Deoxygenative Reduction of Carbon Dioxide to Methane, Toluene, and Diphenylmethane with [Et<sub>2</sub>Al]<sup>+</sup> as Catalyst

Khandelwal, Manish; Wehmschulte, Rudolf J.

doi:10.1002/anie.201201282

Cited by 176 publications

(108 citation statements)

References 41 publications

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“…A limited number of metal-based catalysts have been shown to reduce CO 2 to yield different reduction products including formate (HCOO − ), carbon monoxide (CO), formaldehyde (CH 2 O), methanol (CH 3 OH), and methane (CH 4 ) (2, 6-13). Common features of homogeneous catalysts for CO 2 reduction to CH 4 are low reaction rates (e.g., turnover frequencies) and limited number of turnovers (e.g., turnover number) before inactivation of the catalyst (37,38). Further, for electrochemical reductions, a high overpotential is required, with production of H 2 as a waste of electron flux (39,40).…”

Section: Discussionmentioning

confidence: 99%

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Yang

Moure

Dean

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

108

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A doubly substituted form of the nitrogenase MoFe protein (α-70 Val→Ala , α-195 His→Gln ) has the capacity to catalyze the reduction of carbon dioxide (CO 2 ) to yield methane (CH 4 ). Under optimized conditions, 1 nmol of the substituted MoFe protein catalyzes the formation of 21 nmol of CH 4 within 20 min. The catalytic rate depends on the partial pressure of CO 2 (or concentration of HCO 3 − ) and the electron flux through nitrogenase. The doubly substituted MoFe protein also has the capacity to catalyze the unprecedented formation of propylene (H 2 C = CH-CH 3 ) through the reductive coupling of CO 2 and acetylene (HC≡CH). In light of these observations, we suggest that an emerging understanding of the mechanistic features of nitrogenase could be relevant to the design of synthetic catalysts for CO 2 sequestration and formation of olefins.is an abundant and stable form of carbon that is the product of respiration and burning of fossil fuels. As a result of these activities, the atmospheric concentration of CO 2 , a greenhouse gas, has been rising over the last century and contributing to global warming (1). There is strong interest in developing methods for sequestering CO 2 either by capturing it or by chemically converting it to valuable chemicals (2-5). Of particular interest are possible routes to reduction of CO 2 by multiple electrons to yield methanol (CH 3 OH) and methane (CH 4 ), which are renewable fuels (2). The reduction of CO 2 is difficult, with a limited number of reports of metal-based compounds able to catalyze these reactions (6-13). In biology, only a few enzymes are known to reduce CO 2 (14-18), and none of these can catalyze the eight electron reduction to CH 4 .The bacterial Mo-dependent nitrogenase enzyme catalyzes the multielectron/proton reduction of dinitrogen (N 2 ) to two ammonia (NH 3 ) at a metal cluster designated FeMo-cofactor [7Fe-9S-1Mo-1C-R-homocitrate] (Fig. 1) in a reaction that requires ATP hydrolysis and evolution of H 2 , with a minimal reaction stoichiometry shown in Eq. 1 (19)(20)(21)(22).Given that nitrogenase is effective at catalyzing the difficult multielectron reduction of N 2 , it was of interest to determine whether this enzyme might also catalyze the reduction of CO 2 to the level of CH 4 . Nitrogenase is known to have the capacity to reduce a variety of other small, relatively inert, doubly or triply bonded compounds, such as acetylene (HC≡CH) (19,23). It has been shown that an alternative form of nitrogenase, which contains V in place of Mo in the active site cofactor, has the remarkable capacity to reduce CO and couple multiple CO molecules, yielding short chain alkenes and alkanes such as ethylene (C 2 H 4 ), ethane (C 2 H 6 ), propylene (C 3 H 6 ), and propane (C 3 H 8 ) (24,25). In contrast, the Mo-nitrogenase is only able to reduce CO at exceedingly low rates (24). However, we have found that the MoFe protein can be remodeled by substitution of amino acid residues that provide the first shell of noncovalent interactions with the active site FeMo cofa...

