Square-planar coordinated polyanions of palladium, platinum, and gold stannaborate [SnB11H11]2- coordination chemistry

The tetrasubstituted polyanions of platinum, palladium, and gold [M(SnB(11)H(11))(4)](x-) (x=6, M=Pd, Pt; x=5, M=Au) have been prepared and characterized by single-crystal X-ray diffraction, elemental analysis, IR, Raman, (11)B, and (119)Sn heteronuclear NMR spectroscopy. In the case of the platinum derivative [Bu(3)MeN](6)[Pt(SnB(11)H(11))(4)] (2) (119)Sn M?ssbauer spectroscopy has been carried out. The isolated salts are stable towards moisture and air and the complexes 2 and 3 were treated with 1,3-bis(diphenylphosphino)propane (dppp) to give the respective substitution products [Bu(3)MeN](2)[(dppp)M(SnB(11)H(11))(2)] (M=Pd, Pt).     

CHARACTERIZATION AND CATALYTIC PERFORMANCE OF PLATINUM SUPPORTED ON Sn-MgAl_2O_4

IntroductionSupportedPt-Sncatalystsareimpo~inthepdrileumandpthechendcalindustricsbecauseoftheirsuperiorcatalyticperformances.Forexample,Pt-Snsupportedonaneutralsupporthasbeenreportedtoexhibithighdehydrogenationselectivityanddebilitythansupportedplatinumca…     

高分散直接甲醇燃料电池Pt／C阴极电催化剂的制备过程机理与表征

 通过调变的多元醇法制备了40％Pt／C直接甲醇燃料电池阴极电催化剂，应用透射电镜（TEM）及X射线衍射（XRD）方法表征催化剂．结果表明，由该制备方法可得到高分散，金属粒子粒径分布窄的高载量贵金属催化剂．TEM统计结果表明，调变多元醇法制备的40％Pt／C催化剂的金属粒子平均粒径约为2．9nm．直接甲醇燃料电池单池性能测试表明，该方法制得的40％Pt／C的电催化氧还原能力比同型商品催化剂更好．另外，利用UV－Vis光谱研究了催化剂的制备过程．结果表明，在调变的多元醇法中，Pt4＋的还原是一步完成的．     

2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺与铂(Ⅳ)显色反应的研究

研究了２－（３，５－二氯－２－吡啶偶氮）－５－二甲氨基苯胺（３，５－ｄｉＣｌ－ＰＡＤＭＡ）与铂（Ⅳ）的显色反应及铂配合物的质子化行为。结果表明，在０．０４～０．４８ｍｏｌ／Ｌ的Ｈ２ＳＯ４溶液中，于加热的条件下，试剂可与铂（Ⅳ）形成稳定的１∶２绿蓝色ＰｔＬ２Ｈ２＋２配合物，其最大吸收波长位于６３４ｎｍ，表观摩尔吸光系数为９．７３×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，桑德尔灵敏度为０．００２μｇ·ｃｍ－２。铂配合物的三级质子化常数分别为：ｌｇＫａ１＝３．９１，ｌｇＫａ２＝－２．２１，ｌｇＫａ３＝－３．３７。较大量的常见金属离子及除钯、钌外的其它贵金属离子不干扰测定。利用Ｐｔ，Ｐｄ与试剂反应所需的温度差异，可以用差减法消除微量Ｐｄ的干扰．铂（Ⅳ）浓度在每１０ｍＬ０～７．５μｇ范围内符合比尔定律。所拟方法用于二次合金管理样－８８及催化剂中微量铂的测定，结果满意。     

Further studies on dppm-stabilized mixed-metal clusters: X-ray structure of PdPtCoCl(CO)3(μ-dppm)2 1

