Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a...Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.展开更多
A new cyclometalated iridium（IlI） complex Ir（DPP）3 （DPP=2,3-diphenylpyrazine） was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confir...A new cyclometalated iridium（IlI） complex Ir（DPP）3 （DPP=2,3-diphenylpyrazine） was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT （singlet metal to ligand charge-transfer） and aMLCT （triplet metal to ligand charge-transfer） absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.展开更多
AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： Th...AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： The short-circuit current （Isc） technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis （RIA） and a special mouse model of cystic fibrosis.RESULTS： IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2＇-dicarboxylic acid （DPC） and glibenclamide, but resistant to 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid disodium salt hydrate （DIDS）. Removal of Na^＋ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^＋ replacement or apical Na^＋ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2＋ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine （[BMX） was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP （1 mmol/L） elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin （10μmol/L）. The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator （CFTR） presenting defective CFTR functions and secretions.CONCLUSION： TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.展开更多
Two pyrazine-containing macrocyclic polyazomethines 2 and 3 were synthesized by direct [2 ＋ 2] and [3 ＋ 3] condensation reactions between 2,21-[pyrazine-2,3-diylbis（oxy）]dibenzaldehyde （1） and hydrazine. Both 2 ...Two pyrazine-containing macrocyclic polyazomethines 2 and 3 were synthesized by direct [2 ＋ 2] and [3 ＋ 3] condensation reactions between 2,21-[pyrazine-2,3-diylbis（oxy）]dibenzaldehyde （1） and hydrazine. Both 2 and 3 were characterized by NMR, HRMS, and their structures were determined via X-ray crystal diffraction studies.展开更多
Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a mu...Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a multimodal warning display. Signalling through more than one sensory pathway may enhance the rate of avoidance learning, and the memorability of the learned avoidance. A common insect warning odor, pyrazine, has previously been shown to increase the rate of learned avoidance of unpalatable yellow prey by domestic chicks （GaUus gallus domesticus）, and the odor also improved memory of this learned avoidance. However, to date no research has examined this response to pyrazine odor using wild birds under natural conditions. This study used wild robins （Erithacus rubecula） to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor. The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator, but that the effect of pyrazine on learned avoidance was much weaker than was found with domestic chicks .展开更多
Novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes(BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3 N-BF3·Et...Novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes(BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3 N-BF3·Et2 O for the first time.The absorption maxima of pyrazine-fused BOPYPY are obviously bathochromic shifts,in contrast to those of the reported BOPPY,indicating that the discrepant substitute groups between pyridine and pyrazine result in the remarkable wavelength difference.The new series of BO PYPYs possess high molar extinction coefficients,high fluorescence quantum yields,and larger Stokes shifts.A Knoevenagel reaction of BOPYPY with 4-dimethylaminobenzaldehyde smoothly produced the dye with the extension of π-conjugation.Dimethylamino-containing BOPYPY as a pH-responsive fluorescent sensor could detect pH value.展开更多
Three alternating conjugated polymers,namely PFTP,PCz TP,and PSi TP,which combine a thieno[3,4-b]pyrazine(TP)unit with different benzene-based donor units such as 9,9-dioctylfluorene,9-heptadecyl-9H-carbazole and 5,5-...Three alternating conjugated polymers,namely PFTP,PCz TP,and PSi TP,which combine a thieno[3,4-b]pyrazine(TP)unit with different benzene-based donor units such as 9,9-dioctylfluorene,9-heptadecyl-9H-carbazole and 5,5-dioctyl-5H-dibenzo[b,d]silole,were synthesized in good yield(>85%)and high molecular weight up to Mn=5.82×10^(4) via direct arylation polymerization(DAr P).All the resultant polymers exhibit moderate bandgap of about 1.80 e V and strong deep red/near-infrared emitting in the solid state.Among them,the PSi TP-based electroluminescence(EL)devices with an architecture of ITO/PEDOT:PSS/PTAA/emitting layer/TPBi/Li F/Al give the best performance with a maximum luminance of 2543 cd/m^(2) at 478 m A/cm^(2).This work expands the application scope of high-performance conjugated polymers which can be synthesized by DAr P.展开更多
An effective route to pyrrolo[1,2-a]pyrazines is described via reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives in the presence of 20 mol%of sulfamic acid.
