The first electronic structural study of the complete valence shell binding energy spectra of the antimicrobial agent diacetyl, encompassing both the outer and inner valence regions, is reported. The binding energy sp...The first electronic structural study of the complete valence shell binding energy spectra of the antimicrobial agent diacetyl, encompassing both the outer and inner valence regions, is reported. The binding energy spectra as well as the individual orbital momentum profiles have been measured by using a high resolution （e, 2e） electron momentum spectrometer （EMS） at an impact energy of 1200eV plus the binding energy, and using symmetric noncoplanar kinematics. The experimental orbital electron momentum profiles are compared with self-consistent field （SCF） theoretical profiles calculated using the Hartree-Fock approximation and Density Functional theory predictions in the target Kohn-Sham approximation which includes some treatment of correlation via the exchange and correlation potentials with a range of basis sets. The pole strengths of the main ionization peaks from the inner valence orbitals are estimated.展开更多
Catalytic hydrogenation of diacetyl monoxime to tetramethylpyrazine, by the homogeneous catalysts generated in situ from some transition metal chlorides with triphenylphosphine in ethanol under H-2 pressure of 0.6 sim...Catalytic hydrogenation of diacetyl monoxime to tetramethylpyrazine, by the homogeneous catalysts generated in situ from some transition metal chlorides with triphenylphosphine in ethanol under H-2 pressure of 0.6 similar to 4.6 MPa at 100 similar to 150 degrees C, has been studied. The optimum H-2 partial pressure was observed at about 1.3 MPa. The maximum conversion of diacetyl monoxime and yield of tetramethylpyrazine were 97% and 90%, respectively.展开更多
Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedi...Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedione and aldehydes at both higher and lower temperature even in lower concentration.They al so show catalytic selectivity at lower temperature.展开更多
Premature plant senescence induced by abiotic stresses is a major cause of agricultural losses worldwide. Tools for suppressing stress-induced plant senescence are limited. Here, we report that diacetyl, a natural com...Premature plant senescence induced by abiotic stresses is a major cause of agricultural losses worldwide. Tools for suppressing stress-induced plant senescence are limited. Here, we report that diacetyl, a natural compound emitted by the plantbeneficial bacterium Bacillus amyloliquefaciens,suppresses abscisic acid-mediated foliar senescence in Arabidopsis thaliana under various abiotic stress conditions. Our results establish diacetyl as an effective protector against stressinduced plant senescence and reveal a molecular mechanism for bacteria-enhanced plant stress resistance.展开更多
The effect of metallic ions on the nitrolysis of DAPT [3,7-diacetyl-1,3,5,7-tetraazabicyclo（3.3.1）nonane] and HA （hexamine） was investigated by experimental and theoretical approaches. The combinatorial reagent, M...The effect of metallic ions on the nitrolysis of DAPT [3,7-diacetyl-1,3,5,7-tetraazabicyclo（3.3.1）nonane] and HA （hexamine） was investigated by experimental and theoretical approaches. The combinatorial reagent, M（NO3）n/Ac20/NH4NO3 （M=Mg2＋, Cu2＋, Pb2＋, Bi3＋, Fe3＋ and Zr4＋）, was found to be efficient in the experiment of the nitrolysis of DAPT. A key intermediate during the nitrolysis of DAPT was detected by 1H NMR. The formation mechanism of the intermediate was proposed and analyzed. Some discrepant results for the nitrolysis of DAPT and HA catalyzed by different metallic nitrates were explained based on hard-soft and acid-base principle and stabilized energy of ion-complex. From the latter point of view, some cations with high polarizable ligands, e.g., O802CF3-, （CF3SO2）2N-, and （C4F9SO2）2N-, can increase the yields. Two newly designed catalysts, Cu[（CF3SO2）2N]2 and Cu[（C4F9SO2）2N]2, were tested to be highly efficient.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant Nos 19854002, 19774037 and 10274040） and the Research Fund for the Doctoral Program Foundation of Institution of Higher Education of China （Grant No 1999000327）.
文摘The first electronic structural study of the complete valence shell binding energy spectra of the antimicrobial agent diacetyl, encompassing both the outer and inner valence regions, is reported. The binding energy spectra as well as the individual orbital momentum profiles have been measured by using a high resolution （e, 2e） electron momentum spectrometer （EMS） at an impact energy of 1200eV plus the binding energy, and using symmetric noncoplanar kinematics. The experimental orbital electron momentum profiles are compared with self-consistent field （SCF） theoretical profiles calculated using the Hartree-Fock approximation and Density Functional theory predictions in the target Kohn-Sham approximation which includes some treatment of correlation via the exchange and correlation potentials with a range of basis sets. The pole strengths of the main ionization peaks from the inner valence orbitals are estimated.
文摘Catalytic hydrogenation of diacetyl monoxime to tetramethylpyrazine, by the homogeneous catalysts generated in situ from some transition metal chlorides with triphenylphosphine in ethanol under H-2 pressure of 0.6 similar to 4.6 MPa at 100 similar to 150 degrees C, has been studied. The optimum H-2 partial pressure was observed at about 1.3 MPa. The maximum conversion of diacetyl monoxime and yield of tetramethylpyrazine were 97% and 90%, respectively.
文摘Five novel bis—(N—alkyl—N,N—dimethyl ammoni(?)n)polyethyleneglyool ether salts prepared by our previously reported proced(?)e show high catalytic efficiency in the condensation of 1,4—diacetyl— 2,5—piperazinedione and aldehydes at both higher and lower temperature even in lower concentration.They al so show catalytic selectivity at lower temperature.
文摘Premature plant senescence induced by abiotic stresses is a major cause of agricultural losses worldwide. Tools for suppressing stress-induced plant senescence are limited. Here, we report that diacetyl, a natural compound emitted by the plantbeneficial bacterium Bacillus amyloliquefaciens,suppresses abscisic acid-mediated foliar senescence in Arabidopsis thaliana under various abiotic stress conditions. Our results establish diacetyl as an effective protector against stressinduced plant senescence and reveal a molecular mechanism for bacteria-enhanced plant stress resistance.
文摘The effect of metallic ions on the nitrolysis of DAPT [3,7-diacetyl-1,3,5,7-tetraazabicyclo（3.3.1）nonane] and HA （hexamine） was investigated by experimental and theoretical approaches. The combinatorial reagent, M（NO3）n/Ac20/NH4NO3 （M=Mg2＋, Cu2＋, Pb2＋, Bi3＋, Fe3＋ and Zr4＋）, was found to be efficient in the experiment of the nitrolysis of DAPT. A key intermediate during the nitrolysis of DAPT was detected by 1H NMR. The formation mechanism of the intermediate was proposed and analyzed. Some discrepant results for the nitrolysis of DAPT and HA catalyzed by different metallic nitrates were explained based on hard-soft and acid-base principle and stabilized energy of ion-complex. From the latter point of view, some cations with high polarizable ligands, e.g., O802CF3-, （CF3SO2）2N-, and （C4F9SO2）2N-, can increase the yields. Two newly designed catalysts, Cu[（CF3SO2）2N]2 and Cu[（C4F9SO2）2N]2, were tested to be highly efficient.
