To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density funct...To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density functional theory(DFT)approach to design a high-efficiency catalyst for the selective electrocatalytic upgrading of vanillin via hydrodeoxygenation(HDO).The optimal pyridinic and pyrrolic nitrogen carbon transition metal(TM)-based monolayers exhibit excellent activity for producing2-methoxy-4-methylphenol(MMP)from vanillin.The pyridinic and pyrrolic nitrogen carbon substrates can provide unique sites to support TM atoms,and TM-pyridinic or pyrrolic N moieties serve as catalytic activity sites for the electrocatalytic upgrading of vanillin.Our DFT calculations suggest that the pyridinic N@TM(TM=Zr,Ru,Rh,Os and Ir)and pyrrolic N@TM(TM=Rh and Os)catalysts possess high activity for MMP synthesized from vanillin,and they have a relatively small limiting potential(U_(L))of the rate-determining step.A new route reaction path was used to explore the activity of metal nitrogendoped carbon catalysts,finding that a single metal atom through strong electron correlation between metal and N_(4)C_(8)sites can improve the activity of the vanillin HDO process.Our results show that pyridinic N@Ir and pyrrolic N@Rh with limiting potential(U_(L))of 0.04 and 0.29 V are the most preferable candidate catalysts for the vanillin HDO process.The high stability and relatively low|U_(L)|for vanillin electrocatalytic upgrading are the best candidate electrocatalysts.This work proposes new ideas for designing and developing novel catalysts for selective HDO of biomass under real conditions.展开更多
Pyridinic N is widely regarded as the active center while pyrrolic N has low‐activity in metal‐free N‐doped carbon for electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to CO,but this viewpoint remains open to qu...Pyridinic N is widely regarded as the active center while pyrrolic N has low‐activity in metal‐free N‐doped carbon for electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to CO,but this viewpoint remains open to question.In this study,through density functional theoretical calculations,we first illustrate that the intrinsic activity of pyrrolic N is high enough for effectively catalyzing CO_(2)RR,however,due to the interplay with the neighboring pyridinic N sites,the activity of pyrrolic N is dramatically suppressed.Then,experimentally,metal‐free N‐doped carbon spheres(NCS)electrocatalysts without significant pyridinic N content are prepared for CO_(2)RR.The pyrrolic N in NCS shows a direct‐positive correlation with the performance for CO_(2)RR,representing the active center with high activity.The optimum NCS could produce syngas with a wide range of CO/H_(2) ratio(0.09 to 12)in CO_(2)RR depending on the applied potential,meanwhile,the best selectivity of 71%for CO can be obtained.Intentionally adding a small amount of pyridinic N to the optimum NCS dramatically decreases the activity for CO_(2)RR,further verifying the suppressed activity of pyrrolic N sites by the neighboring pyridinic N sites.This work reveals the interaction between a variety of N species in N‐doped carbon,and the potential of pyrrolic N as the new type of active site for electrocatalysts,which can improve our understanding of the electrocatalysis mechanism and be helpful for the rational design of high‐efficient electrocatalysts.展开更多
Carbon dots(CDs)with solvatochromic emission colors in different solvents have attracted much attention as a new class of luminescent nanomaterial owing to their facile synthesis and low production cost.In this work,w...Carbon dots(CDs)with solvatochromic emission colors in different solvents have attracted much attention as a new class of luminescent nanomaterial owing to their facile synthesis and low production cost.In this work,we prepared two kinds of CDs with solvatochromic emissions:green emission CDs(G-CDs)and multicolor emission CDs(M-CDs).G-CDs synthesized from o-phenylenediamine exhibited weak photoluminescence emission(quantum yield 2.8%-6.1%)and 39 nm solvatochromic shifts(492-531 nm).In contrast,M-CDs prepared from o-phenylenediamine and 4-aminophenol showed 87 nm solvatochromic shift range(505-592 nm)and much higher photoluminescence quantum yield(18.4%-32.5%).The two CDs exhibited different emission,absorption,and photoluminescence lifetime.The origin of solvatochromic shifts and the formation mechanism of CDs were demonstrated by analyzing the structures and compositions of two CDs.High percentages of pyrrolic nitrogen and amino nitrogen make wider solvatochromic shifts and higher quantum yields.The results were well supported by density functional theory calculations.This effective strategy to expand solvatochromic shift range and improve quantum yields could open a new window to prepare satisfied solvatochromic carbon dots.展开更多
Pyrrole is a heterocycle with four carbon atoms and a nitrogen atom,which is extensively used in the pesticide and pharmaceutical industries.In addition,it has a series of analogs such as pyrrolidine,pyrroline,and pyr...Pyrrole is a heterocycle with four carbon atoms and a nitrogen atom,which is extensively used in the pesticide and pharmaceutical industries.In addition,it has a series of analogs such as pyrrolidine,pyrroline,and pyrrolidone.Pesticides containing pyrrole and its analogs have been formally marketed as fungicides,including fenpiclonil,fludioxonil,the insecticide chlorfenapyr,and the herbicide fluorochloridone.In this paper,we analyze the structure-activity relationships(SARs)of pesticides containing these structures.We summarize the characteristics possessed by the most highly active pyrrole and its analogs and provide an overview of research on pyrrole compounds with insecticidal,antimicrobial,herbicidal,and antiviral properties in the past 20 years.It is hoped to provide ideas for the development and design of this type compounds in pesticides and to assist researchers in this area.展开更多