The title compound,2,6-bis（2-pyridinylmethyl）-3,5-bis（2-hydroxyl-5-chlorophe nyl）-pyrazine（C26H12Cl2N4O2C2H8O2,Mr=551.41）,has been synthesized and characterized by LC-ESIMS,NMR,UV and IR spectroscopy as well as ...The title compound,2,6-bis（2-pyridinylmethyl）-3,5-bis（2-hydroxyl-5-chlorophe nyl）-pyrazine（C26H12Cl2N4O2C2H8O2,Mr=551.41）,has been synthesized and characterized by LC-ESIMS,NMR,UV and IR spectroscopy as well as by X-ray single-crystal diffraction.The compound behaves as a substituted pyrazine.The hydrogen atoms on C（2） and C（3） are substituted by 2-pyridinyl,whereas those on C（1） and C（4） are substituted by 2-hydroxyl-5-chlorophenyl.It crystallizes in the monoclinic system,space group P21/c with a=8.9433（12）,b=32.003（4）,c=10.5209（18）,β=111.199（2）°,V=2807.5（7）3,Z=4,Dc=1.305 mg/m3,F（000）=1144 and μ=0.094 mm-1.A total of 13235 reflections were collected in the range of 2.17～25.01o by using a phi and omega scan mode,of which 4923 were unique（Rint=0.0692） and 2872 observed reflections with Ⅰ 〉2σ（Ⅰ） were used in the structure solution and refinement.展开更多
A novel 2-D lead-containing hybrid compound, [（PbCl2）（μ-Pyz）1/2], （Pyz = pyrazine） 1, has been synthesized by the hydrothermal assembly of pyrazine with lead chloride. Elemental analysis and X-ray crystal struc...A novel 2-D lead-containing hybrid compound, [（PbCl2）（μ-Pyz）1/2], （Pyz = pyrazine） 1, has been synthesized by the hydrothermal assembly of pyrazine with lead chloride. Elemental analysis and X-ray crystal structure analyses were carded out for the structural determination and characterization of the title compound. Compound 1 crystallizes in orthorhombic, space group lbam, with a = 19.5558（18）, b = 7.1939（6）, c = 7.5449（6） A, V = 1061.44（16） .A^3, C2H2Cl2NPb, Mr= 318.14, Z = 8, Dc= 3.982 g/cm^3, μ = 32.63 mm^-1, F（000） = 1096.0, R = 0.0368 and wR = 0.0901 for 623 observed reflections （I 〉 2σ（I））.展开更多
The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in...The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in triclinic,space group P1,with a=7.339（5）,b=13.105（5）,c=14.097（5）,α=84.377（5）,β=76.921（5）,γ=79.628（5）°,V=1296.7（11） 3,C 48 H 50 Ag 4 N 8 O 17 S 4,M r=1570.68,Z=1,D c=2.011 g/cm 3,μ=1.732 mm-1,F（000）=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections （I 2σ（Ⅰ））.Compound 1 shows a rare one-dimensional （1D） double chain,and the chains are further connected through secondary bonding,hydrogen bonds,and π-π interactions to generate a three-dimensional （3D） supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.展开更多
A new copper(Ⅱ) complex of CuLCl_2, where L = N^1-(1-pyrazin-2-yl-ethylidene)-ethane-1,2-diamine, a tridentate Schiff base derived from 2-acetylpyrazine has been prepared. The complex has been characterized by FT-IR,...A new copper(Ⅱ) complex of CuLCl_2, where L = N^1-(1-pyrazin-2-yl-ethylidene)-ethane-1,2-diamine, a tridentate Schiff base derived from 2-acetylpyrazine has been prepared. The complex has been characterized by FT-IR, elemental analysis and single-crystal X-ray diffraction studies. Structural studies reveal that CuLCl_2 is a mononuclear copper(Ⅱ) complex with distorted square pyramidal geometry. Antifungal activity of CuLCl_2 was investigated by use of microcalorimetric measurement system and evaluated against S. pombe. It has high antifungal activity with IC_(50) = 213 μg/mL.展开更多
Two two-dimensional coordination polymers, [Cd（μ1,3-SCN-）2（μ1,6-L）]n 1 and [Co（μ1,3-SCN-）2（μ1,6-L）]n 2, have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide （L） and thiocyanate as mixed bridging l...Two two-dimensional coordination polymers, [Cd（μ1,3-SCN-）2（μ1,6-L）]n 1 and [Co（μ1,3-SCN-）2（μ1,6-L）]n 2, have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide （L） and thiocyanate as mixed bridging ligands, and their crystal structures were determined by X-ray crystallography. Both crystals belong to monoclinic system, space group C2/c. The other crystal parameters are as follows： for complex 1： α = 9.732（3）, b =14.658（5）, c = 8.811（3） A, β = 102.935（4）°, Z = 4, V= 1225.1（7） A^3, C8H8CdN4O2S2, Mr = 368.71, Dc = 1.999 g/cm^3, F（000） = 720 and μ= 2.117 mm^-1; for complex 2： α = 9.528（7）, b = 14.563（11）, c = 8.415（6） A, β= 102.195（9）°, V= 1141.3（14） A^3, Z = 4, C8H8CoN4O2S2, Mr = 315.23, Dc = 1.835 g/cm^3, F（000） = 636 and μ = 1.863 mm^-1. The two complexes show similar two-dimensional sheet structures. Along the c axis one-dimensional chains are constructed by the coordination of Cd（Ⅱ） （or Co（Ⅱ）） ions with μ1,6-L bridging ligand, and the μ1,3-SCN- bridging ligands make the chains connect to each other, resulting in the formation of a two-dimensional sheet on the ac plane.展开更多
