DFT study of alkene hydrogenation catalyzed by Rh(acac)(CO)2

Yuan, Xiang‐Ai; Bi, Siwei; Ding, Yangjun; Liu, Lingjun; Sun, Min

doi:10.1016/j.jorganchem.2010.03.015

Cited by 14 publications

(6 citation statements)

References 59 publications

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“…Therefore, lack of the required basicity on Rh sites could at least partially explain the inability of Rh(CO) 2 /HY30 to participate in oxidative addition of H 2 . Some literature reports also indicate that the oxidative addition of H 2 to Rh(CO) 2 complexes is a thermodynamically unfavorable process because of the presence of the initial substitution step during which the strong Rh–CO bond must be broken and only a weak Rh-(η 2 -H 2 ) bond is formed . Regardless of the case, one can assume that the ligand environment of Rh sites in Rh(CO) 2 /HY30 must be modified in order to facilitate activation of H 2 species.…”

Section: Resultsmentioning

confidence: 99%

Effect of Si/Al Ratio and Rh Precursor Used on the Synthesis of HY Zeolite-Supported Rhodium Carbonyl Hydride Complexes

et al. 2015

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Rh(CO) 2 complexes anchored on various dealuminated HY zeolites were used as precursors for the surfacemediated synthesis of Rh(CO)(H) x species. The carbonyl ligands of the initial Rh(CO) 2 complexes react with gas-phase C 2 H 4 to form Rh(CO)(C 2 H 4 ) species and subsequently well-defined Rh(CO)(H) x complexes when the former are exposed to H 2 at room temperature. Zeolite-supported Rh(C 2 H 4 ) 2 and Rh(NO) 2 can also be used as precursors, but both complexes must be converted into Rh(CO) 2 first to allow the formation of Rh(CO)(H) x species. The Rh(CO)(H) x species thus formed are characterized by a set of well-defined ν CO and ν RhH bands in their Fourier transfrom infrared spectra. Density fuctional theory calculations provide strong evidence for the formation of a family of Rh(CO)(H 2 ), Rh(CO)(H) 2 , and Rh(CO)(H) complexes, all of which are attached differently to the zeolite framework. The fraction of each individual complex formed varies significantly with the Si/Al ratio of the zeolite and the nature of the precursor used and therefore has an effect on the number and intensity of infrared bands observed experimentally.

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Section: Resultsmentioning

confidence: 99%

Effect of Si/Al Ratio and Rh Precursor Used on the Synthesis of HY Zeolite-Supported Rhodium Carbonyl Hydride Complexes

et al. 2015

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“…Enantioselectivity in Rh-catalyzed asymmetric hydrogenation was initially reported to originate from rate differences of oxidative addition of H 2 to diastereomeric square-planar Rh(I) complexes. , However, more recent mechanistic studies combining experiments with DFT calculations − provide increasing evidence for a dihydride mechanism instead of the initially suggested unsaturated pathway (Scheme ) …”

Section: Rhodiummentioning

confidence: 99%

“…Enantioselectivity in Rhcatalyzed asymmetric hydrogenation was initially reported to originate from rate differences of oxidative addition of H 2 to diastereomeric square-planar Rh(I) complexes. 367,368 However, more recent mechanistic studies combining experiments with DFT calculations 369−373 provide increasing evidence for a dihydride mechanism instead of the initially suggested unsaturated pathway (Scheme 28). 374 In this context, Gridnev et al investigated the Rh− ThangPHOS-catalyzed asymmetric hydrogenation of methyl (Z-α) acetylaminocinnamate (MAC) employing experimental NMR studies in combination with DFT computations at the CPCM (methanol) B3LYP/6-31+G(2d,2p)(SDD) level of theory.…”

Section: Hydrogenationmentioning

confidence: 99%

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

et al. 2015

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“…The substitution processes have been assumed to require low activation energy values. 29,30,31 The neutral square planar rhodium(I) amino-amido complex 9 is the precursor for the catalytic active species: the olefin-amido intermediate [Rh{Ph 2 P(CH 2 ) 3 OEt} 2 (NC 5 H 10 )(styrene)] (a, Figure 10). The resulting complex a presents a distorted square planar geometry where the amido N-atom forms an angle of 95.08 o with the C-C centroid of the olefin group which lies roughly perpendicular to the coordination plane.…”

Section: Dft Calculations On the Mechanism Of The Catalytic Oxidativementioning

confidence: 99%

Mechanistic Studies on the Catalytic Oxidative Amination of Alkenes by Rhodium(I) Complexes with Hemilabile Phosphines

et al. 2012

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Abstract:Cationic rhodium(I) complexes having P,O-functionalized arylphosphine ligands are efficient catalysts for the regioselective antiMarkovnikov oxidative amination of styrene with piperidine. The mechanism of the catalytic reaction has been investigated by spectroscopic means under stoichiometric and catalytic conditions. In the presence of piperidine the catalyst precursor [Rh{κ 2 -P,O-Ph 2 P(CH 2 ) 3 OEt} 2 ] + (5) gives the piperidine complex [Rh{κ 1 -PPh 2 P(CH 2 ) 3 OEt} 2 (HNC 5 H 10 ) 2 ] + (8) that was transformed into the neutral amidopiperidine species [Rh{κ 1 -PPh 2 P(CH 2 ) 3 OEt} 2 (NC 5 H 10 )(HNC 5 H 10 )] (9) under thermal conditions. NMR studies carried out in the presence of styrene under catalytic conditions showed that 9 is a key species in the catalytic oxidative amination of styrene. Related cyclooctadiene-containing catalyst precursors [Rh(cod){κ 1 -PPh 2 P(CH 2 ) 3 OEt} n ] + (n = 1, 2) also gave 9 under the same conditions. The proposed catalytic cycle has been established by a series of DFT calculations including the transition states of the key steps that have been found and characterized. These studies have shown that, after the elimination of the enamine, the regeneration of catalytic active species takes place by direct transfer of the proton of a piperidine ligand to the alkyl group, resulting from the insertion of styrene into Rh-H bond, with formation of ethylbenzene. Against the expectations, the formation of a dihydride intermediate by NH oxidative addition is a highly energy-demanding process. Catalyst 5 has also been applied for the oxidative amination of substituted vinylarenes with several secondary cyclic and acyclic amines.

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DFT study of alkene hydrogenation catalyzed by Rh(acac)(CO)2

Cited by 14 publications

References 59 publications

Effect of Si/Al Ratio and Rh Precursor Used on the Synthesis of HY Zeolite-Supported Rhodium Carbonyl Hydride Complexes

Effect of Si/Al Ratio and Rh Precursor Used on the Synthesis of HY Zeolite-Supported Rhodium Carbonyl Hydride Complexes

Computational Studies of Synthetically Relevant Homogeneous Organometallic Catalysis Involving Ni, Pd, Ir, and Rh: An Overview of Commonly Employed DFT Methods and Mechanistic Insights

Mechanistic Studies on the Catalytic Oxidative Amination of Alkenes by Rhodium(I) Complexes with Hemilabile Phosphines

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