Mechanistic investigation on hydrogenation and hydrosilylation of ethylene catalyzed by rhenium nitrosyl complex

Liu, Lingjun; Bi, Siwei; Sun, Min; Yuan, Xiang‐Ai; Li, Ping

doi:10.1016/j.jorganchem.2009.05.038

Cited by 11 publications

(10 citation statements)

References 46 publications

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“…The alkane release steps of these catalyses were indeed reductive eliminations from a Re +III (H)(alkyl) species. In contrast, the previously reported [ReH 2 (olefin)(NO)(PR 3 ) 2 ] (R = cy, i Pr) systems were suggested to follow catalytic routes involving either Re(+I)/Re(+III) or Re(+I)/Re(−I) redox changes (Scheme ). This capability to generate redox couples at different oxidation state levels makes rhenium very prone to hydrogenations with significantly differing coordination spheres.…”

Section: Introductionmentioning

confidence: 70%

“…The reactions of the tricyclohexylphosphine and triisopropylphosphine derivatives [ReH(η 2 -BH 4 )(NO)(PR 3 ) 2 ] (R = cy ( 1cy ), R = i Pr ( 1 i Pr )) with ethylene were studied earlier and furnished access to the stable dihydride olefin complexes [ReH 2 (η 2 -C 2 H 4 )(NO)(PR 3 ) 2 ] (R = cy ( 2cy ), i Pr ( 2 i Pr )), which corresponded to a substitution process replacing the BH 3 unit as BH 3 ·THF and a slightly modified pathway along the Re(+I)/Re(+III) cycle of Scheme and according to Scheme .…”

Section: Introductionmentioning

confidence: 99%

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Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

2012

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The borohydride complex [Re +I H(η 2 -BH 4 )(NO)-(PPh 3 ) 2 ] (1ph) reacts with ethylene to yield [Re +I H 2 (η 2 -C 2 H 4 )(NO)(PPh 3 ) 2 ] (2ph) and triethylborane formed by ethylene hydroboration. Subsequent ethylene insertion into the Re−H bond of 2ph and uptake of another 1 equiv of ethylene led to the kinetically stable cis-hydrido−ethyl complex [Re +I H(Et)-(η 2 -C 2 H 4 )(NO)(PPh 3 ) 2 ] (3ph). 3ph was found to slowly reductively eliminate ethane. The rate of this process was determined by quantitative NMR spectroscopy in the temperature range from 293 to 338 K, enabling calculation of the activation parameters (ΔH ⧧ = 68.7 kJ mol −1 , ΔS ⧧ = −94 J mol −1 K −1 ; half-life time 1.8 h at 303 K). The reaction was found to follow firstorder kinetics in c(3ph) and is zeroth order in c(C 2 H 4 ) and c(PPh 3 ), ruling out preceding ligand dissociation. The presumptive intermediate [Re −I (η 2 -C 2 H 4 )(NO)(PPh 3 ) 2 ] could not be traced, since it rapidly reacted further with ethylene, furnishing the stable butadiene complex [Re −I (η 2 -C 2 H 4 )(η 4 -C 4 H 6 )(NO)(PPh 3 )] (4ph) in 88% yield. This transformation of dehydrogenative ethylene coupling is suggested to involve the elementary steps of rhenacyclopentane formation from two coordinated ethylene ligands and then double C−H activation via β-hydride shifts to generate the butadiene unit and formal H 2 elimination from the rhenium dihydride with concomitant triphenylphosphine elimination. An X-ray crystallographic study confirmed the spectroscopically derived pentacoordinate structure of 4ph.

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Section: Introductionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

2012

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“…Previous theoretical studies confirmed the suitability of this catalyst model. [28][29][30][31]. All calculations were conducted using the Gaussian package 09 [32].…”

Section: Methodsmentioning

confidence: 99%

A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

Hosni

Tangour²,

Achour³

2019

Preprint

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A DFT study of hexene hydrogenation catalysed by the RuH(CO)(Cl)(PCy3)2 complex is presented. The investigation explores the feasibility of two different mechanisms: the first exploits a single phosphine complex and the second uses a two phosphines complex. The energy barriers involving a hydrogen transfer have a ten kcal.mol-1 higher than the one obtained through the single-phosphine mechanism. These results confirm the experimental hypothesis claiming that the departure of a phosphine is favourable at the beginning of the reaction which is the substitution of the catalyst model RuHCl(CO)(PMe3)2 by the real catalyst RuHCl(CO)(PCy3)2 shows no significant influence on the energetic barriers of hexene hydrogenation mechanism. The most important step of the mechanism is the kinetically determining step. The heterolytic cleavage of ruthenium-complexed H2 molecule leads to the generation of two Ru-H bonds and the oxidation of the ruthenium from Ru(II) to Ru(IV). The energy profile of this step is not relative to an elementary reaction because a shouldering is observed after the transition state. This results in an unusual gradient norm profile with five extrema. This is a direct consequence of the asynchronous nature of the different processes taking place during this step. In the case of the model complex RuHCl(CO)(IMes)(PMe3) with IMes = ( N , N '-bis( mesityl)imidazol-2-ylidene), an increase of the free enthalpy of activation is observed during the kinetically determining step, which is in agreement with the experimental work.

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“…Interestingly, rhenium mono-nitrosyl complex C16 developed by Berke et al, can also promote the catalytic hydrosilylation of cyclohexene [ 45 ] ( Scheme 16 a) under similar conditions that those employed for ketones (0.5 mol% cat., 80 °C, 3 h). This process was investigated theoretically by the group of Li with ethylene and trimethylsilane as model reactants ( Scheme 16 b) [ 59 ]. The proposed catalytic cycle starts with the insertion of the ethylene ligand into the Re-H bond, followed by the cleavage of the agostic interaction involved in VIII-1 to afford VIII-2 .…”

Section: Hydrosilylation Of C=c Bondsmentioning

confidence: 99%

Hydrosilylation Reactions Catalyzed by Rhenium

et al. 2021

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Mechanistic investigation on hydrogenation and hydrosilylation of ethylene catalyzed by rhenium nitrosyl complex

Cited by 11 publications

References 46 publications

Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

Hydrosilylation Reactions Catalyzed by Rhenium

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Mechanistic investigation on hydrogenation and hydrosilylation of ethylene catalyzed by rhenium nitrosyl complex

Cited by 11 publications

References 46 publications

Ethylene Reactions of a [ReH(η2-BH4)(NO)(PPh3)2] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

Ethylene Reactions of a [ReH(η2-BH4)(NO)(PPh3)2] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

A DFT Study of the Hexene Hydrogenation Catalysed by the Complex RuH(CO)(Cl)(PCy3): Monophosphine vs Diphosphine Paths

Hydrosilylation Reactions Catalyzed by Rhenium

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Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene

Ethylene Reactions of a [ReH(η²-BH₄)(NO)(PPh₃)₂] Complex: Reductive Elimination of Ethane and Oxidative Coupling to Butadiene