In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were designed.Density functional theory was employed to investigate the relationships betwe...In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were designed.Density functional theory was employed to investigate the relationships between the structures and properties.The calculated results indicated that the properties of these designed compounds were influenced by the energetic groups and heterocyclic substituents.The-N3 energetic group was found to be the most effective substituent to improve the heats of formation of the designed compounds while the tetrazole ring/-C(NO_(2))_(3) group contributed much to the values of detonation properties.The analysis of bond orders and bond dissociation energies showed that the addition of-NHNH2,-NHNO_(2),-CH(NO_(2))_(3) and-C(NO_(2))_(3) groups would decrease the bond dissociation energies remarkably.Compounds A8,B8,C8,D8,E8,and F8 were finally screened as the potential candidates for high energy density materials since these compounds possess excellent detonation properties and acceptable thermal stabilities.Additionally,the electronic structures of the screened compounds were calculated.展开更多
In this present, a new series of Schiffbases from 2,5-di（p-aminophenyl）-3,6-diphenyl pyrazine in the presence of the benzil, 4-bromo benzaldehyde, 4-chlor benzaldehyde, 4-hydroxy benzaldehyde, 4-nitro benzaldehyde a...In this present, a new series of Schiffbases from 2,5-di（p-aminophenyl）-3,6-diphenyl pyrazine in the presence of the benzil, 4-bromo benzaldehyde, 4-chlor benzaldehyde, 4-hydroxy benzaldehyde, 4-nitro benzaldehyde and 4-methyl benzaldehyde were studied. The structures of the synthesized compounds were determined on the basis of their Infra-red spectra, H-nuclear magnetic resonase and analysis elemental analysis spectral data. The purity of the synthesized compounds was checked by performing thin layer chromatography. The antibacterial activity was evaluated by paper disc diffusion method.展开更多
Binary and ternary complexes of Cd（II） involving pyrazine 2,3-dicarboxylic acid （pzdca） and various biologically relevant ligands containing different functional groups are investigated at 25 ℃, I = 0.10 M （NaNO...Binary and ternary complexes of Cd（II） involving pyrazine 2,3-dicarboxylic acid （pzdca） and various biologically relevant ligands containing different functional groups are investigated at 25 ℃, I = 0.10 M （NaNO3） and in 20% （v/v） ethanol-water media. The ligands （L） used are amino acids, dicarboxylic acids and peptides. The results showed the formation of Cd （pzdca） （L） complexes with amino acids and dicarboxylic acids. Peptides form both Cd （pzdca） （L） complexes and the corresponding deprotonated amide species Cd （pzdca） （LH-1）. The relative stabilities of ternary complexes are compared with those of the corresponding binary complexes in terms of AlogK values. The concentration distribution of the complexes in solution was evaluated.展开更多
Previous studies have shown that glycine and proline are pharmacophores that display antibacterial activity.In the present study,glycine and proline were derivated to diketopiperazine compounds by chemical synthesis m...Previous studies have shown that glycine and proline are pharmacophores that display antibacterial activity.In the present study,glycine and proline were derivated to diketopiperazine compounds by chemical synthesis method,and their antibacterial activities were evaluated by three strains of spoilage bacteria,Escherichia coli,Pseudomonas aeruginosa and Shewanella putrefaciens,and the relationship of their antibacterial activities and structures was also investigated.Uv-vis spectrophotometry was used to determine the growth curves of three kinds of active indicator bacteria.Minimum inhibitory concentration(MIC)was determined by micro broth dilution method.The results showed that 2-methyl-3-(methylthio)pyrazine had significant antibacterial activity against three strains of the bacteria,and its MIC was 1.25%.It indicates 2-methyl-3-(methylthio)pyrazine has the potential to be developed as a kind of preservative in future.展开更多
Developing organic multiple-resonance(MR)deep-blue emitters with narrow full widths at half maximum(FWHMs)is crucial for enhancing the color purity of organic light-emitting diodes(OLEDs).However,the exploration of ne...Developing organic multiple-resonance(MR)deep-blue emitters with narrow full widths at half maximum(FWHMs)is crucial for enhancing the color purity of organic light-emitting diodes(OLEDs).However,the exploration of new MR cores remains very limited to date.Furthermore,redshifting the emission color of MR emitters is also a formidable challenge.Pyrazine,characterized by its planar and rigid structure,exhibits a strong electronegativity,which may make it a promising candidate for constructing MR emitters with a red shifted emission compared to