萘相萃取吸光光度法测定微量锌

5—Br—PADAP是一灵敏的金属显色剂,用5—Br—PADAP测定金属锌已有不少报道。本文用萘作为萃取剂,固—液分离Zn(Ⅱ)—5—Br—PADAP,对萘相分离物用乙醇—丙酮混合溶剂溶解,试验表明,Zn(Ⅱ)—5—Br—PADAP络合物能被萘相完全萃取,Zn(Ⅱ)在0～5.0μg/7ml范围内符合比耳定律,建立萘相萃取吸光光度法。该络合物最大吸收峰λ_(max)=555nm,表观摩尔吸光系数为1.23×10~5。本法灵敏度高,操作简便、快速,用于食品、水样中锌的测定,结果满意。     

吸光光度法测定煤矸石中镓

有乳化剂OP存在下 ,在pH 8.5的三乙醇胺 盐酸介质中 ,5 Br PADAP与镓生成红色络合物 ,其最大吸收波长为 5 5 5nm ,表观摩尔吸光系数为 1.2 5× 10 5L·mol- 1·cm- 1。测得络合物的组成比为镓 (Ⅲ )∶5 Br PADAP =1∶1,含镓 0～ 10 μg/ 2 5ml符合比耳定律 ,采用乙酸丁酯萃取以分离干扰离子 ,分析了煤矸石中微量镓 ,获得了满意的结果     

4-(2-噻唑偶氮)-苯二甘氨酸的合成及其与钯显色反应的研究

报道了水溶性 4 ( 2 噻唑偶氮 ) 苯二甘氨酸 (TAPC)新试剂的合成。该试剂对钯具有较高灵敏度和选择性。在 0 .5mol/LHNO3介质中 ,TAPC与Pd(Ⅱ )形成 2∶1蓝色配合物 ,最大吸收波长 632nm。钯浓度在 0 μg/mL～ 1 .6μg/mL范围内符合比耳定律 ,表观摩尔吸光系数ε632 =5× 1 0 4 L·mol- 1 ·cm- 1 。可允许许多离子共存 ,可直接用于含钯分子筛样中微量钯的测定     

新显色剂meso—四（3—氯—4羟基—5—甲氧基苯基）卟啉与Pd（Ⅱ）的显色反应

研究了meso 四 (3 氯 4 羟基 5 甲氧基苯基 )卟啉 [T(3Cl 4H 5MOP)P]与Pd(Ⅱ )的显色反应。在阴离子表面活性剂十二烷基硫酸钠 (SDS)与乳化剂OP存在下 ,在pH 2 .0的Britton Robinsin广泛缓冲介质中 ,Pd(Ⅱ )与T(3Cl 4H 5MOP)P形成 1∶1的稳定配合物 ,其最大吸收峰位于 4 2 2nm处 ,表观摩尔吸光系数ε4 2 2 =4 .78× 10 5L·mol- 1·cm- 1,钯量在 0～ 8.0 μg/ 2 5ml范围内符合比耳定律。应用此法测定催化剂中的痕量Pd(Ⅱ ) ,结果满意。     

新显色剂5-磺酸基[杯(4)芳烃偶氮]氨基喹啉的合成及与钯显色反应的研究

合成了新试剂 5 磺酸基 [杯 (4)芳烃偶氮 ]氨基喹啉 (SCAQ) ,研究了该试剂与钯 (Ⅱ )显色反应的适宜条件 ,在pH 8.0的缓冲介质中 ,在非离子表面活性剂TritonX 10 0存在下 ,试剂与钯(Ⅱ )生成 1∶1稳定配合物 ,建立了测定钯 (Ⅱ )的光度法新体系 ,体系至少可稳定 6h ,λmax=6 6 0nm ,ε =7.88× 10 4 L·mol- 1·cm- 1,钯 (Ⅱ )浓度在 0～ 30 μg/ 2 5ml范围内服从比耳定律。方法已用于钯催化剂中钯 (Ⅱ )的测定 ,结果与原子吸收光谱法相符 ,RSD为 1.5 %～ 2 .6 %。     

双(6-氧-丁烯二酸单酯)-β-环糊精对钯(Ⅱ)-2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚显色反应的作用及其应用

研究了双 (6-氧 -丁烯二酸单酯 ) -β-环糊精 (简称β- CD衍生物 )对 Pd( ) - 2 - (5-溴 - 2 -吡啶偶氮 ) - 5-二乙氨基苯酚 (简称 Pd( ) - 5- Br- PADAP)显色反应的增敏作用。在 p H=4.0～ 5.0的 HAc- Na Ac介质中 ,该体系最大吸收波长为 590 nm,表观摩尔吸光系数为 6.71× 1 0 4 L· mol-1· cm-1,钯 ( )含量在0～ 1 1 μg/1 0 m L范围内服从比尔定律。方法用于活性炭载体催化剂和矿样中钯的测定     

