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
In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized th...In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized the reaction procedure to easily obtain 5-chloro-[1,2,4]triazolo[4,3-a ]pyrazin-3-amine. Various types of halogenated pyrazines can successfully undergo this process. We synthesized a series of 1-(pyrazin-2-yl)guanidines and [1,2,4]triazolo[4,3-a ]pyrazin-3-amines, and then elucidated their structures based on their ~1H-NMR, ^(13)C-NMR, ESI-HRMS, and nuclear Overhauser effect spectra.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
3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single...3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a=4.8659（10）, b=7.4233（15）, c=11.602（2）, α=96.904（2）, β=92.422（3）, γ=107.454（2）°, V=395.51（14）3 , Z=2, Dc=1.689g/cm3 , F（000）=208, μ（MoKα）=0.149 mm-1 , the final R=0.0473 and wR=0.1306 for 2853 observed reflections （I〉2σ （I））. A three-dimensional framework was assembled through intermolecular hydrogen bonding between water and 3-carboxy-2-pyrazine-carbohydroxamic acid molecules.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
A complex,namely[Cu_(4)(L)_(2)(CH_(3)O)_(2)(CH_(3)OH)_(4)(SO_(4))_(2)]SO_(4)·6CH_(3)OH(1)(L=N,N′-bis-(1-(3-ethyl-pyrazin-2-yl)-ethylidene)-hydrazine)has been synthesized and characterized by single-crystal X-ray...A complex,namely[Cu_(4)(L)_(2)(CH_(3)O)_(2)(CH_(3)OH)_(4)(SO_(4))_(2)]SO_(4)·6CH_(3)OH(1)(L=N,N′-bis-(1-(3-ethyl-pyrazin-2-yl)-ethylidene)-hydrazine)has been synthesized and characterized by single-crystal X-ray diffraction,elemental analysis and IR spectroscopy.X-ray diffraction analysis results show that in complex 1,each Cu(Ⅱ)center with a distorted octahedron geometry is coordinated by two N atoms from one pyrazin-2-yl-ethylideneamine subunit,and four O atoms involving one O atom from one neutral methanol,oneμ2-bridged O atom from one methoxy anion,oneμ2-bridged O and one monodentate O atoms from two independent sulfate anions,thus forming an ideal planar four-membered Cu4 core.In addition,the fluorescence spectra indicate that the interaction of complex 1 with DNA is stronger than that of the ligand L.CCDC:1844807,L;1844806,1.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
Co-crystallization of pztcH_4 with 4,4＇-bipyridine（4,4＇-bipy） in pH = 3-4 and 1-2 gave two new binary molecular adducts： [（4,4＇-bipy H2）（pztc H2）]（1） and [（4,4＇-bipy H2）（pztcH3）（Cl）]·4H2O（2）,...Co-crystallization of pztcH_4 with 4,4＇-bipyridine（4,4＇-bipy） in pH = 3-4 and 1-2 gave two new binary molecular adducts： [（4,4＇-bipy H2）（pztc H2）]（1） and [（4,4＇-bipy H2）（pztcH3）（Cl）]·4H2O（2）, respectively. Compounds 1 and 2 have been characterized by IR, elemental analysis, NMR and X-ray single-crystal diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 5.7752（12）, b = 7.9126（16）, c = 9.4492（19） ？, α = 97.49（3）, β = 107.71（3）, γ = 94.52（3）o, V = 404.62（14） A^3, Z = 1, μ = 0.137 mm^1, Dc = 1.692 Mg/m^3, C18H12N4O8, Mr = 412.32, F（000） = 212, S = 1.025, R = 0.0360 and wR = 0.0973. Compound 2 crystallizes in monoclinic, space group C2/c with a = 17.093（3）, b = 7.7665（16）, c = 18.414（4） A, β = 113.36（3）o, V = 2244.1（8） A^3, Z = 4, μ = 0.244 mm^-1, Dc = 1.542 Mg/m^3, C18H21ClN4O12, Mr = 520.84, F（000） = 1080, S = 1.021, R = 0.0343 and wR = 0.0978. In compound 1, pztc H22- anions self-formed 2-D sheets by strong Oacid-H···Oacidhydrogen bonds, which are further extended to form a 3-D supramolecular network bridged with 4,4？-bipy via N-H···Oacid interactions. In compound 2, besides the 1-D chain constructed by pztc H3-itself through strong H-bond Oacid-H···Oacid, the other chain is constructed with 4,4？-bipy H22＋, Cl-anion and water molecules by moderate H-bonds and Ow-H···Cl and N-H···Ow. The two chains are linked with μ3-connected water molecules resulting from the combination of strong synthon-assisted H-bonding Oacid-H···Ow to afford an interlaced 3-D network.展开更多