indolo[3,2,1-jk]carbazole(ICz)-based MR molecules.Herein,a series of polycyclic aromatic hydrocarbons(PAHs)with MR characteristics are designed and synthesized by integrating a pyrazine core with various electron-donating segments,which exhibit the narrowband deep-blue emission peaks ranging from 423 to 459 nm with FWHMs<50 nm in toluene.It is demonstrated that increasing donor strength and changing meta-to paraoriented nitrogen atom can induce the bathochromic emission.Theoretical investigations reveal that the non-bonding orbital characteristic of pyrazine suppress the undesired stretching vibration and promote resonance effect.The optimized deep-blue OLEDs fabricated with the pyrazine-embedded MR emitters demonstrate a high external quantum efficiency(EQE)of 23.5%,and narrowband emission with an electroluminescence peak at 454 nm.展开更多
Organic electrode materials are gaining prominence for their diverse structural compositions,versatile design capabilities,ample availability,biodegradability,and relatively mild synthesis procedures,positioning them ...Organic electrode materials are gaining prominence for their diverse structural compositions,versatile design capabilities,ample availability,biodegradability,and relatively mild synthesis procedures,positioning them as an increasingly attractive alternative to traditional inorganic electrode materials.Capitalizing on these advantages,molecular structures incorporating pyrazine functional unit have emerged as a focal point of research in recent years.This paper provides a comprehensive review of pyrazine-containing organic electrode materials with a detailed examination of their structures,synthesis methods,electrochemical reaction mechanisms and applications in rechargeable metal-ion organic batteries.Furthermore,the relationship between their intrinsic structures and electrochemical properties is summarized in detail.Finally,the further perspectives and challenges of pyrazine-containing electrode materials are discussed for superior-performance organic batteries.展开更多
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfe...A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-on voltages of their single-layer electroluminescent (EL) devices (ITO/PEDOT/polymer/LiF/Al) were at 6.1-4.0 V,which were much lower than that of PFO (7.0 V).The maximum brightness,current efficiency,and external quantum efficiency of all PFBY copolymers were higher than those of the PFO homopolymer.The single-layer device of PFBY5 was the best one in the copolymers,with a maximum brightness of 485 cd/m2,a current efficiency of 0.29 cd/A,and an external quantum efficiency of 0.10%.The introduction of PVK and TPBI for the multilayer device of PFBY5 increased the device efficiencies,which showed a maximum brightness of 3012 cd/m2,a maximum current efficiency of 1.81 cd/A,and an external quantum efficiency of 0.66%.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52300120 and 52070144)the Fundamental Research Funds for the Central Universities(No.22120240465).
文摘Regulating the photo-response region of iron metal-organic frameworks(Fe-MOFs)is a viable strategy for enhancing their practical application in the visible-light driven photo-Fenton-like process.This study developed a novel pyrazine-based Fe-MOFs(MIL-101(Fe)-Pz)by substituting the 1,4-dicarboxybenzene acid ligands in typical MIL-101(Fe)with 2,5-pyrazinedicarboxylic acid(PzDC),in which sodium acetate was used as coordinative modulator to control the crystal size(2–3μm).The incorporation of Fe-pyridine N coordination structures originated from PzDC ligands gave MIL-101(Fe)-Pz narrowed band gap(1.45 eV)than MIL-101(Fe)(2.54 eV)resulting in improved visible-light adsorption capacity(λ>420 nm),and also increased the proportion of Fe(Ⅱ)in the Fe-clusters.Thus MIL-101(Fe)-Pz exhibited a synergistic enhanced photo-Fenton-like catalytic performance under visible-light irradiation.The MIL-101(Fe)-Pz/H_(2)O_(2)/Vis system could degrade 99%of sulfamethoxazolewithin 30min,whichwas 10-fold faster than that of the pristine MIL-101(Fe),it also effectively removed other organic micropollutants with high durability and stability.Mechanistic analysis revealed that the PzDC ligands substitution decreased the band gap of MIL-101(Fe),giving MIL-101(Fe)-Pz appropriate band structure(-0.40∼1.05 V vs.NHE)which can cover several light-driven process for the generation of reactive oxygen species,including Fe(Ⅲ)reduction and H_(2)O_(2) activation for accelerating•OH generation,as well as oxygen reduction reaction for generating H_(2)O_(2),O_(2)^(•−) and ^(1)O_(2).This study highlights the role of pyridine-N containing ligands in regulating the band structure of Fe-MOFs,providing valuable guidance for the design of Fe-MOFs photocatalysts.
