以meso-四(对羟基苯)卟啉荧光光度测定微量锌

本文研究制定了应用meso-四(对羟基苯)卟啉荧光光度测定痕量锌的方法。在PH8.3—9.6,锌与T (4—HP)P反应生成1:1的配合物.配合物的激发波长为448mm,发射波长为635nm。本法测定下限为0.6PPb,已用于测定自来水及头发中的微量锌。     

2,4-二羟基苯甲醛缩甘氨酸的合成及荧光法测定粮食中痕量锌

合成了新席夫碱试剂2,4 二羟基苯甲醛缩甘氨酸(DHBZGC),并测定了其结构,基于Zn(Ⅱ)与DHBZGC OP形成配合物,导致体系荧光增敏的特性,提出了一种测定痕量锌的荧光方法。在pH6.5～8.0,NaH2PO4 Na2HPO4缓冲溶液和OP存在时,Zn(Ⅱ)与DHBZGC形成1∶1的配合物。在λex为330nm,λem为445nm处产生的荧光增敏最大,Zn(Ⅱ)在0～100μg·L-1范围内符合线性关系,检出限为0.4μg·L-1。方法应用于粮食中痕量锌的测定,结果满意。     

1,5-二(2-羟基苯亚甲基)-二氨基硫脲与锌荧光反应研究

研究了含硫酰腙试剂1,5-二(2-羟基苯亚甲基)-二氨基硫脲与锌荧光反应的特性及最佳反应条件,建立了荧光光度法测量微量锌的新方法。在pH4.70的HOAc-NaOAc溶液中,试剂与Zn2+形成物质的量之比为1∶1的配合物,在最大激发波长eλx=400nm和最大发射波长eλm=464nm处,锌的线性范围为0~780μg.L-1,检出限为12μg.L-1,线性相关系数为0.9998。方法简便快速地用于含锌食盐、人发中锌的测定。     

5-溴水杨基荧光酮荧光熄灭法测定微量锌

基于Zn(Ⅱ)对5口溴水杨基荧光酮(5-BrSAF)体系的荧尤熄灭效应,建立了测定微量Zn(Ⅰ)的荧光分析新方法。在pH 8,60的硼砂-盐酸缓冲介质中,当激发波长λex＝365nm,荧光发射波长λem＝538nm时,锌含量在0～10～μg/25ml范围内与体系的荧光熄灭程度呈线性关系,检出限为4．Oμg·-1。方法灵敏,选择性好,用于水样及药物中微量锌的测定,结果满意。     

1-(4-硝基苯基)-3-(5-氯吡啶)三氮烯的合成及其与锌的显色反应

报道了 1 ( 4 硝基苯基 ) 3 ( 5 氯吡啶 )三氮烯 (NPCPDT)的合成及其与锌的显色反应研究。在TX 1 0 0的存在下 ,pH 1 1 0的Na2 B4 O7 NaOH缓冲溶液中 ,该试剂能与锌发生显色反应 ,锌与NPCPDT形成摩尔比为 1∶2型的黄色配合物 ,在 440nm处有一最大正吸收 ,在 5 3 5nm处有一最大负吸收。以 440nm为参比波长 ,5 3 5nm为测量波长进行双波长测定 ,表观摩尔吸光系数为2 42× 1 0 5L·mol- 1·cm- 1,锌的质量浓度在 0～ 0 48μg/mL范围内符合比尔定律。用拟定方法测定人发中的微量锌 ,结果满意     

高灵敏度分光光度法测定茶叶中锌的含量

研究了在聚乙烯醇(PVA)存在下,Zn2+ - SCN—- RhB高灵敏度显色反应体系,采用分光光度法测定茶叶中微量锌的新方法.结果表明,络合物的最大吸收峰在605 nm处,摩尔吸光系数为1.59×106 L·mol—1·cm—1,Zn2+的质量浓度在0.0~0.04 μg/mL范围内服从比尔定律.该法用于测定茶叶中锌...     

