One-pot two-step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver-catalysed C-O/C-N bond formation...One-pot two-step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver-catalysed C-O/C-N bond formation is reported, Catalytic activities were investigated by controlling catalyst loading, reaction pressure and time, and very high turnover number （turnover frequency） was obtained： 3350 （35 h-1） with 0.01 mol% silver catalyst under 0.1 MPa, and up to 13360 （139 h-1） with 0.005 mol% silver catalyst under 2.0 MPa at room temperature. The strategy was ingeniously regulated, and synchronously afforded a wide range of β-oxopropylcarbamate and 1,3-oxazolidin-2-one motifs in excellent yields and selectivity together with unprecedented high turnover number （TON） and turnover frequency （TOF） value.展开更多
Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was repo...Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was reported the fabrication of large-area FS-2D Au films with controllable lattice orientations via an electrochemical hydrogen-detaching method.It was further characterized the catalytic properties of FS-2D Au.The(111)-oriented FS-2D Au with 20 nm in thickness shows a catalytic conversion up to 43.8% for the oxidation of cyclohexane as a model reaction system,a result of more than double of generally reported values.The exceptionally high catalytic activity could be attributed to the flexible structure of the FS-2D Au catalyst,which differs from the rigid structure of general catalysts.The results give useful implications for large-scale productions of a variety of FS-2D metals with controllable orientations,by which their applications may not be confined to catalysis chemistry.展开更多
基金We are grateful to the National Natural Science Foundation of China （21602232）, the Natural Science Foundation for Youths of Shanxi （201701D221057）, and the Project of ＂Utilization of Low Rank Coal＂ Strategic Leading Special Fund, Chinese Academy of Sciences （XDA-07070800, XDA-07070400）.
文摘One-pot two-step stepwise reaction of terminal propargylic alcohols, carbon dioxide, and primary/secondary amines for the effective synthesis of various urethanes through robust silver-catalysed C-O/C-N bond formation is reported, Catalytic activities were investigated by controlling catalyst loading, reaction pressure and time, and very high turnover number （turnover frequency） was obtained： 3350 （35 h-1） with 0.01 mol% silver catalyst under 0.1 MPa, and up to 13360 （139 h-1） with 0.005 mol% silver catalyst under 2.0 MPa at room temperature. The strategy was ingeniously regulated, and synchronously afforded a wide range of β-oxopropylcarbamate and 1,3-oxazolidin-2-one motifs in excellent yields and selectivity together with unprecedented high turnover number （TON） and turnover frequency （TOF） value.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.FRFSD-12-027A)the New Century Excellent Talents in Universities (No.NCET-12-0778)+2 种基金Innovation on Working Methodology of Ministry of Science and Technology of China (No.2012IM030500)the National Natural Science Foundation of China (No.51328202)China Scholarship Council (No.201308110345)
文摘Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was reported the fabrication of large-area FS-2D Au films with controllable lattice orientations via an electrochemical hydrogen-detaching method.It was further characterized the catalytic properties of FS-2D Au.The(111)-oriented FS-2D Au with 20 nm in thickness shows a catalytic conversion up to 43.8% for the oxidation of cyclohexane as a model reaction system,a result of more than double of generally reported values.The exceptionally high catalytic activity could be attributed to the flexible structure of the FS-2D Au catalyst,which differs from the rigid structure of general catalysts.The results give useful implications for large-scale productions of a variety of FS-2D metals with controllable orientations,by which their applications may not be confined to catalysis chemistry.