Pyrrolo[3,2-b]pyrrole is a good building block for radical photoini-tiators.In this study,free-radical photoinitiator 1,4-bis(4-bro-mophenyl)-2,5-bis(4-(trifluo-romethyl)phenyl)-1,4-dihydropy-rrolo[3,2-b]pyrrole(PyBF)...Pyrrolo[3,2-b]pyrrole is a good building block for radical photoini-tiators.In this study,free-radical photoinitiator 1,4-bis(4-bro-mophenyl)-2,5-bis(4-(trifluo-romethyl)phenyl)-1,4-dihydropy-rrolo[3,2-b]pyrrole(PyBF),con-taining a symmetric trifluo-romethyl(-CF3)end group,is syn-thesized via a one-step aldehyde-ketone condensation re-action for light-emitting diode(LED)photopolymerization.The-CF3 groups are incorporated into the 2,5-phenyl on the pyrrolo[3,2-b]pyrrole core.PyBF rapidly initiates the photopolymerization of acrylate pre-polymers and monomers under LED illumination at 365 and 405 nm.A possible photolysis mechanism is provided.In the presence of amines,PyBF increases the gel fraction rate of polyethylene glycol diacrylate(PEGDA)from 63.4%to 80.0%,indicating good potential as a two-component photoinitiator.PyBF exhibits a thermal decomposition temperature in an ex-cess of 300℃,comparable to that of a commercial photoinitiator(diphenyl(2,4,6-trimethyl-benzoyl)phosphine oxide,TPO),indicating its thermal stability.PyBF shows low migration in light-curing materials.Scanning electron microscopy images indicate that the materials of the PyBF/TPO/PEGDA mixture cured using the PyBF/TPO two-component photoinitia-tor system exhibit a smooth surface,in contrast to those cured with PyBF/PEGDA and TPO/PEGDA systems.The cured materials also display low curing shrinkage.Therefore,the pyrrolo[3,2-b]pyrrole radical photoinitiator exhibits high photoactivity in visible-light pho-topolymerization reactions.展开更多
This is a report of the differences in abundances of pyrrolic nitrogen compounds and distribution of alkylated carbazoles among various oils from the Tarim Basin. At the same time, their geochemical significance is di...This is a report of the differences in abundances of pyrrolic nitrogen compounds and distribution of alkylated carbazoles among various oils from the Tarim Basin. At the same time, their geochemical significance is discussed.展开更多
Pyrroles are important structural units of natural products,drug molecules,biomolecules and functional material molecules.Efficient synthesis ofα-functionalized pyrroles with different substituents from easily access...Pyrroles are important structural units of natural products,drug molecules,biomolecules and functional material molecules.Efficient synthesis ofα-functionalized pyrroles with different substituents from easily accessible starting materials is still challenging.Herein,a facile and regioselective coarctate reaction of enynals involving a free carbene intermediate has been developed,which allows the divergent and practical de novo synthesis of variousα-furanyl pyrroles andα-cyclopropenyl pyrroles derivatives with good to excellent yields and high efficiency under mild conditions.This approach features readily accessible starting materials,high functional group compatibility,step economy and scalability,which would complement previous methods and support expansion of the toolbox for the synthesis of valuable,but previously inaccessible,highly substituted and electron-richα-functionalized pyrroles.展开更多
The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS s...The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.展开更多
The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and...The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in studying petroleum migration of paleo-pool. During the basin＇s first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin （at the end of Silurian period） and the second-stage in the Awati area （in Permian）, the petroleum experienced a long-distance migration. During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian, the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag. The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first. Then, it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong. In Tabei Uplift, during the first-stage of pool formation, the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag. It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly, and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions. During the second-stage pool formation in the Silurian beds in the areas around Awati sag, the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag. The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths, and the petroleum was finally trapped in higher locations.展开更多
Carbazole compounds in crude oils from the Tazhong uplift of the Tarim basin have been fractionated and detected and successfully used to study petroleum migration and trace source rocks in the study area. Alkylcarbaz...Carbazole compounds in crude oils from the Tazhong uplift of the Tarim basin have been fractionated and detected and successfully used to study petroleum migration and trace source rocks in the study area. Alkylcarbazoles have been found in large amounts in the oil samples analyzed and alkylbenzocarbazoles detected in a small concentration only in part of the samples, but alkyldibenzocarbazoles have not been found in oils. Based on the distribution of G1, G2 and G3 of C2-alkylcarbazoles, the ratio of C3-carbazoles to C2-carbazoles and the relative amounts of alkylcarbazoles and alkylbenzocarbazoles, one can know that the vertical oil migration in the Tazhong uplift is generally from below upward, i.e. from the Ordovician through the Silurian to the Carboniferous. Evidently, source rocks in the uplift should be lower Palaeozoic strata (Ordovician and Cambrian). This study shows that carbazoles are of great importance in the study of petroleum migration and source rocks.展开更多
Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carb...Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carbon materials show great potential for potassium-ion storage,poor rate performance,and unsatisfactory cycle lifespan in existing carbon-based PIBs anode,it also cannot match the dynamics and stability of the capacitor cathode.Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials.Hence,we prepare carbon nanofibers and g-C_(3)N_(4)composites with high nitrogen contents(19.78 at%);moreover,the sum of pyrrolic N and pyridinic N is up to 59.51%.It achieves high discharge capacity(391 m Ah g^(-1)at0.05 A g^(-1)),rate capacity(141 m Ah g^(-1)at 2 A g^(-1)),and long cycling performance(201 m Ah g^(-1)at 1 A g^(-1)over 3000 cycles)when as an anode for PIBs.Furthermore,it can deliver promising discharge capacity of132 m Ah g^(-1)at 0℃.Moreover,as battery anode for potassium-ion hybrid capacitors(PIHC)device with an active carbon cathode,it delivers energy/power density(62 and 2102 W kg^(-1))as well as high reversible capacity(106 m Ah g^(-1)at 1 A g^(-1)).展开更多
Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and on...Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed,leading to great challenges to identify the real active sites on the electrode.In this work,Ti/TiO_(2)-based electrodes calcined under air,nitrogen,or urea atmospheres were selected as electrocatalysts for two-electron water oxidation.Electrochemical analyses were applied to evaluate the catalytic activity and selectivity.The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy,while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering.The results demonstrated that Ti/TiO_(2) nanotube arrays served as the support,while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H_(2)O_(2) production.This finding provided a new horizon to design efficient catalysts for H_(2)O_(2) production.展开更多
In-depth exploration of the relationship among different adsorption sites is conducive to design of efficient adsorbents for target pollutants removal from water.In this study,the experiments,multivariate non-linear r...In-depth exploration of the relationship among different adsorption sites is conducive to design of efficient adsorbents for target pollutants removal from water.In this study,the experiments,multivariate non-linear regression and density functional theory calculations are applied to explore the possible synergistic effects of three nitrogen(N)-containing sites on cow dung biochar surface for sulfamethoxazole(SMX)adsorption.Notably,a strong synergistic effect between pyridinic N and pyrrolic N sites was found for sulfamethoxazole adsorption.The adsorption energies of SMX on four pyrrolic N-coupled pyridinic N structures were-1.02,-0.41,-0.49 and-0.72 e V,much higher than the sum of adsorption energies(-0.31 e V)on pyrrolic N and pyridinic N.Besides,the alteration of Mulliken charge revealed that the simultaneous presence of pyridinic N and pyrrolic N improved the electron transfer remarkably from-0.459 e and 0.094 e to-0.649 e and 0.186 e,benefiting for SMX adsorption.This work firstly explored the possible synergies of adsorption sites on biochar surface for organic contaminants removal from water,which shed new lights on the adsorption mechanism and provided valuable information to design efficient adsorbents in the field of water treatment.展开更多
Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
With home-made multi-walled carbon nanotubes （MWCNTs, simplified as CNTs in later text） as support, CNT-supported Co-Mo-S catalysts, denoted as x%（mass percentage）MoiCoj/CNTs, were prepared. Their catalytic perfor...With home-made multi-walled carbon nanotubes （MWCNTs, simplified as CNTs in later text） as support, CNT-supported Co-Mo-S catalysts, denoted as x%（mass percentage）MoiCoj/CNTs, were prepared. Their catalytic performance for thiophene hydrodesulfurization （HDS） and pyrrole hydrodenitrification （HDN） reactions was studied, and compared with the reference system sup- ported by AC. Over the 7.24%Mo3Co1/CNTs catalyst at reaction condition of 1.5 MPa, 613 K, C4H4S/H2=3.7/96.3（molar ratio） and GHSV≈8000 mlswP/（g-cat.h）, the specific HDS activity of thiophene reached 3.29 mmolc4H4S/（s.molMo）, which was 1.32 times as high as that （2.49 mmolc4H4S/（s.molMo）） of the AC-based counterpart, and was 2.47 times as high as that （1.33 mmolc4H4S/（s-molMo）） of the catalysts supported by AC with the respective optimal MoaCol-loading amount, 16.90%Mo3Co1/AC. Analogous reaction-chemical behaviours were also observed in the case of pyrrole HDN. It was experimentally found that using the CNTs in place of AC as support of the catalyst caused little change in the apparent activation energy for the thiophene HDS or pyrrole HDN reaction, but led to a significant increase in the concentration of catalytically active Mo-species （Mo^4＋） at the surface of the functioning catalyst. On the other hand, H2-TPD measurements revealed that the CNT-supported catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures ranging from room temperature to about 673 K. This unique feature would help to generate microenvironments with higher stationarystate concentration of active hydrogen-adspecies at the surface of the functioning catalyst. Both factors mentioned above were favorable to increasing the rate of thiophene HDS and pyrrole HDN reactions.展开更多
A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition.Macroporous strongly acidic styrol resin(D001) as a novel,...A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition.Macroporous strongly acidic styrol resin(D001) as a novel,efficient,cost-effective,and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions.The pyrroles were obtained in high yields in short reaction times.展开更多
