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设计了一种化学发光免疫分析试剂吖啶酯的合成新路线,以二苯胺为原料合成吖啶-9-羧酸,经酰氯化后与3-(4-羟基苯基)-丙酸-N-羟基琥珀酰亚胺酯反应得4-(2-琥珀酰亚胺基氧羰基乙基)苯基-9-吖啶羧酸酯,最后与氟磺酸甲酯反应即得4-(2-琥珀酰亚胺基氧羰基)苯基-10-甲基吖啶-9-羧酸酯氟磺酸盐(俗称吖啶酯). 相似文献
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本文研究了水溶液中γ-环糊精诱导2-萘甲酸酯的光二聚反应.γ-环糊精的限制性疏水空腔能够容纳两个2-萘甲酸甲酯(或乙酯)分子形成稳定的2:1包结复合物NA@γ-CD,光照NA@γ-CD包结物水溶液能高效、快速、高选择地生成2-萘甲酸酯的类立方烷光二聚体,并且该反应有一定程度的对映体选择性. 相似文献
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本文用聚四乙二醇柔性链将9-氨基啶和不同取代基的苯甲酸酯连接起来,合成了一类新型二元分子体系。对各体系中9-氨基啶的电子转移荧光猝灭进行了研究,并根据稳态荧光猝灭计算了体系中的荧光猝灭效率和荧光猝灭速率常数。 相似文献
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本工作合成了硫代α-萘甲酸-s-苯酯和硫代苯甲酸-s-苯并噻唑酯,对其光化学和光物理行为进行了研究。由于萘基和苯并噻唑基的引入,有效地增加了该类化合物的最大吸收光谱范围,并在受光激发后,可观察到有荧光发射。工作中发现,硫代α-萘甲酸-s-苯酯荧光发射强度会随光照时间的增加而加强,这是因该化合物光解时生成了有高荧光量子产率的α,α'-联萘;但在硫代苯甲酸-s-苯并噻唑酯的光解中观察不到上述现象,文章对所得结果进行了讨论。 相似文献
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拓扑结构对聚合物性能具有重要影响.本文通过调控聚合条件制备内环化聚(β-氨基酯)并探究其生物物理性能.以三羟甲基丙烷三丙烯酸酯(TMPTA)和4-吗啉丙胺(MPA)为单体并控制其投料比及体系单体浓度,利用迈克尔加成反应制备了两种内环化聚(β-氨基酯).使用凝胶渗透色谱仪(GPC)、核磁共振波谱仪(NMR)和原子力显微镜(AFM)等对内环化聚(β-氨基酯)的化学组成、拓扑结构和生物物理性能进行表征与分析.结果表明,随着环化度的增加,聚(β-氨基酯)对DNA压缩能力增强,降解速率加快,质子缓冲能力提高,细胞毒性增大.本文研究结果为制备和表征内环化聚(β-氨基酯)提供了新思路,也为设计有效的基因递送载体提供了依据. 相似文献
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用叠氮钠和D-苯基甘氨酸为原料合成了2-[4-取代苯基-2-氧-3-酰氨基-1-吖啶基]-2-苯基乙酸类化合物. 在叠氮乙酰氯和亚胺化合物在三乙胺存在下在-78℃时进行环缩合反应, 可导致立体专一性合成顺-甲基-2-(4-取代苯基-2-酮-3-叠氮-1-吖啶基)-2-苯基乙酸, 催化氢化或硫化氢可减少叠氮基和得到氨基β-内酰胺后者被酰化生成α-酰氨基-β-内酰胺, 在温和碱性条件下选择性地氢化酯基既不会影响β-内酰胺环, 又不全影响酰胺侧链. 合成了二十个标题化合物, 其中九个被表明对β-内酰胺酶有抑制活性. 相似文献
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Abstract— Orotic acid (I) and 3-methylorotic acid (II) are the only orotic acid derivitives which efficiently sensitire emission from Eu(III) in D2 O solution. This emission is only weakly sensitized by I-methylorotic acid (III), 1,3-dimethylorotic acid (IV), the methyl and isopropyl esters of orotic acid (V) 6-acetyluracil (VI) and not sensitized at all by the bases uracil. thymine and their nucleosides. Substituent groups on either the carboxyl group or the N-l position of the ring thus prevent efficient energy transfer from the excited orotic acid to Eu(III). These structural requirements for efficient energy transfer are the same as the structural requirements for formation of a stable. bidentate. ground state complex between Eu(III) and orotic acid (VII) (Sarpotdar and Burr, 1978).
