93081-71-1Relevant academic research and scientific papers
Experimental and computational studies of ruthenium(II)-catalyzed addition of arene C-H bonds to olefins
Lail, Marty,Bell, Christen M.,Conner, David,Cundari, Thomas R.,Gunnoe, T. Brent,Petersen, Jeffrey L.
, p. 5007 - 5020 (2004)
Hydroarylation reactions of olefins are catalyzed by the octahedral Ru(II) complex TpRu-(CO)(NCMe)(Ph) (1) (Tp = hydridotris(pyrazolyl)borate). Experimental studies and density functional theory calculations support a reaction pathway that involves initial acetonitrile/olefin ligand exchange and subsequent olefin insertion into the ruthenium-phenyl bond, Metal-mediated C-H activation of arene to form a Ru-aryl bond with release of alkyl arene completes the proposed catalytic cycle. The cyclopentadienyl complex CpRu(PPh 3)2(Ph) produces ethylbenzene and styrene from a benzene/ethylene solution at 90°C; however, the transformation is not catalytic. A benzene solution of (PCP)Ru(CO)(Ph) (PCP = 2,6-(CH 2Pt-Bu2)2C6H 3) and ethylene at 90°C produces styrene in 12% yield without observation of ethylbenzene. Computational studies (DFT) suggest that the C-H activation step does not proceed through the formation of a Ru(IV) oxidative addition intermediate but rather occurs by a concerted pathway.
H-C Bond Cleavage by (ν5-Cyclopentadienyl)bis(triorganylphosphine)ruthenium Organyl Complexes
Lehmkuhl, Herbert,Bellenbaum, Marita,Grundke, Juergen,Mauermann, Heiko,Krueger, Carl
, p. 1719 - 1728 (2007/10/02)
Ruthenium(II) complexes of the type Cp(MenPh3-nP)2RuR with R = CH3, and R = CH2CMe3 have been prepared from the appropriate ruthenium chloride and alkyllithium or alkylmagnesium chloride.Of the methyl complexes having at least one phenyl group in the phosphane ligand, 17 reacts at 20 deg C and 14, 19, and 21 upon warming by intramolecular H-C(phenyl) bond cleavage and elimination of methane to give the ortho-metallated products Cp(MenPh3-nP) 15, 18, 20, and 22.The neopentyl ruthenium complexes 23, 25, 32, 34, and 36 react in an intermolecular manner with benzene by H-C(benzene) bond cleavage and elimination of neopentane to give the phenylruthenium compounds 24, 26, 33, 35, and 37.Whereas the Me3P-complex 36 as well as (C5H5)(Me3P)(Ph3P)RuCH2CMe3 (30) react with benzene to give neopentane and the phenyl complexes 37 and 31, the complexes 23, 25, 32, and 34 react to give undeuterated neopentane and the phenyl compounds 24, 26, 33, and 35.The phenyl complex 24 and the ruthenium compounds having benzyl (34) or p-tolyl groups (40) react with toluene to give an equilibrium mixture of the m- and p-tolyl complexes 38 and 40.H-C(arene) bond cleavage is also observed with other aromatic compounds such as phenyl bromide or naphthalene.In the case of 36 bond cleavage occurs selectively in the position meta to the substituent to give 42 and 43.Styrene, in contrast, reacts with 36 with cleavage of the vinylic 1(E)-H-C bond to give 44, while ethylene reacts to give the (ν2-ethylene)-vinylruthenium complex 45, which upon warming isomerizes with ethylene insertion into the vinyl-Ru bond to give the ν3-1-methylallyl compound 46. - In the H-C bond cleavage reaction, (C5Me5)Ru complexes are more reactive than the corresponding systems with a C5H5 group, and in both series the reactivity decreases with increasing basicity of the phosphine ligand. - The crystal structure analysis of Cp(Ph3P)(Me3P)RuCH2CMe=CH2 (13) is described.
Spaltung aromatischer und vinylischer C-H-Bindungen durch Cyclopentadienylruthenium(II)-Komplexe
Lehmkuhl, Herbert,Bellenbaum, Marita,Grundke, Juergen
, p. C23 - C26 (2007/10/02)
Neopentylruthenium complexes of the type Cp(MenPh3-nP)2RuCH2CMe3 (Cp = C5H5, C5Me5; n = 0-3) react with aromatic C-H bonds in benzene or toluene to give the corresponding phenyl- or tolyl-ruthenium compounds and neopentane.With toluene, a mixture of the m- and p-tolyl complexes is formed.The reactivity of the neopentylruthenium compounds decreases with increasing degree of methyl substitution at the phosphorus atom, and with bidentate phosphane ligands.A permethylated Cp group increases the reactivity. (C5Me5)(Me3P)2RuCH2CMe3 reacts also with the vinylic C-H bond of ethylene to form an (η2-ethylene)vinylruthenium complex.
