钯（Ⅱ）对钒（V）—锰（Ⅱ）—Tween—20—二安替比林—（间—羟基）—苯基甲？…

在酸性介质中钯（Ⅱ）对Ｖ（Ｖ）－Ｍｎ（Ⅱ）－Ｔｗｅｅｎ－２０－ＤＡｍＨＭ体系显色反应有阻抑作用，基于此建立了一种测定钯的动力学分析方法，并研究了该阻抑反应的动力学参数。方法的线性范围为２０～２４０μｇＰｄ（Ⅱ）／Ｌ检测限为８．４×１０＾－９ｇＰｄ（Ⅱ）／ｍＬ。该体系灵敏度高，稳定性好，用于石钯渣和钯催化剂中钯（Ⅱ）的测定，结果满意。     

钯(Ⅱ)对钒(Ⅴ)-锰(Ⅱ)-Tween-20-二安替比林-(间-羟基)-苯基甲烷体系显色反应的抑制作用及应用

在酸性介质中钯（Ⅱ）对Ⅴ（Ⅴ）－Ｍｎ（Ⅱ）－Ｔｗｅｅｎ－２０－ＤＡｍＨＭ体系显色反应有阻抑作 用，基于此建立了一种测定钯的动力学分析方法，并研究了该阻抑反应的动力学参数。方法 的线性范围为２０～２４０μｇ　Ｐｄ（Ⅱ）／Ｌ，检测限为８．４×１０－９ｇＰｄ（Ⅱ）／ｍＬ。该体系灵敏度高，稳 定性好，用于石钯渣和钯催化剂中把（Ⅱ）的测定，结果满意。     

新显色剂2—[2—（6—甲基—苯并噻唑）偶氮]—5—二甲氨基苯磺酸与钯（Ⅱ）…

合成了新试剂２－［２－（６－甲基－苯并噻唑）偶氮］－５－二氨基苯磺酸，并研究了其与钯（Ⅱ）的显色反应。实验表明，该试剂与钯（Ⅱ）反在生成１：１蓝色水溶性络合物，在阴离面活性剂十二烷基硫酸钠（ＳＤＳ）存在下可稳定２４ｈ，其最大吸收波长为６１５ｎｍ，表观摩尔吸光系数为７．９４×１０＾４．ｍｏｌ＾－＾１．ｃｍ＾－＾１。钯量在０－０．８μｇ／ｍｌ范围内符合比尔定律。本法是目前测定钯（Ⅱ）的高灵敏度显色反应     

分光光度法同时测定铂和钯的新体系

提出了在酸性溶液中以２－（３,５－二氯－２－吡啶偶氮）－５－二甲氯基苯胺（３,５－ｄｉＣｌ－ＰＡＤＭＡＷ）作为光度法同时测定铂（Ⅳ）、钯（Ⅱ）的新体系。研究发现,而钯（Ⅱ）与试剂在室温即可定量反应,在铂（Ⅳ）配合物的最大吸收峰处,二者吸光度具有良好的加和性。基于二者显色反应的温度差异,建立了铂（Ⅳ）、钯（Ⅱ）同时测定的新方法。铂（Ⅳ）、钯（Ⅱ）质量浓度分别为０～０．７５ｍｇ／Ｌ,０～１．２ｍｇ／Ｌ     

多核钯（Ⅱ）－镍（Ⅱ）（1：1）酞菁对Heck反应的催化研究

使用多核钯（Ⅱ）－镍（Ⅱ）（１：１）酞菁作催化剂催化Ｈｅｃｋ反应，得到１２种较高产率的取代Ｅ－１，２－二苯乙烯、Ｅ－肉桂酸和Ｅ－甲基肉桂酸。催化剂的催化活性可与均相催化剂乙酸钯（Ⅱ）的催化活性相比。本文所用催化剂易制备且可重复使用１４次左右。     

