培氟沙星一铽（Ⅲ）-牛血清白蛋白体系的荧光光谱及其应用

在pH8.2的％Tris-HCl缓冲溶液中，Tb^3＋与培氟沙（PEFX）成的配合物受290nm紫外光激发发出Tb^3＋的特征荧光峰，加入牛血清白蛋白（BSA）能大大增强体系的荧光强度，由此建立了PEFX-Tb^3＋配合物探针测定BSA的方法。与PEFX-Tb^3＋二元配合物相比，PEFX-Tb^3＋-BSA三元体系荧光强度显著增强。研究了反应的最佳条件，并对PEFX-Tb^3＋-BSA荧光增强作用的机理进行了探讨。     

铽-聚二甲基硅氧烷配合物的荧光特性

用多种谱学方法证明聚二甲基硅氧烷(PDMS)中的氧原子能与Tb3+键合生成Tb3+和PDMS的配合物(Tb3+-PDMS), 并发现生成配合物后, PDMS和Tb3+的荧光发射同时得到增强. 荧光强度的增强与配合物中Tb3+含量有关, 当配合物中Tb3+的含量为2.0%(w)时, 配合物的荧光强度最大, 可增强1547%左右.     

一种含磷三足体衍生物及其铕配合物的合成及性能表征

设计合成了一种新型含磷的水溶性三足体衍生物[L:N-二(吡啶-二氨基乙酰基)甲基磷酸]及其Eu(Ⅲ)的配合物,用红外吸收光谱、元素分析、差热-热重和紫外光谱法等技术手段对该配合物进行了表征,用荧光光谱法研究了室温下该配合物和牛血清白蛋白(BSA)的相互作用。 结果表明,配体与苦味酸铕形成1:1型配合物Eu(pic)₃L;配合物与BSA之间有很强的结合作用;配合物对BSA内源荧光的猝灭方式为静态猝灭;配合物与BSA的作用力为分子间氢键和范德华力。 分别考察了Fe³⁺和Cu²⁺对配合物与BSA结合作用的影响,证明Fe³⁺和Cu²⁺能够以金属离子桥键与配合物结合使配合物-BSA的稳定性增强。 根据Foster型偶极-偶极无辐射能量转移机理可知,配合物可以和BSA以偶极-偶极无辐射进行能量传递。     

基于铽-沙拉沙星配合物的荧光增强测定人血清白蛋白

Tb3+和沙拉沙星(SRFX)反应生成二元配合物,发射Tb3+的特征荧光。人血清白蛋白(HSA)能够增强Tb3+-SRFX配合物的荧光强度,据此,建立了荧光法测定HSA的新方法。在最佳测定条件下,当HSA的浓度在0.50～90.0 mg/L时,Tb3+-SRFX-HSA体系荧光强度的增强和HSA的浓度有良好的线性关系,方法的检出限为0.13 mg/L。用该方法测定了人血清中HSA的含量,回收率在99.2%～99.6%之间。同时对荧光强度增强的机理进行了探讨。     

铕-铽-钆-六氟乙酰丙酮三元配合物的合成与温敏发光性质

合成了铕-铽-钆-六氟乙酰丙酮(HFA)三元配合物Eu0.4Tb0.4Gd0.2(HFA)3(TPPO)2(TPPO: 三苯基氧化磷), 其组成和结构经元素分析和红外吸收光谱确认; 研究了三元配合物的发光性能, 以及铽、钆离子对铕离子发光性能的影响. 结果表明, 配合物中存在着声子支助的Tb3+→Eu3+的能量转移, 增强了Eu3+离子的室温特征荧光发射, 且样品的发光颜色随温度的改变而变化, 具有温敏特性.     

铽、镝-3-噻吩乙酸二元、三元配合物的合成及表征

合成了四种新型的铽、镝的二元、三元配合物.通过元素分析、EDTA配位滴定分析表明其通式为RETh3·2H2O,RETh3phen(RE=Dy,Tb;Th=3-噻吩乙酸根;phen=1,10邻菲啰啉);对配合物进行了紫外光谱、红外光谱、荧光光谱、热重分析.结果表明,二元配合物在100℃左右失去结晶水,三元配合物具有较好的稳定性;在TbTh3phen中,3-噻吩乙酸和邻菲啰罗啉能很好地将能量传递给Tb3+离子,Tb3+离子546nm绿色荧光发射峰最强.     