Several 2,5-dimethyl-N-substituted pyrroles were prepared by the condensation of different substituted anilines with 2,5- hexanedione using nano lead oxide as an efficient and recyclable catalyst.All the synthesized c...Several 2,5-dimethyl-N-substituted pyrroles were prepared by the condensation of different substituted anilines with 2,5- hexanedione using nano lead oxide as an efficient and recyclable catalyst.All the synthesized compounds are confirmed through IR, ~1H NMR,^（13）C NMR and mass spectral data.Nano lead oxide β-PbO（P85） was prepared by dissolving lead acetate dihydrate in 1- propanol at a pH 9.0 under stirring at 85℃.The structural study and surface morphology of the lead oxide（PbO） were characterized using X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and the functional groups of the PbO sample were investigated using infrared spectrophotometer.展开更多
Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages fo...Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages form this loop by secreting SDF-1 and TGF-β and the impacts of neotuberostemonine(NTS)and tuberostemonine(TS).Mice were intratracheally injected with 3 U·kg^(-1)bleomycin and orally administered with 30 mg·kg^(-1)NTS or TS.Primary pulmonary fibroblasts(PFBs)and MH-S cells(alveolar macrophages)were used in vitro.The animal experiments showed that NTS and TS improved fibrosis related indicators,inhibited fibroblast activation and macrophage M2 polarization,and reduced the levels of TGF-β and SDF-1 in alveolar lavage fluid.Cell experiments showed that TGF-β1 may activated fibroblasts into myofibroblasts secreting SDF-1 by activating the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1αpathways.It was also found for the first time that SDF-1 was able to directly polarize macrophages into M2 phenotype secreting TGF-β through the same pathways as mentioned above.Moreover,the results of the cell coculture confirmed that fibroblasts and macrophages actually developed a feedback loop to promote fibrosis,and the secretion of TGF-β and SDF-1 was crucial for maintaining this loop.NTS and TS may disturb this loop through inhibiting both the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1α pathways to improve pulmonary fibrosis.NTS and TS are stereoisomeric alkaloids with pyrrole[1,2-ajazapine skeleton,and their effect on improving pulmonary fibrosis may be largely attributed to their parent nucleus.Moreover,this study found that inhibition of both the AKT and ERK pathways is essential for maximizing the improvement of pulmonary fibrosis.展开更多
The electrochemical performance of lithium-sulfur(Li-S)batteries is strongly hampered by the shuttle effect and slow redox kinetics of lithium polysulfides(Li PSs).Surface modified interlayer of a separator of Li-S ba...The electrochemical performance of lithium-sulfur(Li-S)batteries is strongly hampered by the shuttle effect and slow redox kinetics of lithium polysulfides(Li PSs).Surface modified interlayer of a separator of Li-S batteries is demonstrated to be an effective strategy to overcome this problem.Herein,cobalt nanoparticles confined in nitrogen co-doped porous carbon framework(Co-CN)were developed from pyrolysis of ZIF-67 and used as interlayer of PP separator for Li-S batteries,and were functionalized by four pyrrole derivatives,1-phenylpyrrole,1-methyl pyrrole,1-(p-toluenesulfonyl)pyrrole,and 1-pyrrole,respectively,which were screened in terms of the electron-withdrawing/donating ability of the substituent groups on the pyrrolic nitrogen.The impact of the molecular structure of pyrrole derivatives on the interaction with Li PSs and the electrochemical performance of Li-S batteries were explored by nuclear magnetic resonance and theoretical calculation.It is uncovered that 1-phenylpyrrole shows the highest enhancement of redox kinetics of Li PSs,attributing to the optimal interaction with Co nanoparticles and Li PSs.Therefore,1-phenylpyrrole modified Co-CN interlayer enables the best electrochemical performance for the Li-S batteries,delivering a specific capacity of 562 m Ah g^(-1)at 5 C and a capacity of 538,526,and 449 m Ah g^(-1)after 500 cycles at 1,2,and 3 C,respectively.At a high sulfur loading of 5.5 mg cm^(-2),it achieves a capacity of 440 m Ah g^(-1)after 500 cycles at 1 C.This work reveals the interaction mechanism among Li PSs,Co nanoparticles and the molecular modifiers in improving the electrochemical performance of Li-S batteries.展开更多
基金financially supported by the National Key R&D Program of China(No.2022YFA1505700)the National Natural Science Foundation of China(Nos.22205232,51971157 and 21601187)+2 种基金the Natural Science Foundation of Fujian Province(No.2023J01310231)XinJiang Tianshan Talent Program(No.2022SNGGNT104)support by High-performance Computing Platform of Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China。
文摘To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density functional theory(DFT)approach to design a high-efficiency catalyst for the selective electrocatalytic upgrading of vanillin via hydrodeoxygenation(HDO).The optimal pyridinic and pyrrolic nitrogen carbon transition metal(TM)-based monolayers exhibit excellent activity for producing2-methoxy-4-methylphenol(MMP)from vanillin.The pyridinic and pyrrolic nitrogen carbon substrates can provide unique sites to support TM atoms,and TM-pyridinic or pyrrolic N moieties serve as catalytic activity sites for the electrocatalytic upgrading of vanillin.Our DFT calculations suggest that the pyridinic N@TM(TM=Zr,Ru,Rh,Os and Ir)and pyrrolic N@TM(TM=Rh and Os)catalysts possess high activity for MMP synthesized from vanillin,and they have a relatively small limiting potential(U_(L))of the rate-determining step.A new route reaction path was used to explore the activity of metal nitrogendoped carbon catalysts,finding that a single metal atom through strong electron correlation between metal and N_(4)C_(8)sites can improve the activity of the vanillin HDO process.Our results show that pyridinic N@Ir and pyrrolic N@Rh with limiting potential(U_(L))of 0.04 and 0.29 V are the most preferable candidate catalysts for the vanillin HDO process.The high stability and relatively low|U_(L)|for vanillin electrocatalytic upgrading are the best candidate electrocatalysts.This work proposes new ideas for designing and developing novel catalysts for selective HDO of biomass under real conditions.
