Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence ...Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence is primarily influenced by conjugated domains and surface states,the underlying interaction mechanisms remain poorly understood.This study explores a graded nitro-engineering approach to simultaneously regulate surface states and sp^(2)conjugated domains through nitro(-NO_(2))modulation,enabling comprehensive color tuning.Using o-phenylenediamine(o-PD)as the carbon source and adjusting nitric acid(HNO_(3))concentrations,we synthesized tricolor-emitting nitro-functionalized CQDs(NO_(2)-CQDs).At lower-NO_(2) concentrations,luminescence is mainly influenced by surface states,where the electron-withdrawing effect of-NO_(2) enhancesπ-electron delocalization and stabilizes sp^(2)conjugation.With increasing-NO_(2) content,the lowest unoccupied molecular orbital(LUMO)energy level decreases(-2.12 eV to-3.39 eV),resulting in a red-shift in fluorescence.At higher-NO_(2) concentrations,luminescence is primarily affected by the sp^(2)conjugated domain,where steric hindrance reduces molecular planarity and conjugation,leading to a blue-shift in fluorescence as the sp^(2)domain size decreases(4.03 nm to 2.83 nm).Combining experimental results with density functional theory(DFT)calculations,we reveal the dual role of-NO2in modulating CQDs luminescence,an approach rarely achieved through surface functionalization.This work presents a novel strategy for precise tuning of CQDs luminescence across the visible spectrum.展开更多
Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for...Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.展开更多
Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various ...Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO<sub>2</sub> concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .展开更多
Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a no...Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.展开更多
The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-（β-hydroxyethylsulfonyl）chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chloroben...The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-（β-hydroxyethylsulfonyl）chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chlorobenzenesulfinic acid to form the target product, 2-nitro-4-（β- hydroxyethylsulfonyl）chlorobenzene, there presented three kinds of side reactions： 1. Condensation and elimination of HCI to form biphenyl sulfone derivatives; 2. Addition to give bisulfonyl ethane derivative via vinyl sulfone; and 3. Hydroxylethylation on O-atom to produce hydroxylethylsulfinate due to the tautomerism of sulfinic acid.展开更多
Intermolecular Stetter reaction of aromatic aldehydes with（E）-（2-nitrovinyl）cyclohexane catalyzed by thiazolium A has been developed.The reaction rate and efficiency are profoundly impacted by the presence of thio...Intermolecular Stetter reaction of aromatic aldehydes with（E）-（2-nitrovinyl）cyclohexane catalyzed by thiazolium A has been developed.The reaction rate and efficiency are profoundly impacted by the presence of thiourea B.The reaction affords moderate to good yields of the Stetter product.Some factors influencing yield were discussed.展开更多
Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free co...Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.展开更多
Methyluracil and 5-nitro-6-methyluracil react with variable molar quantities of benzoyl chloride in acetonitrile-pyridine at room temperature to give 1-N, 3-N-dibenzoyl-6- methyluracil 3b and 1-N-benzoyl-5-nitro-6-met...Methyluracil and 5-nitro-6-methyluracil react with variable molar quantities of benzoyl chloride in acetonitrile-pyridine at room temperature to give 1-N, 3-N-dibenzoyl-6- methyluracil 3b and 1-N-benzoyl-5-nitro-6-methyluracil 4b. The reactive rates of debenzoylation of 3b and 4b were investigated.展开更多
Dinitropyrenes (DNP) were prepared by nitration of pyrene, and the product was characterized by MS and elemental analysis. Three isomers of DNP were separated by HPLC and identified by 1H-NMR. The eating sequence on t...Dinitropyrenes (DNP) were prepared by nitration of pyrene, and the product was characterized by MS and elemental analysis. Three isomers of DNP were separated by HPLC and identified by 1H-NMR. The eating sequence on the normal phase column is 1, 3-DNP, 1, 6-DNP and 1, 8-DNP, whereas is 1, 6-DNP, 1. 8-DNP and 1. 3-DNP on the reversed phase column. The separation of three DNP isomers under different chromatographic conditions was also discussed.展开更多
UHF-SCF-AM1 MO calculations were performed for two kinds of pyrolysis reactions of seven nitro derivatives of methylbenzene(homolysis reactions by the rupture of bond C-NO_2 into radicals and isomerization reactions ...UHF-SCF-AM1 MO calculations were performed for two kinds of pyrolysis reactions of seven nitro derivatives of methylbenzene(homolysis reactions by the rupture of bond C-NO_2 into radicals and isomerization reactions in the way of methyl H transferring to the ortho nitro O atom). The molecular geometries of the reactants, the transition states and the products of the fourteen reactions were fully optimized. The activation energies for these two kinds of reactions have been obtained. The results indicate that this category of compounds is more easily pyrolyzed by being initiated via isomerization reactions. A parallel relationship exists between the activation energy of the isomerization reactions and the impact sensitivity of the seven titled compounds.展开更多
