The homologous series of octa-n-alkylsilsesquioxanes (nalkylPOSS) was prepared by hydrosilylation of octahydrido-octasilsesquioxane H 8 T 8 with terminal n-alkenes in good yields (n = 2−18). The compounds were characterized by NMR spectroscopy ( 1 H, 13 C, 29 Si), MALDI−TOF and ESI MS. Most of them have also been characterized using X-ray crystallography, including some polymorphs. The packing systems of the octa-n-alkylsilsesquioxanes are reported. Two types of packing have been observed, rod-like and disk-like (interdigitated). Some n-alkylPOSS crystals were formed in which the chains are tilted away from the axes of the cubic core. It was also observed that as alkylchains are flexible they can take up a variety of conformations. Melting points of the homologous series showed an odd−even alternating effect for alkyl chains longer than four CH 2 units. The TGA of n-alkylPOSS under nitrogen showed that the thermal stability temperatures are between 200 and 400°C. Pyrolysis-gas chromatography/mass spectrometry has been used to elucidate the thermal degradation process of T 8 (n-C n H 2n+1 ) 8 (n = 11 and 18). Thermal cracking along the whole alkyl chain was observed rather than simple loss of the complete arm.

The development of a Lewis acid-promoted aza-Prins reaction to form piperidines and pyrrolidines is described. Indium trichloride has been found to be a highly successful and mild Lewis acid for promoting this reaction. A thorough mechanistic investigation is described, including the factors that influence the formation of the 5- or 6-membered ring product(s).

The presence of strongly electron withdrawing groups on alkoxysilanes, EWG-(CH2) n -Si­(OEt)3 (where n = 1–3 and the electron-withdrawing group EWG contains an Si–C­(sp3) bond), facilitates the formation and encapsulation of the fluoride anion in a silsesquioxane cage. Such species have been studied by 19F and 29Si NMR spectroscopy and X-ray crystallography together with MALDI-TOF and ESI mass spectrometry. The EWG must not be a good leaving group. Interestingly, this strategy led only to the T8 cage and excellent yields were obtained (81–95%) even without solvent. A wide range of functionalities were used. This new route offers an opportunity to build novel nanometer-sized 3-D molecular structures with a variety of functionalities which have not been accessible in the past.

Spangolite, Cu 6 Al(SO 4 )(OH) 12 Cl·3H 2 O, is a hydrated layered copper sulfate mineral. The Cu 2+ ions of each layer form a systematically depleted triangular lattice which approximates a maple leaf lattice. We present details of the crystal structure, which suggest that in spangolite this lattice actually comprises two species of edge linked trimers with different exchange parameters. However, magnetic susceptibility measurements show that despite the structural trimers, the magnetic properties are dominated by dimerization. The high temperature magnetic moment is strongly reduced below that expected for the six s = 1/2 in the unit cell.

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Electrodeposition of copper and nickel on a variety of substrates including conductive polymer films with two different compositions has been studied. The enhancement of the copper and nickel electrodeposition rate was observed for composite polypyrrole films with cation-exchange properties in comparison to undoped polypyrrole films with anionexchange properties. Significant enhancement of the nickel electrodeposition rate on both types of conductive polymer vs. the bare gold electrode was also found. An explanation of these effects is presented. An electrochemical quartz crystal microbalance (EQCM) with 10 MHz AT-cut piezoelectrodes was used in this study. Use of the EQCM technique allowed for simultaneous monitoring of voltamperometric and resonance frequency vs. potential or time characteristics. The thickness of electropolymerized polypyrrole films as well as the amounts of electrodeposited metals were controlled by monitoring the EQCM resonant frequency. The nucleation density has been determined from scanning electron microscope experiments.Another useful application of metal deposition on polymers is in the fabrication of composite materials, e.g., metal-polymer-metal multilayers.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.172.10.194 Downloaded on 2014-11-01 to IP

Clinoptilolite is a natural microporous material possessing a versatile range of cation exchange properties that are exploited in many industrial processes. The dehydration and cation mobility of three prototype forms, Cs−, K−, and Na−clinoptilolite, have been studied using in situ synchrotron energy dispersive and microcrystal diffraction with a novel hybrid simulation technique. This exposes the different responses of the framework, cation, and water components to dehydration processes. The responses are illustrated for the Cs and Na forms using structural snapshots and statistically averaged parameters. The “heat collapse” framework transformation has been identified with the pure Na form by both the in situ diffraction data and the computer modeling.

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