一种简单的化学传感体系对草酸根的比色识别（英文）

制备了一种基于2,7-萘二酚衍生物的双核锌配合物Zn-2L,在水溶液中(HEPES 0.01 mol·dm3,pH=7.4)Zn2L与指示剂邻苯二酚紫(PV)构筑成一种比色化学传感体系(CE)。该化学传感体系对草酸根具有良好的选择性识别作用,向CE溶液中加入草酸根引起溶液颜色由蓝色变为黄色。除丙二酸根对草酸根的识别具有轻微干扰外,其他二元酸离子包括邻苯二甲酸根,间苯二甲酸根,对苯二甲酸根,丁二酸根,戊二酸根,己二酸根对草酸根的识别无明显干扰。     

离子色谱法测定实验室废水中邻苯二甲酸根

建立离子色谱–抑制电导检测法测定实验室废水中邻苯二甲酸根的新方法.采用SH–AC–3型阴离子交换柱为分离柱,以12.0 mmol/L Na2CO3溶液为淋洗液,流量为1.0 mL/min,柱温为35℃,采用等度洗脱的方式可将邻苯二甲酸根与氯化物、硝酸盐和硫酸盐等常见阴离子完全分离,通过抑制电导检测.邻苯二甲酸根的色谱峰...     

草酸根掺杂立方体溴化银乳剂颗粒的增感效应研究

使用反馈式微机控制双注乳化仪,在晶体生长过程中一定时间内,加入一定量的草酸盐,制得了草酸根离子处于晶体颗粒次表面的立方体溴化银微晶乳剂.对其实验过程的考察和感光性能的测试结果表明,(1)草酸根掺杂于次表面的溴化银乳剂与未掺杂乳剂相比较,无论是原始乳剂,还是经过化学增感,或用染料进行光谱增感后的乳剂,感光度都有明显提高(S_d/S₀≥1.5),有明显的增感效应;(2)无论是原始乳剂,还是经过化学增感,或光谱增感后的乳剂,草酸根掺杂立方体溴化银乳剂颗粒的灰雾水平都不高;(3)草酸根掺杂立方体溴化银颗粒与甲酸根掺杂的溴化银乳剂相比,产生的增感效应相差不大;(4)与甲酸根掺杂立方体溴化银颗粒相比,草酸根掺杂立方体溴化银颗粒的制备方法明显较前者要简单得多,颗粒形状也优于前者.     

刚性4-取代双三唑配体构筑的三个锌配合物的合成和荧光

在室温下合成了3个新的配位聚合物{[Zn(4?Nbdc)(btx)]·2H₂O}_n(1·2H₂O)、[Zn(btx)_1.5(1,3?bdac)]n(2)和{[Zn(mbtx)(1,3?bdc)(H₂O)₂]·H₂O}_n(3)(btx=1,4?二(4H?1,2,4?三唑)苯,mbtx=1,3?二(4H?1,2,4?三唑)苯,4?Nbdc=4?硝基邻苯二甲酸根,1,3?bdac=间苯二乙酸根,1,3?bdc=间苯二甲酸根),测试了配合物的单晶结构,并从元素分析、红外和粉末衍射等方面进行表征。单晶X射线衍射表明,配合物1是二维(4,4)网格结构,配合物2和3都是一维链状结构。配合物2中的π?π作用将一维链连接成三维网格结构。在配合物3中,分子间氢键将一维链连接成二维网格,2套二维网格在分子间氢键的作用下相互穿插得到2D+2D→2D的网格结构。同时,还研究了3个配位聚合物的荧光和热稳定性。     

基于有机小分子的焦磷酸根荧光探针研究进展

焦磷酸根(PPi)作为一种重要的生物功能阴离子在生命科学、环境科学、药物领域和化学过程等方面起着非常重要的作用.鉴于荧光分析具有操作简便、灵敏度高等突出优点,设计合成高效的PPi荧光探针成为近年来超分子化学研究的热点之一.综述了近年来PPi荧光识别与传感的多种设计策略与原理,主要包括基于荧光增强或淬灭型识别,激基缔合物识别,荧光指示剂置换,静电或氢键作用识别等.DPA-金属离子络合物,尤其是DPA-Zn2+络合物,作为识别基团对PPi有着显著的亲和性和选择性识别能力.DPA-Zn2+络合物与多种荧光团或者荧光指示剂组合而形成的化学传感体系已经被广泛应用于PPi荧光识别与传感.     

