A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recomb...A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recombinant strain could grow on aniline as sole carbon, nitrogen and energy source. Enzymatic assays revealed that the exogenous genes including aniline dioxygenase (AD) and catechol 2,3-dioxygenase (C230) genes could well express in the recombinant strain with the activities of AD and C230 up to 0.31 U/mg wet cell and 1.92 U/mg crude proteins, respectively. The AD or C23O of strain AN3 could only catalyze aniline or catechol but not any other substituted substrates. This recombinant strain contained a recombinant plasmid, pKC505-AN1, in which a 29.7-kb DNA fragment from Delftia sp. AN3 was inserted. Sequencing and open reading frame (orfs) analysis of this 29.7 kb fragment revealed that it contained at least 27 orfs, among them a gene cluster (consisting of at least 16 genes, named danQTA1A2BRDCEFG1HIJKG2) was responsible for the complete metabolism of aniline to TCA-cycle intermediates. This gene cluster could be divided into two main parts, the upper sequences consisted of 7 genes (danQTA1A2BRD) were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, and the central genes (danCEFG1HIJKG2) were expected to encode meta-cleavage pathway enzymes for catechol degradation to TCA-cycle intermediates. Unlike clusters tad from Delftia tsuruhatensis AD9 and tdn from Pseudomonas putida UCC22, in this gene cluster, all the genes were in the same transcriptional direction. There was only one set of C230 gene (danC) and ferredoxin-like protein gene (danD). The presence of only one set of these two genes and specificity of AD and C230 might be the reason for strain AN3 could only degrade aniline. The products of danQTA1A2BRDC showed 99%-100% identity to those from Delftia acidovorans 7N, and 50%-85% identity to those of tad cluster from D. tsuruhatensis AD9 in amino acid residues. Besides this dan cluster, the 29.7 kb fragment also contained genes encoding the trans-membrane transporter and transposases which might be needed for transposition of the gene cluster. Pulsed-field gel electrophoresis (PFGE) and plasmid curing experiments suggested that the dan cluster might be encoded on the chromosome of strain AN3. The GenBank accession number for the dan cluster of Delftia sp. AN3 is DQ661649.展开更多
The title complex [Cu3L3(H2O)]DMFH2O (H2L = 4-(3-hydroxy-2-ethyl-4- pyridinone-1-yl)-aniline condensation salicylaldehyde) was obtained. The single-crystal X-ray study shows that it is a trinuclear compound [Cu3(C20H1...The title complex [Cu3L3(H2O)]DMFH2O (H2L = 4-(3-hydroxy-2-ethyl-4- pyridinone-1-yl)-aniline condensation salicylaldehyde) was obtained. The single-crystal X-ray study shows that it is a trinuclear compound [Cu3(C20H15N2O3)3(H2O)]DMFH2O. The coordi- nation sphere about each copper ion in the complex consists of two oxygen atoms from hydroxylpyridinone moiety of one ligand and one oxygen and one nitrogen atoms from salicyladehyde Schiff-base moiety of another ligand arranged in a slightly distorted square planar geometry. Among the three copper ions, one (Cu(2)) is coordinated by the other oxygen atom of water molecule on the fifth coordinate position to form a distorted square pyramid geometry. The crystal is of monoclinic, space group P21/c with a = 12.9202(5), b = 27.197(1), c = 17.0116(7) ? b = 100.588(1), V = 5875.9(4) 3, Z = 4, C63H57N7O12Cu3, Mr = 1294.78, Dc = 1.464 g/cm3, m = 1.146 mm-1, F(000) = 2668, R = 0.0784 and wR = 0.1546 for 6926 observed reflections with I > 2s(I). The differences of coordinate bond lengths are observed between anhydrous and hydrous units: in the former unit, the average bond lengths are 1.978 ?for CuN (azomethine), 1.883 ?for CuO (phenolic) in Schiff-base moiety, 1.959 ?for CuO (keto), and 1.919 ?for CuO (hydroxy) in hydroxypyridinone moiety; while those in the latter are longer with the following corresponding values: 1.985(5), 1.908(5), 1.993(5) and 1.919(4) ? respectively. The Cu(2)O (water) bond length is 2.375(6) ?展开更多
The Ag/γ-Fe_2O_3 nanocomposite was synthesized by solvothermal reduction method via using ferric nitrate and silver nitrate as raw materials, and ethylene glycol as the reducing agent. The composite was characterized...The Ag/γ-Fe_2O_3 nanocomposite was synthesized by solvothermal reduction method via using ferric nitrate and silver nitrate as raw materials, and ethylene glycol as the reducing agent. The composite was characterized by X-ray powder diffraction, scanning electron microscope, transmission electron microscope, and energy dispersive X-ray. The prepared Ag/γ-Fe_2O_3 was used for the catalytic hydrogenation of nitrobenzene to aniline by hydrazine hydrate. The factors such as the silver content in the catalyst, reaction time, reaction temperature and the regeneration of catalyst were investigated. The results showed that the yield of aniline reached 100% by utilizing the 1%wt(nitrobenzene) Ag/γ-Fe_2O_3 for the catalytic hydrogenation of nitrobenzene for 3 h to obtain aniline at 78 ℃, hydrazine hydrate as the hydrogen source, while the silver content in the catalyst was 3%mol.展开更多