Two complexes[Ni(L)(OAc)](1)and[Co(L)2]Cl·4CH3OH(2)(HL=2-aceto-3-methylpyrazine N-(4-fluorophenyl)thiosemicarbazone)have been synthesized and structurally determined by single-crystal X-ray diffraction,elemental ...Two complexes[Ni(L)(OAc)](1)and[Co(L)2]Cl·4CH3OH(2)(HL=2-aceto-3-methylpyrazine N-(4-fluorophenyl)thiosemicarbazone)have been synthesized and structurally determined by single-crystal X-ray diffraction,elemental analysis and IR spectroscopy.X-ray diffraction analysis results show that the Ni(Ⅱ)ion in complex 1 with a distorted square planar geometry is surrounded by one anionic TSC ligand with NNS donor set and one monodentate acetate.By contrast,Co(Ⅲ)ion coordinates with two tridentate TSC ligands,and thus possessing a distorted octahedron coordination geometry.Moreover,the fluorescence spectra indicate that the interactions of complexes 1 and 2 with DNA are stronger than that of the ligand HL.CCDC:1848437,1;1848438,2.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.
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
The title complex, [Mn（DPPZ）（PZDC）（H2O）] 1 （DPPZ = dipyrido[3,2 -a：2＇,3＇- c]phenazine and H2PZDC = pyrazine-2,3-dicarboxylic acid）, has been hydrothermally synthesized and structurally characterized by X-ra...The title complex, [Mn（DPPZ）（PZDC）（H2O）] 1 （DPPZ = dipyrido[3,2 -a：2＇,3＇- c]phenazine and H2PZDC = pyrazine-2,3-dicarboxylic acid）, has been hydrothermally synthesized and structurally characterized by X-ray single-crystal diffraction, elemental analyses, IR, TG- DTA and magnetic susceptibility measurement. It crystallizes in triclinic, space group P1^- with a = 6.6842（5）, b = 7.5741（6）, c = 20.5755（15）A, α = 90.1160（10）, β = 97.0560（10）, γ = 97.3350（10）°, V= 1025.16（13）A^3, Z = 2, MnC24H14N6O5, Mr= 521.35, Dc= 1.689 g/cm^3, F（000） = 530, μ（MoKa） = 0.699 mm^-1, R = 0.0366 and wR = 0.0810. Compound 1 contains one- dimensional chains which are further stacked through π-π interactions to form a 3D supramolecular architecture. The water molecule O（1W） is involved in hydrogen bonding interactions with symmetric carboxylate oxygen atom 0（4） at （x＋ 1, y＋1, z） and symmetric PZDC nitrogen atom N（6） at （1-x, 1-y, 1-z）, which completes the structure of 1. Magnetic susceptibility measurement indicates that the compound behaves a weak antiferromagnetic exchange interaction.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
A new metal-organic coordination polymer [Zn（pzdc）（mbix）]n·nH2O（H2pzdc = pyrazine-2,3- dicarboxylic acid, mbix = 1,3-bis（imidazol-1-ylmethyl）-benzene） 1 has been hydrothermally synthesized and structurall...A new metal-organic coordination polymer [Zn（pzdc）（mbix）]n·nH2O（H2pzdc = pyrazine-2,3- dicarboxylic acid, mbix = 1,3-bis（imidazol-1-ylmethyl）-benzene） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in monoclinic system, space group P21/n with a = 8.5519（6）, b = 14.8764（10）, c = 16.4108（11） A, β = 103.4520（10）o, V = 2030.5（2）A^3, C（20）H（18）N6O5Zn, Mr = 487.77, Dc = 1.596 g/cm^3, F（000） = 1000, Z = 4, μ（MoK α） = 1.257 mm^-1, the final R = 0.0260 and w R = 0.0706 for 3445 observed reflections（I 〉 2σ（I））. The structure of 1 exhibits a one-dimensional chain-like structure. In addition, natural bond orbital（NBO） analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program. The calculation results show obvious covalent interaction between the coordinated atoms and Zn（Ⅱ） ion.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
