茜素红-Cu(Ⅱ)配合物用于荧光法测定废水中的S2-

采用荧光光谱法和紫外可见吸收光谱法研究了pH 6.55的Britton-Robin-son(B-R)缓冲溶液中S2-与茜素红(ARS)-Cu(Ⅱ)配合物间的相互作用。S2-的加入使ARS-Cu(Ⅱ)配合物在587 nm处的荧光强度显著增强,并且溶液颜色由红色变成黄色。结果显示:S2-对Cu(Ⅱ)的强结合能力致使配合物ARS-Cu(Ⅱ)分解,释放出ARS,致使体系的荧光光谱和吸收光谱均发生明显变化。S2-浓度在1.02×10-6~2.2×10-5mol/L范围内,体系荧光强度变化与S2-浓度呈良好的线性关系,方法检出限为1.02×10-7mol/L。已用于废水中S2-量的测定,回收率为95.3%~102.0%。     

茜素红-硼酸配合物双重光谱响应测定微量铜离子

采用荧光光谱法和紫外可见吸收光谱法研究了Cu2 与茜素红(ARS)-H3BO3配合物间的相互作用。Cu2 使ARS-H3BO3配合物在587 nm处的荧光猝灭,并且溶液颜色由黄色变为红色。研究结果显示:Cu2 对ARS的强结合能力使ARS-H3BO3配合物分解,同时形成ARS-Cu2 配合物,致使体系的荧光光谱和吸收光谱均发生明显变化。Cu2 浓度在1.0×10-6~2.4×10-5mol/L范围内,体系荧光强度变化与Cu2 浓度呈现良好的线性关系,方法检出限为1.01×10-7mol/L。该方法用于废水中Cu2 的测定,回收率为95.5%~101.0%。     

茜素红与蛋白质分子Langmuir吸附聚集反应研究

在pH4.3的B-R缓冲体系中,用微相吸附-光谱修正技术[1]研究了茜素红(ARS)与牛血清白蛋白(BSA)、人血清白蛋白(HSA)的结合反应。其吸附结合常数分别为:KBSA-ARS=3.950×104,KHSA-ARS=4.377×104。染料与蛋白的最大结合数分别为NARS∶NBSA=9∶1,NARS∶NHSA=7∶1。经光谱修正技术计算结合产物的实际摩尔吸光系数分别为εBSA-ARS(537nm)=2.517×104L.mol-1.cm-1,εHSA-ARS(519nm)=2.051×104L.mol-1.cm-1,检出限BSA为19mg/L,HSA为23mg/L。经探讨该结合反应机理符合Langmuir吸附聚集反应方程。     

4-(4-三氟甲基)苯基-2,6-二(4-氨基苯基)吡啶与BSA相互作用的研究

合成了一种单晶化合物4-(4-三氟甲基)苯基-2,6-二(4-氨基苯基)吡啶(MPAPP),采用荧光光谱法,紫外吸收光谱法,原子力显微镜法(AFM),电化学阻抗谱法和圆二色谱法(CD)研究了其与牛血清蛋白(BSA)的相互作用。AFM发现BSA与MPAPP发生了作用,电化学阻抗法表明BSA与MPAPP是以形成复合物的形式相互作用。由紫外吸收光谱及Stern-Volmer方程判断MPAPP对BSA的猝灭过程主要为静态猝灭,根据双对数方程计算出温度在299 K,305K,311 K时,BSA与MPAPP的结合常数Ka分别为4.53×106L/mol、4.33×105L/mol、4.47×104L/mol,结合位点数n分别为1.28、1.08、0.88。由热力学参数方程获得ΔH、ΔS和ΔG的值分别为-160.32 kJ/mol、-423.33 J/mol/K、-33.74 kJ/mol,推断出二者的作用力类型主要为范德华力和氢键。根据Frster能量转移理论得到BSA与MPAPP的结合距离r为1.17 nm(299 K),并利用同步荧光光谱法和CD研究了MPAPP对BSA构象的影响,结果表明MPAPP的加入没有引起BSA构象的变化。     

盐酸多赛平与牛血清白蛋白结合反应光谱法研究

用荧光法和紫外-可见光谱法研究了在生理条件下,盐酸多赛平(DH)和牛血清白蛋白(BSA)结合反应的特征。实验发现DH对BSA的荧光有较强猝灭作用,DH的紫外吸收光谱和BSA的荧光光谱有一定程度的重叠现象,20℃反应的结合常数为4.42×104mol/L,DH在BSA分子上色氨酸残基所在区域的结合位点数为1.75,结合反应的标准焓变、标准熵变、标准吉布斯自由能分别为-15.16kJ/mol、36.83J/(mol.K)、-25.95kJ/mol,作用距离r=3.70nm。     

