Rh(III)-Catalyzed One-Step Synthesis of ortho-Alkynylated Perylene Imide Dyes: Optical and Electrochemical Properties of New Derivatives

A one-step Rh-catalyzed site-selective ortho-C−H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C−H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization.     

Rhodium-catalyzed addition of arylstannanes to carbon-heteroatom double bond

The addition of arylstannanes to the carbon-heteroatom double bond in the presence of a catalytic amount of a cationic rhodium complex ([Rh(cod)(MeCN)₂]BF₄) was examined. The reactions of aldehydes, α-dicarbonyl compounds, and N-substituted aldimines with the arylstannanes gave corresponding alcohols, α-hydroxy carbonyl compounds, and amines, respectively. An arylrhodium complex generated by the transmetalation with the arylstannane was probably the active catalytic species.     

Hydroformylation: a versatile tool for the synthesis of new β-formyl-metalloporphyrins

Formyl derivatives of protoporphyrin-IX dimethyl ester metal complexes were obtained via hydroformylation reactions, catalysed by rhodium-triphenylphosphine complexes. The regioselectivity of the reaction is remarkably dependent on the metal centre of the porphyrin, yielding 100% of the branched aldehyde with zinc(II) complexes and 75% with the nickel(II). The NMR characterisation of the new compounds was carried out after their derivatisation into acetals.     

锰、铑原卟啉IX-二甲酯配合物共振拉曼光谱研究

合成了MnPPCl,RhPPCl,RhPPN3,RhPP(CO)Cl四种配合物 (PP =ProtophyrinIXDimethy1Ester) ,用元素分析、红外吸收光谱及紫外吸收光谱确定了配合物的组成 ,测定了它们的共振拉曼光谱 ,对特征谱带进行了归属。分析了拉曼谱带和电子吸收谱带变化的原因 ,提出了谱带频率的变化受金属离子外层d电子和轴配体的影响。     

熔融萃取法富集痕量铂和铑─石墨炉原子吸收光谱测定

本文报道以２－硫基苯并噻唑（ＭＢＴ）为络合剂，用熔融萘萃取痕量的铂和铑，继用石墨炉原子吸收光谱法直接测定之。文中曾对一些有关参数作了试验，并找出各参数的最优值，对共存离子的允许量也作了试验。最后用国家标样和部级管理样核对本法，结果令人满意。     

聚-4,7-二硫杂壬基倍半硅氧烷铑配合物的合成与催化硅氢化性能

本文叙述了一种新型有机硅聚合物负载配位催化剂——聚-4,7-二硫杂壬基倍半硅氧烷铑配合物的合成、结构及其对烯烃硅氢化反应的催化性能.标题配合物在用量为烯烃摩尔量的十万分之一时仍具有良好的催化活性,烯烃的转化数达到80,000.     

Dirhodium(II)-catalyzed carbonyl ylide generation. Stereoelectronic control in dioxolane formation

The combination of ethyl diazoacetate with aryl aldehydes in the presence of copper(I) or rhodium(II) catalysts results in the formation of 1,3-dioxolane products in moderate to good yields. These reactions occur through a pathway that involves ylide intermediates. Catalyst-dependent diastereocontrol is observed and suggests that metal-associated ylides are involved in the product-determining step. The influence of aryl aldehyde substituents has been determined. Current address. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 961–965, May, 1998.     

The use of imidazolium ionic liquids for the formation and stabilization of ir0 and rh0 nanoparticles: efficient catalysts for the hydrogenation of arenes

Stable transition-metal nanoparticles of the type [M(0)](n) are easily accessible through the reduction of Ir(I) or Rh(III) compounds dissolved in "dry" 1-n-butyl-3-methylimidazolium hexafluorophosphate ionic liquid by molecular hydrogen. The formation of these [M(0)](n) nanoparticles is straightforward; they are prepared in dry ionic liquid whereas the presence of the water causes the partial decomposition of ionic liquid with the formation of phosphates, HF and transition-metal fluorides. Transmission electron microscopy (TEM) observations and X-ray diffraction analysis (XRD) show the formation of [Ir(0)](n) and [Rh(0)](n) nanoparticles with 2.0-2.5 nm in diameter. The isolated [M(0)](n) nanoparticles can be redispersed in the ionic liquid, in acetone or used in solventless conditions for the liquid-liquid biphasic, homogeneous or heterogeneous hydrogenation of arenes under mild reaction conditions (75 degrees C and 4 atm). The recovered iridium nanoparticles can be reused several times without any significant loss in catalytic activity. Unprecedented total turnover numbers (TTO) of 3509 in 32 h, for arene hydrogenation by nanoparticles catalysts, have been achieved in the reduction of benzene by the [Ir(0)](n) in solventless conditions. Contrarily, the recovered Rh(0) nanoparticles show significant agglomeration into large particles with a loss of catalytic activity. The hydrogenation of arenes containing functional groups, such as anisole, by the [Ir(0)](n) nanoparticles occurs with concomitant hydrogenolysis of the C-O bond, suggesting that these nanoparticles behave as "heterogeneous catalysts" rather than "homogeneous catalysts".