文摘Pyridinic N is widely regarded as the active center while pyrrolic N has low‐activity in metal‐free N‐doped carbon for electrocatalytic CO_(2) reduction reaction(CO_(2)RR)to CO,but this viewpoint remains open to question.In this study,through density functional theoretical calculations,we first illustrate that the intrinsic activity of pyrrolic N is high enough for effectively catalyzing CO_(2)RR,however,due to the interplay with the neighboring pyridinic N sites,the activity of pyrrolic N is dramatically suppressed.Then,experimentally,metal‐free N‐doped carbon spheres(NCS)electrocatalysts without significant pyridinic N content are prepared for CO_(2)RR.The pyrrolic N in NCS shows a direct‐positive correlation with the performance for CO_(2)RR,representing the active center with high activity.The optimum NCS could produce syngas with a wide range of CO/H_(2) ratio(0.09 to 12)in CO_(2)RR depending on the applied potential,meanwhile,the best selectivity of 71%for CO can be obtained.Intentionally adding a small amount of pyridinic N to the optimum NCS dramatically decreases the activity for CO_(2)RR,further verifying the suppressed activity of pyrrolic N sites by the neighboring pyridinic N sites.This work reveals the interaction between a variety of N species in N‐doped carbon,and the potential of pyrrolic N as the new type of active site for electrocatalysts,which can improve our understanding of the electrocatalysis mechanism and be helpful for the rational design of high‐efficient electrocatalysts.
基金We appreciate the financial supports from the Board or Regent Supporting Fund(BORSF)Endowed Professorshipthe Lousiana State University Shreveport(LSUS)R&D Funds+1 种基金the Qingdao Municipal Science and Technology Commission(No.16-5-1-86-jch)the Scientific Research Foundation of Qingdao University of Science and Technology(QUST)(No.210/010022914).
文摘Carbon dots(CDs)with solvatochromic emission colors in different solvents have attracted much attention as a new class of luminescent nanomaterial owing to their facile synthesis and low production cost.In this work,we prepared two kinds of CDs with solvatochromic emissions:green emission CDs(G-CDs)and multicolor emission CDs(M-CDs).G-CDs synthesized from o-phenylenediamine exhibited weak photoluminescence emission(quantum yield 2.8%-6.1%)and 39 nm solvatochromic shifts(492-531 nm).In contrast,M-CDs prepared from o-phenylenediamine and 4-aminophenol showed 87 nm solvatochromic shift range(505-592 nm)and much higher photoluminescence quantum yield(18.4%-32.5%).The two CDs exhibited different emission,absorption,and photoluminescence lifetime.The origin of solvatochromic shifts and the formation mechanism of CDs were demonstrated by analyzing the structures and compositions of two CDs.High percentages of pyrrolic nitrogen and amino nitrogen make wider solvatochromic shifts and higher quantum yields.The results were well supported by density functional theory calculations.This effective strategy to expand solvatochromic shift range and improve quantum yields could open a new window to prepare satisfied solvatochromic carbon dots.
基金financial support from the National Natural Science Foundation of China(No.32072445)the Science and Technology Plan Project of Guizhou Province(Qiankehezhicheng[2024]the general 083)+5 种基金the Program of Introducing Talents to Chinese Universities(No.D20023)the Central Government Guides Local Science and Technology Development Fund Projects(Qiankehezhongyindi(2023)001)Key Agricultural Technology R&D Projects of the Xinjiang Production and Construction Corps(NYHXGG,2023AA602)the Frontiers Science Centre for Asymmetric Synthesis and Medicinal Molecules,Department of Education,Guizhou Province[Qianjiaohe KY(2020)004]the specific research fund of The Innovation Platform for Academicians of Hainan Province(No.SQ2020PTZ0009)。
文摘Pyrrole is a heterocycle with four carbon atoms and a nitrogen atom,which is extensively used in the pesticide and pharmaceutical industries.In addition,it has a series of analogs such as pyrrolidine,pyrroline,and pyrrolidone.Pesticides containing pyrrole and its analogs have been formally marketed as fungicides,including fenpiclonil,fludioxonil,the insecticide chlorfenapyr,and the herbicide fluorochloridone.In this paper,we analyze the structure-activity relationships(SARs)of pesticides containing these structures.We summarize the characteristics possessed by the most highly active pyrrole and its analogs and provide an overview of research on pyrrole compounds with insecticidal,antimicrobial,herbicidal,and antiviral properties in the past 20 years.It is hoped to provide ideas for the development and design of this type compounds in pesticides and to assist researchers in this area.
