荧光光度法测定环境水样中的苯酚和对苯二酚

建立了荧光光度法直接测定环境水样中的苯酚和对苯二酚的新方法.通过β-环糊精增敏,三维荧光扫描选择测量波长,在波长对为λex/λem=273/307 nm时测定苯酚,苯酚的线性范围为0～1×10-4 mol/L,检出限为6.6×10-8 mol/L;在波长对为λex/λem=295/331 nm时测定对苯二酚, 对苯二酚的线性范围为0～1.5×10-5 mol/L,检出限为5.2×10-9 mol/L,回收率达到93.5%～103.5%.     

盐酸吡格列酮与曙红Y相互作用的荧光和共振光散射光谱研究

在HCl-NaOAc酸性缓冲介质中,曙红Y(EY)与盐酸吡格列酮(PGH)反应形成1∶1的离子缔合物,不仅引起曙红Y的荧光猝灭(FLU),更能导致共振散射(RRS)的显著增强。荧光猝灭的激发和发射波长分别为λex=524nm和λem=544nm;最大共振散射波长为308nm,并在540nm处产生一共振峰。方法的线性范围分别为9.04×10-7～2.05×10-5mol/L(FLU)和1.6×10-7～5.1×10-6mol/L(RRS),检出限分别为1.88×10-7mol/L(FLU)和4.82×10-8mol/L(RRS)。研究了荧光和共振散射的光谱特征、适宜的反应条件及影响因素,据此建立了灵敏、简便、快速测定抗糖尿病药物盐酸吡格列酮的新方法。     

新型荧光试剂1,5-二(4,6-二氯三嗪)-氨基萘与酪氨酸相互作用

合成了一种新型三嗪荧光探针1,5-二(4,6-二氯三嗪)-氨基萘并利用元素分析、IR和核磁共振谱进行了表征。在pH=12.0的柠檬酸钠-NaOH缓冲溶液中,与酪氨酸在35℃下反应30 min后,λex/λem=400 nm/465 nm处,1,5-二(4,6-二氯三嗪)-氨基萘与酪氨酸反应使体系的荧光强度增强,且增强的荧光强度与酪氨酸的浓度成正比,依此建立了一种测定酪氨酸的新方法。测定的线性范围是1.1×10-7~1.1×10-5mol/L,检出限为6.8×10-8mol/L。该方法成功用于测定人尿和血清样品中的酪氨酸。     

槲皮素-Mg(Ⅱ)二元络合物荧光体系的研究及应用

研究了槲皮素-Mg(Ⅱ)荧光体系的形成条件,建立一种测定槲皮素的新方法。在pH=9.2的硼酸盐缓冲溶液中,槲皮素可与Mg(Ⅱ)形成2∶1的络合物,在激发波长λex=450nm,发射波长λem=530nm时,体系的荧光强度与槲皮素浓度在4.3×10-8～3.2×10-6 mol/L范围内呈良好的线性关系,检出限为4.3×10-8 mol/L。该法成功地应用于番泻叶中槲皮素含量的测定。     

分子光谱法研究曙红Y与马来酸罗格列酮相互作用及其分析应用

在HCl-NaAc酸性缓冲介质中,曙红Y(EY)与马来酸罗格列酮(ROM)反应形成1∶1的离子缔合物,不仅引起吸收光谱(UV)的变化和EY的荧光猝灭(FS),更能导致共振瑞利散射(RRS)的显著增强,并产生新的RRS光谱。以试剂为参比,吸收光谱的最大褪色波长为510nm;荧光猝灭的激发波长λex和发射波长λem分别为521和544nm;最大共振散射波长λRRS为307nm,并在532nm处形成较强的散射峰。各方法的线性范围分别为4.98×10-7～7.5×10-6 mol/L(UV)、8.34×10-8～1.79×10-5 mol/L(FS)和4.66×10-9～1.25×10-5 mol/L(RRS),检出限分别为1.49×10-7 mol/L(UV)、2.50×10-8 mol/L(FS)和1.40×10-9 mol/L(RRS)。文中研究了吸收、荧光和共振散射的光谱特征、适宜的反应条件及影响因素,并对荧光猝灭机制及RRS的增强进行了讨论,据此建立了灵敏、简便、快速测定抗糖尿病药物马来酸罗格列酮的新方法。     