基金supported by National Natural Science Foundation of China(No.51873085)Natural Science Foundation of Liaoning Province-Outstanding Youth Foundation(No.2022-YQ-14)+2 种基金Liaoning Revitalization Talents Program(No.XLYC2007056)China Scholarship Council(CSC Scholarship,No.202006800009)the Shenyang Science and Technology Project(No.RC230707)。
文摘Precise control of luminescence in carbon quantum dots(CQDs),from single-color to full-color emission,is crucial for advancing their applications in biomedical imaging and display technologies.While CQDs luminescence is primarily influenced by conjugated domains and surface states,the underlying interaction mechanisms remain poorly understood.This study explores a graded nitro-engineering approach to simultaneously regulate surface states and sp^(2)conjugated domains through nitro(-NO_(2))modulation,enabling comprehensive color tuning.Using o-phenylenediamine(o-PD)as the carbon source and adjusting nitric acid(HNO_(3))concentrations,we synthesized tricolor-emitting nitro-functionalized CQDs(NO_(2)-CQDs).At lower-NO_(2) concentrations,luminescence is mainly influenced by surface states,where the electron-withdrawing effect of-NO_(2) enhancesπ-electron delocalization and stabilizes sp^(2)conjugation.With increasing-NO_(2) content,the lowest unoccupied molecular orbital(LUMO)energy level decreases(-2.12 eV to-3.39 eV),resulting in a red-shift in fluorescence.At higher-NO_(2) concentrations,luminescence is primarily affected by the sp^(2)conjugated domain,where steric hindrance reduces molecular planarity and conjugation,leading to a blue-shift in fluorescence as the sp^(2)domain size decreases(4.03 nm to 2.83 nm).Combining experimental results with density functional theory(DFT)calculations,we reveal the dual role of-NO2in modulating CQDs luminescence,an approach rarely achieved through surface functionalization.This work presents a novel strategy for precise tuning of CQDs luminescence across the visible spectrum.
基金supported by the fundamental research funds of Zhejiang Sci-Tech University(No.22212286-Y)the Natural Science Foundation of Zhejiang Province(No.LQ24B040003)。
文摘Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.
文摘Phosphorus fertilizers from less pure sedimentary sources become increasingly important, due to depletion of phosphorus from igneous rock of high quality. Consequently, robust methods with potential to remove various types of hazardous elements are required. Among such impurities, hexavalent chromium (Cr(VI)) is very likely to become a future challenge. Different industrial ways to treat phosphate rock are currently being practised, and we have here studied how chromium behaves when using the nitro-phosphate process. The reduction mechanism of Cr (VI) in nitric acid and phosphoric acid solutions was investigated by measuring redox potential and UV-VIS spectra. The results show that Cr (VI) is not stable in strong nitric acid solutions. Reduction of Cr (VI) species decreased with decreasing temperature, NO<sub>2</sub> concentration, ionic strength and absence of light. These findings support the proposed reduction reaction:The reduction rate was observed proportional to the nitric acid decomposition: .
文摘Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
基金financially supported by the Research Program from Korea Institute of Industrial Technology(EM220011)the Technology Innovation Program(20020229,Development of technology for manufacturing catalysts and electrode parts by use of low contents precious metals of rare metals) funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)+2 种基金the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT)(2022R1F1A1072569)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science,ICT & Future Planning(NRF2020R1C1C1010493)“Regional Innovation Strategy(RIS)” through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(MOE)(2021RIS-004)。
文摘Development of electrodes with high electrocatalytic activity and stability is essential for solving problems that still restrict the extensive application of vanadium redox flow batteries(VRFBs).Here,we designed a novel negative electrode with superior electrocatalytic activity by tailoring nitrogen functional groups,such as newly formed nitro and pyridinic-N transformed to pyridonic-N,from the prenitrogen-doped electrode.It was experimentally confirmed that an electrode with pyridonic-N and nitro fuctional groups(tailored nitrogen-doped graphite felt,TNGF) has superior electrocatalytic acivity with enhanced electron and mass transfer.Density functional theory calulations demonstrated the pyridonic-N and nitro functional groups promoted the adsorption,charge transfer,and bond formation with the vanadium species,which is consistent with expermental results.In addition,the V2+/V3+redox reaction mechanism on pyridonic-N and nitro functional groups was estabilised based on density functional theory(DFT) results.When TNGF was applied to a VRFB,it enabled enhanced-electrolyte utilization and energy efficiencies(EE) of 57.9% and 64.6%,respectively,at a current density of 250 mA cm^(-2).These results are 18.6% and 8.9% higher than those of VRFB with electrode containing graphitic-N and pyridinicN groups.Interestingly,TNGF-based VRFB still operated with an EE of 59% at a high current density of300 mA cm^(-2).The TNGF-based VRFB exhibited stable cycling performance without noticeable decay of EE over 450 charge-discharge cycles at a current density of 250 mA cm^(-2).The results of this study suggest that introducing pyridonic-N and nitro groups on the electrode is effective for improving the electrochemical performance of VRFBs.