简便吸收光谱法测定饮料中共存色素诱惑红和柠檬黄

建立了同时测定饮料中共存色素诱惑红和柠檬黄的简便吸收光谱法。在pH 7.2～8.7 Tris-HCl介质中,诱惑红和柠檬黄与双绿SF反应生成离子缔合物。诱惑红-双绿SF在可见光区有正吸收峰(496 nm)和负吸收峰(570 nm),诱惑红的质量浓度在0.03～12.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为1.79×104L/(mol·cm)(496 nm)和2.43×104L/(mol·cm)(570 nm),检出限为29μg/L (496 nm)和27μg/L(570 nm),定量限分别为0.78 mg/kg和0.73 mg/kg。柠檬黄-双绿SF在422 nm和660 nm处分别产生1个较强的正吸收峰,柠檬黄的质量浓度在0.04～13.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为2.13×104L/(mol·cm)(422 nm)和1.59×104L/(mol·cm)(660 nm),检出限为32μg/L(422 nm)和35μg/L(660 nm),定量限分别为0.87 mg/kg和0.95 mg/kg。当用双波长法测定时,表观摩尔吸光系(κ)为4.22×104L/(mol·cm)(诱惑红体系)和3.72×104L/(mol·cm)(柠檬黄体系),诱惑红体系的检出限和定量限分别为0.014 mg/L和0.38 mg/kg,加标回收率和相对标准偏差分别为98.0%～102%和2.3%～2.8%;柠檬黄体系的检出限和定量限分别为0.017 mg/L和0.46 mg/kg,加标回收率和相对标准偏差分别为97.5%～103%和1.1%～2.2%。该法适于饮料中诱惑红和柠檬黄的测定。     

苯并咪唑衍生的单核钴(Ⅱ)和单核镍(Ⅱ)配合物与DNA和蛋白质的结合反应性及细胞毒活性研究

利用紫外吸收光谱、荧光光谱、圆二色光谱(CD)等各种光谱手段对比地研究了由苯并咪唑衍生的单核钴配合物[Co(EDTB)]2+(1)和单核镍配合物[Ni(EDTB)]2+(2)(这里EDTB为N,N,N′,N′-四(2′-苯并咪唑甲基)-1,2-乙二胺)与小牛胸腺DNA(CTDNA)和牛血清白蛋白(BSA)的相互作用。结果表明,在生理条件下,配合物1和2均能通过插入方式较强的与CT-DNA结合,诱导DNA构象的改变;且配合物1对DNA的结合能力略强于2,其结合常数分别为Kb(1)=3.23×104L·mol-1和Kb(2)=2.40×104L·mol-1。配合物与BSA相互作用的研究表明,1和2均能与BSA发生较强的相互作用,结合常数均处在104~105 L·mol-1;该结合引起了BSA微环境和构象发生变化,且使BSA内源荧光被淬灭,淬灭机理为静态淬灭。利用MTT法研究了配合物1和2对小鼠白血病细胞株P388和人非小细胞肺癌细胞株A-549的体外细胞毒活性,实验结果表明,配合物1和2对P388不敏感,对A-549在高浓度(10-4~10-5 mol·L-1)下表现出与顺铂相当的细胞毒活性。     

聚苯乙烯凝胶色谱柱分离头孢呋辛钠聚合物杂质

建立了聚苯乙烯基质的凝胶色谱柱系统对头孢呋辛钠中聚合物杂质(或称缩合物杂质)的分离分析方法.凝胶色谱柱为MKF-GPC-100柱(100 mm×7.8 mm,5 μm),流动相为0.01 mol/L的磷酸盐缓冲液(pH 7.0)-乙腈(70:30,体积比),流速1.0 mL/min,检测波长254 nm.头孢呋辛钠与其...     

α-硫辛酸与牛血清白蛋白的相互作用

利用荧光光谱和紫外-可见吸收光谱研究了在缓冲溶液中不同温度下α-硫辛酸(ALA)与牛血清白蛋白(BSA)的相互作用。结果表明,ALA对BSA的内源荧光猝灭为静态猝灭过程,猝灭常数KSV分别为4.65×103L/mol(26℃)和4.46×103L/mol(37℃)。依据Frster非辐射能量转移机制,得到给体(BSA)-受体(ALA)间的结合距离r=2.90 nm,能量转移效率E=5%。测定了该反应在不同温度下的结合常数KA=4.31×103L/mol(26℃),4.27×103L/mol(37℃),以摩尔比1∶1结合。根据不同温度下的结合常数确定了相互作用过程的热力学参数,并根据热力学参数确定了ALA与BSA之间作用力主要是静电作用。     

光谱法研究硝基苯与牛血清蛋白的相互作用

本文应用荧光分析法研究了不同酸度、温度和反应时间条件下,硝基苯对牛血清蛋白(BSA)的荧光猝灭作用。实验结果表明在激发波长λex=280nm,发射波长λem=342nm,浓度为0.05 mol·L-1,pH=7.50的TrisHCl缓冲溶液中,猝灭效果最为明显。计算289,304和318 K温度下二者的结合常数分别为:1.25×104、1.00×104和0.833×104L·mol-1。通过Gibbs-Helmholtz方程对其相互作用的热力学参数进行计算(ΔH=-10.7 kJ·moL-1;ΔS=41.4 J·moL-1·K-1),表明二者之间是静电相互作用。实验结果表明,硝基苯对牛血清蛋白荧光猝灭方式为静态猝灭,最后使用紫外吸收光谱法对其作用机理进一步确认。     

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%.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.