The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical...The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical precursor,enabling efficient access to skeletally diverse silicon-containing azaheterocycles including pyrrolidine,indoline and isoindoline bearing anα-tertiary stereocenter with high enantioselectivity.The key to the success includes the use of Cu(I)/CPA cooperative catalyst system and theβ-silicon effect of the silyl group to stabilize the in situ generated carbocation intermediate.展开更多
One-dimensional V2O5 nanowires have been synthesized inside the channels of mesoporous silica SBA-15 through chemical approach, which involves aminosilylation of silanol groups on the silica surface, anchoring of isop...One-dimensional V2O5 nanowires have been synthesized inside the channels of mesoporous silica SBA-15 through chemical approach, which involves aminosilylation of silanol groups on the silica surface, anchoring of isopoly acid, H6V10O28, by neutralization of basic amine groups, and thermal decomposition. The formation and physicochemical properties of the nanowires were monitored and studied by TG-DTA, variable temperature in situ XRD, TEM, N2 sorption measurements and UV-Vis DRS. The results indicate that V2O5 nanowires formed within SBA-15 channels belong to orthorhombic polycrystal domains. The oxygen-to-metal charge transfer band of V2O5 nanowires shows a blue shift in comparison with bulk V2O5, which clearly exhibits the quantum size effect of nanowires.展开更多
Keggin-type molybdovanadophosphoric acids （HPA）, H4PMo11VO40 （1）, H5PMo10V2O40 （2） and H6PMo9V3O40 （3） were anchored onto γ-aminopropyltriethoxysilane （APTS） aminosilylated silica mesoporous SBA-15 through ...Keggin-type molybdovanadophosphoric acids （HPA）, H4PMo11VO40 （1）, H5PMo10V2O40 （2） and H6PMo9V3O40 （3） were anchored onto γ-aminopropyltriethoxysilane （APTS） aminosilylated silica mesoporous SBA-15 through acid-base neutralization and the resulting HPA/APTS/SBA-15 were characterized by BET, TEM, XRD, ICP, FFIR and ^31p MAS NMR. The characterization results indicate that the Keggin-structure of these HPAs is preserved within the mesoporous silica host. The samples were tested for catalytic aerobic oxidation of acetaldehyde heterogeneously in liquid phase under ambient condition. The electrostatic force between heteropoly acid and amino groups grafted on the silica channel surface leads to strong immobilization of HPA inside SBA-15 which is against the leaching during the reaction. The good catalytic performance and easy recycle of these catalysts make them as potential environmental friendly catalysts for elimination of indoor air pollutants.展开更多
基金supported by the National Natural Science Foundation of China(21722203,21831002,21801116,21572096)Shenzhen Special Funds for the Development of Biomedicine,Internet,New Energy,and New Material Industries(JCYJ20170412152435366,JCYJ20170307105638498,JCYJ20180302180235837)+1 种基金Guangdong Natural Science Foundation(2018A030310083)Shenzhen Nobel Prize Scientists Laboratory Project(C17783101)
文摘The catalytic radical-initiated asymmetric 1,2-aminosilylation of alkene with a hydrosilane under Cu(I)/CPA cooperative catalysis has been developed.This method features the use of hydrosilane as the reductive radical precursor,enabling efficient access to skeletally diverse silicon-containing azaheterocycles including pyrrolidine,indoline and isoindoline bearing anα-tertiary stereocenter with high enantioselectivity.The key to the success includes the use of Cu(I)/CPA cooperative catalyst system and theβ-silicon effect of the silyl group to stabilize the in situ generated carbocation intermediate.
基金the National Natural Science Foundation of China (Nos. 20005310, 203710
文摘One-dimensional V2O5 nanowires have been synthesized inside the channels of mesoporous silica SBA-15 through chemical approach, which involves aminosilylation of silanol groups on the silica surface, anchoring of isopoly acid, H6V10O28, by neutralization of basic amine groups, and thermal decomposition. The formation and physicochemical properties of the nanowires were monitored and studied by TG-DTA, variable temperature in situ XRD, TEM, N2 sorption measurements and UV-Vis DRS. The results indicate that V2O5 nanowires formed within SBA-15 channels belong to orthorhombic polycrystal domains. The oxygen-to-metal charge transfer band of V2O5 nanowires shows a blue shift in comparison with bulk V2O5, which clearly exhibits the quantum size effect of nanowires.
基金Project supported by the National Natural Science Foundation Committee of China （Nos. 20371013, 20273017, 20421303） and the Major State Basic Research Development Program of China （No. 2003CB615807）.
文摘Keggin-type molybdovanadophosphoric acids （HPA）, H4PMo11VO40 （1）, H5PMo10V2O40 （2） and H6PMo9V3O40 （3） were anchored onto γ-aminopropyltriethoxysilane （APTS） aminosilylated silica mesoporous SBA-15 through acid-base neutralization and the resulting HPA/APTS/SBA-15 were characterized by BET, TEM, XRD, ICP, FFIR and ^31p MAS NMR. The characterization results indicate that the Keggin-structure of these HPAs is preserved within the mesoporous silica host. The samples were tested for catalytic aerobic oxidation of acetaldehyde heterogeneously in liquid phase under ambient condition. The electrostatic force between heteropoly acid and amino groups grafted on the silica channel surface leads to strong immobilization of HPA inside SBA-15 which is against the leaching during the reaction. The good catalytic performance and easy recycle of these catalysts make them as potential environmental friendly catalysts for elimination of indoor air pollutants.