文摘The reaction of 3-nitro-4-chlorobenzenesulfinic acid and ethylene oxide to obtain 2-nitro-4-（β-hydroxyethylsulfonyl）chlorobenzene had been studied. Except hydroxyethylation on the sulfur atom of 3-nitro-4-chlorobenzenesulfinic acid to form the target product, 2-nitro-4-（β- hydroxyethylsulfonyl）chlorobenzene, there presented three kinds of side reactions： 1. Condensation and elimination of HCI to form biphenyl sulfone derivatives; 2. Addition to give bisulfonyl ethane derivative via vinyl sulfone; and 3. Hydroxylethylation on O-atom to produce hydroxylethylsulfinate due to the tautomerism of sulfinic acid.
基金supported by the Prospective Research Funds of Jiangsu Provincial Department of Science and Technology (No. BY2015049-02)the Open-end Funds of Jiangsu Key Laboratory of Marine Biotechnology, Huaihai Institute of Technology, (No. 2014HS005)the Funds of Technology Research of Lianyungang (No. CG1301)
文摘Intermolecular Stetter reaction of aromatic aldehydes with（E）-（2-nitrovinyl）cyclohexane catalyzed by thiazolium A has been developed.The reaction rate and efficiency are profoundly impacted by the presence of thiourea B.The reaction affords moderate to good yields of the Stetter product.Some factors influencing yield were discussed.
文摘Poly ethylene glycols (PEG-200, 400, 600, 4000 and 6000) supported reactions were conducted with certain α, β-unsaturated acids in presence of metal nitrates under solvent free (solid state) and mineral acid free conditions. The reactants were ground in a mortar with a pestle for about 30 minutes. The aromatic acids underwent nitro decarboxylation and afforded β-nitro styrene derivatives in very good yield while α, β-unsaturated aliphatic carboxylic acids gave corresponding nitro derivatives. Addition of PEG accelerated rate of the reaction enormously. Reaction times substantially decreased from several hours to few minutes followed by highly significant increase in the product yield. Among the several PEGs PEG-300 has been found to be much more effective than other PEGs.
基金We thank the National Natural Science Foundation of China(NO．20172007)for financial support
文摘Methyluracil and 5-nitro-6-methyluracil react with variable molar quantities of benzoyl chloride in acetonitrile-pyridine at room temperature to give 1-N, 3-N-dibenzoyl-6- methyluracil 3b and 1-N-benzoyl-5-nitro-6-methyluracil 4b. The reactive rates of debenzoylation of 3b and 4b were investigated.
文摘Dinitropyrenes (DNP) were prepared by nitration of pyrene, and the product was characterized by MS and elemental analysis. Three isomers of DNP were separated by HPLC and identified by 1H-NMR. The eating sequence on the normal phase column is 1, 3-DNP, 1, 6-DNP and 1, 8-DNP, whereas is 1, 6-DNP, 1. 8-DNP and 1. 3-DNP on the reversed phase column. The separation of three DNP isomers under different chromatographic conditions was also discussed.
文摘UHF-SCF-AM1 MO calculations were performed for two kinds of pyrolysis reactions of seven nitro derivatives of methylbenzene(homolysis reactions by the rupture of bond C-NO_2 into radicals and isomerization reactions in the way of methyl H transferring to the ortho nitro O atom). The molecular geometries of the reactants, the transition states and the products of the fourteen reactions were fully optimized. The activation energies for these two kinds of reactions have been obtained. The results indicate that this category of compounds is more easily pyrolyzed by being initiated via isomerization reactions. A parallel relationship exists between the activation energy of the isomerization reactions and the impact sensitivity of the seven titled compounds.