硫酸铵-碘化钾-乙醇体系萃取分离钯

传统的萃取分离法主要是采用与水互不相溶的有机溶剂作萃取溶剂,有的反应速度慢,传质速率低,分配比较小而需要在振荡器上进行较长时间振荡或多次萃取才能达到定量萃取的目的。均相萃取、异相分离萃取体系可以克服异相萃取分离技术中的一些缺点而受到重视[1,2]。本文以乙醇为萃取溶剂,均相萃取、异相分离Pd(Ⅱ)。试验表明硫酸铵存在下乙醇与水分相过程中,Pd(Ⅱ)与I-开成的PdI42-与质子化乙醇(C2H5OH2+)形成电中性的缔合物(C2H5OH2+)2·PdI42-被乙醇相萃取,能使Pd(Ⅱ)从Fe(Ⅲ)、Al(Ⅲ)、Zn(Ⅱ)、Mn(Ⅱ)、Ni(Ⅱ)、Cr(Ⅲ)、Co(Ⅱ)…     

硫酸铵-硫氰酸铵-乙醇体系萃取分离铂

从pH 3.0的水溶液中,在较大量的硫酸铵存在下,Pt(Ⅳ)以Pt(SCN)62-形式定量萃取入乙醇中。萃取体系中各试剂的适宜用量为硫氰酸铵溶液20 g.L-1,硫酸铵溶液300 g.L-1,乙醇0.30 mL.mL-1,按此条件可达到Pt(Ⅳ)与适量的Ni(Ⅱ),Cr(Ⅲ),Co(Ⅱ),Fe(Ⅱ),Mn(Ⅱ),Al(Ⅲ),Rh(Ⅲ)等离子分离。此方法已用于催化剂Ni-Pt/Al2O3试样分析中作为分离手段。对一件上述催化剂试样进行5次测定,测得铂的平均结果为w(Pt)0.104%,RSD为1.7%。     

高选择性新试剂5-(2-羟基-5-磺酸基苯偶氮)罗丹宁与钯显色反应的研究及应用

介绍高选择性新试剂5-(2-羟基-5-磺酸基苯偶氮)罗丹宁(S-HBAR)与钯显色反应的研究与应用,建立了测定钯的新方法。在H_3PO_4介质中,在乳化剂OP存在下,S-HBAR与Pd(Ⅱ)形成稳定的红色配合物,最大吸收波长为500nm。钯浓度在0～70μg/25 mL范围内符合比耳定律。表观摩尔吸光系数ε=3.5×10~4 L/(mol·cm),选择性好。该方法无需加入掩蔽剂或其他分离手段,即可直接用于Pd-C催化剂和矿石中钯的测定。     

萃取光度法测定钯

本文研究了在盐酸介质中钯与氯化亚锡和2-巯基苯并噻唑(MBT)显色体系的生成及萃取条件。实验表明,在2.8—4.0M盐酸介质中所生成的Pd(Ⅱ)-Sn(Ⅱ)-MBT三元络合物易为乙酸乙酯所萃取,且萃取液可直接用于钯的光度测定。络合物的最大吸收波长为368nm,但在此波长处试剂也存在强烈吸收,故实际测量移至380nm,其摩尔吸光系数ε=1.03×10~4,室温下放置8小时吸光度维持不变。用连续变化法和平衡移动法测得络合物的组成比为1:2:2。钯量在0—24微克/10毫升范围内符合比尔定律。对于20微克钯的测定,Ir(Ⅳ)5毫克,Ag(Ⅰ)、Cu(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Pb(Ⅱ)、Sb(Ⅴ)、Bi(Ⅲ)各0.5毫克,Fe(Ⅲ)0.1毫克不构成干扰;但Pt(Ⅳ)、Rh(Ⅲ)有严重干扰。采用丁二肟萃取钯而与铂、铑分离,存在于有机相中的丁二肟钯络合物于盐酸介质中再转化为Pd(Ⅱ)-Sn(n)-MBT三元络合物,按所拟条件测定钯从而消除铂、铑的干扰。方法适用于某些贵金属冶金物料中钯的测定。主要试剂2M氯化亚锡的3.6M盐酸溶液,用时现配;0.1M MBT的乙醇溶液;0.5%丁二肟乙醇溶     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.