功能性三价铕离子的金属有机骨架选择性荧光识别芘

成功设计并通过水热法合成了一种具有功能性三维结构的镧系金属有机骨架 Eu-4L,其配体为二苯胺四羧酸衍生物(H₄L)。Eu-4L 的骨架中含有 3D 空腔,且其比表面积较高。Eu-4L 不仅热稳定性较高,且在 pH 为 3~11 的范围内稳定性良好。Eu-4L可以作为荧光探针选择性识别稠环芳烃芘,其检测限为5 μmol·L^-1,具有较高的灵敏度,且具备可循环重复利用的特性。Eu-4L荧光识别芘的作用机理为稳态荧光识别机理。此外,对Eu-4L的荧光识别选择性、竞争能力也进行了详细地讨论。     

基于香豆素的荧光探针的合成及其对硫离子的识别性能

以4-甲基-7-羟基香豆素为荧光团、 2,4-二硝基苯磺酸酯为识别位点,合成了荧光探针L,并通过核磁共振波谱(HNM)和元素分析对其结构进行表征。探针L对S^2-的识别具有单一选择性和良好的抗干扰性,且呈现明显的荧光增强效应。探针L测定S^2-的检出限为0.319μmol/L。通过核磁氢谱、荧光滴定及等摩尔滴定法确证了探针L对S^2-的识别机理。     

一种基于喹唑啉酮衍生物的荧光探针对次氯酸根离子的识别

次氯酸根(ClO~-)在人体免疫系统中发挥着重要的作用,其识别与检测备受关注。本文设计合成了一种含有喹唑啉酮骨架的腙型荧光探针(HEMQ),并通过~1H NMR、~(13)C NMR、高分辨质谱(HRMS)表征了其结构。探针HEMQ在V(乙醇)∶V(水)=1∶1(c(PBS)=0.02 mol/L,pH=8.7)溶液中对ClO~-具有良好的选择性且响应快速,荧光发生显著猝灭。探针HEMQ对ClO~-具有较高的灵敏度,检测限为1.0×10-4mol/L。此外,ClO~-可引起探针溶液由黄色到无色的颜色变化,因此HEMQ可作为比色、荧光双通道响应的ClO~-探针。     

一种基于吗啉衍生物的Fe3+/Cu2+荧光探针

以9-蒽醛为荧光基团,吡唑和吗啉为识别基团,合成了一种荧光分子探针4-((3-(1-苯基-5-吡啶基-4,5-二氢-1H-吡唑-3-基)蒽-9-基)甲基)吗啉(L)。其结构经1H NMR、13C NMR表征,利用荧光发射光谱和紫外吸收光谱研究其离子识别性能。结果表明,探针L对Fe~(3+)和Cu~(2+)具有较强的选择性识别性能,荧光量子产率分别从0.47降到0.21和0.14;探针L的溶液颜色分别从淡黄色变为棕褐色和蓝色,裸眼可判断探针L选择性识别Fe~(3+)和Cu~(2+)。另外,根据Fe~(3+)、Cu~(2+)和H+不同组合时探针L的量子产率构建了分子水平上的三输入"NOR"逻辑门电路。     

芘-环八四噻吩衍生物的合成与发光现象研究

环八四噻吩(COTh)是一类新发现的具有聚集诱导发光(AIE)特性的"马鞍型"分子.将发光基团芘引入到COTh分子骨架,设计合成了三种芘-环八四噻吩化合物,即单芘基环八四噻吩(Py-COTh)、四芘基环八四噻吩(4Py-COTh)以及四(三(三甲硅基)环八四噻吩基)芘(12TMS-4COTh-Py).考察了它们的吸收光谱、溶液态与冻结态(77K)下的荧光光谱以及聚集诱导发光(AIE)行为.研究发现COTh分子骨架上芘基数量的增加对分子的共轭效应影响较小,但其单分子与聚集态的发光行为显著增强且发光峰位红移;而芘基骨架上COTh基团数量的增加,增加了分子的共轭效应,造成了吸收光谱与荧光发射光谱峰位的大范围红移.这些光物理现象与分子结构存在着显著的构效关系.     