含磷三足体稀土铕(Ⅲ)配合物与牛血清白蛋白的作用机理

在p H=7.3的Tris-HCl缓冲溶液(模拟生理条件)中,采用荧光光谱、循环伏安曲线和紫外光谱研究了N-二(苯-二氨基甲酰基)甲基磷酸铕(Ⅲ)配合物[Eu(pic)3L]与牛血清白蛋白(BSA)的相互作用.实验结果表明:配合物与BSA可以形成1∶1结合型无荧光复合物Eu(pic)3L-BSA,Eu(pic)3L对BSA内源荧光的猝灭类型为静态猝灭.根据双对数回归方程计算出二者在不同温度下的结合常数K及结合位点数n,通过热力学参数得出配合物与BSA之间以氢键和范德华力为主.根据Foster的偶极-偶极无辐射能量转移机理可知配合物与BSA之间可能以偶极-偶极无辐射能量转移方式进行能量传递.分别考察了Fe3+和Cu2+对配合物与BSA结合作用的影响,推测Fe3+和Cu2+可能在配合物与BSA间起"离子架桥"作用,使Eu(pic)3L-BSA复合物的稳定性增强.循环伏安法研究结果表明配合物与BSA相互作用形成无电活性的Eu(pic)3L-BSA复合物,使得溶液中游离的配合物浓度降低.     

对叔丁基杯[6]芳烃稀土配合物的合成及荧光性能研究

合成了以对叔丁基[6]芳烃(H6L)及DMF为配体,单一稀土RE3+(sm3+,Dy3+,Tb3+)及混合稀土Tb3+:(Ln3+(Ln3+=Gd3+,Y3+)为中心的5种稀土配合物.对其进行了元素分析、摩尔电导、红外光谱、差热分析、紫外光谱、核磁共振氢谱及荧光性能研究.荧光光谱的测试表明:Tb3+及其掺杂配合物具有较强的特征荧光,荧光惰性离子(Gd3+,Y3+)对Tb3+的荧光有增强作用,其中Y3+的敏化效果明显.     

诺氟沙星-Tb3+-牛血清白蛋白相互作用的荧光光谱研究

采用诺氟沙星-Tb3 体系,在pH 9.0的Tris-HCl缓冲溶液中,利用牛血清白蛋白(BSA)能增强诺氟沙星的特征荧光的特性,建立了BSA的定量分析方法。结果表明:当诺氟沙星浓度/[Tb3 ]在1/8~1/12范围内时,BSA的加入量与体系的荧光增强(ΔF)有良好的线性关系,线性范围为0~25μg/mL,相关系数r=0.998。并初步探讨了BSA的存在对诺氟沙星-Tb3 体系荧光增强的作用机理。     

含磷三足体稀土铕(Ⅲ)配合物与牛血清白蛋白的作用机理

在pH=7.3的Tris-HCl缓冲溶液(模拟生理条件)中, 采用荧光光谱、 循环伏安曲线和紫外光谱研究了N-二(苯-二氨基甲酰基)甲基磷酸铕(Ⅲ)配合物[Eu(pic)₃L]与牛血清白蛋白(BSA)的相互作用. 实验结果表明: 配合物与BSA可以形成1∶1结合型无荧光复合物Eu(pic)₃L-BSA, Eu(pic)₃L对 BSA 内源荧光的猝灭类型为静态猝灭. 根据双对数回归方程计算出二者在不同温度下的结合常数K及结合位点数n, 通过热力学参数得出配合物与 BSA 之间以氢键和范德华力为主. 根据Foster的偶极-偶极无辐射能量转移机理可知配合物与BSA之间可能以偶极-偶极无辐射能量转移方式进行能量传递. 分别考察了Fe³⁺和Cu²⁺对配合物与BSA结合作用的影响, 推测Fe³⁺和Cu²⁺可能在配合物与BSA间起“离子架桥”作用, 使Eu(pic)₃L-BSA复合物的稳定性增强. 循环伏安法研究结果表明配合物与BSA相互作用形成无电活性的Eu(pic)₃L-BSA复合物, 使得溶液中游离的配合物浓度降低.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.