CdTe/CdS量子点共振瑞利散射光谱法测定细胞色素C

以3-巯基丙酸为稳定剂,合成了具有特殊光学性质的水溶性核壳型CdTe/CdS量子点.基于细胞色素C对该量子点的共振瑞利散射有显著的增强作用,建立了一种快速检测细胞色素C的方法.在pH 7.0的磷酸盐缓冲液(PBS)中,量子点在385 nm波长处的共振瑞利散射的增强与细胞色素C浓度呈线性关系,线性范围为0.036～1.31 mg·L-1,检出限为10.8 μg·L-1.方法已用于人体血清中细胞色素C含量的测定,并用标准加入法测得方法的回收率在90.4%～933.2%之间.     

铜掺杂ZnSe量子点荧光探针测定镉(Ⅱ)

基于镉(Ⅱ)与ZnSe/Cu量子点之间的荧光猝灭作用,提出了用ZnSe/Cu量子点作为荧光探针测定镉的方法。通过微波辅助加热,在水溶液中合成了巯基丙酸修饰的ZnSe/Cu量子点。用荧光光谱、紫外光谱研究了ZnSe/Cu量子点与镉(Ⅱ)的相互作用。在pH为7.4的三羟甲基氨基甲烷-盐酸缓冲溶液和1.5×10-4 mol·L-1 ZnSe/Cu量子点溶液中测定镉(Ⅱ)。镉(Ⅱ)的质量浓度在0.025~0.40mg·L-1范围与ZnSe/Cu量子点荧光猝灭强度呈线性关系,方法的检出限(3s/k)为0.021 6mg·L-1。方法应用于水样的测定,回收率为98.0%,102%。对0.15mg·L-1镉(Ⅱ)标准溶液测定11次,测定值的相对标准偏差为6.7%。     

盐酸吖啶黄-脱氧核糖核酸反应体系的共振瑞利散射及其应用

研究了盐酸吖啶黄与脱氧核糖核酸(DNA)之间的共振瑞利散射(RRS)增强作用,提出了共振瑞利散射技术测定核酸的方法。在pH 6.4的B-R缓冲溶液中,盐酸吖啶黄与脱氧核糖核酸结合使溶液共振瑞利散射强度增强,其最大散射峰位于505 nm处,而在330 nm波长处有一稍弱的散射峰。DNA质量浓度在0.04~0.80 mg.L-1范围内,与RRS强度呈线性关系,检出限(3S/N)为0.023 mg.L-1。应用于测定合成样品中DNA含量并测得回收率为98.0%~104.0%。初步探讨了反应机理,盐酸吖啶黄与DNA间的相互作用包含有静电引力、π-π堆积力。     

阿米卡星与碲化镉量子点和牛血清白蛋白所形成的复合物之间的相互作用

以3-巯基丙酸为稳定剂,聚乙烯吡咯烷酮为表面活性剂,采用水热法合成了具有优异光学性质的碲化镉量子点.量子点与牛血清白蛋白(BSA)结合使荧光强度明显增大.对BSA测定的线性范围为0.68～13.6 mg·L-1,检出限为0.26 mg·L-1.阿米卡星对碲化镉量子点-BSA复合物的荧光有明显猝灭作用,荧光猝灭程度与其浓度呈线性关系.结果表明为静态猝灭,阿米卡星与BSA按物质的量比1比1结合,结合常数为6.47×103L·mol-1.用圆二色光谱技术探讨了阿米卡星对BSA构象的影响.     

吩噻嗪染料亚甲基蓝共振瑞利散射法测利福平

建立了测定痕量利福平的共振瑞利散射(RRS)法。在NaOH溶液中,利福平与亚甲基蓝相互作用后,共振瑞利散射显著增强,在371 nm处的ΔIRRS最强。利福平的质量浓度在0.20～1.65 mg.L-1范围内与△IRRS成正比,检出限(3Sb/S)为0.038 mg.L-1。该法可用于人体血液及市售利福平药物中利福平含量的测定,结果满意。     