芘修饰杯芳烃对钠离子的高选择性荧光传感

经六步反应合成了新型杯[4]芳烃衍生物,其中杯[4]芳烃上缘的芘基作为荧光团,下缘的四个乙酯基作为离子载体,该化合物的结构经核磁和质谱鉴定.通过荧光光谱研究了主体化合物对碱、碱土金属离子的键合行为.结果表明主体化合物能够高选择性的识别钠离子,稳定常数为2190L·mol^-1.当加入钠离子时,芘基的excimer峰下降,同时monomer峰逐渐上升,而其它碱、碱土金属离子的加入没有导致主体化合物荧光光谱的变化.因此,该新型的杯[4]芳烃衍生物可以作为钠离子的荧光传感器.     

一种基于1,8-双取代芘的荧光探针对Cu~(2+)和焦磷酸根的接力识别

以1,8-二乙炔基芘和8-氨基喹啉为原料,通过click反应合成了一种双取代芘荧光探针L,表征了其结构.探针L可以在THF/H_2O(V∶V=1∶1,HEPES,1×10~(-2) mol/L,p H=7.4)中快速识别Cu~(2+),其他离子没有干扰.Job’s实验和高分辨质谱证明L与Cu~(2+)的结合计量比为1∶1,密度泛函理论计算表明L与Cu~(2+)形成了多元配合物.此外,L-Cu~(2+)对PPi具有良好的选择性和灵敏度,且响应快速,其检测限可达到6.32μmol·L~(-1),有潜在的应用价值.     

基于甲基丙烯酰胺基芘荧光载体光聚合膜的奥硝唑传感器

合成了一种端基烯键的芘衍生物荧光载体-甲基丙烯酰胺基芘(MAAP)。基于光聚合反应将该荧光载体共聚固定于玻片表面,利用奥硝唑对共价固定膜甲基丙烯酰胺基芘的熄灭作用,研制了一种测定奥硝唑的荧光传感器。传感器避免了荧光载体的泄漏,具有较好的稳定性、重现性和选择性,使用寿命长。奥硝唑测定的线性范围为1.0×10-6~1.0×10-3mol/L;检出限为4.0×10-7mol/L;将传感器用于水样中奥硝唑的直接测定,回收率在93.8%~110.5%。     

基于咔唑-席夫碱的高选择性裸眼和荧光识别Cu~(2+)的探针

合成了一种新型基于咔唑-席夫碱识别Cu~(2+)的荧光探针L.利用紫外-可见和荧光光谱研究了探针L对阳离子的识别性能.实验结果显示,当加入Cu~(2+)时,探针L的CH_3CN溶液显示出明显的颜色变化,由黄色变为无色.这表明,利用探针L可裸眼识别Cu~(2+).通过荧光光谱分析实验发现,在CH_3CN溶剂中,探针L对Cu~(2+)具有较高的选择性和灵敏度,其荧光强度随着Cu~(2+)的浓度增大而逐渐增强,不受其它金属离子影响,抗干扰能力强.探针L与Cu~(2+)的结合常数为1.38×10~4 L/mol,检测限为2.34×10~(-7) mol/L,低于世界卫生组织(WHO)规定的饮用水中Cu~(2+)的最大含量20mmol/L.探针L在检测环境中的Cu~(2+)含量方面具有潜在应用价值.     

噻唑并[3,2-a]嘧啶衍生物的合成及其在水介质中识别Fe3 的性能

噻唑[3,2-a]并嘧啶衍生物具有多种生物活性,但其较差的溶解性限制了其应用。本文在7-(3-氨基苯并呋喃-2-基)-噻唑并[3,2-a]嘧啶-5-酮的芳香环上引入三乙二醇单甲醚,成功合成了化合物L,并利用核磁、质谱对其结构进行了表征。在pH 3.4~6.4范围内,化合物L可在HEPES水溶液中荧光"开-关"识别Fe~(3+),其他金属离子对识别作用没有干扰,该荧光探针具有较高的选择性和较低的检测限。     

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%.     

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.     

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.     

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.