We, therefore, propose that sensitization of Eu(III) emission by orotic acid at pH 5 is an example of energy transfer within the bidentate complex of Eu(III) and orotic acid. We also propose that the complexed orotic acid is itself excited by eollisional energy transfer from free triplet excited orotic acid (since the concentration of complex measured to be present. 5–7%, is too low to account for the efficiency of the sensitization). We also propose that emission from the excited complexed Eu(III) can be either from the complexed ion or from free Eu(III)* resulting from dissociation of the complex during the lifetime of the excited ion.
The efficiency of Eu(III) sensitized emission is shown to depend on the concentrations of Eu(III). orotic acid and pH with relationships kinetically consistent with the above hypothesis. 相似文献
We, therefore, propose that sensitization of Eu(III) emission by orotic acid at pH 5 is an example of energy transfer within the bidentate complex of Eu(III) and orotic acid. We also propose that the complexed orotic acid is itself excited by eollisional energy transfer from free triplet excited orotic acid (since the concentration of complex measured to be present. 5–7%, is too low to account for the efficiency of the sensitization). We also propose that emission from the excited complexed Eu(III) can be either from the complexed ion or from free Eu(III)* resulting from dissociation of the complex during the lifetime of the excited ion.
The efficiency of Eu(III) sensitized emission is shown to depend on the concentrations of Eu(III). orotic acid and pH with relationships kinetically consistent with the above hypothesis. 相似文献
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Tai-Bao Wei You-Ming Zhang Hai Wang Li-Ming Gao 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1539-1544
Reaction of aryloxyacetic acid hydrazide or arenedioxydiacetic acid hydrazide with 2-ethoxybenzoy chloride and ammonium thiocyanate under the condition of solid–liquid phase transfer catalysis using polyethylene glycol-400 (PEG-400) as the catalyst yielded the corresponding thiosemicarbazide or bisthiosemicarbazide derivatives of 2-ethoxybenzoic acid in good-to-excellent yield. 相似文献
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By the study of absorption and fluorescence spectra and the lifetime of fluorescence at room and low temperatures of 2,6-dimethyl naphthalene dicarboxylate (DMN) in different concentrations of sulfuric acid, different interactions between molecules of DMN and sulfuric acid have been observed. These interactions have been revealed by the absorption spectra of charge transfer complex in the ground state, emission of exciplex, absorption spectra of hydrogen bonding interaction, absorption and emission spectra after proton transfer and different lifetimes before and after protonation. The interaction mechanism of DMN and sulfuric acid through first the CT complex and exciplex then hydrogen bonding and finally proton transfer is proposed. 相似文献
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Abstract— The light-harvesting Chl-a/b protein complex (LHC) of Lactuca sativa L. was examined for pigment content, excitation energy transfer and behavior under acidic conditions:
(1) Lettuce LHC contains Chl-a, Chl-b and xanthophylls (lutein, neoxanthin, lactucaxanthin, viola-xanthin) at a molar ratio of 6:4:3; their contribution to the absorbance of the LHC between 390 and 530 nm is estimated to be about 31% (Chl-a), 26% (Chl-h) and 43% (xanthophylls).
(2) Energy transfer from xanthophylls and Chl-fe to Chl-a takes place at 100% transfer efficiency.
(3) LHC exhibits an unusual acid stability: in contrast to complexes of photosystem I or II, LHC-bound chlorophylls are not converted to phaeophytin and LHC apoprotein is not denatured at pH 1.5; also, energy transfer is maintained.
(4) Pronase or trypsin treatment do not affect acid stability and energy transfer.
(5) Treatments that break down acid stability (heat, urea or TritonX–100) also inhibit energy transfer.
