Fast characterization of functionalized silica materials by silicon-29 surface-enhanced NMR spectroscopy using dynamic nuclear polarization.

We demonstrate fast characterization of the distribution of surface bonding modes and interactions in a series of functionalized materials via surface-enhanced nuclear magnetic resonance spectroscopy using dynamic nuclear polarization (DNP). Surface-enhanced silicon-29 DNP NMR spectra were obtained by using incipient wetness impregnation of the sample with a solution containing a polarizing radical (TOTAPOL). We identify and compare the bonding topology of functional groups in materials obtained via a sol-gel process and in materials prepared by post-grafting reactions. Furthermore, the remarkable gain in time provided by surface-enhanced silicon-29 DNP NMR spectroscopy (typically on the order of a factor 400) allows the facile acquisition of two-dimensional correlation spectra.

Highly efficient aerobic oxidation of alkenes over unsupported nanogold.

An octylsilane-stabilized colloidal dispersion of 2 nm crystalline gold nanoparticles is highly active and selective for the aerobic oxidations of stilbene and cyclohexene in methylcyclohexane.

Unexpected, spontaneous and selective formation of colloidal Pt3Sn nanoparticles using organometallic Pt and Sn complexes.

The facile and selective synthesis of small crystalline Pt(3)Sn alloy nanoparticles was performed at room temperature under H(2), using a colloidal approach without the use of extra-stabilizing ligands. The Pt(3)Sn alloy was found to be obtained spontaneously as the unique phase regardless of the number of tin equivalents introduced.

AgOC(CF(3))(3): an alternative and efficient reagent for preparing transition metal-NHC-carbene complexes.

AgOC(CF(3))(3), a soluble source, was found to be a convenient reagent for the one-pot preparation of Ag-NHC and M-NHC complexes starting from imidazoliums (M = Au, Ir, Pd and Ru).