Phosphine complexes of silylruthenium hydrides. Interaction of silicon hydride with RuH2(PPh3)4, RuCl2(PPh3)3, and RuHCl(PPh3)3

Kono, Hiromichi; Wakao, N.; Ito, Kazushi; Nagai, Yoichiro

doi:10.1016/s0022-328x(00)92514-2

Cited by 42 publications

(7 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hydride signals persisted even when different silanes were used or in the absence of water in the mixture, indicating that the origin of the hydride is the silane and that the two ruthenium hydride species most likely do not contain silyl groups. This observation is consistent with previous results that reported the occurrence of Ru–halide/Si–H exchange. , Unfortunately, the FTIR signals of these intermediates could not be recorded presumably because of their low concentrations or overlap with the much more intense precursor signals, hence preventing further characterization.…”

Section: Resultssupporting

confidence: 92%

“…This [Ru]-THF complex is an important catalytic intermediate that can be deactivated upon PPh 3 substitution to afford Ru(CO) 2 (PPh 3 ) 2 Br 2 (Table , entry 6). The silane then binds weakly to the ruthenium center, most likely with the SiH bond approaching in a σ-mode in order to reduce steric hindrance caused by overcrowding of ligands. , The subsequent step involves the formation of either a (i) [Ru]-H intermediate with elimination of silyl bromide (R 3 SiBr) or (ii) [Ru]-SiR 3 intermediate with elimination of HBr. ,, From the NMR data, it appears that at least two ruthenium hydride species have been detected rendering pathway (i) to be highly possible. The reactive 16-electron [Ru]-H monomer forms Ru(CO) 2 (PPh 3 )(H 2 O)(H)Br upon water coordination.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

2011

View full text Add to dashboard Cite

Dimeric Ru(II) complexes Ru2(CO)4L2X4 (L = CO or PPh3; X = Cl or Br) have been found to catalyze the hydrolysis of silanes to produce hydrogen gas and silanols with turnover numbers in excess of 104 at room temperature. Deuteration and mass spectrometric studies have established that the hydrogen gas originates from one hydrogen atom from water and the other from silane. Ruthenium hydride intermediates have been detected in the NMR spectrum during the early stage of the reaction, while the FTIR spectra of more stable complexes such as Ru(CO)2(PPh3)(THF)Br2 and Ru(CO)2(PPh3)2(H)Br have been recorded upon completion of catalysis. A mechanism has been proposed to account for the ruthenium-catalyzed silane hydrolysis based on the experimental data.

show abstract

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

2011

View full text Add to dashboard Cite

show abstract

“…The three hydrides exchange until the temperature limit of 203 K. The observed minimum T 1 value is 90 ms at 233 K (C 7 D 8 , 250 MHz) ruling out a hydrido dihydrogen formulation but not a short contact between the three hydrides. This complex is therefore formulated as a trihydridoruthenium(IV) complex, only a limited number of examples of which are known . The presence of the (η 3 -cyclohexenyl)(dicyclohexyl)phophine ligand was supported by the 13 C NMR spectrum.…”

Section: Resultsmentioning

confidence: 99%

Versatile Reactivity of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂ toward Functionalized Olefins: Olefin Coordination versus Hydrogen Transfer via the Stepwise Dehydrogenation of the Phosphine Ligand

et al. 1996

View full text Add to dashboard Cite

Treatment of RuH2(H2)2(PCy3)2 (1) with ethylene leads to the formation of [RuH{η3-C6H8)PCy2}(C2H4)(PCy3)] (2), which contains an η3-cyclohexenyl ring. Upon addition of 3 equiv of an alkene bearing σ-donor substituents such as CH2CH(SiEt3) or CH2CHtBu, 1 transforms in high yield into the trihydridoruthenium(IV) complex [RuH3{(η3-C6H8)PCy2}(PCy3)] (3) and the corresponding alkane is obtained quantitatively. Further hydrogen abstraction from 1 can be achieved by using 5 equiv of alkene, leading to the hydridoruthenium(II) complex [RuH{(η3-C6H8)PCy2}{(η2-C6H9)PCy2}] (4). This is the first complex where C−H activation within two cyclohexyl rings of two tricyclohexylphosphines has occurred. 4 can also be obtained by treatment of 3 with 2 equiv of alkene. The reactions can be reversed by bubbling dihydrogen into a solution of 2−4 yielding 1 at the final stage of hydrogenation. 3 and 4 undergo rapid H−D exchange with the deuterated solvent. Reaction of 1 with alkenes bearing electron-withdrawing substituents such as CH2CHCO2Me or trans-MeO2CCHCHCO2Me allows the formation of the hydrido dihydrogen complexes [RuH(H2)(η2-O2CCH2CH3)(PCy3)2] (5) and [RuH(H2)(η2-O2CCH2CH2CO2Me)(PCy3)2] (6), respectively. An X-ray structure determination on 5 was carried out. Surprisingly, reaction of 1 with cis-MeO2CCHCHCO2Me yielded the alkene-coordinated complex [RuH2(η2-CH3O2CCHCHCO2CH3)(PCy3)2] (7). Variable-temperature NMR studies on 7 showed a barrier of rotation for the alkene of 10.5 kcal/mol. 7 was shown to catalyze cis−trans MeO2CCHCHCO2Me isomerization.