文摘A new cyclometalated iridium（IlI） complex Ir（DPP）3 （DPP=2,3-diphenylpyrazine） was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT （singlet metal to ligand charge-transfer） and aMLCT （triplet metal to ligand charge-transfer） absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.
基金Supported by the Innovation and Technology Fund of Hong Kong, China
文摘AIM： To investigate the effect of tetramethylpyrazine （TMP）, an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS： The short-circuit current （Isc） technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis （RIA） and a special mouse model of cystic fibrosis.RESULTS： IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2＇-dicarboxylic acid （DPC） and glibenclamide, but resistant to 4,4＇-diisothiocyanatostilbene-2,2＇-disulfonic acid disodium salt hydrate （DIDS）. Removal of Na^＋ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^＋ replacement or apical Na^＋ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2＋ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine （[BMX） was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP （1 mmol/L） elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin （10μmol/L）. The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator （CFTR） presenting defective CFTR functions and secretions.CONCLUSION： TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.
基金Shanghai Commission for Science and Technology(Nos.06Pj14034,06DZ19002,and 10ZR1409700)Ministry of Education(No.106078) for financial support
文摘Two pyrazine-containing macrocyclic polyazomethines 2 and 3 were synthesized by direct [2 ＋ 2] and [3 ＋ 3] condensation reactions between 2,21-[pyrazine-2,3-diylbis（oxy）]dibenzaldehyde （1） and hydrazine. Both 2 and 3 were characterized by NMR, HRMS, and their structures were determined via X-ray crystal diffraction studies.
文摘Toxic insects advertise their defended state to potential predators using warning displays. Frequently these displays use cues through more than one sensory modality, and combine color, smell and sound to produce a multimodal warning display. Signalling through more than one sensory pathway may enhance the rate of avoidance learning, and the memorability of the learned avoidance. A common insect warning odor, pyrazine, has previously been shown to increase the rate of learned avoidance of unpalatable yellow prey by domestic chicks （GaUus gallus domesticus）, and the odor also improved memory of this learned avoidance. However, to date no research has examined this response to pyrazine odor using wild birds under natural conditions. This study used wild robins （Erithacus rubecula） to investigate whether wild birds avoided yellow baits that smelled of pyrazine more strongly than those presented with no odor. The results provide some evidence that pyrazine odor does increase the level of protection an aposematic insect gains from a wild avian predator, but that the effect of pyrazine on learned avoidance was much weaker than was found with domestic chicks .
基金supported by the National Natural Science Foundation of China (No.21542004)Young and Middle-aged Scientific and Technological Innovation Talents of Shenyang Science and Technology Bureau (No.RC170140)+4 种基金Natural Science Foundation of Liaoning Province (No.20170540721)Basic research on the application of Industrial Development of Shenyang Science and Technology Bureau (No.18013027)Liaoning BaiQianWan Talents Programthe Distinguished Professor Project of Liaoning province (No.20183532)the Chinese Scholarship Council (No.20183058) for financial support
文摘Novel 5,6,5,6-tetracyclic pyrazine/pyrrole-fused unsymmetric bis(BF2) fluorescent dyes(BOPYPYs) were obtained by reaction of pyrrole-2-carboxaldehyde with 1-(pyrazin-2-yl)hydrazine in the presence of Et3 N-BF3·Et2 O for the first time.The absorption maxima of pyrazine-fused BOPYPY are obviously bathochromic shifts,in contrast to those of the reported BOPPY,indicating that the discrepant substitute groups between pyridine and pyrazine result in the remarkable wavelength difference.The new series of BO PYPYs possess high molar extinction coefficients,high fluorescence quantum yields,and larger Stokes shifts.A Knoevenagel reaction of BOPYPY with 4-dimethylaminobenzaldehyde smoothly produced the dye with the extension of π-conjugation.Dimethylamino-containing BOPYPY as a pH-responsive fluorescent sensor could detect pH value.