Two complexes[Ni L(HL)](OAc)(1)and[Zn L(OAc)]_(n)(2)(HL=1-(3-ethylpyrazin-2-yl)ethylidene)-4-methylthiosemicarbazide)have been synthesized and structurally determined by single-crystal X-ray diffraction.The results sh...Two complexes[Ni L(HL)](OAc)(1)and[Zn L(OAc)]_(n)(2)(HL=1-(3-ethylpyrazin-2-yl)ethylidene)-4-methylthiosemicarbazide)have been synthesized and structurally determined by single-crystal X-ray diffraction.The results show that the Ni(Ⅱ)ion in 1 is surrounded by two independent thiosemicarbazone ligands with N4 S2 donor set,one of which is anionic.However,in complex 2,the Zn(Ⅱ)ion with a distorted tetragonal pyramid coordination geometry is five-coordinated,involving twoμ-OCO acetate anions,one tridentate enolizated ligand L-,thus forming one dimension chain-like framework along a axis.Moreover,the fluorescence spectra indicate that the interactions of the complexes with DNA are stronger than that of the thiosemicarbazone ligand.CCDC:1587278,1;1587280,2.展开更多
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
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
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
A novel pyrazine-2,3-dicarboxylic acid bridged Co(II) phen complex 2 ∞ [Co- ...A novel pyrazine-2,3-dicarboxylic acid bridged Co(II) phen complex 2 ∞ [Co- (phen)(μ-L)3/3]?H2O (H2L = pyrazine-2,3-dicarboxylic acid) has been hydrothermally synthesized, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group P21/n with a = 11.480(2), b = 11.885(2), c = 12.939(3) ?, β = 110.55(3)°, V = 1653.1(6) ?3, Mr = 423.25, Dc = 0.425 g/cm3, Z = 4, R = 0.0361 and wR = 0.1011. The title complex consists of 2D 2 ∞ [Co(phen)(μ-L)3/3] layers and crystal water molecules. Each Co atom is octahedrally coordinated by three N atoms and three O atoms to form 2D 2 ∞ [Co(phen)(μ-L)3/3] polymeric layers. Furthermore, such 2D layers are stacked into 3D supramolecular frameworks via Van der Waals’ intermolecular forces, strong and weak hydrogen-bond interactions. The coordination phen and crystal water molecules are resided into cavities of the frameworks.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.
基金supported by the National Nature Science Foundation of China(Nos.21576195 and 21776207)
文摘In this study, we applied a novel, mild, and convenient synthetic method involving the oxidative cyclization of 1-(pyrazin-2-yl)guanidine derivatives to produce [1,2,4]triazolo[4,3-a ]pyrazin-3-amines. We optimized the reaction procedure to easily obtain 5-chloro-[1,2,4]triazolo[4,3-a ]pyrazin-3-amine. Various types of halogenated pyrazines can successfully undergo this process. We synthesized a series of 1-(pyrazin-2-yl)guanidines and [1,2,4]triazolo[4,3-a ]pyrazin-3-amines, and then elucidated their structures based on their ~1H-NMR, ^(13)C-NMR, ESI-HRMS, and nuclear Overhauser effect spectra.
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 National Natural Science Foundation of China (No. 20861007)Science Foundation of State Key Laboratory of Structural Chemistry (No. 20100009)Science and Technology Research Projects in Department of Education of Jiangxi Province (No. GJJ08026)
文摘3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a=4.8659（10）, b=7.4233（15）, c=11.602（2）, α=96.904（2）, β=92.422（3）, γ=107.454（2）°, V=395.51（14）3 , Z=2, Dc=1.689g/cm3 , F（000）=208, μ（MoKα）=0.149 mm-1 , the final R=0.0473 and wR=0.1306 for 2853 observed reflections （I〉2σ （I））. A three-dimensional framework was assembled through intermolecular hydrogen bonding between water and 3-carboxy-2-pyrazine-carbohydroxamic acid molecules.