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Section: Discussionmentioning

confidence: 99%

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Yang

Moure

Dean

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

108

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“…Piers and co‐workers subsequently disclosed a catalyst system based on the frustrated Lewis pair (FLP) 2,2,6,6‐tetramethylpiperidine (TMP)/B(C 6 F 5 ) 3 , which reacts with CO 2 and Et 3 SiH to form a formatoborate species that is subsequently hydrosilylated in the presence of excess B(C 6 F 5 ) 3 to form methane 14b. Lastly, Wehmschulte and co‐workers recently reported that the highly reactive Lewis acid Et 2 Al + catalyzes the conversion of CO 2 to methane as well as other hydrocarbons upon reaction with hydrosilanes, albeit at elevated temperatures and long reaction times 14c…”

Section: Methodsmentioning

confidence: 99%

Mild Reduction of Carbon Dioxide to Methane with Tertiary Silanes Catalyzed by Platinum and Palladium Silyl Pincer Complexes

Mitton

Turculet

2012

Chemistry A European J

147

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“…6 In fact, the only catalytic reaction that results in the complete deoxygenation of CO 2 is its reduction into methane by hydrogenation, hydrosilylation, or electrochemical methods 7. Interestingly, Wehmschulte and co‐workers recently observed that toluene and diphenylmethane could be obtained as side‐products in the silylium‐catalyzed hydrosilylation of CO 2 into methane in the presence of benzene 7f…”

Section: Methodsmentioning

confidence: 99%

Complete Catalytic Deoxygenation of CO₂ into Formamidine Derivatives

et al. 2012

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C1, seen them all: A catalytic transformation that uses CO2 as an oxygen‐free C1 building block is presented. The reductive functionalization of CO2 is promoted by N‐heterocyclic carbenes or guanidines as organocatalysts in the presence of amines and hydrosilanes. This diagonal strategy selectively affords benzimidazoles, quinazolinones, 3,4‐dihydroquinazolines, formamidines, and their derivatives, directly from CO2 under mild conditions.

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Deoxygenative Reduction of Carbon Dioxide to Methane, Toluene, and Diphenylmethane with [Et₂Al]⁺ as Catalyst

Abstract: The strong Lewis acid [Et(2)Al](+) catalyzes the reduction of carbon dioxide with hydrosilanes under mild conditions to methane. In benzene solution, the side products toluene and diphenylmethane are also obtained through Lewis acid catalyzed benzene alkylation by reaction intermediates.

Cited by 176 publications

References 41 publications

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Mild Reduction of Carbon Dioxide to Methane with Tertiary Silanes Catalyzed by Platinum and Palladium Silyl Pincer Complexes

Complete Catalytic Deoxygenation of CO₂ into Formamidine Derivatives

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Deoxygenative Reduction of Carbon Dioxide to Methane, Toluene, and Diphenylmethane with [Et2Al]+ as Catalyst

Abstract: The strong Lewis acid [Et(2)Al](+) catalyzes the reduction of carbon dioxide with hydrosilanes under mild conditions to methane. In benzene solution, the side products toluene and diphenylmethane are also obtained through Lewis acid catalyzed benzene alkylation by reaction intermediates.

Cited by 176 publications

References 41 publications

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Carbon dioxide reduction to methane and coupling with acetylene to form propylene catalyzed by remodeled nitrogenase

Mild Reduction of Carbon Dioxide to Methane with Tertiary Silanes Catalyzed by Platinum and Palladium Silyl Pincer Complexes

Complete Catalytic Deoxygenation of CO2 into Formamidine Derivatives

Contact Info

Product

Resources

About

Deoxygenative Reduction of Carbon Dioxide to Methane, Toluene, and Diphenylmethane with [Et₂Al]⁺ as Catalyst

Complete Catalytic Deoxygenation of CO₂ into Formamidine Derivatives