用3-巯基丙酸修饰的CdTe量子点作为荧光探针对镉离子的荧光光度测定

对水热合成CdTe量子点的方法加以改进,并合成了用3-巯基丙酸(MPA)修饰的CdTe量子点(MPA-CdTe QD′s)。该量子点具有荧光特性,激发、发射波长分别为320,558nm。试验了17种常见金属离子对此量子点荧光强度的影响,结果发现只有Cd(Ⅱ)离子对其荧光有增强作用;Hg(Ⅱ)、Cu(Ⅱ)、Ag(Ⅰ)则对其荧光有猝灭作用,加入适量抗坏血酸和碘化钾可消除这3种金属离子的荧光猝灭作用。试验在pH 6的缓冲介质中,以20μL MPA-CdTe QD′s作为荧光探针,加入不同浓度的Cd(Ⅱ)离子并在反应6min后,体系的荧光增强程度与Cd(Ⅱ)离子浓度在5.0×10-7~3.9×10-5 mol·L-1范围内呈线性关系,检出限(3s/k)为4.8×10-7 mol·L-1。     

氯霉素、甲砜霉素与曙红Y的共振瑞利散射光谱及应用

在pH 1.30的酸性介质中,曙红Y(EOSY)分别与氯霉素(CHP)、甲砜霉素(TAP)相互作用形成离子缔合物,使共振瑞利散射(RRS)显著增强并产生新的RRS光谱。CHP–EOSY体系的最大RRS峰位于313nm,线性范围为0.015～0.32 mg.L-1,检出限为0.013 mg.L-1;TAP–EOSY体系的最大RRS峰位于314nm,线性范围为0.018～0.39 mg.L-1,检出限为0.012 mg.L-1。据此发展了以曙红Y为探针,用共振瑞利散射法测定氯霉素、甲砜霉素的方法。方法简便快速,有较高灵敏度,可用于实际样品中氯霉素、甲砜霉素的测定。     

溴代十六烷基吡啶增敏共振瑞利散射法测定药物中的维生素B_1含量

在pH 6.38的三羟甲基氨基甲烷-盐酸缓冲溶液和溴代十六烷基吡啶存在下,维生素B_1与氯酚红结合生成的缔合物使共振瑞利散射显著增强并产生新的共振瑞利散射光谱,最大共振瑞利散射峰位于339nm处,维生素B_1的质量浓度在0.03~0.42mg·L~(-1)内与其对应的共振瑞利散射增强程度(ΔI/_(RRS))呈线性关系,检出限(3s/k)为0.004 2mg·L~(-1)。据此提出了溴代十六烷基吡啶增敏共振瑞利散射法测定药物中的维生素B_1的方法。应用此方法分析了维生素B_1药物,加标回收率在99.2%~102%之间,测定值的相对标准偏差(n=6)在2.1%~2.5%之间。     

基于硫化镉量子点的荧光猝灭效应测定微量钴离子

以巯基丙酸作稳定剂制备了单分散的硫化镉量子点。在pH=7的反应介质中,钴离子对硫化镉量子点的荧光有很强的猝灭作用,且钴离子的浓度在1.0×10-5~2.5×10-4 mol·L-1内与硫化镉量子点的荧光猝灭强度(ΔF/F)之间的关系符合Stern-Volmer方程,方法的检出限(3s)为1.3×10-6 mol·L-1,据此提出了测定微量钴含量的方法。加标回收率在93.8%~105%之间,测定值的相对标准偏差(n=6)均小于4.0%。     

双偶氮染料刚果红共振瑞利散射法测大观霉素

建立了测定痕量大观霉素的共振瑞利散射法。在pH 3.25的Tris-盐酸缓冲介质中,大观霉素与酸性双偶氮染料刚果红相互作用后使体系的共振瑞利散射强度(ΔIRRS)明显增强,在370 nm处的ΔIRRS最大。增强的共振瑞利散射强度ΔIRRS与0.015~0.33 mg·L-1范围的大观霉素呈良好的线性关系,方法的检出限(3Sb/S)为0.012mg·L-1。该法用于市售大观霉素药物及人尿中大观霉素含量的测定,结果满意。     

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%.     

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.     

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.     

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.     

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.     

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.