnetic shielding, and absorption.

Flower-like Co superstructures composed of leaf-like flakes were synthesized via a facile hydrothermal approach independent of surfactants or complex precursors. The evolution of the morphology and crystal phase was closely related to the variation of the electrode potentials, in which NaOH and hydrazine hydrate played crucial roles. The microwave electromagnetic and absorbing properties of the flower-like Co/wax composites varied strongly with the mass ratios (l) of Co powder to wax. At the low l of Co powder to wax, flower-like Co superstructures functioned as the random distributed patches in wax matrix and, therefore composites exhibited frequency selective surface (FSS) behaviors. Owing to high conductance and eddy current losses, however, composites with high l showed excellent microwave absorption performances, with a minimum reflection loss (R L ) of À40.25 dB observed at 6.08 GHz, corresponding to a matching thickness of 2.5 mm. In particular, the absorption bandwidth (R L # À20 dB) was 13.28 GHz. The current work provides insights into the absorption mechanism of flower-like complex absorption materials.