show abstract

“…During the preparation of this paper, Werner et al reported the preparation of the very similar complex RuH 2 Cl 2 (P i Pr 3 ) 2 (4-i Pr) identified by an X-ray crystal structure. 13 Several ruthenium(IV) hydrido derivatives have been described, [27][28][29] and we reported a few years ago the synthesis of a similar but 18-electron complex RuH 2 -(OCOCF 3 ) 2 (PCy 3 ) 2 . Interestingly, the latter compound, although electronically saturated, was shown to be thermally unstable and to lose H 2 slowly in solution.…”

Section: Theoretical Study Of a Model For 1 (I) Stability Of Differen...mentioning

confidence: 99%

Fluxionality and Isomerism of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂: INS, NMR, and Theoretical Studies

Rodrı́guez

Sabo-Étienne²,

Chaudret³

et al. 1998

Inorg. Chem.

View full text Add to dashboard Cite

To study the fluxionality of the bis(dihydrogen) complex RuH(2)(H(2))(2)(PCy(3))(2) (1), NMR spectra were recorded in Freons (mixture of CDCl(3), CDFCl(2), and CDF(2)Cl). 1 was found to remain fluxional at all temperatures, but the presence of CDCl(3) necessary for its solubilization induces its transformation into, first, RuHCl(H(2))(2)(PCy(3))(2) (3) and the new ruthenium(IV) dihydride RuH(2)Cl(2)(PCy(3))(2) (4). 4 is produced selectively in pure CDCl(3) but reacts further to give a mixture of chloro complexes. 4 was isolated from the reaction of 1 with aqueous HCl in Et(2)O and shows a fluxional process attributed to the interconversion between two symmetrical isomers. The activation parameters of this process were obtained by (1)H NMR line shape analysis, as well as those corresponding to the exchange between 3 and free dihydrogen. The fluxionality of the dihydrogen-hydride system is also evident at a much faster time scale than that of NMR studies in the inelastic neutron scattering observations of the rotation of the dihydrogen ligands. The geometries and relative energies of several isomers of complexes 1, 3, and 4 were studied using density functional theory (DFT) and MP2 methods, together with a few coupled-cluster (CCSD(T)) calculations. In contrast to what might have been expected, the two hydrides and the two H(2) units of 1 lie in the same plane, due to the attractive "cis effect" created by the hydrides. The two H(2) ligands adopt cis positions in the lowest-energy isomer. Rotation of the two dihydrogen ligands has been analyzed using DFT calculations. A slight preference for a C(2) conrotatory pathway has been found with a calculated barrier in good agreement with the experimental INS value. Two low-energy isomers of 4 have been characterized computationally, both of which have C(2)(v)() symmetry, consistent with the solution NMR spectra.

show abstract

Phosphine complexes of silylruthenium hydrides. Interaction of silicon hydride with RuH2(PPh3)4, RuCl2(PPh3)3, and RuHCl(PPh3)3

Cited by 42 publications

References 23 publications

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

Versatile Reactivity of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂ toward Functionalized Olefins: Olefin Coordination versus Hydrogen Transfer via the Stepwise Dehydrogenation of the Phosphine Ligand

Fluxionality and Isomerism of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂: INS, NMR, and Theoretical Studies

Contact Info

Product

Resources

About

Phosphine complexes of silylruthenium hydrides. Interaction of silicon hydride with RuH2(PPh3)4, RuCl2(PPh3)3, and RuHCl(PPh3)3

Cited by 42 publications

References 23 publications

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

Catalytic Hydrogen Generation from the Hydrolysis of Silanes by Ruthenium Complexes

Versatile Reactivity of the Bis(dihydrogen) Complex RuH2(H2)2(PCy3)2 toward Functionalized Olefins: Olefin Coordination versus Hydrogen Transfer via the Stepwise Dehydrogenation of the Phosphine Ligand

Fluxionality and Isomerism of the Bis(dihydrogen) Complex RuH2(H2)2(PCy3)2: INS, NMR, and Theoretical Studies

Contact Info

Product

Resources

About

Versatile Reactivity of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂ toward Functionalized Olefins: Olefin Coordination versus Hydrogen Transfer via the Stepwise Dehydrogenation of the Phosphine Ligand

Fluxionality and Isomerism of the Bis(dihydrogen) Complex RuH₂(H₂)₂(PCy₃)₂: INS, NMR, and Theoretical Studies