Metal-organic frameworks(MOFs)are well-documented for visible light photocatalysis because of their tailorable structures and tunable absorptions through organic linkers.By employing a highly conjugated linker,4,4'...Metal-organic frameworks(MOFs)are well-documented for visible light photocatalysis because of their tailorable structures and tunable absorptions through organic linkers.By employing a highly conjugated linker,4,4',4'',4'''-(pyrene-1,3,6,8-tetrayltetrakis(ethyne-2,1-diyl))tetrabenzoic acid,the optical absorption of the MOF NU-1100 is effectively tuned to visible light below 600 nm region.Under green light irradiation,NU-1100 triggers charge separation and modulates electron transfer from the linkers to the Zr_(6)O_(4)(OH)_(4)^(12+)clusters,driving the oxidation of sulfides to sulfoxides.Notably,adding a redox mediator radically expedites the oxidation of sulfides by NU-1100 photocatalysis,TEMPO(2,2,6,6-tetramethylpiperidine-N-oxyl)and 4-carboxy-TEMPO.At least 2.7 and 5.2 times of conversions of phenyl methyl sulfide are achieved by NU-1100 photocatalysis with TEMPO and 4-carboxy-TEMPO,respectively.A series of characterizations illustrate that 4-carboxy-TEMPO is adsorbed onto the exterior surface of Zr_(6)O_(4)(OH)_(4)^(12+)clusters of NU-1100 to mediate hole transfer and achieve higher charge transfer efficiency.Mechanistic studies indicate that superoxide is the essential reactive oxygen species and that the oxidation of sulfides is driven by an electron transfer pathway.This study demonstrates the integration of redox mediators with MOFs can drive more efficient visible light photocatalytic reactions.展开更多
Reactive oxygen species(RoS)are essential for biological processes like cell signaling and chemical processes like organic oxidation.Moreover,the sufficient generation of RoS plays a significant role in targeted tumor...Reactive oxygen species(RoS)are essential for biological processes like cell signaling and chemical processes like organic oxidation.Moreover,the sufficient generation of RoS plays a significant role in targeted tumor treatments or oxidation of organics.Herein,a hydrazone-linked porphyrin covalent organic framework(Por-DETH-COF)is developed for red light-induced generation of ROS like singlet oxygen(^(1)O_(2))or superoxide(O_(2)·^(-))to undertake different but targeted oxidations.First,^(1)O_(2)is adopted in photodynamic therapy(PDT)for the oxidation of glioma cells.The PDT efficiency of Por-DETH-COF on the apoptosis of glioma cells is explored through flow cytometry and western blot assay.The apoptosis rate of glioma cells significantly increases over Por-DETH-COF under 660nm red light illumination,suggestive of the potency of^(1)O_(2).Second,O_(2)^(·-)is employed for the targeted oxidation of thiols.A series of thiols could be efficiently oxidized to corresponding disulfides over Por-DETH-COF under 660 nm red light illumination,indicative of the significance of O_(2)^(·-).This work highlights the potential of covalent organic frameworks in generating Ros for precise medical applications of complex chemical environments.展开更多
Visible light photocatalysis of covalent organic frameworks(COFs) has made significant progress in recent years. Benzotrithiophene(BTT), a planar, electron-rich building block, turns out to be foundational in assembli...Visible light photocatalysis of covalent organic frameworks(COFs) has made significant progress in recent years. Benzotrithiophene(BTT), a planar, electron-rich building block, turns out to be foundational in assembling COFs in which the fullπ-conjugation of BTT is essential to facilitate electron transfer. Herein, a sp~2 carbon-conjugated COF, namely BTT-sp~2c-COF, is assembled from benzo[1,2-b:3,4-b′:5,6-b′′]trithiophene-2,5,8-tricarbaldehyde and [1,1′:4′,1′′-terphenyl]-4,4′′-dicarbonitrile towards photocatalysis. More importantly, TEMPO(2,2,6,6-tetramethylpiperidin-1-yl)oxyl, 1 mol%) could considerably accelerate the selective oxidation of organic sulfides with O_(2) over BTT-sp~2c-COF. TEMPO mediates hole transfer between BTT-sp~2c-COF and organic sulfides, and O-atoms are incorporated into sulfoxides via an electron transfer pathway. Merging BTT-sp~2c-COF photocatalysis with TEMPO generally applies to transforming organic sulfides into sulfoxides. This work implies the full π-conjugation of electron-rich building blocks into COFs is a viable strategy for selective visible light photocatalysis.展开更多
