The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic expo...The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic exponential attenuation-type oscillating curve was found when the polymerization was carried out in air, but this phenomenon was not found in nitrogen. It is supposed that this unique kinetic performance may be attributed to nitroxyl radicals that are produced in situ from the oxidation of ATMP. ATMP polymer with narrow polydispersity (d = 1.03) can be obtained by photoinduced solution polymerization of ATMP. The signal detected in ESR may be assigned to the nitroxyl radicals in the matrix of ATMP polymer. Since this kind of recycling of nitroxyl radicals is well documented for the photostabilizing mechanism of HALS, the present results may serve as a kinetic evidence for this mechanism.展开更多
Selective oxidation of biomass and its derivatives to dicarboxylic acids represents a promising route for biomass valorization.However,the co-presence of multiple functional groups in biomass molecules makes the selec...Selective oxidation of biomass and its derivatives to dicarboxylic acids represents a promising route for biomass valorization.However,the co-presence of multiple functional groups in biomass molecules makes the selective oxidation of particular functional a challenging task.Here,we demonstrate an efficient electrocatalytic system consisting of nickel oxide(NiO)and a nitroxyl radical,i.e.,2,2,6,6-tetrame thylpiperidine-1-oxyl(TEMPO)or 4-acetamido-TEMPO(ACT),for the selective oxidation of key bioplatform molecules including glucose,xylose and 5-hydroxymethylfurfural(HMF)into corresponding dicarboxylic acids,i.e.,glucaric acid,xylaric acid,and 2,5-furandicarboxylic acid(FDCA).NiO is clarified as the active catalyst for the oxidation of aldehyde in bio-platform molecules to carboxylic acid,while TEMPO or ACT is responsible for the oxidation of primary alcohol to aldehyde.The combination of NiO and TEMPO or ACT significantly accelerated the tandem oxidation of aldehyde and hydroxyl groups in glucose,xylose and HMF,thus achieving excellent yields(83%-99%)of dicarboxylic acids.Moreover,the combination catalyst enables the selective oxidation of glucose and xylose with high concentrations(e.g.,20 wt%),which offers a promising strategy for biomass valorization.展开更多
Nitroxyl(HNO)has been reported to possess unique biological and pharmacological performances,and emerged as a novel therapy for congestive heart failure.Recent studies also suggest that HNO may be produced and involve...Nitroxyl(HNO)has been reported to possess unique biological and pharmacological performances,and emerged as a novel therapy for congestive heart failure.Recent studies also suggest that HNO may be produced and involved in important metabolisms in mitochondria.However,due to its high reactivity and short life properties,fast,sensitive and selective observation and monitoring of HNO related dynamic changes in mitochondria still remains a great challenge.Herein,we synthesized a mitochondria-targeting near-infrared(NIR)fluorescent probe(DCMHNO)for rapid detection of HNO with remarkably high sensitivity,selectivity and photostability.DCMHNO shows fast response(about 4 min)towards HNO via 2-(diphenylphosphino)benzoyl group through the Staudinger reaction to boost the bright NIR emission(700 nm)with excellent sensitivity(detection limit of 13 nM),high p H stability and very low interference from other species.DCMHNO can selectively locate in mitochondria and visualize exogenous and endogenous HNO in live He La cells with high biocompatibility and photostability.The probe could also monitor the interaction between NO and H2 S that gives rise to the generation of HNO in live He La cells.In addition,DCMHNO was further utilized in ex vivo NIR imaging of HNO in live mouse liver tissues at the depth of about 50μm.In vivo imaging of HNO with high signal-to-noise ratio in live mice was also realized by using DCMHNO.These remarkable imaging performances could render NIR DCMNHNO as a useful tool to reveal HNO related dynamic changes in live samples.展开更多
基金the National Natural Science Foundation of China(No.20274023)key project foundation of National Ministry of Education(No.02114)Guangdong Province Natural Science Foundation of China(No.021241)for supporting this work.