2—[2‘—（4’—甲基—苯并噻唑）偶氮]—5—二甲氨基苯甲酸与钯（Ⅱ）显色反应…

合成了新试剂２－［２＇－（４＇－甲基－苯并噻唑）偶氮］－５－二甲氨基苯甲酸，并研究了其与钯（Ⅱ）的显色反应。实验表明，在５０％乙醇介质中，该试剂与钯（Ⅱ）反应生成１：１络合物，其最大吸收波长为６９８ｎｍ，表观摩尔吸光系数为５．８３×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。     

新显色剂3,3′-二甲基联苯重氮氨基偶氮苯与钯显色反应的研究及其应用

研究了在表面活性剂Ｎ－氯代十六烷基吡啶（ＣＰＣ）存在下，新显色剂３，３′－二甲基联苯重氮氨基偶氮苯（ＤＭＤＰＤＡＡ）与钯（Ⅱ）显色反应的适宜条件。结果表明，在ｐＨ８．０～９．０范围内，钯（Ⅱ）与ＤＭＤＰＤＡＡ形成２∶２紫红色配合物，其最大吸收波长位于６００ｎｍ，配合物的表观摩尔吸光系数为８．４１×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，钯浓度在０～１２μｇ／２５ｍＬ范围内遵守比尔定律，该方法灵敏度较高，选择性较好，用于含钯催化剂中微量钯的测定。     

水杨醛肟修饰碳糊电极吸附溶出伏安法测定钯(Ⅱ)的研究

报道了水杨醛肟化学修饰碳糊（ＳＡＭＣＰ）电极的制备,研究了钯（Ⅱ）在该电极上的阴极溶出伏安特性。在ＰＨ２．６的ＮＨ４Ｃｌ底液中,钯（Ⅱ）在－０．７８Ｖ处有一灵敏的阴极溶出峰,峰电流与钯（Ⅱ）的浓度在４．７＊１０＾－８－２．８＊１０＾－５ｍｏｌ／Ｌ之间呈良好的线性关系。     

新显色剂N-对甲苯基-N′-(氨基对苯磺酸钠)硫脲的合成及与钯(Ⅱ)的显色反应

合成了新试剂Ｎ－对甲苯基－Ｎ′－（氨基对苯磺酸钠）硫脲（ＰＭＰＴ）。经红外、紫外、核磁共振和元素分析等方法测试,确定了其组成和结构,并研究了新试剂与钯（Ⅱ）的显色反应,建立了光度法测定微量钯（Ⅱ）的新方法。在ｐＨ３．６～５．８的ＨＡｃ－ＮａＡｃ缓冲体系中,该试剂和钯（Ⅱ）形成一种稳定的组成比（摩尔比）为１∶２的水溶性配合物,其最大吸收峰位于３１８．６ｎｍ处,表观摩尔吸光系数为２．６６×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。钯（Ⅱ）在８．０～４２４μｇ／Ｌ服从比尔定律,相关系数ｒ＝０．９９９７。将该法应用于阳极泥和矿石样品中微量钯的测定,获得满意的结果。     

新催化动力学光度法测定痕量钯

在磷酸－邻苯二甲酸氢钾缓冲溶液（ｐＨ２．０）中,利用钯（Ⅱ）对次磷酸钠还原二甲苯蓝ＦＦ褪色的催化作用,建立了用斜率法测定痕量钯的新动力学分光光度法。在加入金（Ⅲ）的条件下,钯（Ⅱ）的检测下限为２．７×１０－１１ｇ／ｍＬ,线性范围为０．０４～６．０ｎｇ／ｍＬ。该法已应用于测定二次阳极泥中钯的含量。     

5-（5-溴-2-吡啶偶氮）-2，4-二氨基甲苯催化光度法测定钯

在H2SO4介质和室温条件下,微量钯（Ⅱ）对KBrO3氧化5-（5-溴-2-吡啶偶氮）-2,4-二氨基甲苯（5-Br-PA—DAT）褪色反应具有显著的催化作用,据此建立了测定微量钯的催化光度法．方法的检测限为0．034mg／L,线性范围0．2～0．75mg／L．已用于钯碳催化剂及水样中钯含量的测定,标准加入回收率为97．2％～99．0％,结果满意．     

