Experimental and Theoretical Investigations on the Catalytic Hydrosilylation of Carbon Dioxide with Ruthenium Nitrile Complexes

Deglmann, Peter; Ember, Erika; Hofmann, Peter; Pitter, Stephan; Walter, Olaf

doi:10.1002/chem.200600396

Cited by 122 publications

(74 citation statements)

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“…This accounts, at least in an approximate way, for the fact that these compounds do not enter or leave the reaction mixture as a gas. [35] Also, the vibrational partition function contribution to the Gibbs free-energy values was omitted as the calculated vibrational spectra of the complexes were found to exhibit extremely small restricted rotational frequencies. Effects of anharmonicity and numerical accuracy, therefore, would lead to artifacts in statistical thermodynamics.…”

Section: Methodsmentioning

confidence: 99%

“…Effects of anharmonicity and numerical accuracy, therefore, would lead to artifacts in statistical thermodynamics. [35] To evaluate the influence of the solvent on the relative energies, singlepoint energies were computed employing the COSMO [48] solvation model with the dielectric constant of acetone and the catalysis reaction solvent, CH 2 Cl 2 .…”

Section: Methodsmentioning

confidence: 99%

“…For general accuracy of the energetics in organometallic reactions, benchmark calculations have shown this level of theory to yield satisfactory results. [35,[36][37][38][39][40][41][42][43][44][45] Stationary points on the potential-energy surface were characterized as either minima or transition states by the presence of (respectively) zero or one significant imaginary frequency in the BP86/SV(P) vibrational spectrum, obtained by second analytic derivative calculations. [46,47] All Gibbs free-energy values refer to 298.15 K and 0.1 MPa pressure.…”

Section: Methodsmentioning

confidence: 99%

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Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Schneider¹,

Finger²,

Haferkemper³

et al. 2009

Chemistry A European J

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A detailed density functional theory (DFT) computational study (using the BP86/SV(P) and B3LYP/TZVP//BP86/SV(P) level of theory) of the rhodium-catalyzed hydrosilylation of ketones has shown three mechanistic pathways to be viable. They all involve the generation of a cationic complex [L(n)Rh(I)]+ stabilized by the coordination of two ketone molecules and the subsequent oxidative addition of the silane, which results in the Rh-silyl intermediates [L(n)Rh(III)(H)SiHMe2]+. However, they differ in the following reaction steps: in two of them, insertion of the ketone into the Rh-Si bond occurs, as previously proposed by Ojima et al., or into the Si-H bond, as proposed by Chan et al. for dihydrosilanes. The latter in particular is characterized by a very high activation barrier associated with the insertion of the ketone into the Si-H bond, thereby making a new, third mechanistic pathway that involves the formation of a silylene intermediate more likely. This "silylene mechanism" was found to have the lowest activation barrier for the rate-determining step, the migration of a rhodium-bonded hydride to the ketone that is coordinated to the silylene ligand. This explains the previously reported rate enhancement for R2SiH2 compared to R3SiH as well as the inverse kinetic isotope effect (KIE) observed experimentally for the overall catalytic cycle because deuterium prefers to be located in the stronger bond, that is, C-D versus M-D.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Schneider¹,

Finger²,

Haferkemper³

et al. 2009

Chemistry A European J

Self Cite

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“…[1][2][3] A variety of catalysts have been discovered and developed for this reaction, including complexes of Co, 4 Cu, [5][6][7][8] Ir, [9][10][11][12][13][14] Ni, [15][16][17] Pd/Pt, 18 Rh, 19 Ru, [20][21][22][23][24][25] Sc, 26 Zn, [27][28][29] and Zr, 30 frustrated Lewis pairs, [31][32][33][34][35][36] organocatalysts, [37][38][39][40][41][42] alkali metal carbonates, 43 and even polar solvents such as DMF. 38 These reactions result in various reduction products including silyl-formates, -acetals, andethers, CO, and methane.…”

Section: Introductionmentioning

confidence: 99%

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

Morris

Weetman

Wennmacher

et al. 2017

Catal. Sci. Technol.