基金the financial support of the Tianjin Technical Expert Project(22YDTPJC00620)。
文摘Pyrrolo[3,2-b]pyrrole is a good building block for radical photoini-tiators.In this study,free-radical photoinitiator 1,4-bis(4-bro-mophenyl)-2,5-bis(4-(trifluo-romethyl)phenyl)-1,4-dihydropy-rrolo[3,2-b]pyrrole(PyBF),con-taining a symmetric trifluo-romethyl(-CF3)end group,is syn-thesized via a one-step aldehyde-ketone condensation re-action for light-emitting diode(LED)photopolymerization.The-CF3 groups are incorporated into the 2,5-phenyl on the pyrrolo[3,2-b]pyrrole core.PyBF rapidly initiates the photopolymerization of acrylate pre-polymers and monomers under LED illumination at 365 and 405 nm.A possible photolysis mechanism is provided.In the presence of amines,PyBF increases the gel fraction rate of polyethylene glycol diacrylate(PEGDA)from 63.4%to 80.0%,indicating good potential as a two-component photoinitiator.PyBF exhibits a thermal decomposition temperature in an ex-cess of 300℃,comparable to that of a commercial photoinitiator(diphenyl(2,4,6-trimethyl-benzoyl)phosphine oxide,TPO),indicating its thermal stability.PyBF shows low migration in light-curing materials.Scanning electron microscopy images indicate that the materials of the PyBF/TPO/PEGDA mixture cured using the PyBF/TPO two-component photoinitia-tor system exhibit a smooth surface,in contrast to those cured with PyBF/PEGDA and TPO/PEGDA systems.The cured materials also display low curing shrinkage.Therefore,the pyrrolo[3,2-b]pyrrole radical photoinitiator exhibits high photoactivity in visible-light pho-topolymerization reactions.
文摘This is a report of the differences in abundances of pyrrolic nitrogen compounds and distribution of alkylated carbazoles among various oils from the Tarim Basin. At the same time, their geochemical significance is discussed.
基金the National Natural Science Foundation of China(Nos.22071062 and 22271096)the Fundamental Research Funds for the Central Universities,SCUT(No.2022ZYGXZR107)funded by the National Postdoctoral Research Program(No.GZC20230839)。
文摘Pyrroles are important structural units of natural products,drug molecules,biomolecules and functional material molecules.Efficient synthesis ofα-functionalized pyrroles with different substituents from easily accessible starting materials is still challenging.Herein,a facile and regioselective coarctate reaction of enynals involving a free carbene intermediate has been developed,which allows the divergent and practical de novo synthesis of variousα-furanyl pyrroles andα-cyclopropenyl pyrroles derivatives with good to excellent yields and high efficiency under mild conditions.This approach features readily accessible starting materials,high functional group compatibility,step economy and scalability,which would complement previous methods and support expansion of the toolbox for the synthesis of valuable,but previously inaccessible,highly substituted and electron-richα-functionalized pyrroles.
基金Project supported by the Shandong Provincial Natural Science Foundation,China(Grant Nos.ZR2022MA025 and ZR2020MA077).
文摘The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.
文摘The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in studying petroleum migration of paleo-pool. During the basin＇s first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin （at the end of Silurian period） and the second-stage in the Awati area （in Permian）, the petroleum experienced a long-distance migration. During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian, the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag. The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first. Then, it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong. In Tabei Uplift, during the first-stage of pool formation, the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag. It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly, and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions. During the second-stage pool formation in the Silurian beds in the areas around Awati sag, the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag. The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths, and the petroleum was finally trapped in higher locations.
基金This study was partially supported by the State Educational Commission Foundation for Returned Students.
文摘Carbazole compounds in crude oils from the Tazhong uplift of the Tarim basin have been fractionated and detected and successfully used to study petroleum migration and trace source rocks in the study area. Alkylcarbazoles have been found in large amounts in the oil samples analyzed and alkylbenzocarbazoles detected in a small concentration only in part of the samples, but alkyldibenzocarbazoles have not been found in oils. Based on the distribution of G1, G2 and G3 of C2-alkylcarbazoles, the ratio of C3-carbazoles to C2-carbazoles and the relative amounts of alkylcarbazoles and alkylbenzocarbazoles, one can know that the vertical oil migration in the Tazhong uplift is generally from below upward, i.e. from the Ordovician through the Silurian to the Carboniferous. Evidently, source rocks in the uplift should be lower Palaeozoic strata (Ordovician and Cambrian). This study shows that carbazoles are of great importance in the study of petroleum migration and source rocks.