The electrochemical synthesis of three-dimensional (3D) polyaniline (PAN) network structure on 3-aminobenzenesulfonic acid (ABSA) functionalized glassy carbon electrode (GCE) and its electro-catalytic oxidation toward...The electrochemical synthesis of three-dimensional (3D) polyaniline (PAN) network structure on 3-aminobenzenesulfonic acid (ABSA) functionalized glassy carbon electrode (GCE) and its electro-catalytic oxidation towards ascorbic acid (AA) had been studied. ABSA was first covalently grafted on GCE surface via the direct electrochemical oxidation of ABSA on GCE, which was followed by the electrochemical polymerization of aniline on the ABSA functionalized GCE. Then PAN-ABSA composite film modified GCE (PAN-ABSA/GCE) was obtained. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and electrochemical techniques had been employed to characterize the obtained electrodes. Due to the effective doping of ABSA in PAN, the redox electro-activity of PAN had been extended to neutral and even the basic media, thus, the PAN-ABSA composite film modified GCE could be used for electro-catalytic oxidation of AA in 0.1 M phosphate buffer solution (PBS, pH 6.8). At PAN-ABSA/GCE the oxidation over-potential of AA shifted from 0.39 V at GCE to 0.17 V with a greatly enhanced current response. The electro-catalytic oxidation peak current of AA increased linearly with the increasing AA concentration over the range of 5.00 × 10-4-1.65 × 10-2 M with a correlation coefficient of 0.9973. The detection limit (S/N = 3) for AA was 1.16 × 10-6 M. Chronoamperometry had also been employed to investigate the electro-catalytic oxidation of AA at PAN-ABSA/GCE. The modified electrode had been used for detecting AA in real samples with satisfactory results.展开更多
An efficient environment-friendly synthesis of N-phenylpiperidine was developed from aniline and 1,5-pentanediol over γ-Al2O3 catalyst under atmospheric pressure. The conversion of 1,5-pentanediol reached 97% and the...An efficient environment-friendly synthesis of N-phenylpiperidine was developed from aniline and 1,5-pentanediol over γ-Al2O3 catalyst under atmospheric pressure. The conversion of 1,5-pentanediol reached 97% and the selectivity for N-phenylpiperidine attained 94%. The structure of the catalyst was characterized by NH3-TPD and BET. The influences of calcination temperature of the catalyst and reaction temperature on activity and selectivity of the catalyst were investigated.展开更多
We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidaz...We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidazole as activator.展开更多
文摘A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recombinant strain could grow on aniline as sole carbon, nitrogen and energy source. Enzymatic assays revealed that the exogenous genes including aniline dioxygenase (AD) and catechol 2,3-dioxygenase (C230) genes could well express in the recombinant strain with the activities of AD and C230 up to 0.31 U/mg wet cell and 1.92 U/mg crude proteins, respectively. The AD or C23O of strain AN3 could only catalyze aniline or catechol but not any other substituted substrates. This recombinant strain contained a recombinant plasmid, pKC505-AN1, in which a 29.7-kb DNA fragment from Delftia sp. AN3 was inserted. Sequencing and open reading frame (orfs) analysis of this 29.7 kb fragment revealed that it contained at least 27 orfs, among them a gene cluster (consisting of at least 16 genes, named danQTA1A2BRDCEFG1HIJKG2) was responsible for the complete metabolism of aniline to TCA-cycle intermediates. This gene cluster could be divided into two main parts, the upper sequences consisted of 7 genes (danQTA1A2BRD) were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, and the central genes (danCEFG1HIJKG2) were expected to encode meta-cleavage pathway enzymes for catechol degradation to TCA-cycle intermediates. Unlike clusters tad from Delftia tsuruhatensis AD9 and tdn from Pseudomonas putida UCC22, in this gene cluster, all the genes were in the same transcriptional direction. There was only one set of C230 gene (danC) and ferredoxin-like protein gene (danD). The presence of only one set of these two genes and specificity of AD and C230 might be the reason for strain AN3 could only degrade aniline. The products of danQTA1A2BRDC showed 99%-100% identity to those from Delftia acidovorans 7N, and 50%-85% identity to those of tad cluster from D. tsuruhatensis AD9 in amino acid residues. Besides this dan cluster, the 29.7 kb fragment also contained genes encoding the trans-membrane transporter and transposases which might be needed for transposition of the gene cluster. Pulsed-field gel electrophoresis (PFGE) and plasmid curing experiments suggested that the dan cluster might be encoded on the chromosome of strain AN3. The GenBank accession number for the dan cluster of Delftia sp. AN3 is DQ661649.