文摘Metal-organic frameworks(MOFs)are well-documented for visible light photocatalysis because of their tailorable structures and tunable absorptions through organic linkers.By employing a highly conjugated linker,4,4',4'',4'''-(pyrene-1,3,6,8-tetrayltetrakis(ethyne-2,1-diyl))tetrabenzoic acid,the optical absorption of the MOF NU-1100 is effectively tuned to visible light below 600 nm region.Under green light irradiation,NU-1100 triggers charge separation and modulates electron transfer from the linkers to the Zr_(6)O_(4)(OH)_(4)^(12+)clusters,driving the oxidation of sulfides to sulfoxides.Notably,adding a redox mediator radically expedites the oxidation of sulfides by NU-1100 photocatalysis,TEMPO(2,2,6,6-tetramethylpiperidine-N-oxyl)and 4-carboxy-TEMPO.At least 2.7 and 5.2 times of conversions of phenyl methyl sulfide are achieved by NU-1100 photocatalysis with TEMPO and 4-carboxy-TEMPO,respectively.A series of characterizations illustrate that 4-carboxy-TEMPO is adsorbed onto the exterior surface of Zr_(6)O_(4)(OH)_(4)^(12+)clusters of NU-1100 to mediate hole transfer and achieve higher charge transfer efficiency.Mechanistic studies indicate that superoxide is the essential reactive oxygen species and that the oxidation of sulfides is driven by an electron transfer pathway.This study demonstrates the integration of redox mediators with MOFs can drive more efficient visible light photocatalytic reactions.
基金supported by the National Natural Science Foundation of China(No.22072108).
文摘Reactive oxygen species(RoS)are essential for biological processes like cell signaling and chemical processes like organic oxidation.Moreover,the sufficient generation of RoS plays a significant role in targeted tumor treatments or oxidation of organics.Herein,a hydrazone-linked porphyrin covalent organic framework(Por-DETH-COF)is developed for red light-induced generation of ROS like singlet oxygen(^(1)O_(2))or superoxide(O_(2)·^(-))to undertake different but targeted oxidations.First,^(1)O_(2)is adopted in photodynamic therapy(PDT)for the oxidation of glioma cells.The PDT efficiency of Por-DETH-COF on the apoptosis of glioma cells is explored through flow cytometry and western blot assay.The apoptosis rate of glioma cells significantly increases over Por-DETH-COF under 660nm red light illumination,suggestive of the potency of^(1)O_(2).Second,O_(2)^(·-)is employed for the targeted oxidation of thiols.A series of thiols could be efficiently oxidized to corresponding disulfides over Por-DETH-COF under 660 nm red light illumination,indicative of the significance of O_(2)^(·-).This work highlights the potential of covalent organic frameworks in generating Ros for precise medical applications of complex chemical environments.
基金supported by the National Natural Science Foundation of China (22072108)。
文摘Visible light photocatalysis of covalent organic frameworks(COFs) has made significant progress in recent years. Benzotrithiophene(BTT), a planar, electron-rich building block, turns out to be foundational in assembling COFs in which the fullπ-conjugation of BTT is essential to facilitate electron transfer. Herein, a sp~2 carbon-conjugated COF, namely BTT-sp~2c-COF, is assembled from benzo[1,2-b:3,4-b′:5,6-b′′]trithiophene-2,5,8-tricarbaldehyde and [1,1′:4′,1′′-terphenyl]-4,4′′-dicarbonitrile towards photocatalysis. More importantly, TEMPO(2,2,6,6-tetramethylpiperidin-1-yl)oxyl, 1 mol%) could considerably accelerate the selective oxidation of organic sulfides with O_(2) over BTT-sp~2c-COF. TEMPO mediates hole transfer between BTT-sp~2c-COF and organic sulfides, and O-atoms are incorporated into sulfoxides via an electron transfer pathway. Merging BTT-sp~2c-COF photocatalysis with TEMPO generally applies to transforming organic sulfides into sulfoxides. This work implies the full π-conjugation of electron-rich building blocks into COFs is a viable strategy for selective visible light photocatalysis.