Guanidine‐Functionalized Resin‐Supported Pd(0) Catalyst: Activity,Reusability, and Redeposition of Active Pd Species in Heck Vinylation

The guanidine‐functionalized resin‐supported Pd(0) catalyst [GDR·Pd(0)] is highly active in Heck reaction of aryl bromides with acrylic acid or styrene without the need to exclude air. The catalyst can be recycled at least 9 times without significant loss of activity in N‐methyl‐2‐pyrrolidone at 140 °C. The Heck reaction proceeds homogeneously with dissolved palladium species and the dissolved active palladium species can redeposit onto the surface of catalyst in the reaction. The XRD peak shifting of Pd phases in the catalyst provides the evidence for the re‐deposition of the active palladium species.     

Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

A selective and sensitive method for determination of platinum and palladium(Ⅱ）in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.     

Second and first-derivative spectrophotometry for efficient simultaneous and individual determination of palladium and cobalt using 1-(2-pyridylazo)-2-naphthol in sodium dodecylsulfate micellar media.

1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous and individual determination of palladium and cobalt at trace levels. PAN complexes of palladium and cobalt at neutral pH form green-color neutral complexes, which are soluble in aqueous SDS micellar media. Under optimum conditions, calibration graphs for individual determinations by zero and first-derivative spectrophotometry, and also for simultaneous determinations by second-derivative spectrophotometry were obtained. A zero-crossing method using second-derivative spectrophotometry at 628 or 578 and 614 nm, respectively, for cobalt and palladium was used for simultaneous determinations. The method is able to determine the cobalt-to-palladium ratio, 5:1 to 1:10 (Wt/Wt), accurately. The accuracy and reproducibility of the determination method for various known amounts of cobalt and palladium in their binary mixtures were tested. The effects of diverse ions on the determination of cobalt and palladium to investigate the selectivity of the method were also studied. The recommended procedures were applied to a synthetic binary alloy, cobalt in vitamin B12 and B-complex ampoules, a Co2O3-Co3O4 laboratorial chemical mixture, some synthetic cobalt-alloy samples, a Pd-charcoal catalyst, and some synthetic palladium alloys.     

Preparation,structural characterization of a novel egg-shell palladium sulfide catalyst and its application in selective reductive alkylation reaction

A novel egg-shell Pd-S catalyst with palladium metal as the core and a membrane of palladium sulfide as the surface has been prepared by sulphidizing Pd/C with H₂S.This catalyst is effective for the reductive alkylation of p-amino diphenylamine（PADPA） and methylisobutyl ketone（MIBK） to afford N-（1,3-dimethylbutyl）-N′-phenyl-p-phenylenedianine（DBPPD） with conversion up to 99.42%and selectivity to 97.46%.Comparing with the other common palladium sulfide catalysts,the membrane of palladium sulfide on the surface and the core of palladium metal cause the Pd on the surface of the new catalyst in a lower sulfur coordination, which improves its activity.Our result indicates that this new egg-shell Pd-S/C is an efficient hydrogenation catalyst.     

Solid-supported cross-coupling catalysts derived from homogeneous nickel and palladium coordination complexes

Solid-supported catalysts derived from homogeneous nickel(II) and palladium(II) non-symmetrical salen-type coordination complexes have been prepared and shown to be effective in the heterogeneous catalysis of carbon-carbon cross-coupling reactions. The nickel catalyst has been used in room-temperature Tamao-Kumada-Corriu reactions and the palladium catalyst in the Heck reaction at elevated temperatures. The complexes were prepared by improved methods and characterised by spectroscopic techniques. Comparisons between the solid-supported catalysts and their homogeneous analogues are reported. The single-crystal structure determination of the nickel and palladium complexes [M(salenac-OH)][M = Ni, Pd; salenac-OH = 9-(2',4'-dihydroxyphenyl)-5,8-diaza-4-methylnona-2,4,8-trienato](2-)] is reported.     