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A complex,namely[Cu_(4)(L)_(2)(CH_(3)O)_(2)(CH_(3)OH)_(4)(SO_(4))_(2)]SO_(4)·6CH_(3)OH(1)(L=N,N′-bis-(1-(3-ethyl-pyrazin-2-yl)-ethylidene)-hydrazine)has been synthesized and characterized by single-crystal X-ray diffraction,elemental analysis and IR spectroscopy.X-ray diffraction analysis results show that in complex 1,each Cu(Ⅱ)center with a distorted octahedron geometry is coordinated by two N atoms from one pyrazin-2-yl-ethylideneamine subunit,and four O atoms involving one O atom from one neutral methanol,oneμ2-bridged O atom from one methoxy anion,oneμ2-bridged O and one monodentate O atoms from two independent sulfate anions,thus forming an ideal planar four-membered Cu4 core.In addition,the fluorescence spectra indicate that the interaction of complex 1 with DNA is stronger than that of the ligand L.CCDC:1844807,L;1844806,1.
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supported by the National Natural Science Foundation of China(No.21571094)
文摘Co-crystallization of pztcH_4 with 4,4＇-bipyridine（4,4＇-bipy） in pH = 3-4 and 1-2 gave two new binary molecular adducts： [（4,4＇-bipy H2）（pztc H2）]（1） and [（4,4＇-bipy H2）（pztcH3）（Cl）]·4H2O（2）, respectively. Compounds 1 and 2 have been characterized by IR, elemental analysis, NMR and X-ray single-crystal diffraction. Compound 1 crystallizes in triclinic, space group P1 with a = 5.7752（12）, b = 7.9126（16）, c = 9.4492（19） ？, α = 97.49（3）, β = 107.71（3）, γ = 94.52（3）o, V = 404.62（14） A^3, Z = 1, μ = 0.137 mm^1, Dc = 1.692 Mg/m^3, C18H12N4O8, Mr = 412.32, F（000） = 212, S = 1.025, R = 0.0360 and wR = 0.0973. Compound 2 crystallizes in monoclinic, space group C2/c with a = 17.093（3）, b = 7.7665（16）, c = 18.414（4） A, β = 113.36（3）o, V = 2244.1（8） A^3, Z = 4, μ = 0.244 mm^-1, Dc = 1.542 Mg/m^3, C18H21ClN4O12, Mr = 520.84, F（000） = 1080, S = 1.021, R = 0.0343 and wR = 0.0978. In compound 1, pztc H22- anions self-formed 2-D sheets by strong Oacid-H···Oacidhydrogen bonds, which are further extended to form a 3-D supramolecular network bridged with 4,4？-bipy via N-H···Oacid interactions. In compound 2, besides the 1-D chain constructed by pztc H3-itself through strong H-bond Oacid-H···Oacid, the other chain is constructed with 4,4？-bipy H22＋, Cl-anion and water molecules by moderate H-bonds and Ow-H···Cl and N-H···Ow. The two chains are linked with μ3-connected water molecules resulting from the combination of strong synthon-assisted H-bonding Oacid-H···Ow to afford an interlaced 3-D network.
文摘Two complexes[Ni(L)(OAc)](1)and[Co(L)2]Cl·4CH3OH(2)(HL=2-aceto-3-methylpyrazine N-(4-fluorophenyl)thiosemicarbazone)have been synthesized and structurally determined by single-crystal X-ray diffraction,elemental analysis and IR spectroscopy.X-ray diffraction analysis results show that the Ni(Ⅱ)ion in complex 1 with a distorted square planar geometry is surrounded by one anionic TSC ligand with NNS donor set and one monodentate acetate.By contrast,Co(Ⅲ)ion coordinates with two tridentate TSC ligands,and thus possessing a distorted octahedron coordination geometry.Moreover,the fluorescence spectra indicate that the interactions of complexes 1 and 2 with DNA are stronger than that of the ligand HL.CCDC:1848437,1;1848438,2.