4-溴-1，8-萘酰亚胺衍生物室温磷光性质研究

本文研究了在环己烷存在下,β-环糊精诱导N-二氨乙基-4-溴-1,8-萘酰亚胺(DBN)的室温磷光(RTP),λex/λem=347/572 nm.详细考察了影响DBN室温磷光的各种因素,如β-环糊精、环己烷用量等.在pH 1.0～4.0范围内,RTP强度随pH值增大而减小.优化实验条件下,DBN的浓度在2.0×10-5～9.0×10-5mol/L范围内与RTP强度呈良好的线性关系,相关系数r=0.9984,栓出限为6.7×10-6mol/L.该方法已用于水样中DBN含量的测定,回收率为98.3%～102.6%,相对标准偏差小于1.4%.     

微波消解-荧光猝灭法测定痕量铜的研究

利用微波消解前处理样品,在(CH2)6N4(六亚甲基四胺)-HCl介质中,溶液中的铜能与甲磺酸加替沙星形成稳定的络合物,使甲磺酸加替沙星的内源性荧光显著猝灭,据此建立了铜-甲磺酸加替沙星的荧光分析新方法.该体系的最大激发波长λex=365 nm,最大发射波长λem=500 nm,铜浓度在4.0×10-8 ～1.2×10-5 mol/L范围内,与荧光猝灭程度成正比.检出限为1.2×10-8 mol/L,回收率为97% ～104%.该法可直接用于测定铜含量,结果令人满意.     

茜素红荧光探针的设计及对化妆品中Pb~(2+)的检测

在pH 6.2的弱酸性介质中,茜素红与铅反应生成荧光络合物,且荧光强度与铅离子的浓度在一定范围内呈线性关系,由此建立了简单快速测定化妆品中的铅含量的新方法。实验探讨了反应体系的pH、表面活性剂、缓冲溶液、显色剂用量、反应时间、反应温度对体系荧光强度的影响。以激发和发射波长λ_(ex)/λ_(em)=510 nm/620 nm测定铅离子浓度,线性范围为8×10~(-8)~1.2×10~(-5)mol/L,R~2=0.9983,检出限为1.04×10~(-8) mol/L。方法可用于快速测定化妆品中的铅含量。     

间苯二胺-罗丹明B共聚物的合成及在银离子检测中的应用

通过一步高温水热法合成了间苯二胺-罗丹明B共聚物,通过扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、紫外可见吸收光谱(UV-Vis)、荧光(PL)等实验对聚合物进行了表征。在激发波长(λex)和发射波长(λem)分别为475 nm和598 nm处聚合物有强荧光产生。在多种金属离子中,随着银离子的加入,聚合物荧光逐渐增强,由此建立了水溶液中银离子测定的荧光分析方法。方法线性检测范围为2×10-10~7×1010mol/L,检出限为1×10-10mol/L。     

铽-依诺沙星-SDS敏化荧光猝灭法检测雷公藤红素

在pH 9.3的氨-氯化铵缓冲溶液中,铽(Ⅲ)能与依诺沙星、十二烷基硫酸钠(SDS)形成荧光配合物(λex=330 nm、λem=545 nm),SDS的存在能增强配合物的荧光强度。研究发现,在该反应体系中加入适量雷公藤红素溶液后,铽(Ⅲ)与依诺沙星络合物的激发、发射峰位置不变,但其荧光强度呈规律性下降。据此,建立了简单、快速、灵敏地测定雷公藤红素的荧光分析方法。雷公藤红素的浓度在5.2×10-6～8.4×10-5 mol/L范围内呈良好线性关系,方法的检出限为4.1×10-8 mol/L。     

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.