The coincidental breakdown of energy transfer and acid stability points at one underlying process, namely, the breakdown of a structure that enables protection of chlorophylls from proton attack and close contiguity of xanthophylls and chlorophylls as required for energy transfer. Dense packing of xanthophylls and chlorophylls within lipophilic crevices of the LHC is suggested. 相似文献
(1) Lettuce LHC contains Chl-a, Chl-b and xanthophylls (lutein, neoxanthin, lactucaxanthin, viola-xanthin) at a molar ratio of 6:4:3; their contribution to the absorbance of the LHC between 390 and 530 nm is estimated to be about 31% (Chl-a), 26% (Chl-h) and 43% (xanthophylls).
(2) Energy transfer from xanthophylls and Chl-fe to Chl-a takes place at 100% transfer efficiency.
(3) LHC exhibits an unusual acid stability: in contrast to complexes of photosystem I or II, LHC-bound chlorophylls are not converted to phaeophytin and LHC apoprotein is not denatured at pH 1.5; also, energy transfer is maintained.
(4) Pronase or trypsin treatment do not affect acid stability and energy transfer.
(5) Treatments that break down acid stability (heat, urea or TritonX–100) also inhibit energy transfer.
The coincidental breakdown of energy transfer and acid stability points at one underlying process, namely, the breakdown of a structure that enables protection of chlorophylls from proton attack and close contiguity of xanthophylls and chlorophylls as required for energy transfer. Dense packing of xanthophylls and chlorophylls within lipophilic crevices of the LHC is suggested. 相似文献
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对 3种具不同结构 (三氯甲基 )三嗪化合物的光致生酸及光敏化生酸问题进行了研究 .从其吸收光谱、荧光光谱、荧光猝灭以及光致生酸过程的测定结果表明 ,三嗪化合物的敏化光致生酸具有电子转移性质 .发现在三嗪化合物分子中存在着归属于核的局域发光以及分子内的电荷转移发光两个部分 .局域的激发与发光和化合物光致生酸有着密切的关系 ,而电荷转移发光则会增强或扩充化合物的吸收和发射光谱范围 ,在光致生酸中也有重要的作用 .一种完美的光致生酸化合物分子的设计和合成必须对上述两个方面均加以注意 ,使能达到互补和协同的作用 相似文献
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Thomas Schreckenbach Bärbel Walckhoff Dieter Oesterhelt 《Photochemistry and photobiology》1978,28(2):205-211
Abstract— The fluorescence spectra of various reduced bacteriorhodopsin chromophore species indicate energy transfer from aromatic amino acid side chains of the protein to the retinyl moiety. Binding studies with retinol reveal that energy transfer occurs only when the retinyl moiety is bound in the chromophoric site of the protein. Retroretinol is a fluorescent probe for the binding site. 相似文献
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Several macroporous polymeric adsorbents(NDA-999,XAD-8,X-5 and XAD-2)were emplyed in the study to adsorb phenylacetic acid from aqueous solution.Effect of salt and ambient temperature on adsorption was studied using NDA-999 adsorbent and the adsorption process conforms to Freundlich′s model reasonably.Adsorption dynamics were conducted in batch experiments in order to make clear the mechanism of adsorption process.It is proved that the squared driving force mass transfer model can be adopted to elucidate the process.The treatment process of industrial wastewater containing high strength of phenylacetic acid was proposed for cleaner production of phenylacetic acid. 相似文献
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Abstract— The photoreduction of oxonine, thionine and selenine with the reducing agent allylthiourea was investigated by flash photolysis. The oxonine triplet state was produced by triplet-triplet energy transfer with 9,10-dibromoanthracene as donor. For all three dyes the rate constant of the electron transfer is considerably higher for the acid triplet form than that of the corresponding reaction of the basic triplet form. It is shown that the higher reactivity of the acid triplet can be related to its higher reduction potential which is available from the difference of the pK values of triplet and semiquinone of the dye. 相似文献
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Abstract— –The structures of the primary radicals formed by 2537 Å photolysis at —196° of alanine peptides of varying size have been determined. The conversion of the primary to stable secondary radicals on heat treatment has been followed in detail by ESR techniques and the chemical change shown to be intermolecular hydrogen atom transfer. The primary photochemical event is shown to be decarboxylation, but photodamage cannot be prevented by conversion of the carboxyl group to an acid derivative. 相似文献