Synthesis of 2-Oxazolidinones. -The reaction of carbon dioxide with propargylic amines is promoted by a protic ionic liquid such as 1,8-diazabicyclo[5.4.0]-7-undecenium 2-methylimidazolide (DBM) that acts also as a solvent to give the corresponding oxazolidinones in high yields. The reaction proceeds under mild, metal-free conditions. The cheap and green solvent can be easily recycled and reused at least five times without significant loss of catalytic activity and selectivity. A reaction mechanism is proposed on the basis of detailed DFT studies. -(HU, J.; MA*, J.; ZHU, Q.; ZHANG, Z.; WU, C.; HAN, B.; Angew.

Au nanoparticles with diameters ranging between 15 and 170 nm have been synthesised in aqueous solution using a seed-mediated growth method, employing hydroxylamine hydrochloride as a reducing agent. Thiolated polyethylene glycol (mPEG-SH) polymers, with molecular weights ranging from 2100 to 51 000 g mol-1, were used as efficient particle stabilising ligands. Dynamic light scattering and zeta potential measurements confirmed that the overall mean diameter and zeta potential of the capped nanoparticles increased in a non-linear way with increasing molecular weight of the mPEG-SH ligand. Electron microscopy and thermal gravimetric analysis of the polymer-capped nanoparticles, with a mean gold core diameter of 15 nm, revealed that the grafting density of the mPEG-SH ligands decreased from 3.93 to 0.31 PEG nm-2 as the molecular weight of the ligands increased from 2100 to 51 400 g mol-1 respectively, due to increased steric hindrance and polymer conformational entropy with increase in the PEG chain length. Additionally, the number of bound mPEG-SH ligands, with a molecular weight of 10 800 g mol-1, was found to increase in a non-linear way from 278 (σ = 42) to approximately 12 960 PEG (σ = 1227) when the mean Au core diameter increased from 15 to 115 nm respectively. However, the grafting density of mPEG10 000-SH ligands was higher on 15 nm Au nanoparticles and decreased slightly from 1.57 to 0.8 PEG nm-2 when the diameter increased; this effect can be attributed to the fact that smaller particles offer higher surface curvature, therefore allowing increased polymer loading per nm2. Au nanoparticles were also shown to interact with CT-26 cells without causing noticeable toxicity

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Mesoporous titania and titania nanotubes, with high surface-to-volume ratios, have recently been reported to demonstrate improved properties compared to colloids, films and other forms of titania in applications such as photocatalysts, [1,2] gas sensors, [3] photovoltaic cells [4][5][6] and rechargeable lithium batteries. [7][8][9][10] Therefore, particular attention has been paid to the preparation of titania nanotubes, or arrays of tubes, and many methods have been developed including the hydrothermal treatment of TiO 2 nanoparticles with alkali solution, [8][9][10][11][12][13] anodization of titanium foil, [14,15] deposition of sol-gels within templates, [16][17][18] hydrolysis of TiF 4 under acidic conditions, [19] sonication of titania particles in aqueous NaOH solution, [20] and surfactant-assisted templating methods. [21,22] Materials with mesoporous structures possess an extraordinarily high surface area. The synthesis of titania nanotubes, with mesoporous walls and hence high surface areas, will be invaluable for all applications employing the wide bandgap semiconductor. Therefore, there is a requirement for the development of a facile and reproducible way to prepare titania nanotubes with well-defined mesoporous wall structures. We have previously shown that one-dimensional mesoporous silica nanotubes and nanowires can be fabricated inside the pores of anodic aluminum oxide (AAO) membranes.[23] Recently, Chae et al. reported the preparation of titania nanofibres with wormhole-like mesoporous structure using AAO as a 'hard template'. [24] Even though mesoporous SiO 2 nanotubes and titania nanofibres have been prepared, the fabrications of TiO 2 nanotubes with well ordered mesopores are still a challenge because of the complexity of sol-gel chemistry. Herein, we report the preparation of titania nanotubes with mesoporous walls within AAO membranes and their application in a high rate rechargeable lithium battery. Well-aligned titania nanotube arrays were fabricated via a drying process utilizing supercritical CO 2 after the dissolution of the membranes. These mesoporous titania nanotubes, with a 3-dimensional (3D) network structure, were investigated as the electrode material of a rechargeable lithium battery. The structure of the mesoporous nanotubes was specifically designed to allow efficient transport of both lithium ions and electrons, which are necessary for a high rate rechargeable battery. The experimental results obtained proved that the mesoporous nanotube structure plays an important role in the efficiency of the high rate performance of the battery. Scanning electron microscope (SEM) images of the titania nanotubes annealed at 150°C are shown in Figure 1. Well-defined nanotubes are observed occupying most of the pores of the AAO. The size and uniformity of the nanotubes fabricated by this templating method are closely related to the pore size and quality of the alumina membranes employed.[17] Nanotubes prepared within a 0.2 lm Whatman AAO membrane have an outer diameter of approximately 200 nm...