文摘The photoinduced bulk polymerization of a reactive-hindered amine light stabilizers (r-HALS), 4-acryloyl-2, 2, 6,6-tetramethylpiperidinyl (ATMP), was performed at 80 C by using a DPC technique. An unique periodic exponential attenuation-type oscillating curve was found when the polymerization was carried out in air, but this phenomenon was not found in nitrogen. It is supposed that this unique kinetic performance may be attributed to nitroxyl radicals that are produced in situ from the oxidation of ATMP. ATMP polymer with narrow polydispersity (d = 1.03) can be obtained by photoinduced solution polymerization of ATMP. The signal detected in ESR may be assigned to the nitroxyl radicals in the matrix of ATMP polymer. Since this kind of recycling of nitroxyl radicals is well documented for the photostabilizing mechanism of HALS, the present results may serve as a kinetic evidence for this mechanism.
基金financial supported by the National Key R&D program of China(2018YFB1501602)the National Natural Science Foundation of China(22121001,22172127 and 91945301)。
文摘Selective oxidation of biomass and its derivatives to dicarboxylic acids represents a promising route for biomass valorization.However,the co-presence of multiple functional groups in biomass molecules makes the selective oxidation of particular functional a challenging task.Here,we demonstrate an efficient electrocatalytic system consisting of nickel oxide(NiO)and a nitroxyl radical,i.e.,2,2,6,6-tetrame thylpiperidine-1-oxyl(TEMPO)or 4-acetamido-TEMPO(ACT),for the selective oxidation of key bioplatform molecules including glucose,xylose and 5-hydroxymethylfurfural(HMF)into corresponding dicarboxylic acids,i.e.,glucaric acid,xylaric acid,and 2,5-furandicarboxylic acid(FDCA).NiO is clarified as the active catalyst for the oxidation of aldehyde in bio-platform molecules to carboxylic acid,while TEMPO or ACT is responsible for the oxidation of primary alcohol to aldehyde.The combination of NiO and TEMPO or ACT significantly accelerated the tandem oxidation of aldehyde and hydroxyl groups in glucose,xylose and HMF,thus achieving excellent yields(83%-99%)of dicarboxylic acids.Moreover,the combination catalyst enables the selective oxidation of glucose and xylose with high concentrations(e.g.,20 wt%),which offers a promising strategy for biomass valorization.
基金supported by the National Natural Science Foundation of China(21663005,21871060,21672220,81501591)the Natural Science Foundation of Jiangxi Province(2018ACB21009,20181BAB213007)+1 种基金the Science and Technology Plan of Shenzhen(JCYJ20170818113851132)the Research Grants Council of Hong Kong(16301614,16305015,AoE/P-03/08,Ao E/P-02/12,A-HKUST 605/16,N_HKUST604/14)
文摘Nitroxyl(HNO)has been reported to possess unique biological and pharmacological performances,and emerged as a novel therapy for congestive heart failure.Recent studies also suggest that HNO may be produced and involved in important metabolisms in mitochondria.However,due to its high reactivity and short life properties,fast,sensitive and selective observation and monitoring of HNO related dynamic changes in mitochondria still remains a great challenge.Herein,we synthesized a mitochondria-targeting near-infrared(NIR)fluorescent probe(DCMHNO)for rapid detection of HNO with remarkably high sensitivity,selectivity and photostability.DCMHNO shows fast response(about 4 min)towards HNO via 2-(diphenylphosphino)benzoyl group through the Staudinger reaction to boost the bright NIR emission(700 nm)with excellent sensitivity(detection limit of 13 nM),high p H stability and very low interference from other species.DCMHNO can selectively locate in mitochondria and visualize exogenous and endogenous HNO in live He La cells with high biocompatibility and photostability.The probe could also monitor the interaction between NO and H2 S that gives rise to the generation of HNO in live He La cells.In addition,DCMHNO was further utilized in ex vivo NIR imaging of HNO in live mouse liver tissues at the depth of about 50μm.In vivo imaging of HNO with high signal-to-noise ratio in live mice was also realized by using DCMHNO.These remarkable imaging performances could render NIR DCMNHNO as a useful tool to reveal HNO related dynamic changes in live samples.