2，4-二氯苯氧乙酸构筑的三核锌(Ⅱ)配合物的合成、晶体结构及性能分析

以2,4-二氯苯氧乙酸(HL)和2,2′-联吡啶(2,2′-bipy)为配体合成了一个三核锌(Ⅱ)配合物[Zn3L6(2,2′-bipy)2]。该配合物晶体属三斜晶系,空间群P1,晶胞参数:a=1.073 85(6)nm,b=1.329 58(7)nm,c=1.515 80(10)nm,α=66.961 0(10)°,β=69.387 0(10)°,γ=72.992 0(10)°,V=1.833 77(19)nm3,Dc=1.656 g.cm-3,Z=1,μ(Mo Kα)=1.483 mm-1,F(000)=920,最终偏离因子R1=0.030 6,wR2=0.075 7。由于2,4-二氯苯氧乙酸根的桥联配位作用,配合物形成了三核结构。在该配合物的分子中,位于中间位置的锌(Ⅱ)离子的配位数是6,处于八面体配位环境中,而位于端位的2个锌(Ⅱ)离子的配位数都是5,处于三角双锥配位环境中。本工作还测定了标题配合物的磁性、荧光和电化学性能,结果表明:在28~300 K范围内,配合物有抗磁性;当激发波长为664 nm时,配合物在660 nm附近有1个强的荧光发射峰;在循环伏安过程中配合物的电子转移是准可逆的,对应的电极反应是Zn(Ⅱ)/Zn(0)。     

Zn~(2+)-邻菲啰啉-亮黄缔合体系双波长光度法测定锌

在pH5.7的NaAc-HAc缓冲溶液中,Zn2+与邻菲啰啉(phen)和亮黄(BY)反应生成稳定的离子缔合物[Zn(phen)3]BY,使BY褪色,492 nm处出现正吸收峰,379 nm处出现负吸收峰。选定测量波长为492 nm,参比波长为379 nm,建立了双波长光度法测定微量锌的新方法。表观摩尔吸光系数为3.01×104L.mol-1.cm-1,线性范围为0~1.5μg/mL,检出限为18.5μg/L。方法用于测定锌强化营养盐和健康平衡盐中锌,相对标准偏差为0.69%~0.87%(n=5),回收率为98.4%~99.3%。     

汞(Ⅱ)-邻菲啰啉-水杨基荧光酮荧光猝灭体系的研究及应用

在pH 8.0～9.0的KH2PO4-Na2B4O7缓冲溶液中,在乳化剂OP存在下,溶液中的汞(Ⅱ)与邻菲啰啉(o-phen)和水杨基荧光酮(SAF)反应生成一多元配合物,使水杨基荧光酮溶液的荧光猝灭,据此建立了测定痕量汞的荧光分析法.体系的激发波长λex=365.0 nm,发射波长λem=580 nm.汞的浓度在0～80μg/L范围内与△F存在良好的线性关系.方法的检出限为1.04 ng/mL.对1μgHg(Ⅱ)进行11次平行测定,其相对标准偏差RSD=1.9%,配合物的组成比为Hg(Ⅱ)o-phenSAF=122.方法用于环境水样中痕量汞的测定.     

新最色剂5-(4-苯乙酮基偶氮)-8-羟基喹啉与锌显色反应的研究及应用

研究了新显色剂5-(4-苯乙酮基偶氮)-8-羟基喹啉(P-AAHQ)与Zn(Ⅱ)的显色反应条件,在阳离子表面活性剂CTMAB存在下,pH 4.0～5.5缓冲介质中,形成稳定的1:2红色配合物,最大吸收波长为520nm,ε=1.01×10~5,含Zn(Ⅱ)量在0～20μg/25ml范围内符合比耳定律。采用氟化钾—磷酸盐混合掩蔽剂,方法用于人发、面食和黄连中微量锌的测定。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.