基金financially supported by the National Natural Science Foundation of China(Nos.21604063 and 52173010)the Program for Prominent Young College Teachers of Tianjin Educational Committee。
文摘Three alternating conjugated polymers,namely PFTP,PCz TP,and PSi TP,which combine a thieno[3,4-b]pyrazine(TP)unit with different benzene-based donor units such as 9,9-dioctylfluorene,9-heptadecyl-9H-carbazole and 5,5-dioctyl-5H-dibenzo[b,d]silole,were synthesized in good yield(>85%)and high molecular weight up to Mn=5.82×10^(4) via direct arylation polymerization(DAr P).All the resultant polymers exhibit moderate bandgap of about 1.80 e V and strong deep red/near-infrared emitting in the solid state.Among them,the PSi TP-based electroluminescence(EL)devices with an architecture of ITO/PEDOT:PSS/PTAA/emitting layer/TPBi/Li F/Al give the best performance with a maximum luminance of 2543 cd/m^(2) at 478 m A/cm^(2).This work expands the application scope of high-performance conjugated polymers which can be synthesized by DAr P.
文摘An effective route to pyrrolo[1,2-a]pyrazines is described via reaction of ethylenediamine,acetylenic esters and nitrostyrene derivatives in the presence of 20 mol%of sulfamic acid.
基金supported by the research grant of Phytochemistry Key Laboratory of Shaanxi Province (No. 02js40)
文摘The title compound,2,6-bis（2-pyridinylmethyl）-3,5-bis（2-hydroxyl-5-chlorophe nyl）-pyrazine（C26H12Cl2N4O2C2H8O2,Mr=551.41）,has been synthesized and characterized by LC-ESIMS,NMR,UV and IR spectroscopy as well as by X-ray single-crystal diffraction.The compound behaves as a substituted pyrazine.The hydrogen atoms on C（2） and C（3） are substituted by 2-pyridinyl,whereas those on C（1） and C（4） are substituted by 2-hydroxyl-5-chlorophenyl.It crystallizes in the monoclinic system,space group P21/c with a=8.9433（12）,b=32.003（4）,c=10.5209（18）,β=111.199（2）°,V=2807.5（7）3,Z=4,Dc=1.305 mg/m3,F（000）=1144 and μ=0.094 mm-1.A total of 13235 reflections were collected in the range of 2.17～25.01o by using a phi and omega scan mode,of which 4923 were unique（Rint=0.0692） and 2872 observed reflections with Ⅰ 〉2σ（Ⅰ） were used in the structure solution and refinement.
基金This work was supported by the National Natural Science Foundation of China (No. 20173063), the State Key Basic Research and Development Plan of China (001CB108906), and the NSF of Fujian Province (E0020001)
文摘A novel 2-D lead-containing hybrid compound, [（PbCl2）（μ-Pyz）1/2], （Pyz = pyrazine） 1, has been synthesized by the hydrothermal assembly of pyrazine with lead chloride. Elemental analysis and X-ray crystal structure analyses were carded out for the structural determination and characterization of the title compound. Compound 1 crystallizes in orthorhombic, space group lbam, with a = 19.5558（18）, b = 7.1939（6）, c = 7.5449（6） A, V = 1061.44（16） .A^3, C2H2Cl2NPb, Mr= 318.14, Z = 8, Dc= 3.982 g/cm^3, μ = 32.63 mm^-1, F（000） = 1096.0, R = 0.0368 and wR = 0.0901 for 623 observed reflections （I 〉 2σ（I））.
基金supported by the Science Foundation of Suihua University (K1001005)
文摘The title complex,[Ag 2 （L1） 2 （Pyr）·2.5H 2 O] 1 （L1=6-amino-1-naphthalenesulfonate anion,Pyr=pyrazine）,has been synthesized and characterized by single-crystal X-ray diffraction analysis.It crystallizes in triclinic,space group P1,with a=7.339（5）,b=13.105（5）,c=14.097（5）,α=84.377（5）,β=76.921（5）,γ=79.628（5）°,V=1296.7（11） 3,C 48 H 50 Ag 4 N 8 O 17 S 4,M r=1570.68,Z=1,D c=2.011 g/cm 3,μ=1.732 mm-1,F（000）=782,S=1.148,the final R=0.0436 and wR=0.1181 for 4130 observer reflections （I 2σ（Ⅰ））.Compound 1 shows a rare one-dimensional （1D） double chain,and the chains are further connected through secondary bonding,hydrogen bonds,and π-π interactions to generate a three-dimensional （3D） supramolecular structure.The luminescent property of 1 was also studied in the solid state at room temperture.
