We have demonstrated that poly(2-aminothiophenol)-stablized gold nanoparticles with proper gold size and polymer thickness are active catalysts for Suzuki-Miyaura cross-coupling reaction of aryl halides with arylboronic acids in water and air for the first time. High yields can be obtained with aryl halides or arylboronic acids bearing a variety of substituents. This new finding will undoubtedly broaden the application of gold nanoparticles in organic catalytic reactions.
Self-assembly of amphiphilic block copolymer in water suffers from the undesired encapsulation of hydrophobic reactive motifs in core-forming block, which deteriorates the performance as aqueous catalysts. This problem can be circumvented by polymerisation-induced self-assembly (PISA). Herein, we report a new strategy for one-pot synthesis of reactive block copolymer nanoparticles whose hydrophobic reactive motifs decorate surrounding core-shell interfaces. We demonstrate fast RAFT aqueous dispersion polymerisation of a commercial available specialty monomer, diacetone acrylamide (DAAM), under visible light irradiation at 25 o C. PISA is induced by polymerisation via sequentially dehydration, phase separation and reaction acceleration, and thus complete conversion in 30 min. Replacement of minimal DAAM by NH3 + -monomer induces slight hydration of the core-forming block, and thus a low polydispersity of resultant statistic-block copolymer. Moreover, simultaneous in situ self-assembly and chain growth favours adjustment of newly-added NH3 + -units outward to core-shell interfaces while the major DAAM units collapse to hydrophobic PISA-cores. Both lead to timely and selective self-assembly into the new reactive nanoparticles whose NH3 + -motifs decorate surrounding core-shell interfaces. These nanoparticles well suit fabrication of advanced nanoreactors whose hydrophobic dative metal centres decorate surrounding interfaces via simultaneous imine conversion and Zn(II)-coordination. Such PISA-nanostructures endow hydrophobic metal centres with huge and accessible specific surface area and are stabilized by water-soluble shells. Therefore, this strategy holds fascinating potentials for the fabrication of metalloenzyme-inspired aqueous catalysts.Enzyme inspired interface-decorated media-accessible reactive nanoparticles are now available via PISA by aqueous dispersion RAFT of commodity-DAAM with minimal NH 3 + -monomer.
Defective TiO(2-x) was synthesized via a facile anodization technique. Electron paramagnetic resonance spectra confirmed the presence of oxygen vacancy, which extended the photon-absorbance deeply into the visible-light region. By stripping off the nanotubes on top, a hexagonally dimpled layer of black TiO(2-x) was exposed and exhibited remarkable photocatalytic activity.
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