Air-stable metallic Co nanoparticles were incorporated into the pores or anchored onto the external surface of an ordered mesporous carbon/SBA-15 composite by simply treating the cobalt precursor-impregnated surfactant-containing SBA-15 via the Reaction under Autogenic Pressure at Elevated Temperature (abbreviated to RAPET) process, resulting in bifunctional Co@carbon/ SBA-15 composites. Surfactant-containing mesoporous SBA-15 (denoted as surf-SBA-15 composite) was firstly impregnated with a cobalt precursor solution and then calcined under autogenic pressure at elevated temperature using a Swagelok-like high-temperature autoclave in an N 2 atmosphere. During the RAPET process, the cobalt precursor impregnated into the channel of the surf-SBA-15 composites decomposed and was reduced by the surfactant species, meanwhile, the surfactant, which was used as a soft template for the formation of mesoporous silica, was carbonized and coated onto the internal and the external surface of mesoporous silica and partially onto the incorporated metallic Co nanoparticles, forming Co nanoparticles encapsulated by a mesoporous carbon/SBA-15 composite (mesoporous Co@carbon/SBA-15) in situ. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption measurements and X-ray diffraction (XRD). The influences of the concentration of cobalt precursors on the morphologies and the magnetic properties of the mesoporous Co@carbon/silica composites were studied. The adsorption/separation ability of the magnetic mesoporous composite to organic guest molecules and the stability of the nanosized metallic Co decorations in air or in an acid environment were also investigated.
An
unprecedented Sc(OTf)3-catalyzed C2-selective cyanation/defluorination
cascade of perfluoroalkylated 3-indolylmethanols with TMSCN is described,
which provides a novel and practical strategy for the synthesis of
structurally diverse 3-(2-cyano)-indolyl substituted gem-difluoroalkenes and β-fluoro-β-perfluoroalkylalkenes.
The reaction features excellent regio- and stereoselectivity and broad
substrate scope. Notably, the obtained gem-difluoroalkenes
and β-fluoro-β-perfluoroalkylalkenes could be easily transformed
into 3-fluoro(perfluoroalkyl)-β-carbolines with excellent efficiency
simply by treating them with Grignard reagents or DIBAL-H under mild
reaction conditions.
A synthetic approach for the synthesis 2phosphoryl-3-monofluorovinylindoles via cascade regioselective dehydrative phosphorylation/stereoselective defluorination of difluoromethylated 3-indolylmethanols and H-phosphine oxides under catalyst-and additive-free conditions is described. The reaction could be scaled-up without the need for column chromatography purification.
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