52090-23-0Relevant academic research and scientific papers
Syntheses, structures, and immobilization of ruthenium(II) complexes with alkoxysilane groups functionalized N,N′-diamine and phosphine ligands
Ji, Jiao,Shi, Li-Miao,Wu, Fule,Xin, Zhi-Feng,Jia, Ai-Quan,Zhang, Qian-Feng
, p. 1314 - 1324 (2020)
Treatment of [RuCl2(PPh3)3] with N-(β-aminoethyl)-γ-aminopropylmethylbimethoxysilane (L1) in tetrahydrofuran at room temperature gave a mononuclear ruthenium(II) complex [Ru(PPh3)2Cl2 (κ2-N,N-L1)] (1). Condensation of γ-aminopropyltriethoxysilane and potassium diphenylphosphine in the molar ratio of 1:1 in tetrahydrofuran afforded phosphine (PPh2)(CH2)3Si(OEt)3 (L2) with ethoxysilane groups. Reaction of [Ru(η6-p-cymene)Cl2]2 with L2 in refluxing tetrahydrofuran afforded a ruthenium(II) phosphine complex [Ru(η6-p-cymene)Cl2(κ-P-L2)] (2). Complexes 1 and 2 were systematically characterized by microanalyses, FT-IR, and NMR spectroscopies. Their structures have been unambiguously established by single-crystal X-ray diffraction. Immobilization of 1 and 2 on SBA-15 and characterization of these hybrid heterogeneous catalysts were studied by transmission electron microscopy (TEM), FT-IR, and low-pressure N2 adsorption/desorption measurements. Transfer hydrogenation of acetophenone was also briefly investigated with the heterogeneous catalysts.
Promoting effect of Al on tethered ligand-modified Rh/SiO2 catalysts for ethylene hydroformylation
Liu, Jia,Yana, Li,Ding, Yunjie,Jiang, Miao,Dong, Wenda,Song, Xiangen,Liu, Tao,Zhu, Hejun
, p. 127 - 132 (2015/05/05)
A Rh/SiO2 catalyst with excellent activity and stability for ethylene hydroformylation was developed by modifying with tethered diphenylphosphinopropyl and doped with an Al promoter. The catalyst was characterized by means of N2 adsorption/desorption isotherms, transmission electron microscope, NH3 temperature programmed desorption, Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance. Experimental results showed that the existence of the Al promoter inhibited the growth of Rh particles, increased the number of exposed Rh atoms, changed the acidity of the catalyst surface, promoted in situ formation of active species that were similar to their corresponding homogeneous counterparts, and enhanced electron density of the P atom in the phosphine ligand.
Heterogenized Wilkinson-type catalyst for transfer hydrogenation of carbonyl compounds
Bogar, Krisztian,Krumlinde, Patrik,Bacsik, Zoltan,Hedin, Niklas,Baeckvall, Jan-E.
experimental part, p. 4409 - 4414 (2011/10/01)
Wilkinson's catalyst [RhCl(PPh3)3] was heterogenized on common silica by the use of a grafting/anchoring technique. The immobilized catalyst showed high activity and selectivity in transfer hydrogenation reactions of a range of carbonyl compounds in 2-propanol. Reactions carried out in 2-propanol at reflux afforded the corresponding alcohols in high yields in short reaction times. The heterogeneous feature of the catalyst allows for easy recovery and efficient reuse in the same reaction up to 5 times without any detectible loss of catalytic activity. Wilkinson's catalyst [RhCl(PPh 3)3] has been immobilized on silica through a monodentate phosphane ligand and used in the transfer hydrogenation of alkyl and aryl carbonyl compounds. The use of 2-propanol as both hydrogen donor and solvent allows for high yields of the corresponding alcohols under mild reaction conditions. The recyclability of this heterogenized Rh catalyst is also demonstrated.
Nanostructured dioxomolybdenum(VI) catalyst for the liquid-phase epoxidation of olefins
Castro, Alichandra,Alonso, Joao C.,Valente, Anabela A.,Neves, Patricia,Brandao, Paula,Felix, Vitor,Ferreira, Paula
experimental part, p. 1405 - 1412 (2010/07/16)
A new organosilica hybrid mesoporous material (HM) containing phosphane oxide surface groups was prepared via the "dual" organosilane templated co-condensation of 4-bis-(triethoxysilyl)benzene and (diphenylphosphanyl)propyltriethoxysilane, followed by post-synthesis oxidation of the phosphane surface groups. The HM material was used to immobilise the [Mo(O)2Cl2] complex. The resultant material (HM-Mo) is an active and selective catalyst in the liquid-phase epoxidation of olefins [cis-cyclooctene, (R)-(+)-limonene, trans-2-octene, 1-octene] with tBuOOH at 55°C and gives comparable epoxide yields to those observed for the free complex [MoCl2(O)2{OP(CH2CH3)(Ph) 2}2] (1), under similar reaction conditions: the crystal structure of complex 1 remains the same after reaction with tBuOOH. The oxidant is essentially consumed in the HM-Mo or 1 catalysed epoxidation of the olefin. In the case of limonene (possesses endo- and exocyclic C=C bonds), the molar ratio of 1,2-epoxy-p-menth-8-ene/1,2-8,9-diepoxy-p-menthane at ca. 90% conversion (reached after 24 h reaction) is ca. 5 and 10 for 1 and HM-Mo, respectively, indicating a favourable regioselectivity towards the epoxidation of the endocyclic C1-C2 double bond, especially in the case of the heterogeneous catalyst.
