Polymeric micelles with carboxyl groups in the core(PMCC)were prepared by chemical cross-linking induced micellization of chlorinated polystyrene-b-poly(acrylic acid)(PS-b-PAA)by glycol in dichloromethane.The crosslin...Polymeric micelles with carboxyl groups in the core(PMCC)were prepared by chemical cross-linking induced micellization of chlorinated polystyrene-b-poly(acrylic acid)(PS-b-PAA)by glycol in dichloromethane.The crosslinking of chlorinated PAA blocks results in the formation of micelle core,whereas PS block chains form the micelle shell.The chlorination of PAA produces anhydride groups,which make carboxyl groups during the crosslinking reaction with glycols,hence the resultant micelles contain carboxyl groups in the core.As the concentration of polymers can be as high as 50 g/mL,therefore,PMCC can be prepared with a high efficiency,and the powder micelle product was obtained by direct precipitation in methanol-water mixture.The PMCC were characterized by means of FTIR,1H NMR,DLS and SEM.展开更多
Visible light‐driven carboxylation with CO_(2) have emerged as a sustainable and powerful way to transfer waste to treasure.However,it is still challenging for aryl fluorides due to the low reactivities of both C(sp2...Visible light‐driven carboxylation with CO_(2) have emerged as a sustainable and powerful way to transfer waste to treasure.However,it is still challenging for aryl fluorides due to the low reactivities of both C(sp2)−F bonds and CO_(2).Herein,we report the first photocatalytic carboxylation of aryl C−F bonds with CO_(2).The visible‐light photoredox catalysis enables selective carboxylation of strong C(sp2)−F bonds in diverse polyluoroarenes,such as penta‐,tetra‐,and tri‐fluoroarenes under mild conditions,providing a facile access to a series of important polyfluoroaryl carboxylic acids with good yields.In contrast to previous reports of direct capture of polyfluoroaryl radicals,mechanistic studies suggest that the reduction of fleeting polyfluoroaryl radicals into polyfluoroaryl anions might be involved in this transformation,which may open a new avenue for photocatalytic functionalization of aryl C−F bonds.展开更多
A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild rea...A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild reaction conditions.This reaction provides a facile and sustainable method for the synthesis of tricarboxylates by using CO_(2) as the carboxylic source.展开更多
文摘Polymeric micelles with carboxyl groups in the core(PMCC)were prepared by chemical cross-linking induced micellization of chlorinated polystyrene-b-poly(acrylic acid)(PS-b-PAA)by glycol in dichloromethane.The crosslinking of chlorinated PAA blocks results in the formation of micelle core,whereas PS block chains form the micelle shell.The chlorination of PAA produces anhydride groups,which make carboxyl groups during the crosslinking reaction with glycols,hence the resultant micelles contain carboxyl groups in the core.As the concentration of polymers can be as high as 50 g/mL,therefore,PMCC can be prepared with a high efficiency,and the powder micelle product was obtained by direct precipitation in methanol-water mixture.The PMCC were characterized by means of FTIR,1H NMR,DLS and SEM.
文摘Visible light‐driven carboxylation with CO_(2) have emerged as a sustainable and powerful way to transfer waste to treasure.However,it is still challenging for aryl fluorides due to the low reactivities of both C(sp2)−F bonds and CO_(2).Herein,we report the first photocatalytic carboxylation of aryl C−F bonds with CO_(2).The visible‐light photoredox catalysis enables selective carboxylation of strong C(sp2)−F bonds in diverse polyluoroarenes,such as penta‐,tetra‐,and tri‐fluoroarenes under mild conditions,providing a facile access to a series of important polyfluoroaryl carboxylic acids with good yields.In contrast to previous reports of direct capture of polyfluoroaryl radicals,mechanistic studies suggest that the reduction of fleeting polyfluoroaryl radicals into polyfluoroaryl anions might be involved in this transformation,which may open a new avenue for photocatalytic functionalization of aryl C−F bonds.
文摘A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild reaction conditions.This reaction provides a facile and sustainable method for the synthesis of tricarboxylates by using CO_(2) as the carboxylic source.
