34692-09-6Relevant articles and documents
ALKYL-, ALKENYL- UND HYDRIDO-OLEFIN-KOMPLEXE DES RUTHENIUMS
Lehmkuhl, Herbert,Grundke, Juergen,Benn, Reinhard,Schroth, Gerhard,Mynott, Richard
, p. C5 - C8 (1981)
Cp(PPh3)2Ru-prim.alkyl complexes 2-6 and the η1-alkenylruthenium compound 7 have been prepared by treatment of the corresponding chlororuthenium compound 1 with the appropriate organomagnesium halides.Magnesium compounds with sec.- or tert.-alkyl groups afford the hydrido-Ru-complex 8 via olefin elimination.At 80 deg C 3-5 eliminate one PPh3 and are converted into the hydridoolefin-complexes 9-11.Stable Cp(PPh3)Ru-η1,η2-4-alkenyl complexes 14 and 15 are obtained if β-H-elimination is prevented by trans configuration of Ru and β-H in a cyclopropyl system.
Photochemical studies of (η5-C5H 5)Ru(PPh3)2Cl and (η5-C 5H5)Ru(PPh3)2Me: Formation of Si-H and C-H bond activation products
Clark, Johnathan L.,Duckett, Simon B.
supporting information, p. 1162 - 1171 (2014/01/06)
Studies examining the photochemical reactivity of CpRu(PPh 3)2Cl and CpRu(PPh3)2Me towards the two electron donor ligands PEt3, C2H4, DMSO, the CH bond activatable reagents tetrahydrofuran, toluene, and pyridine, and the SiH bond activatable reagents HSiEt3 and HSi(Me) 2CHCH2) are presented. Broadband UV irradiation of CpRu(PPh3)2Cl leads to the formation of mono-substitution products such as CpRu(PPh3)(PEt3)Cl which are inert to further photochemical reaction, although thermally bis-substituted products such as CpRu(PEt3)2Cl can be formed. Room temperature irradiation of the related complex CpRu(PPh3)2Me with L = PEt3, C2H4, and DMSO also produces CpRu(PPh3)(L)Me. However, when these reactions are followed by in situ laser irradiation (325 nm source) at low temperature, three solvent activated isomers (ortho, meta and para) of CpRu(PPh3) 2(C6H4Me) are detected in toluene in addition to η1- and η3-coordinated benzyl species. Furthermore, photolysis in THF leads to both the C-D bond activation product CpRu(PPh3)2(OC4D7) and the labile coordination complex CpRu(PPh3)(THF)Me. Now CH4 rather than CH3D is liberated which suggests the involvement of an orthometallated species. The photochemically driven reaction of CpRu(PPh 3)2Me with HSiEt3 at 198 K generates CpRu(κ2-2-C6H4PPh2)(SiEt 3)H and thereby confirms a role for an orthometallated complex is this process. Irradiation in cyclohexane produces the known orthometallated complex, CpRu(κ2-2-C6H4PPh 2)(PPh3), and CH4 in accordance with this reactivity. The Royal Society of Chemistry 2014.
Addition of catecholborane to a ruthenium-alkyl: Evidence for σ-bond metathesis with a low-valent, late transition metal
Hartwig, John F.,Bhandari, Sonali,Rablen, Paul R.
, p. 1839 - 1844 (2007/10/02)
Addition of catecholborane to the low-valent CpRu(PPh3)2Me complex led to formation of the corresponding ruthenium hydride and methylcatecholborane by a mechanism more characteristic of high-valent metal centers. Kinetic experiments conclusively showed that oxidative addition of the B-H bond did not occur. A stereochemical analysis of the reaction employing, (R,R)- and (R,S)-CpRu(DPPP)Me (DPPP = 1,2-bis(diphenylphosphino)propane) showed that epimerization of the ruthenium center was occurring before product formation and that the species undergoing epimerization never reformed starting material. The exchange reaction, therefore, involved an intermediate whose formation was rate determining. The observation of a primary deuterium isotope effect (1.62±0.13) and the absence of exchange between CpRu(PPh3)Me-d3 and MeBcat provided strong evidence for weakening of the borane B-H bond during formation of the transition state leading to this intermediate. The electronic effect of varying the phosphine ligand suggested a buildup of positive charge at the metal center, consistent with an intermediate possessing a coordinated hydridoborate ligand. All of the data were consistent with a mechanism proceeding through a four-centered transition state that involves partial cleavage of the B-H bond during formation of the B-C bond. Epimerization occurred by dissociation of the resulting hydridoborate ligand to form a three-coordinate ruthenium cation. The intermediate resulting from this step was trapped as a THF complex of the cationic ruthenium center during reactions in this solvent. The unligated three-coordinate cation provided epimerized product, but was not on the pathway to exchange of the boron-hydrogen and ruthenium-methyl groups.
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.
Alkylruthenium(II) Compounds and their β-H-Elimination into (η2-Alkene)hydridoruthenium Complexes
Lehmkuhl, Herbert,Grundke, Juergen,Mynott, Richard
, p. 159 - 175 (2007/10/02)
Reaction of Cp(PPh3)2RuCl (1) with primary alkylmagnesium halides (alkyl = Et, Pr, n-Bu, i-Bu) leads to the corresponding alkylruthenium complexes 4 - 7.Above 50 deg C 4 - 7 lose a PPh3 molecule and form by Ru-β-H-elimination the (η2-alkene)hydridoruthenium complexes 9 - 12.With R = isobutyl the intermediately formed, coordinatively unsaturated Cp(PPh3)Ru - R commplex can be stabilized by complexation with ethylene (50 bar) as (η2-ethylene)isobutylruthenium complex 15.Mechanistic investigations of the ethyl complex 16 indicate that the Ru-β-H-elimination is reversible. - Rotation of the η2-alkene ligand in 9 - 12 leads to temperature-dependent 1H NMR spectra.The 31P chemical shifts of 1,2,4 - 7 and 9 - 12, respectively, are characteristic for the corresponding type of complexes.