基金supported by the National Natural Science Foundation of China(Grants 51772082,51574117,and 51804106)the Research Projects of Degree and Graduate Education Teaching Reformation in Hunan Province(JG2018B031)+2 种基金the Natural Science Foundation of Hunan Province(2019JJ30002,2019JJ50061)the Guangdong Basic and Applied Basic Research Foundation(No.2019B151502045)the National Natural Science Foundation of China(Nos.51802361,51972351)
文摘Potassium-based energy storage devices(PEDS)are considered as hopeful candidates for energy storage applications because of the abundant potassium resources in nature and high mobility in the electrolyte.although carbon materials show great potential for potassium-ion storage,poor rate performance,and unsatisfactory cycle lifespan in existing carbon-based PIBs anode,it also cannot match the dynamics and stability of the capacitor cathode.Nitrogen doping has been proven to be a effective modification strategy to improve the electrochemical performance of carbon materials.Hence,we prepare carbon nanofibers and g-C_(3)N_(4)composites with high nitrogen contents(19.78 at%);moreover,the sum of pyrrolic N and pyridinic N is up to 59.51%.It achieves high discharge capacity(391 m Ah g^(-1)at0.05 A g^(-1)),rate capacity(141 m Ah g^(-1)at 2 A g^(-1)),and long cycling performance(201 m Ah g^(-1)at 1 A g^(-1)over 3000 cycles)when as an anode for PIBs.Furthermore,it can deliver promising discharge capacity of132 m Ah g^(-1)at 0℃.Moreover,as battery anode for potassium-ion hybrid capacitors(PIHC)device with an active carbon cathode,it delivers energy/power density(62 and 2102 W kg^(-1))as well as high reversible capacity(106 m Ah g^(-1)at 1 A g^(-1)).
基金Project(2021JJ30792) supported by the Natural Science Foundation of Hunan Province,ChinaProject(52170031) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China。
文摘Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed,leading to great challenges to identify the real active sites on the electrode.In this work,Ti/TiO_(2)-based electrodes calcined under air,nitrogen,or urea atmospheres were selected as electrocatalysts for two-electron water oxidation.Electrochemical analyses were applied to evaluate the catalytic activity and selectivity.The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy,while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering.The results demonstrated that Ti/TiO_(2) nanotube arrays served as the support,while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H_(2)O_(2) production.This finding provided a new horizon to design efficient catalysts for H_(2)O_(2) production.
基金the National Natural Science Foundation of China(No.52100156)Natural Science Foundation of Tianjin(No.21JCQNJC00400)Shenzhen Science and Technology Program(Nos.GJHZ20200731095801005 and JCYJ20200109150210400)for offering financial support to this research。
文摘In-depth exploration of the relationship among different adsorption sites is conducive to design of efficient adsorbents for target pollutants removal from water.In this study,the experiments,multivariate non-linear regression and density functional theory calculations are applied to explore the possible synergistic effects of three nitrogen(N)-containing sites on cow dung biochar surface for sulfamethoxazole(SMX)adsorption.Notably,a strong synergistic effect between pyridinic N and pyrrolic N sites was found for sulfamethoxazole adsorption.The adsorption energies of SMX on four pyrrolic N-coupled pyridinic N structures were-1.02,-0.41,-0.49 and-0.72 e V,much higher than the sum of adsorption energies(-0.31 e V)on pyrrolic N and pyridinic N.Besides,the alteration of Mulliken charge revealed that the simultaneous presence of pyridinic N and pyrrolic N improved the electron transfer remarkably from-0.459 e and 0.094 e to-0.649 e and 0.186 e,benefiting for SMX adsorption.This work firstly explored the possible synergies of adsorption sites on biochar surface for organic contaminants removal from water,which shed new lights on the adsorption mechanism and provided valuable information to design efficient adsorbents in the field of water treatment.
基金support by the Natural Science Foundation of Zhejiang Province(No.Y4051137,Y405015 and Y4080177)
文摘Michael addition of indole and pyrrole to a variety of α, β-unsaturated ketones was efficiently promoted by a catalytic amount of GaCl3 in aqueous media to afford the corresponding products in good to excellent yields.
基金Supported by National Natural Science Foundation of China (No. 20473063 and No. 20590364).
文摘With home-made multi-walled carbon nanotubes （MWCNTs, simplified as CNTs in later text） as support, CNT-supported Co-Mo-S catalysts, denoted as x%（mass percentage）MoiCoj/CNTs, were prepared. Their catalytic performance for thiophene hydrodesulfurization （HDS） and pyrrole hydrodenitrification （HDN） reactions was studied, and compared with the reference system sup- ported by AC. Over the 7.24%Mo3Co1/CNTs catalyst at reaction condition of 1.5 MPa, 613 K, C4H4S/H2=3.7/96.3（molar ratio） and GHSV≈8000 mlswP/（g-cat.h）, the specific HDS activity of thiophene reached 3.29 mmolc4H4S/（s.molMo）, which was 1.32 times as high as that （2.49 mmolc4H4S/（s.molMo）） of the AC-based counterpart, and was 2.47 times as high as that （1.33 mmolc4H4S/（s-molMo）） of the catalysts supported by AC with the respective optimal MoaCol-loading amount, 16.90%Mo3Co1/AC. Analogous reaction-chemical behaviours were also observed in the case of pyrrole HDN. It was experimentally found that using the CNTs in place of AC as support of the catalyst caused little change in the apparent activation energy for the thiophene HDS or pyrrole HDN reaction, but led to a significant increase in the concentration of catalytically active Mo-species （Mo^4＋） at the surface of the functioning catalyst. On the other hand, H2-TPD measurements revealed that the CNT-supported catalyst could reversibly adsorb a greater amount of hydrogen under atmospheric pressure at temperatures ranging from room temperature to about 673 K. This unique feature would help to generate microenvironments with higher stationarystate concentration of active hydrogen-adspecies at the surface of the functioning catalyst. Both factors mentioned above were favorable to increasing the rate of thiophene HDS and pyrrole HDN reactions.