基金supported by the National Natural Science Foundation of China(No.41701349)
文摘A new copper(Ⅱ) complex of CuLCl_2, where L = N^1-(1-pyrazin-2-yl-ethylidene)-ethane-1,2-diamine, a tridentate Schiff base derived from 2-acetylpyrazine has been prepared. The complex has been characterized by FT-IR, elemental analysis and single-crystal X-ray diffraction studies. Structural studies reveal that CuLCl_2 is a mononuclear copper(Ⅱ) complex with distorted square pyramidal geometry. Antifungal activity of CuLCl_2 was investigated by use of microcalorimetric measurement system and evaluated against S. pombe. It has high antifungal activity with IC_(50) = 213 μg/mL.
基金This work was supported by the National Natural Science Foundation of China (No. 20271043) and the Natural Science Foundation of Shandong Province (Y2005B25)
文摘Two two-dimensional coordination polymers, [Cd（μ1,3-SCN-）2（μ1,6-L）]n 1 and [Co（μ1,3-SCN-）2（μ1,6-L）]n 2, have been synthesized with 2,3-dimethylpyrazine-1,4-dioxide （L） and thiocyanate as mixed bridging ligands, and their crystal structures were determined by X-ray crystallography. Both crystals belong to monoclinic system, space group C2/c. The other crystal parameters are as follows： for complex 1： α = 9.732（3）, b =14.658（5）, c = 8.811（3） A, β = 102.935（4）°, Z = 4, V= 1225.1（7） A^3, C8H8CdN4O2S2, Mr = 368.71, Dc = 1.999 g/cm^3, F（000） = 720 and μ= 2.117 mm^-1; for complex 2： α = 9.528（7）, b = 14.563（11）, c = 8.415（6） A, β= 102.195（9）°, V= 1141.3（14） A^3, Z = 4, C8H8CoN4O2S2, Mr = 315.23, Dc = 1.835 g/cm^3, F（000） = 636 and μ = 1.863 mm^-1. The two complexes show similar two-dimensional sheet structures. Along the c axis one-dimensional chains are constructed by the coordination of Cd（Ⅱ） （or Co（Ⅱ）） ions with μ1,6-L bridging ligand, and the μ1,3-SCN- bridging ligands make the chains connect to each other, resulting in the formation of a two-dimensional sheet on the ac plane.
基金This work was supported by the National Natural Science Foundation of China(No.11602121)the Program for Scientific Research Innovation Team in Colleges and Universities of Ji’nan(No.2018GXRC006).
文摘In order to search for high energy density materials,various 4,8-dihydrodifurazano[3,4-b,e]pyrazine based energetic materials were designed.Density functional theory was employed to investigate the relationships between the structures and properties.The calculated results indicated that the properties of these designed compounds were influenced by the energetic groups and heterocyclic substituents.The-N3 energetic group was found to be the most effective substituent to improve the heats of formation of the designed compounds while the tetrazole ring/-C(NO_(2))_(3) group contributed much to the values of detonation properties.The analysis of bond orders and bond dissociation energies showed that the addition of-NHNH2,-NHNO_(2),-CH(NO_(2))_(3) and-C(NO_(2))_(3) groups would decrease the bond dissociation energies remarkably.Compounds A8,B8,C8,D8,E8,and F8 were finally screened as the potential candidates for high energy density materials since these compounds possess excellent detonation properties and acceptable thermal stabilities.Additionally,the electronic structures of the screened compounds were calculated.
文摘In this present, a new series of Schiffbases from 2,5-di（p-aminophenyl）-3,6-diphenyl pyrazine in the presence of the benzil, 4-bromo benzaldehyde, 4-chlor benzaldehyde, 4-hydroxy benzaldehyde, 4-nitro benzaldehyde and 4-methyl benzaldehyde were studied. The structures of the synthesized compounds were determined on the basis of their Infra-red spectra, H-nuclear magnetic resonase and analysis elemental analysis spectral data. The purity of the synthesized compounds was checked by performing thin layer chromatography. The antibacterial activity was evaluated by paper disc diffusion method.
文摘Binary and ternary complexes of Cd（II） involving pyrazine 2,3-dicarboxylic acid （pzdca） and various biologically relevant ligands containing different functional groups are investigated at 25 ℃, I = 0.10 M （NaNO3） and in 20% （v/v） ethanol-water media. The ligands （L） used are amino acids, dicarboxylic acids and peptides. The results showed the formation of Cd （pzdca） （L） complexes with amino acids and dicarboxylic acids. Peptides form both Cd （pzdca） （L） complexes and the corresponding deprotonated amide species Cd （pzdca） （LH-1）. The relative stabilities of ternary complexes are compared with those of the corresponding binary complexes in terms of AlogK values. The concentration distribution of the complexes in solution was evaluated.
基金Supported by The Tackling-plan Project of Henan Department of Science and Technology (222102310388)Key Scientific Research Plan of Colleges in Henan Province (22B350002)Henan Provincial Medical Science and Technology Research Plan Joint Construction Project (LHGJ20191520).