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 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The project was supported by the Natural Science Foundation of Jilin Province (No. 20060516)the Doctoral Foundation of Jilin Normal University (No. 2006006)+1 种基金the Science and Technology Institute Foundation of Siping City (No. 2005016)the Subject and Base Construction Foundation of Jilin Normal University (No. 2006041)
文摘The title complex, [Mn（DPPZ）（PZDC）（H2O）] 1 （DPPZ = dipyrido[3,2 -a：2＇,3＇- c]phenazine and H2PZDC = pyrazine-2,3-dicarboxylic acid）, has been hydrothermally synthesized and structurally characterized by X-ray single-crystal diffraction, elemental analyses, IR, TG- DTA and magnetic susceptibility measurement. It crystallizes in triclinic, space group P1^- with a = 6.6842（5）, b = 7.5741（6）, c = 20.5755（15）A, α = 90.1160（10）, β = 97.0560（10）, γ = 97.3350（10）°, V= 1025.16（13）A^3, Z = 2, MnC24H14N6O5, Mr= 521.35, Dc= 1.689 g/cm^3, F（000） = 530, μ（MoKa） = 0.699 mm^-1, R = 0.0366 and wR = 0.0810. Compound 1 contains one- dimensional chains which are further stacked through π-π interactions to form a 3D supramolecular architecture. The water molecule O（1W） is involved in hydrogen bonding interactions with symmetric carboxylate oxygen atom 0（4） at （x＋ 1, y＋1, z） and symmetric PZDC nitrogen atom N（6） at （1-x, 1-y, 1-z）, which completes the structure of 1. Magnetic susceptibility measurement indicates that the compound behaves a weak antiferromagnetic exchange interaction.
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 Science and Technology Development Project of Jilin Provincial Science&Technology Department(201205080)the Science and Technology Research Projects of the Education Office of Jilin Province(No.2013.384)
文摘A new metal-organic coordination polymer [Zn（pzdc）（mbix）]n·nH2O（H2pzdc = pyrazine-2,3- dicarboxylic acid, mbix = 1,3-bis（imidazol-1-ylmethyl）-benzene） 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in monoclinic system, space group P21/n with a = 8.5519（6）, b = 14.8764（10）, c = 16.4108（11） A, β = 103.4520（10）o, V = 2030.5（2）A^3, C（20）H（18）N6O5Zn, Mr = 487.77, Dc = 1.596 g/cm^3, F（000） = 1000, Z = 4, μ（MoK α） = 1.257 mm^-1, the final R = 0.0260 and w R = 0.0706 for 3445 observed reflections（I 〉 2σ（I））. The structure of 1 exhibits a one-dimensional chain-like structure. In addition, natural bond orbital（NBO） analysis was performed by the PBE0/LANL2DZ method in Gaussian 03 Program. The calculation results show obvious covalent interaction between the coordinated atoms and Zn（Ⅱ） ion.
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））.
文摘Two complexes[Ni L(HL)](OAc)(1)and[Zn L(OAc)]_(n)(2)(HL=1-(3-ethylpyrazin-2-yl)ethylidene)-4-methylthiosemicarbazide)have been synthesized and structurally determined by single-crystal X-ray diffraction.The results show that the Ni(Ⅱ)ion in 1 is surrounded by two independent thiosemicarbazone ligands with N4 S2 donor set,one of which is anionic.However,in complex 2,the Zn(Ⅱ)ion with a distorted tetragonal pyramid coordination geometry is five-coordinated,involving twoμ-OCO acetate anions,one tridentate enolizated ligand L-,thus forming one dimension chain-like framework along a axis.Moreover,the fluorescence spectra indicate that the interactions of the complexes with DNA are stronger than that of the thiosemicarbazone ligand.CCDC:1587278,1;1587280,2.
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.
基金This work was supported by the Science and Technology Bureau of Jinhua City (No 2003-01-179)
文摘A novel pyrazine-2,3-dicarboxylic acid bridged Co(II) phen complex 2 ∞ [Co- (phen)(μ-L)3/3]?H2O (H2L = pyrazine-2,3-dicarboxylic acid) has been hydrothermally synthesized, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group P21/n with a = 11.480(2), b = 11.885(2), c = 12.939(3) ?, β = 110.55(3)°, V = 1653.1(6) ?3, Mr = 423.25, Dc = 0.425 g/cm3, Z = 4, R = 0.0361 and wR = 0.1011. The title complex consists of 2D 2 ∞ [Co(phen)(μ-L)3/3] layers and crystal water molecules. Each Co atom is octahedrally coordinated by three N atoms and three O atoms to form 2D 2 ∞ [Co(phen)(μ-L)3/3] polymeric layers. Furthermore, such 2D layers are stacked into 3D supramolecular frameworks via Van der Waals’ intermolecular forces, strong and weak hydrogen-bond interactions. The coordination phen and crystal water molecules are resided into cavities of the frameworks.