邻苯二甲酸为背景吸收电解质的毛细管电泳法测定低分子量肝素中的阴离子

在生产和贮存低分子量肝素的过程中,糖链上的硫酸酯基团会被水解而损失活性,因此肝素样品中常可以检测到游离的硫酸根离子,此外在生产过程中还会引入其他阴离子。为了检测低分子量肝素的质量稳定性,常用离子色谱检测低分子量肝素中游离的阴离子。但是相对分子质量较大的低分子量肝素会污染离子色谱柱和抑制器。为此发展了一种灵敏的毛细管电泳方法用于测定低分子量肝素中游离的SO~(2-)_4、Cl~-、F~-、PO~(3-)_4和OAc~-。不同于常用的背景吸收离子铬酸根,采用邻苯二甲酸根作为背景吸收电解质。与铬酸根相比,邻苯二甲酸根与所有待测阴离子电泳淌度匹配得更好,因此可以获得较窄的峰形。而且邻苯二甲酸根在230 nm检测波长下的摩尔吸光系数(4 754 L/(mol·cm))比铬酸根(254 nm,2 400 L/(mol·cm))高。因此,可以将毛细管电泳检测阴离子的灵敏度提高到与离子色谱法相当的水平。通过验证,该方法在0.002~1 mmol/L的浓度范围内具有较好的线性关系,日内(n=6)和日间(n=3)迁移时间和峰面积的相对标准偏差均小于3%。所测阴离子的检出限(S/N=3)和定量限(S/N=10)分别为0.4~0.8μmol/L和2~4μmol/L。该方法可用于监测低分子量肝素的稳定性。     

基于间苯二甲酰腙的荧光探针的合成及其接力识别Al3+和焦磷酸根

设计合成了一种基于2-羟基-1-萘甲醛和间苯二甲酰肼的简单高效的荧光探针L,其结构通过~1H NMR、~(13)C NMR和HRMS进行表征。在乙醇-水(1∶1)的体系中,L能够高选择性识别铝离子,表现出明显的荧光增强,并具有较低的检测限(5. 924×10~(-6)mol/L),二者结合比为1∶2。此外,原位生成的配合物L-2Al~(3+)可接力识别焦磷酸根(PPi),具有良好的选择性和灵敏度,检测限可达4. 756×10~(-5)mol/L。该荧光探针具有潜在的应用价值。     

邻苯二甲酸根桥联镍配位聚合物的合成与晶体结构

合成了邻苯二甲酸根桥联镍配位聚合物{ [ Ni(phth) (phen) (H2O) ]·H2O}n(phth:邻苯二甲酸根二价阴离子;phen: 1, 10-邻菲咯啉),并得到了它的单晶.用X射线单晶衍射法测定了配合物的晶体结构.     

两个二维Cd(Ⅱ)配位聚合物的合成、晶体结构和荧光性质

具有d^10电子结构的简单金属配合物是不发光的。然而,采用具有π共轭芳香类有机物为配体所构建的Zn(Ⅱ)和Cd(Ⅱ)配合物,特别是具有重复单元结构的配位超分子和配位聚合物,能够发射较强的荧光,由于它们的配位数和结构的多样性,如[Cd4(betc)2(phen)2(H2O)]n(bete=1,2,4,5-benzenetetracarboxyl),[Cd(isonicotinate)2(EtOH)](EtOH),使这类化合物往往显示出一些新奇的功能。本文分别采用均苯四甲酸根和烟酸根为桥配体,合成了两种具有二维无限结构的Cd(Ⅱ)配位聚合物,它们在紫外光照射下,可以发出较强的蓝色荧光。     

过渡金属离子与3-氟邻苯二甲酸和1,10-邻菲啰啉配合物的合成、结构及性质

过渡金属离子与3-氟邻苯二甲酸(H2Fpht)、1,10-邻菲啰啉(phen)通过水热反应得到了5个配合物:[M(Fpht)(phen)(H2O)3]·H2O(M=Ni 1,Co 2),[Cu(Fpht)(phen)(H2O)]·H2O(3),[M(Fpht)(phen)(H2O)]·H2O(M=Zn 4,Cd 5)。通过X-射线单晶衍射分析、元素分析、红外分析、荧光分析以及差热-热重分析对配合物进行了表征。配合物1和2为单核分子,中心离子Ni(Ⅱ)和Co(Ⅱ)与3-氟邻苯二甲酸根的1个氧原子,1,10-邻菲啰啉的2个氮原子以及3个配位水分子的3个氧原子配位,形成六配位的扭曲八面体构型。配合物3为Z字形一维链状结构。中心Cu(Ⅱ)离子与2个3-氟邻苯二甲酸根的2个氧原子,1个1,10-邻菲啰啉的2个氮原子以及水分子的1个氧原子配位,形成四方锥构型。配合物4和5具有相似的一维螺旋结构,中心Zn(Ⅱ)和Cd(Ⅱ)离子与2个3-氟邻苯二甲酸根的3个氧原子、1,10-邻菲啰啉的2个氮原子以及水分子中的1个氧原子配位,形成扭曲的八面体构型。     

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.