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The physicochemical characteristic of activated carbon, prepared from Typha latifolia L. by phosphoric acid, was analyzed by spectroscopic analysis. Batch sorption of Cu2+ and Zn2+ ions in aqueous solutions was investigated under different pH value, adsorption time, original content of metal ions, sorbent amount, and temperature. Results showed that adsorption capacity of Cu2+ and Zn2+ increased with the increase of pH value of solution. It needed only about 10 min to reach equilibrium adsorption and pseudo second-order sorption model was used to depict the adsorption process. The thermodynamics studies suggested that the adsorption process was spontaneous and endothermic. Equilibrium adsorption data of both metal ions fitted reasonably well with the Langmuir and Freundlich isotherms. The maximum adsorption capacity of Cu2+ and Zn2+ obtained from the Langmuir adsorption isotherm studies was found to be 34.48 and 28.57 mg g−1, respectively, at pH 6 and temperature of 25°C. Wastewater treatment showed that cattail-based activated carbon prepared by phosphoric acid activation is a promising material for the treatment of metal ions out of industrial wastewater.

The engineering application of natural hyperaccumulators in removing or inactivating metal pollutants from soil and surface water in field trials mostly presents the insurmountable shortcoming of low efficiency owing to their little biomass and slow growth. Based on further understanding of the molecular mechanism of metal uptake, translocation, and also the separation, identification, and cloning of some related functional genes, this article highlights and summarizes in detail the advances in research on transgenic techniques, such as Agrobacterium tumefaciens-mediated transformation and particle bombardment, in breeding of plants for metal resistance and accumulation, and points out that deepening the development of transgenic plants is one of the efficient approaches to improving phytoremediation efficiency of metal-contaminated environments. From the viewpoint of sustainable development, governments should strengthen support to the development of genetic engineering for metal resistance and accumulation in plants. (Managing editor: Li-Hui Zhao)

We report a highly active palladium catalyst for the enantioselective conjugate addition of primary aromatic amines to N-alkenoylcarbamates, furnishing β-amino N-Boc-amides in extremely high yields (>99 %) and unprecedented optical purity (>99 % ee) with just 2 mol % catalyst loading. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

[reaction: see text] Reduction of C5-substituted 2-hydroxychromans selectively provides 2,4-cis-chromans using large silane reductants and 2,4-trans-chromans using the smaller silane PhSiH(3). The stereochemical outcome has been rationalized on the basis of a Curtin-Hammett kinetic situation arising from hydride delivery to two different conformations of an intermediate oxocarbenium ion. This method provides a powerful way to control the relative stereochemistry of these substructures which are prevalent in bioactive natural products.

Investigations of cationic Pd(II) complex 1 as hydroamination catalysts led to the development of highly enantioselective addition of aromatic amines to alkenoyl-N-oxazolidinones, with ee values up to 93%. Factors affecting the yield and selectivity of the reaction were described. Addition of substituted benzylamines to these Michael acceptors was also attempted, and was found to be reversible under catalytic conditions.

Trifluoroacetic acid mediates the hydroarylation of alkenes to afford dihydrocoumarins and dihydroquinolones in good yield. Intermolecular hydroarylation of cinnamic acids by phenols is particularly facile, which leads to the conclusion that previous reports of palladium-catalyzed hydroarylation of cinnamic acids in trifluoroacetic acid are erroneous.

We report a highly active palladium catalyst for the enantioselective conjugate addition of primary aromatic amines to N-alkenoylcarbamates, furnishing β-amino N-Boc-amides in extremely high yields (>99 %) and unprecedented optical purity (>99 % ee) with just 2 mol % catalyst loading. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)