铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究

本文通过对铬(Ⅵ)-亚铁氰化钾-鲁米诺体系化学发光反应的研究,建立了一个测定铬(Ⅵ)的高灵敏化学发光分析法。方法的检出限为2×10~(-11)g/ml铬(Ⅵ);相对标准偏差小于2％(对1×10~(-10)g/ml铬(Ⅵ)11次测定);校正曲线的线性范围是1×10~(-10)～6×10~6g/ml铬(Ⅵ)。此方法已用于环境水样中铬(Ⅵ)的测定。     

无机偶合反应化学发光分析 Ⅱ.H_2O_2-Na_2S_2O_3-鲁米诺体系测定痕量钼

本文将钼催化过氧化氢氧化硫代硫酸钠的反应与鲁米诺-H_2O_2化学发光反应相偶合,建立了痕量钼的无机偶合反应化学发光分析法。此方法的检出限是1.2×10~(-10)g/ml钼,相对标准偏差为2.7％(对5×10~(-9)g/ml钼11次测定),工作曲线的线性范围为1×10~(-9)～1×10~(-3)g/ml。此法巴成功地用于天然水中痕量钼的测定。     

以盐酸肼还原天青I催化光度法测定痕量钼

基于天青Ⅰ与盐酸肼氧化还原反应钼的催化活性,拟定了测定痕量钼新的动力学方法。本法钼的检测限为6×10~(-4)μg/ml,可测定浓度范围为1×10~(-3)～9×10~(-1)μg Mo/ml。本法可用于井水、温泉水和废水中钼的测定。     

电感耦合等离子体原子发射光谱法分析稀土元素的研究(Ⅰ)高纯氧化镧中十四种稀土杂质的测定

研究了ICP-AES法测定高纯氧化镧中十四种稀土杂质的方法。利用简单的加热去溶装置成功地测定了99.99％La_2O_3中14种稀土杂质。10mg/ml La_2O_3基体工作曲线下限为(以氧化物百分含量计算)Ce、Pr、Sm_2×10~(-3);Gd、Tb1×10~(-3);Nd,Lu 8×10~(-4),Er,Ho,Dy4×10~(-4); Tm.Eu 2×10~(-4),Yb 8×10~(-5),Y_4×~(-5)。相对标准偏差为2.8—9.7,回收率为85—114％。     

鲁米诺-I_2-As~(3+)化学发光反应的研究——矿石中砷的测定

本文拟定了鲁米诺-I_2-As~(3+)无机偶合反应化学发光法测As~(3+),不仅灵敏度高(检测限为9.8×10~(-10)g/ml)。线性范围宽(1.0×10~(-7)g/ml—1.0×10~(-9)g/ml),而且选择性好。另外,作者还将表面活性剂用于该体系,使得灵敏度进一步提高,其检测限为3.4×10~(-10)g/ml。将该法用于矿样中As~(3+)的测定,结果令人满意。     

流动注射-邻菲啰啉协同催化化学发光法测定痕量的铜

本文拟订了邻菲啰啉-CTMAB-H_2O_2-Co(Ⅱ)-Cu(Ⅱ)协同催化化学发光体系流动注射测定痕量Cu(Ⅱ)的新方法。方法的检出限为8×10~(-12)g/ml Cu(Ⅱ),线性范围为1×10~(-10)-4×10~(-8)g/ml Cu(Ⅱ),相对标准偏差为0.9％分析速度为160样/小时。本法用于头发和水样中Cu(Ⅱ)的测定取得了满意的结果。     

用偶合反应流动注射化学发光法测定矿样和水样中的痕量铊

将Tl(Ⅲ)置换Co(Ⅱ)-EDTA配合物中的Co(Ⅱ)与Co(Ⅱ)-鲁米诺-H2O2化学发光体系相偶合,建立了流动注射化学发光测定铊的新方法。本方法测定铊的线性范围为3.0×10-6~1.0×10-2mg/mL,检出限为1.0×10-6mg/mL。对1.0×10-4mg/mL的Tl(Ⅲ)标准溶液连续11次测定的相对标准偏差为2.0%。方法可用于矿样和水样中铊的测定。     

新试剂6-(2,4-二羟基苯偶氮)-2,3-二氢-1,4-酞嗪二酮的化学发光研究

本文研究了新试剂6-(2,4-二羟基苯偶氮)6-(2,3-二氢-1,4-酞嗪二酮(DHDHD)的化学发光性质;考察了二十多种金属离子对DHDHD-H_2O_2体系的催化发光情况,拟定了应用该体系化学发光测定钴的新方法。线性范围1.0×10~(-11)g/ml～8.0×10~(-8)g/ml;检测限4×10~(-12)g/ml。     

聚乙烯吡啶化学修饰电极预富集-石墨炉原子吸收法测定酒石酸锑钾的研究

本文研究了聚乙烯吡啶(PVP)化学修饰电极预富集——石墨炉原子吸收法测定酒石酸锑钾的方法。结果表明,在 pH 为3.5的 HCl 介质中,酒石酸锑钾浓度在5.4×10~(-8)～2.2×10~(-6)g/ml 范围内,与吸光度值呈良好的线性关系。对1.1×10~(-6)g/ml 的酒石酸锑钾溶液平行测定9次,相对标准偏差为4.9%,最低检测限为1.6×10~(-8)g/ml。17种异离子及有机物不干扰测定,回收率在97～103%之间,结果令人满意。     

水及血液中痕量铜的化学发光分析

本文采用自制仪器对鲁米诺-氰化钾-铜(Ⅱ)化学发光体系进行了系统研究,选定了测铜的最佳条件。该体系以铜(Ⅱ)作为氧化剂直接氧化鲁米诺产生λ_(max)为425nm的闪烁化学发光。测铜的线性范围为2×10~(-10)—6×10~(-7)/ml,检测下限为9×10~(-l2)g/ml,对10~(-10)g/ml铜(Ⅱ)测定的变异系数为4.6％。采用焦磷酸钠作为掩蔽剂可消除常见共存离子的干扰。此法用于水及人体全血中痕量铜的测定,结果均比较满意。     

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%.     

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.