文摘A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition.Macroporous strongly acidic styrol resin(D001) as a novel,efficient,cost-effective,and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions.The pyrroles were obtained in high yields in short reaction times.
文摘Several 2,5-dimethyl-N-substituted pyrroles were prepared by the condensation of different substituted anilines with 2,5- hexanedione using nano lead oxide as an efficient and recyclable catalyst.All the synthesized compounds are confirmed through IR, ~1H NMR,^（13）C NMR and mass spectral data.Nano lead oxide β-PbO（P85） was prepared by dissolving lead acetate dihydrate in 1- propanol at a pH 9.0 under stirring at 85℃.The structural study and surface morphology of the lead oxide（PbO） were characterized using X-ray diffraction（XRD）,Scanning electron microscopy（SEM） and the functional groups of the PbO sample were investigated using infrared spectrophotometer.
基金supported by the National Natural Science Foundation of China(No.81873075).
文摘Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop.This study was aimed to investigate whether fibroblasts and macrophages form this loop by secreting SDF-1 and TGF-β and the impacts of neotuberostemonine(NTS)and tuberostemonine(TS).Mice were intratracheally injected with 3 U·kg^(-1)bleomycin and orally administered with 30 mg·kg^(-1)NTS or TS.Primary pulmonary fibroblasts(PFBs)and MH-S cells(alveolar macrophages)were used in vitro.The animal experiments showed that NTS and TS improved fibrosis related indicators,inhibited fibroblast activation and macrophage M2 polarization,and reduced the levels of TGF-β and SDF-1 in alveolar lavage fluid.Cell experiments showed that TGF-β1 may activated fibroblasts into myofibroblasts secreting SDF-1 by activating the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1αpathways.It was also found for the first time that SDF-1 was able to directly polarize macrophages into M2 phenotype secreting TGF-β through the same pathways as mentioned above.Moreover,the results of the cell coculture confirmed that fibroblasts and macrophages actually developed a feedback loop to promote fibrosis,and the secretion of TGF-β and SDF-1 was crucial for maintaining this loop.NTS and TS may disturb this loop through inhibiting both the PI3K/AKT/HIF-1αand PI3K/PAK/RAF/ERK/HIF-1α pathways to improve pulmonary fibrosis.NTS and TS are stereoisomeric alkaloids with pyrrole[1,2-ajazapine skeleton,and their effect on improving pulmonary fibrosis may be largely attributed to their parent nucleus.Moreover,this study found that inhibition of both the AKT and ERK pathways is essential for maximizing the improvement of pulmonary fibrosis.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0206703)the National Natural Science Foundation of China(Grant No.U2032151)。
文摘The electrochemical performance of lithium-sulfur(Li-S)batteries is strongly hampered by the shuttle effect and slow redox kinetics of lithium polysulfides(Li PSs).Surface modified interlayer of a separator of Li-S batteries is demonstrated to be an effective strategy to overcome this problem.Herein,cobalt nanoparticles confined in nitrogen co-doped porous carbon framework(Co-CN)were developed from pyrolysis of ZIF-67 and used as interlayer of PP separator for Li-S batteries,and were functionalized by four pyrrole derivatives,1-phenylpyrrole,1-methyl pyrrole,1-(p-toluenesulfonyl)pyrrole,and 1-pyrrole,respectively,which were screened in terms of the electron-withdrawing/donating ability of the substituent groups on the pyrrolic nitrogen.The impact of the molecular structure of pyrrole derivatives on the interaction with Li PSs and the electrochemical performance of Li-S batteries were explored by nuclear magnetic resonance and theoretical calculation.It is uncovered that 1-phenylpyrrole shows the highest enhancement of redox kinetics of Li PSs,attributing to the optimal interaction with Co nanoparticles and Li PSs.Therefore,1-phenylpyrrole modified Co-CN interlayer enables the best electrochemical performance for the Li-S batteries,delivering a specific capacity of 562 m Ah g^(-1)at 5 C and a capacity of 538,526,and 449 m Ah g^(-1)after 500 cycles at 1,2,and 3 C,respectively.At a high sulfur loading of 5.5 mg cm^(-2),it achieves a capacity of 440 m Ah g^(-1)after 500 cycles at 1 C.This work reveals the interaction mechanism among Li PSs,Co nanoparticles and the molecular modifiers in improving the electrochemical performance of Li-S batteries.
