The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffracti...The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffraction analysis at room temperature indicates that the title compound (C21H23N5O12Cl2, Mr = 608.34) crystallizes in triclinic, space group P 1 with a = 7.992(8), b = 12.82(1), c = 13.42(1) A, α = 104.77(2),β = 97.84(2), r= 95.48(2)°, V= 1305(2) A3, Z = 2,DC= 1.549 g/cm3, F(000) = 628 and μ(MoKα) = 0.317 mm-1. The final R and wR factors are 0.0566 and 0.1016, respectively with 4325 independent reflections. The quinoxaline ring makes the dihedral angles of 44.2(2) and 33.9(5)° with two protonated pyridine rings whose dihedral angle is 48.1(6)°. The favored orientation of two protonated pyridine rings is that thek N atoms are opposite to each other. There exist intra- and inter-molecular N-H…O hydrogen bonds and π…π interactions which stabilize the structure further.展开更多
Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PSⅡ) membrane during heat treatment was investigated using...Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PSⅡ) membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PSⅡ membrane and influenced CD spectra of PSⅡ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PSⅡ membrane. The results indicate that PC can protect PSⅡ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.展开更多
基金This work was financially supported by NNSFC(No.29971019)
文摘The diprotonated perchlorate salt of 2,3-di-2-pyridyl-5-nitroquinoxaline [C18H13N5O2](ClO4)2·(CH3OH)·(C2H5OH) has been synthesized and characterized by elemental analysis, IR and NMR spectra. X-ray diffraction analysis at room temperature indicates that the title compound (C21H23N5O12Cl2, Mr = 608.34) crystallizes in triclinic, space group P 1 with a = 7.992(8), b = 12.82(1), c = 13.42(1) A, α = 104.77(2),β = 97.84(2), r= 95.48(2)°, V= 1305(2) A3, Z = 2,DC= 1.549 g/cm3, F(000) = 628 and μ(MoKα) = 0.317 mm-1. The final R and wR factors are 0.0566 and 0.1016, respectively with 4325 independent reflections. The quinoxaline ring makes the dihedral angles of 44.2(2) and 33.9(5)° with two protonated pyridine rings whose dihedral angle is 48.1(6)°. The favored orientation of two protonated pyridine rings is that thek N atoms are opposite to each other. There exist intra- and inter-molecular N-H…O hydrogen bonds and π…π interactions which stabilize the structure further.
基金supported by the State Key Basic Research and Development Program(Grant No.G1998010100)the National Natural Science Foundation of China(Grant No.39890390).
文摘Photosystem Ⅱ membrane was reconstituted with phosphatidylcholine (PC) with different kinds of fatty acyl chains and the protection of PC to photosystem Ⅱ (PSⅡ) membrane during heat treatment was investigated using oxygen electrode, variable fluorescence and circular dichroism (CD) spectroscopy. Heat treatment decreased the oxygen evolution rate and the F′v/Fm′ ratio of PSⅡ membrane and influenced CD spectra of PSⅡ membrane, but PC inhibited the effect of heat treatment on the oxygen evolution rate, the F′v/F′m ratio and CD spectra of PSⅡ membrane. The results indicate that PC can protect PSⅡ membrane against heat treatment and the alterations in the unsaturated fatty acid extent in PC can cause the changes of the protection ability.