The metalloligated mixed-metal cluster [PdPtCo₂(CO)₇(-dppm)₂] (2) (dppm = -Ph₂PCH₂PPh₂) possesses numerous potential reaction centers (e.g., metal(s), metal-metal bonds, CO, and dppm ligands) and this has previously led to an investigation of the site selectivity of reactions with nucleophiles. The exocyclic CO(CO)₄ fragment was substituted with a chloride ligand and the resulting chiral, triangular cluster PdPtCoCl(CO)₃(-dppm)₂ (4) has been structurally characterized. The Pd-Co and Pt-Co edges of this almost equilateral triangle are bridged by a dppm ligand, and two of the three carbonyls borne by the Co atom are semi-triply bridging above and below the plane of the metals. The Co(CO)₃P fragment behaves as an anionic 4-electron donor organometallic bridging group toward thed ⁹-d ⁹ Pd(I)-Pt(I) unit. Crystal data for4, monoclinic space groupP2₁/n with Z=4 in a unit cell of dimensionsa=12.291(3),b=19.321(4),c=23.680(5) Å,=100.05(2)°. The structure has been solved from diffractometer data by Patterson, Fourier methods and refined by full-matrix least squares on the basis of 3512 observed reflections (l>3) toR(F) andR _w(F) values of 0.059 and 0.061.Dedicated to Professor L. F. Dahl on the occasion of his 65th birthday, with our sincere congratulations and best wishes.     

Peculiarities of interactions between the DNA molecule and different isomers and modifications of binuclear coordination compounds of platinum(II)

A comparison has been made of conformational changes in the DNA molecule during its interaction in solution with different binuclear coordination compounds of platinum [Pt(NH₃)₂Cl-R-Pt(NH₃)₂Cl]Cl₂ in cis and trans conformations, which contain cytosine, pyrazine, and carboxypyrazine as the common ligand (R). The influence of concentration of the components, and in particular, of ionic strength of the solution on the complexation process was studied. The influence of the nature of the common ligand, and of cis and trans conformations of coordination compounds on the character of their interaction with DNA was considered. A comparison was made between the structures of DNA complexes with mono-and binuclear compounds with the same set of ligands in the platinum coordination sphere.     

电化学溶解金属铜制备纳米CuO

有机电解合成;铜电极;水解;电化学溶解金属铜制备纳米CuO     

Sm2O3掺杂CeO2纳米粉体的烧结动力学

对Sm2O3掺杂CeO2纳米粉体的烧结性能进行了研究, 得出等速烧结过程中试样的线收缩率、密度、气孔率随烧结温度的变化规律, 它们随烧结温度的变化均呈"S"型曲线关系, 利用非线性回归了等速烧结过程动力学方程. 结果表明, Sm2O3掺杂CeO2纳米粉体的烧结过程分为3个阶段, 当烧结温度低于1000 ℃时, 线收缩率与密度变化较小, 处于烧结的初期; 在1000～1400 ℃时, 随着烧结温度的升高, 线收缩率与体积密度急剧增大, 材料开始烧结并致密化; 当烧结温度高于1400 ℃时, 线收缩率与体积密度趋于一恒定值, 材料已经致密化. 由归一化速率方程可知, 在T=1225 ℃时, 材料的烧结致密化速率最大.     

Exo-H- andendo-H-η4-pentamethylcyclopentadiene complexes of platinum

A mixture ofendo-H andexo-H isomers (1a and1b) of the (⁴-C₅Me₅H)PtCl₂ complex was prepared by the reaction of K₂PtCl₄ with C₅Me₅H in MeOH. The mixture of isomers reacts with CpTl in the presence of TiBF₄ to give a novel complex, [(⁴-C₅Me₅H)Pt(⁵-C₅H₅)]⁺BF₄ ^–, as a mixture ofendo-H- andexo-H-isomers (2a and2b). The data of¹H and¹³C NMR spectroscopy of the resulting complexes are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 514–517, March, 1994.     

Highly sensitive spectrophotometric determination of trace amounts of platinum(IV) with the molybdate-basic dyes-poly(vinyl alcohol) system

Three highly sensitive spectrophotometric methods for the determination of platinum(IV) have been developed, based on its colour reactions with molybdate and basic dyes (BD) in aqueous solution in the presence of poly(vinyl alcohol). Platinum(IV) reacts with molybdate and BD to form ion — association complexes of composition (BD)₂[Pt (MoO₄)₃]. The molar absorptivities are between 6.83 × 10⁵ and 9.51 × 10⁵ dm³mol^–1cm^–1, the highest value being found with nile blue. Suitable conditions for the reactions and the effects of foreign ions were investigated. The methods can be applied to the spectrophotometric determination of trace amounts of platinum(IV) in some catalysts and ores.