Homogeneous gold-catalyzed hydrosilylation of aldehydes

The catalytic hydrosilylation of aldehydes in the presence of PBu₃ modified Au(I)-complexes was investigated. In situ IR and NMR experiments have revealed that both, the ligand PBu₃ and the substrate aldehyde play an important role in stabilizing the gold catalyst and/or forming the catalytically active species. In their absence the reducing power of silane destabilizes the gold (I) catalyst giving rise to gold clusters or particles. Several side reactions involving water and oxygen were also investigated. A plausible reaction pathway as an alternative to the well-accepted mechanism for the transition-metal homogeneously catalyzed hydrosilylation of aldehydes has been proposed to accommodate the experimental observations.     

聚-4-氧杂-6,7-双甲硫基庚基硅氧烷铂络合物的合成及其对烯烃硅氢加成反应的催化特性

4-氧杂-6,7-双甲硫基三甲氧基硅烷用气相法二氧化硅固载,再与氯亚铂酸钾作用,合成了双齿型硫醚铂络合物——聚-4-氧杂-6,7-双甲硫基庚基硅氧烷铂络合物。它对烷氧基硅烷与烯烃的硅氢加成反应具有良好的催化活性和突出的回收再用性能。其结构通过元素分析和XPS进行了表征。     

超支化聚碳硅氮烷的合成与表征

聚碳硅氮烷是一种新型含硅有机金属聚合物,其主链由硅氮碳连接而成,侧链为有机基团;与其它含硅聚合物(聚硅氮烷、聚碳硅烷等)类似,聚碳硅氮烷适于用做力学性能极佳且耐高温氧化的氮化硅(Si3N4)和氮化硅/碳化硅(Si3N4/SiC)复相陶瓷的前驱体.[1]超支化聚合物具有溶解性好、粘度低     

Silica－supported Polysiloxane with Selenacrown Ether Moieties and Its Platinum Complex

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Photoswitching of the reactivity involving hydrosilylation of a 1,1,3,3-tetrahydrodisiloxane bearing two azo groups

A pentacoordinate (E,E)-1,1,3,3-tetrahydrodisiloxane bearing two azo groups gave hydrazobenzene in the fluoride ion-induced hydrolysis involving hydrosilylation of the azo groups followed by cleavage of the Si-C bonds, while a tetracoordinate (E,E)-forms formed by its photoirradiation gave an octaarylsilsesquioxane without cleavage of the Si-C bonds.     

SYNTHESIS AND CATALYTIC HYDROSILYLATION PROPERTY OF POLYSILOXANE-SUPPORTED MERCAPTOSELENAETHER PLATINUM OR RHODIUM COMPLEX

Silica-bound mercaptoselenaether-containing silsesquioxane and its plat-inum or rhodium complex were synthesized from γ-(2,3-epithiopropyl) propyltrimethoxysi-lane via ring-opening reaction with bis(2-hydroxyethyl) sclenide, followed by hydrolysisand immobilization on fumed silica, and then reacting with potassium chloroplatinite orrhodium chloride in acetone under nitrogen atmosphere. It was found that two noble metalcomplexes can catalyze the hydrosilylation of olefins with triethoxysilane effectively. Theinfluences of temperature, the amount of complex used, the nature of olefin on catalyticactivity were investigated.     

有机硅聚合物负载膦铂,膦铑络合物的合成及催化硅氢化性能

从p-氯烯丙苯出发,通过相继地与三甲氧基硅烷进行硅氢加成、二苯膦钾膦化、气相法二氧化硅固载化,再与氯亚铂酸钾或三氯化铑反应,合成了聚γ-(p-二苯膦苯基)丙基硅氧烷铂、铑络合物。两者对烯烃与三乙氧基硅烷的硅氢加成反应具有良好的催化活性。     

Synthesis of a propyldimethylphenylsilane stationary phase using the allyl bonded phase as an intermediate

Summary A propyldimethylphenylsilane stationary phase was prepared by a hydrosilylation reaction on the double bond of an allyl bonded phase intermediate. The carbon load on the silica was between 8.8–9.0%. Evaluation of the material by FTIR indicated high conversion of the double bond by the hydrosilylation reaction. The bonded material displayed reversedphase properties as determined by the retention behavior of alkylarylketones but it was less hydrophobic than either C-8 or C-18. The stability at both low and high pH was excellent. Separations of pharmaceutical compounds, a mixture of anilines, and a mixture of dopamine and epinephrine were satisfactory.     

Hydrosilylation of 1-hexyne promoted by acetone solvated gold atoms derived catalysts

Supported gold nanoparticles, prepared by deposition of acetone solvated Au atoms on supports as carbon and γ-Al₂O₃, behave as valuable catalysts for the regioselective hydrosilylation of 1-hexyne with different silanes. The catalytic behaviour of gold-based systems is compared with the activity of supported platinum catalysts and a different affinity between the metals and the silanes is observed.     

Copper (I) 1,3-R2-3,4,5,6-tetrahydropyrimidin-2-ylidenes (R=mesityl, 2-propyl): synthesis, X-ray structures, immobilization and catalytic activity

The synthesis of novel copper (I) N-heterocyclic carbene complexes is described. Thus, reaction of CuX with 1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene yields CuX(1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (X=Cl, (1a), Br (1b)); however, reaction of CuCl with 1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene yields the bis-N-heterocylcic carbene complex Cu(1,3-dimesityl-3,4,5,6-tetrahydropyrimidin-2-ylidene)₂⁺CuBr₂⁻ (2). A supported version of 1, i.e. PS-DVB-CH₂-OCO-CF₂-CF₂-CF₂-COOCu(1,3-di(2-propyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (3) was prepared from 1 and PS-DVB-CH₂-OCO-CF₂-CF₂-CF₂-COOAg. A copper loading of 4.15 μmol/g was realized. The new compounds were used as catalysts in carbonyl hydrosilylation and cyanosilylation reactions. Excellent reactivity was observed, giving raise to turn-over numbers (TONs) of up to 100,000. Compounds 1a, 1b, and 2 have also been used as catalysts for the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). A linear conversion of monomer with time was observed, however, no control over molecular weight of PMMA was observed.