Aluminum salen complexes bearing appended quaternary ammonium salt substituents have been synthesized and shown to be effective catalysts for the coupling of epoxides and carbon dioxide to generate cyclic carbonates. 27 Al NMR spectra have demonstrated that these exist as both five-and six-coordinate Al(III) species in dimethylsulfoxide (DMSO) solution, whereas only a five-coordinate Al(III) species was detected in the (salen)AlCl analogue in the presence of an external onium salt. The onium salt group tethered on the salen ligand was found to play an important role in enhancing the catalytic activity. The effects of reaction variables such as temperature, time, pressure, molar ratio of epoxide to catalyst on the catalytic performance were systematically investigated. These bifunctional catalysts were found to be highly stable to moisture and oxygen, resistant to impurities, and recyclable with only minor losses in catalytic activity.

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A urea-based bis-silylated bipyridine ligand derived from 4,4Ј-diamino-2,2Ј-bipyridine has been prepared. Organic-inorganic hybrid materials with a high loading of lanthanide 2,2-bipyridine moieties were obtained by using the silylated bipyridine as the only siloxane network precursor in the presence of lanthanide ions (or lanthanide complexes). The insitu formation of lanthanide complexes from lanthanide ions and the silylated bipyridine during the sol-gel processing was confirmed by the luminescence behavior of the obtained hybrid materials and that of the corresponding pure lantha-