Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA...Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.展开更多
A new conformational carbon-carbon bond free radical initiator diethyl [2,3- di(ethoxycarbonyl)-2,3-di(p-nitrophenyl)] succinate (EMNPS) was synthesized and identified by elemental analysis, FAB-MS, IR and 1H NMR spec...A new conformational carbon-carbon bond free radical initiator diethyl [2,3- di(ethoxycarbonyl)-2,3-di(p-nitrophenyl)] succinate (EMNPS) was synthesized and identified by elemental analysis, FAB-MS, IR and 1H NMR spectroscopy. The analytical results of single crystal X-ray show the conforma- tion of EMNPS tends to be a stagger gauche form, and torsion angle of the two gauche phenyls is smaller than 60? There is obvious elongation in central car- bon-carbon bond length (0.161 nm). EMNPS can be decomposed into two relatively stable free radicals measured by ESR. By initiating bulk polymeriza-tion of methyl methacrylate (MMA), EMNPS shows the ability of controlling the molecular weight of polymers.展开更多
A new complex of N,N?-bis(p-nitrophenyl)-2,2?-(p-phenylene-dioxy) diacetamide DMF monohydrate, C25H25N5O9·H2O (Mr = 557.52), has been synthesized and its structure was determined by X-ray crystallography method. ...A new complex of N,N?-bis(p-nitrophenyl)-2,2?-(p-phenylene-dioxy) diacetamide DMF monohydrate, C25H25N5O9·H2O (Mr = 557.52), has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to monoclinic system, space group P21/c with a = 7.2812, b = 25.5894, c = 14.3434 ?, β = 91.110(1)o, V = 2672.0(2) ?3, Dc = 1.386 g/cm3, F(000) = 1168, μ = 0.109 mm-1 and Z = 4. The final R = 0.0493 and wR = 0.1173 for 3389 observed reflections with I > 2σ(I). The asymmetric unit of the title complex consists of monomeric N,N?-bis(p-nitrophenyl)-2,2?-(p-phenyleneioxy)diacetamide 1, one DMF and one water molecule, which are incorporated during recrystallization. The molecules are linked into a three-dimensional network by π…π interactions as well as intermolecular interactions among DMF, water molecule and 1.展开更多
The hydrolysis of p-nitrophenyl acetate (p-NPA) catalyzed by seryl-histidine or histidine has been monitored by electrospray ionization mass spectrometry in the presence of the internal calibration, 8-anilino-1-naphth...The hydrolysis of p-nitrophenyl acetate (p-NPA) catalyzed by seryl-histidine or histidine has been monitored by electrospray ionization mass spectrometry in the presence of the internal calibration, 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS). The half-life of p-NPA in the presence of 10 mmol·L -1 seryl-histidine or histidine at 25 ℃ was 370 min and 70 min respectively. With the occurrence of acetyl seryl-histidine and acetyl histidine in the reaction, and the fact that p-NPA was stable in the presence of 10 mmol·L -1 serine, an imidazolysis mechanism has been proposed, which is in accordance with the reported work.展开更多
文摘Polymeric β-cyclodextrin (β-CD) supported by crosslinked poly(acrylamide-co-vinylamine) was synthesized as anartificial analog of hydrolytic enzyme and its catalysis of the hydrolysis of p-nitrophenyl acetate (p-NPA) was theninvestigated. The result showed that the polymer-supported β-CD could accelerate the hydrolytic reaction of p-NPA morequickly than β-CD itself and crosslinked poly(acrylamide-co-vinylamine) alone. The acceleration rate of the polymer-supported β-CD was about 10 times as fast as that of free β-CD in 0.01 mol/L phosphate buffer (pH 7.4) containing 32%DMSO at 37±0.1℃ when the molar amount of β-CD units in the polymer was equal to that of free β-CD in the experiments.The enhanced acceleration of thc polymer-supported β-CD should be ascribed to the cooperative contribution of theinclusion effect of β-CD ring and the nucleophilic effect of amino groups on the polymeric support.
文摘A new conformational carbon-carbon bond free radical initiator diethyl [2,3- di(ethoxycarbonyl)-2,3-di(p-nitrophenyl)] succinate (EMNPS) was synthesized and identified by elemental analysis, FAB-MS, IR and 1H NMR spectroscopy. The analytical results of single crystal X-ray show the conforma- tion of EMNPS tends to be a stagger gauche form, and torsion angle of the two gauche phenyls is smaller than 60? There is obvious elongation in central car- bon-carbon bond length (0.161 nm). EMNPS can be decomposed into two relatively stable free radicals measured by ESR. By initiating bulk polymeriza-tion of methyl methacrylate (MMA), EMNPS shows the ability of controlling the molecular weight of polymers.
基金The project was supported by the National Natural Science Foundation of China(20275020,20475030)the Outstanding Adult-young Scientific Research Encouraging Foundation of Shandong Province(No.03BS081).
文摘A new complex of N,N?-bis(p-nitrophenyl)-2,2?-(p-phenylene-dioxy) diacetamide DMF monohydrate, C25H25N5O9·H2O (Mr = 557.52), has been synthesized and its structure was determined by X-ray crystallography method. The crystal belongs to monoclinic system, space group P21/c with a = 7.2812, b = 25.5894, c = 14.3434 ?, β = 91.110(1)o, V = 2672.0(2) ?3, Dc = 1.386 g/cm3, F(000) = 1168, μ = 0.109 mm-1 and Z = 4. The final R = 0.0493 and wR = 0.1173 for 3389 observed reflections with I > 2σ(I). The asymmetric unit of the title complex consists of monomeric N,N?-bis(p-nitrophenyl)-2,2?-(p-phenyleneioxy)diacetamide 1, one DMF and one water molecule, which are incorporated during recrystallization. The molecules are linked into a three-dimensional network by π…π interactions as well as intermolecular interactions among DMF, water molecule and 1.
文摘The hydrolysis of p-nitrophenyl acetate (p-NPA) catalyzed by seryl-histidine or histidine has been monitored by electrospray ionization mass spectrometry in the presence of the internal calibration, 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS). The half-life of p-NPA in the presence of 10 mmol·L -1 seryl-histidine or histidine at 25 ℃ was 370 min and 70 min respectively. With the occurrence of acetyl seryl-histidine and acetyl histidine in the reaction, and the fact that p-NPA was stable in the presence of 10 mmol·L -1 serine, an imidazolysis mechanism has been proposed, which is in accordance with the reported work.
