首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
研究了用8-氨基喹啉在pH3.62的HAc-NaAc缓冲溶液中测定痕量Os(Ⅳ)的分光光度法。常用的非贵金属和贵金属离子不干扰测定,并且选择性较好。Os(Ⅳ)与8-氨基喹啉的组成比为1:3,表观摩尔吸光系数ε600=1.3×10^5L/mol·cm。在0~10μg/10mL范围内符合比耳定律。合成样品分析结果良好。  相似文献   

2.
研究了Os(Ⅱ)和4,4’二(二乙氨基)苯硫酮与Pt(Ⅱ)共显色所衍生的配合物,于NucleosilC_8柱上,用含3×10 ̄(-3)mol/LDL-樟脑-10-磺酸和0.02mol/LHAc-NaAc(pH3.5)的乙腈-丙酮-水(72:5:23,V/V)作流动相(1.0mL/min)分离并检测。线性范围为0.2~4.0μg/mLPt;检测限为1.0ngPt。此方法已应用于抗癌药物顺铂和卡铂的分析。  相似文献   

3.
在pH4.5的 0.015 mol/L HAc-NaAc介质中,In铟(Ⅲ)-7-(1-苯偶氮)-8-羟基喹啉-5-磺酸钠(BQ)在滴汞电极上于-0.665-0.70 V(vs.SCE)电位处得到络合物的吸附还原波,其一阶导数峰电流I'p与In(Ⅲ)浓度在4.0× 10~(-8)~3.5 × 10~(-6)mol/L范围内呈良好的线性关系,检测限为1.6 × 10~(-8)mol/L In(Ⅲ).应用该法测定了铅粉和氢氧化铝样品中的微量铟,结果令人满意。对电极反应机理进行了探讨。  相似文献   

4.
亚硝酸根—巯基乙酸—钴(Ⅱ)络合物的极谱吸附波研究   总被引:7,自引:0,他引:7  
魏显有 《分析化学》1998,26(5):548-551
提出了一个测定痕量亚硝酸根的极谱吸附波新体系.在含有巯基乙酸(TGA)和钻.(Ⅱ)的 pH 4.4的 H2SO4-NaAc介质中,得到一灵敏的亚硝酸根络合物单扫极谱吸附波,峰电位为-0.75 V(vs.SCE).峰电位与亚硝酸根浓度在1.1× 10-3-8.7×10-6mol/L范围内呈线性关系.检出限为 5. 5×10-9 mol/L.本法简便快速,选择性好,用于水样和食品中痕量NO-2的测定,结果满意。  相似文献   

5.
魏显有 《分析化学》1995,23(5):502-505
在HCl-NaAc介质(pH2.5)中,用单扫示波极谱法可获得高灵敏的In(Ⅲ)-2-巯基苯骈噻唑(MBT)-7-碘-8-羟基喹啉-5-磺酸(Ferron)三元络合物吸附波,峰电位在一-0.64V(vs.SCE),峰电流与铟浓度在7.0×10^-10mol/L~8.8×10^-7mol/L之间呈线性关系,检出限可达3.0×10^-10mol/L,测得电活性络合物的组成为In(Ⅲ):MBT:1∶1∶  相似文献   

6.
王贵方  周艳梅 《分析化学》1997,25(5):617-617
1引言目前,已有多种杂环偶氮类试剂测定铂的报道,但其在显色灵敏度等方面大多还不理想。本文系统研究了2-(5-溴-2-吡啶偶氮)-5-二甲氨基苯胺(5-Br-PADMA)与Pt(Ⅳ)的显色反应,结果表明,在pH4.0~6.0的酸度范围内,在加热条件下铂(Ⅳ)与试剂形成紫红色络合物。该络合物在1.6mol/L高氯酸溶液中转变为另一型体绿蓝色络合物,表观摩尔吸光系数ε=8.3×104L·mol-1·cm-1,大多数常见金属离子及Au3+、Ag+等贵金属离子在一定范围内对测定无干扰。在EDTA存在下,可…  相似文献   

7.
2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)在极谱和伏安分析中的应用已有一些报道。陈林林等曾经研究过Ti(Ⅳ)-5-Br-PADAP络合物在稀H2SO4-H2C2O4溶液中的极谱行为,但灵敏度不高(1.0×10-7mol/L)。我们发现,在pH4.1左右的HAc-NaAc底液中,Ti(Ⅳ)-5-Br-PADAP-NaClO3体系产生一灵敏的极谱吸附催化波,二次导数峰电位在-0.86V(vs.SCE)左右,波形良好,波高稳定,检测限可达4×10-10mol/L。1 实验部…  相似文献   

8.
碘酸钾存在下极谱催化波法测定陈皮甙   总被引:2,自引:0,他引:2  
过玮  何盈盈  许昭  宋俊峰 《分析化学》2002,30(2):202-203
基于陈皮甙在KIO3存在下产生的极谱催化波,拟定了测定陈皮甙的新方法。在 0.55 mol/L HAc-0.01mol/L NaAc(pH 4.00±0.05)-1.0×10~(-3)mol/L KIO3缓冲溶液中,陈皮甙催化波的峰电位为-1.35 V(vs,SCE),它的一阶导数峰峰电流与陈皮甙浓度在2.6 × 10~(-7)~2.6 × 10~(-6)mol/L范围内呈线性关系(r=0.9970,n=6)。本方法比现有的电化学方法灵敏度高一个数量级。可用于直接测定中草药贯众水提液中陈皮甙含量。  相似文献   

9.
4-氨基-3,5-二甲基-1,2,4-三唑(TZ)与水杨醛缩合形成4-(邻羟苯基亚甲基)-亚胺-3,5-二甲基-1,2,4-三唑Schiff碱(SATZ),该Schiff碱与Cu(ClO_4)_2·6H_2O形成配合物Cu(satz)_2·6H_2O,分子式为C_(22)H_(22)CuN_8O_2·6H_2O。经X射线晶体结构分析表明,晶体属于单斜晶系,空间群P2_1/c,Z=2,α=8.202(1),b=19.569(4),c=8.972(8)A,β=107.72°(2),V=1371.8(5)A3,Dc=1.46g/cm ̄3,μ=0.853mm ̄(-1),F(000)=630,R=0.051,R_w=0.062。分子中2个偶氮甲碱(-C=N-)中   的N原子及2个酚氧原子与中心Cu原子形成规则的菱形平面结构。  相似文献   

10.
测定了双臂套索冠醚双核铜(Ⅱ)配合物[Cu2L(OH)](ClO4)3Me2CO(L-N,N'-二(8-喹啉甲基)-1,4,10,13-四氧-7,16-二氮环八环)的变温磁化率(4 ̄300K),所加场强为5.0×10^5A/m,拟合了变温磁化率数据,得到J=-279.4cm^-2;加上分子场校正后,得J=-257.7cm^-1,Zj'=-30.1cm^-1。拟合结果表明,分子间存在反铁磁性交换作用  相似文献   

11.
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%.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
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.  相似文献   

18.
19.
《Tetrahedron》2014,70(21):3377-3384
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.  相似文献   

20.
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号