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aThe simple perrhenate salt [NĲhexyl) 4 ]ĳ(ReO 4 )] acts as a catalyst for the reduction of organic carbonyls and carbon dioxide by primary and secondary hydrosilanes. In the case of CO 2 , this results in the formation of methanol equivalents via silylformate and silylacetal intermediates. Furthermore, the addition of alkylamines to the reaction mixture favours catalytic amine N-methylation over methanol production under certain conditions. DFT analysis of the mechanism of CO 2 reduction shows that the perrhenate anion activates the silylhydride forming a hypervalent silicate transition state such that the CO 2 can directly cleave a Si-H bond. IntroductionThe hydrosilylation of CO 2 to silylformates and silylethers is an attractive route for CO 2 utilisation as, unlike hydrogenation, this reaction is exergonic due to the comparative ease of Si-H bond activation and the strength of the Si-O bond, and the availability of relatively inexpensive and environmentally benign hydrosilanes. 66 Important to this chemistry is the formation of a lipophilic ion pair in which electrostatic and hydrogen-bonding interactions are enhanced in the hydrophobic phase. This catalyst has the advantages of ease of synthesis and manipulation and lack of air-sensitivity, and the recovery of the precious metal is driven by straightforward reverse phase-transfer. Given the efficacy of this new catalyst system and the use of high oxidation state rhenium oxo complexes in reduction catalysis, it is shown here that perrhenate can act as a catalyst for the reduction of carbon dioxide to methanol equivalents by hydrosilanes, that the methylation of alkylamines using CO 2 as the C 1 source occurs under similar catalytic conditions, and that this method can be used to reduce aldehydes and ketones to silylalcohols. Results and discussion Reduction of carbon dioxideInitially, the reaction between CO 2 (2.5 bar), PhSiH 3 (2.0 mmol), and pyridinium perrhenate 1 (2.0 mol%) at 80°C in C 6 D 6 in a Teflon-tapped NMR tube was monitored by 1 H NMR spectroscopy. However, only 15% consumption of hydrosilane is seen under these conditions after 16 h ( Fig. S2 and S3, ESI †). In contrast, when the reaction is carried out using the simple lipophilic quaternary ammonium salt [NĲhexyl) 4 ]ĳReO 4 ] 2 (2.5 mol%) with PhSiH 3 in C 6 D 6 at 1 bar of

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“…A paper by Deglmann et al 99 has described both experimentally (by using in situ IR spectroscopy) and theoretically (by DFT calculations with an Me 3 SiH model), the catalytic hydrosilylation of carbon dioxide by Me 2 PhSiH with ruthenium nitrile complexes mer-(RuX 3 (MeCN) 3 ) and cis/trans-(RuX 2 (MeCN) 4 ) with X = Br, Cl. They showed that the key steps of the reaction are the transfer of the Me 3 Si moiety to a coordinated halide ligand, resulting in an L n RuH-(XSiMe 3 ) intermediate, CO 2 coordination to Ru in a side-on manner, Me 3 Si transfer to CO 2 , and reductive elimination of the formoxysilane product Me 3 SiOCHO (see Figure 16).…”

Section: Reactions With Electrophilesmentioning

confidence: 99%

Metal Coordination ofCO₂

Mascetti

2014

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Even though carbon dioxide is used in a great number of industrial applications, it remains a molecule with low reactivity. Its activation by coordination to metal complexes is used in both stoichiometric and catalytic reactions. This article describes the different kinds of metal carbon dioxide complexes observed in the gas phase, in cryogenic solids, and in solution, and briefly presents the reactivity of coordinated CO 2 toward electrophiles and nucleophiles.

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Experimental and Theoretical Investigations on the Catalytic Hydrosilylation of Carbon Dioxide with Ruthenium Nitrile Complexes

Cited by 122 publications

References 122 publications

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

Metal Coordination ofCO₂

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Experimental and Theoretical Investigations on the Catalytic Hydrosilylation of Carbon Dioxide with Ruthenium Nitrile Complexes

Cited by 122 publications

References 122 publications

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Multiple Reaction Pathways in Rhodium‐Catalyzed Hydrosilylations of Ketones

Reduction of carbon dioxide and organic carbonyls by hydrosilanes catalysed by the perrhenate anion

Metal Coordination ofCO2

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Metal Coordination ofCO₂