Physico–chemical models of the interactions of cells with solid surfaces, which use contact angles and zeta potentials, indicated more facile adsorption of cells of

29Si-13C couplings were measured in para substituted silylated phenols, X--C6H4--O--SiR1R2R3 (X = NO2, CF3, Cl, F, H, CH3, CH3O). The SiR1R2R3 silyl groups included trimethylsilyl (Si(CH3)3, TMS), tert-butyldimethylsilyl (Si(CH3)2C(CH3)3, TBDMS), dimethylsilyl (SiH(CH3)2, DMS), and tert- butyldiphenylsilyl (Si(C6H5)2C(CH3)3, TBDPS). Previously developed (Si,C,Si)gHMQC methods and narrow 29Si lines allowed the determination of coupling constants over up to five bonds. Besides the number of intervening bonds between the silicon and carbon atoms, all the measurable couplings depend also on the nature of the substituents on the silicon. The two- and three-bond couplings are not affected by ring substitution in the para position. These properties render the 29Si-13C couplings suitable for line assignment in the spectra of silylated polyphenols. The experimental results are in reasonable agreement with theoretical calculations. The calculations show, in agreement with the data reported in the literature for couplings between other nuclei, that the two-bond and three-bond couplings, which are of similar magnitudes, are of opposite signs. If the signs of these geminal and vicinal couplings could be determined experimentally, they would greatly facilitate the line assignment. The four- and five-bond couplings are affected by the substituent X in a nontrivial manner.

New composite materials could reveal attractive capabilities and favourable properties.

Insertion of carbon dioxide into the structure of organic epoxides leads to the formation of valuable cyclic carbonates and polycarbonates. For the purpose of this process, we report here a series of recyclable organocatalysts with superior activity. Carbosilane dendrimers (first to third generation) are employed as a support to which periphery ammonium or phosphonium centers are covalently attached to form a dendritic ionic liquid (DIL). The obtained DILs were tested as homogeneous catalysts in the cycloaddition of CO 2 to epoxides with respect to their activity and recyclability. The catalytic performance of active sites is enhanced by the presence of a proximal hydroxyl group, playing the role of a hydrogen bond donor. An experimentally observed synergistic effect was confirmed by density functional theory calculations. The activity of DILs is affected more by the structure of onium salt than by the size of the support (dendrimer generation). The dendritic catalysts of all tested generations could be recovered by nanofiltration and repeatedly reused. In order to simplify the separation of the catalysts, composite materials were prepared by intercalating the more active ammonium dendrimers into the interlayer space of a natural montmorillonite. The resulting heterogeneous catalysts were easily separable by centrifugation while retaining a reasonable level of activity.