文摘Previous studies have shown that glycine and proline are pharmacophores that display antibacterial activity.In the present study,glycine and proline were derivated to diketopiperazine compounds by chemical synthesis method,and their antibacterial activities were evaluated by three strains of spoilage bacteria,Escherichia coli,Pseudomonas aeruginosa and Shewanella putrefaciens,and the relationship of their antibacterial activities and structures was also investigated.Uv-vis spectrophotometry was used to determine the growth curves of three kinds of active indicator bacteria.Minimum inhibitory concentration(MIC)was determined by micro broth dilution method.The results showed that 2-methyl-3-(methylthio)pyrazine had significant antibacterial activity against three strains of the bacteria,and its MIC was 1.25%.It indicates 2-methyl-3-(methylthio)pyrazine has the potential to be developed as a kind of preservative in future.
基金financial support from the National Natural Science Foundation of China (52130308)Shenzhen Science and Technology Program (JCYJ20220818095816036,ZDSYS20210623091813040)。
文摘Developing organic multiple-resonance(MR)deep-blue emitters with narrow full widths at half maximum(FWHMs)is crucial for enhancing the color purity of organic light-emitting diodes(OLEDs).However,the exploration of new MR cores remains very limited to date.Furthermore,redshifting the emission color of MR emitters is also a formidable challenge.Pyrazine,characterized by its planar and rigid structure,exhibits a strong electronegativity,which may make it a promising candidate for constructing MR emitters with a red shifted emission compared to indolo[3,2,1-jk]carbazole(ICz)-based MR molecules.Herein,a series of polycyclic aromatic hydrocarbons(PAHs)with MR characteristics are designed and synthesized by integrating a pyrazine core with various electron-donating segments,which exhibit the narrowband deep-blue emission peaks ranging from 423 to 459 nm with FWHMs<50 nm in toluene.It is demonstrated that increasing donor strength and changing meta-to paraoriented nitrogen atom can induce the bathochromic emission.Theoretical investigations reveal that the non-bonding orbital characteristic of pyrazine suppress the undesired stretching vibration and promote resonance effect.The optimized deep-blue OLEDs fabricated with the pyrazine-embedded MR emitters demonstrate a high external quantum efficiency(EQE)of 23.5%,and narrowband emission with an electroluminescence peak at 454 nm.
基金supported by the National Natural Science Foundation of China(22278116)Project Funded by China Postdoctoral Science Foundation(2022M710849 and 2023T160137)+4 种基金Department of Education of Hubei Province(Q20221004)Overseas Expertise Introduction Center for Discipline Innovation(D18025)Hubei Provincial Natural Science Foundation of China(2024AFB1016 and 2023AFB479)Key Laboratory of High Temperature Electromagnetic Materials and Structure of MOE(KB202506)Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University,YQZC202505)。
文摘Organic electrode materials are gaining prominence for their diverse structural compositions,versatile design capabilities,ample availability,biodegradability,and relatively mild synthesis procedures,positioning them as an increasingly attractive alternative to traditional inorganic electrode materials.Capitalizing on these advantages,molecular structures incorporating pyrazine functional unit have emerged as a focal point of research in recent years.This paper provides a comprehensive review of pyrazine-containing organic electrode materials with a detailed examination of their structures,synthesis methods,electrochemical reaction mechanisms and applications in rechargeable metal-ion organic batteries.Furthermore,the relationship between their intrinsic structures and electrochemical properties is summarized in detail.Finally,the further perspectives and challenges of pyrazine-containing electrode materials are discussed for superior-performance organic batteries.
基金supported by the National Natural Science Foundation of China (50803062,60977026 & 20904055)the Science Fund for Creative Research Groups (20621401)the Natural Basic Research Foundation of China (973 Program,2009CB623601)
文摘A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-on voltages of their single-layer electroluminescent (EL) devices (ITO/PEDOT/polymer/LiF/Al) were at 6.1-4.0 V,which were much lower than that of PFO (7.0 V).The maximum brightness,current efficiency,and external quantum efficiency of all PFBY copolymers were higher than those of the PFO homopolymer.The single-layer device of PFBY5 was the best one in the copolymers,with a maximum brightness of 485 cd/m2,a current efficiency of 0.29 cd/A,and an external quantum efficiency of 0.10%.The introduction of PVK and TPBI for the multilayer device of PFBY5 increased the device efficiencies,which showed a maximum brightness of 3012 cd/m2,a maximum current efficiency of 1.81 cd/A,and an external quantum efficiency of 0.66%.
