114674-46-3Relevant academic research and scientific papers
Effect (or lack thereof) of ancillary groups on the preparation and spectroscopic properties of ruthenium silyl complexes containing the Cp(PR3)2Ru moiety
Freeman, Samuel T.N.,Lofton, Lori L.,Lemke, Frederick R.
, p. 4776 - 4784 (2008/10/08)
The preparation and characterization of Cp(PR3)2RuSiX3 [PR3 = PPhMe2, SiX3 = SiCl3 (1), SiHCl2 (2), SiH2Cl (3), SiHMeCl (4), SiH3 (7), SiMeH2 (8), SiMe3 (9); PR3 = PPh2Me, SiX3 = SiCl3 (10), SiHCl2 (5), SiH2Cl (6), SiMeCl2 (11)] are described. Ruthenium silyl complexes 1-6 are prepared by the reaction of the ruthenium hydrides, Cp(PR3)2RuH, with the corresponding chlorosilane, ClSiX3; the ruthenium dihydrides [Cp(PR3)2RuH2]Cl were obtained as coproducts. Increasing the steric demand of the phosphine decreased the reactivity of the corresponding ruthenium hydride toward chlorosilanes. Silyl complexes 1-4 undergo chloride/hydride exchange with LiAlH4 to give the corresponding ruthenium hydrosilyl complexes Cp(PPhMe2)2RuSiHX2 [SiHX2 = SiH3 (7), SiMeH2 (8)]. Methylation of 1 with AlMe3 produces Cp(PPhMe2)2RuSiMe3 (9). Complexes 10 and 11 were prepared by the reaction of Cp(PPh2Me)2RuMe with neat hydrosilanes HSiX3 (SiX3 = SiCl3, SiMeCl2) at 100 °C. The effects of the silicon substituents on the spectroscopic properties of 1-11 and the related Cp(PMe3)2RuSiX3 complexes were examined as a function of Tolman's electronic parameter (χi) for the substituents on silicon. The NMR resonance PR3 δ(31P) and the NMR coupling constants, 1JSiH and 2JSiP, exhibit a linear relationship with ∑χi(SiX3). On the other hand, the silyl groups differentiated into three classes, dichlorosilyl, monochlorosilyl, and non-chlorosilyl , when the NMR resonances SiX3 δ(29Si), SiH δ(1H), and SiMe δ(13C) were examined as a function of ∑χi(SiX3). This chloro effect was attributed to Ru-Si silylene character from d(Ru)-*(Si-Cl) π-back-bonding interactions. Surprisingly, changing the phosphine attached to ruthenium had no effect on the spectroscopic properties of the silyl group.
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.