基金This work was supported by the foundation of Natural Science Research of Jiangsu Education Department (02KJB150007)
文摘The title complex [Cu3L3(H2O)]DMFH2O (H2L = 4-(3-hydroxy-2-ethyl-4- pyridinone-1-yl)-aniline condensation salicylaldehyde) was obtained. The single-crystal X-ray study shows that it is a trinuclear compound [Cu3(C20H15N2O3)3(H2O)]DMFH2O. The coordi- nation sphere about each copper ion in the complex consists of two oxygen atoms from hydroxylpyridinone moiety of one ligand and one oxygen and one nitrogen atoms from salicyladehyde Schiff-base moiety of another ligand arranged in a slightly distorted square planar geometry. Among the three copper ions, one (Cu(2)) is coordinated by the other oxygen atom of water molecule on the fifth coordinate position to form a distorted square pyramid geometry. The crystal is of monoclinic, space group P21/c with a = 12.9202(5), b = 27.197(1), c = 17.0116(7) ? b = 100.588(1), V = 5875.9(4) 3, Z = 4, C63H57N7O12Cu3, Mr = 1294.78, Dc = 1.464 g/cm3, m = 1.146 mm-1, F(000) = 2668, R = 0.0784 and wR = 0.1546 for 6926 observed reflections with I > 2s(I). The differences of coordinate bond lengths are observed between anhydrous and hydrous units: in the former unit, the average bond lengths are 1.978 ?for CuN (azomethine), 1.883 ?for CuO (phenolic) in Schiff-base moiety, 1.959 ?for CuO (keto), and 1.919 ?for CuO (hydroxy) in hydroxypyridinone moiety; while those in the latter are longer with the following corresponding values: 1.985(5), 1.908(5), 1.993(5) and 1.919(4) ? respectively. The Cu(2)O (water) bond length is 2.375(6) ?
基金supported by the science and technology support project of Jiangsu Province(No.BY2015057-03)
文摘The Ag/γ-Fe_2O_3 nanocomposite was synthesized by solvothermal reduction method via using ferric nitrate and silver nitrate as raw materials, and ethylene glycol as the reducing agent. The composite was characterized by X-ray powder diffraction, scanning electron microscope, transmission electron microscope, and energy dispersive X-ray. The prepared Ag/γ-Fe_2O_3 was used for the catalytic hydrogenation of nitrobenzene to aniline by hydrazine hydrate. The factors such as the silver content in the catalyst, reaction time, reaction temperature and the regeneration of catalyst were investigated. The results showed that the yield of aniline reached 100% by utilizing the 1%wt(nitrobenzene) Ag/γ-Fe_2O_3 for the catalytic hydrogenation of nitrobenzene for 3 h to obtain aniline at 78 ℃, hydrazine hydrate as the hydrogen source, while the silver content in the catalyst was 3%mol.
文摘The electrochemical synthesis of three-dimensional (3D) polyaniline (PAN) network structure on 3-aminobenzenesulfonic acid (ABSA) functionalized glassy carbon electrode (GCE) and its electro-catalytic oxidation towards ascorbic acid (AA) had been studied. ABSA was first covalently grafted on GCE surface via the direct electrochemical oxidation of ABSA on GCE, which was followed by the electrochemical polymerization of aniline on the ABSA functionalized GCE. Then PAN-ABSA composite film modified GCE (PAN-ABSA/GCE) was obtained. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and electrochemical techniques had been employed to characterize the obtained electrodes. Due to the effective doping of ABSA in PAN, the redox electro-activity of PAN had been extended to neutral and even the basic media, thus, the PAN-ABSA composite film modified GCE could be used for electro-catalytic oxidation of AA in 0.1 M phosphate buffer solution (PBS, pH 6.8). At PAN-ABSA/GCE the oxidation over-potential of AA shifted from 0.39 V at GCE to 0.17 V with a greatly enhanced current response. The electro-catalytic oxidation peak current of AA increased linearly with the increasing AA concentration over the range of 5.00 × 10-4-1.65 × 10-2 M with a correlation coefficient of 0.9973. The detection limit (S/N = 3) for AA was 1.16 × 10-6 M. Chronoamperometry had also been employed to investigate the electro-catalytic oxidation of AA at PAN-ABSA/GCE. The modified electrode had been used for detecting AA in real samples with satisfactory results.
基金supported by the Natural Science Foundation of Liaoning Province(No.20072154)
文摘An efficient environment-friendly synthesis of N-phenylpiperidine was developed from aniline and 1,5-pentanediol over γ-Al2O3 catalyst under atmospheric pressure. The conversion of 1,5-pentanediol reached 97% and the selectivity for N-phenylpiperidine attained 94%. The structure of the catalyst was characterized by NH3-TPD and BET. The influences of calcination temperature of the catalyst and reaction temperature on activity and selectivity of the catalyst were investigated.
文摘We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidazole as activator.