壳聚糖钯(0)配合物催化Heck芳基化反应研究

以天然高分子壳聚糖为载体,室温下通过与氯化钯乙醇溶液作用制得壳聚糖负载氯化钯黄色粉末,再在乙醇溶液中回流还原,制得了壳聚糖钯(0)配合物催化剂,研究了其对碘代苯与丙烯酸Heck芳基化反应的催化性能.结果表明该催化剂具有较高的催化活性和立体选择性,可高转化率、高产率地合成反式苯丙烯酸;通过简单的过滤、溶剂洗涤回收催化剂,并能多次重复使用.该催化剂对其它反应底物的催化性能也进行了探讨.     

Extraction and spectrophotometric determination of Pd(II) with 3,4,4a,5-tetrahydro-3,3,4a-trimethyl-7-(substituted)-pyrimido(1,6-a)-benzimidazole-1-thiol (PBT)

A method for the extraction-spectrophotometric determination of palladium with 3,4,4a,5-tetrahydro-3,3,4a-trimethyl-7-(substituted)-pyrimido(1,6-a)benzimidazole-1-thiol (PBT) is described. PBT-Pd(II) complex is extracted from an acidic aqueous solution (0.01-0.5M HClO(4)) into a chloroform layer. The absorbance is measured at 438 nm and the molar absorptivity found to be 1.033 x 10(4)M(-1) cm(-1). The complex system conforms to Beer's law over the range 1.9-28.5 mug/ml palladium(II). The effects of pH (2-6), HClO(4) concentration, PBT concentration and shaking time were studied. The ratio of metal ion to ligand molecules in the coloured complex was found to be 1:4. The tolerance limit for many metals have been determined. Finally, the method has been applied successfully to the determination of palladium in synthetic mixtures and in the standard palladium carbon powder (palladium catalyst).     

Tandem one-Pot palladium-catalyzed reductive and oxidative coupling of benzene and chlorobenzene

The in situ combination of oxidative coupling of benzene to biphenyl and reductive coupling of chlorobenzene (also to biphenyl) using palladium catalysts (Pd(2+)/Pd(0)) is described. In each cycle, the reductive process regenerates the catalyst for the oxidative process and vice versa. Kinetic investigations show that the reaction rate depends on [C(6)H(6)], [C(6)H(6)Cl], and catalyst loading, with E(a)() = 13 kcal mol(-)(1). The reduced palladium catalyst undergoes deactivation through aggregation and precipitation, but it is observed that during this deactivation process the Pd(0) becomes an active catalyst for the reductive coupling of chlorobenzene. Accordingly, while Pd(0)/C particles are inactive, Pd(0) colloids do catalyze the tandem reaction. Conversion is increased in the presence of a phase-transfer catalyst, presumably due to stabilization of the active Pd(0) clusters. The two halves of the catalytic cycle are examined in the light of previous research, regarding analogous oxidative and reductive coupling reactions, using stoichiometric amounts of PdCl(2) and Pd(0), respectively. The roles of homogeneous PdCl(2) and Pd(0) clusters are discussed.     

A versatile palladium-mediated three-component reaction for the one-pot synthesis of stereodefined 3-arylidene-(or 3-alkenylidene-)tetrahydrofurans.

A one-pot reaction between equimolecular amounts of various propargyl alcohols, Michael acceptors, and unsaturated halides (or triflates) in the presence of a palladium(0) catalyst provides a simple and flexible entry into highly substituted 3-arylidene-(or 3-alkenylidene-)tetrahydrofurans. The efficiency of this palladium-mediated three-component reaction has been shown to be strongly influenced by the nature of the catalyst system, and in this regard, a palladium(0) catalyst generated in situ by reduction of PdCl2(PPh3)2 with n-butyllithium has been found particularly effective.