Electron-Deficient Ru(II) Complexes as Catalyst Precursors for Ethylene Hydrophenylation

Jia, Xiaofan; Tian, Songyuan; Shivokevich, Philip J.; Harman, W. Dean; Dickie, Diane A.; Gunnoe, T. Brent

doi:10.3390/inorganics10060076

Cited by 3 publications

(3 citation statements)

References 61 publications

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“…The energy of methyl acrylate coordination to the phenyl intermediates Int1 formed in the CMD stage changes from −8.1 kcal/mol to +10.6 kcal/mol as the number of carbonyl ligands increases from 1 to 4 in Ru(II) complexes and from 14.2 kcal/mol to 26.9 kcal/mol in Ru(III) mono‐ and di‐carbonyls. It was previously shown that electron‐withdrawing ligands lower the barrier for ethylene insertion into the Ru−phenyl bond [62] . In the present work, we found that electron‐withdrawing carbonyl ligands tend to decrease the height of TS2 but increasing Ru coordination number exerts an opposing effect.…”

Section: Resultssupporting

confidence: 63%

“…It was previously shown that electron-withdrawing ligands lower the barrier for ethylene insertion into the RuÀ phenyl bond. [62] In the present work, we found that electron-withdrawing carbonyl ligands tend to decrease the height of TS2 but increasing Ru coordination number exerts an opposing effect. Thus, TS2 changes from 58.1 kcal/mol to 24.8 kcal/mol and on to 25.2 kcal/mol as the number of carbonyl ligands increases from 1 to 3 in Ru(II) complexes and from 35.3 kcal/mol to 20.6 kcal/mol and on to 28.9 kcal/ mol kcal/mol as the number of carbonyl ligands increases from 0 to 2 in their Ru(III) analogs (Table 3).…”

Section: Oxidative Coupling Initiated By Benzene Activationsupporting

confidence: 50%

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C−H Bond Activation in Ru‐Catalyzed Reactions of Arenes with Olefins: Theoretical Insights into Hydroarylation and Oxidative Coupling Mechanisms

Efremenko

Martin

2023

Israel Journal of Chemistry

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A detailed mechanistic density functional theory (DFT) and coupled cluster study of Csp²−H activation in benzene and methyl acrylate by the catalyst RuClm(CO)n (m=2,3; n=0–4) is presented. We trace the entire reaction pathways from the precursor to the active form of the catalysts followed by catalytic hydroarylation and oxidative coupling reactions. Our results reveal that both computational methods provide very similar qualitative pictures, but only the coupled cluster DLPNO‐CCSD(T1) results are quantitatively consistent with experiment. At the latter level of theory, the Ru(II) and Ru(III) catalyst precursors transform into the same active form of the catalyst, which explains the experimental results. Oxidative addition is extremely endergonic, especially in the presence of CO. Oxidative hydrogen migration (OHM) occurs in complexes with a low Ru coordination number and leads to olefine hydroarylation. Strongly bound carbonyl ligands suppress this interaction. Concerted metalation‐deprotonation (CMD) of the aromatic C−H bond and σ‐bond metathesis mechanisms of catalyst regeneration do not involve Ru−H bonding and form the energetically favorable catalytic cycle of the oxidative coupling reaction. The key interaction in CMD mechanisms consists of proton abstraction by an inner‐sphere Cl‐anion. Carbonyl ligands facilitate CMD by weakening the Ru−Cl bond. An excess of CO slows the interaction by leading to replacement of the reactants in the Ru coordination sphere.

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Section: Resultssupporting

confidence: 63%

Section: Oxidative Coupling Initiated By Benzene Activationsupporting

confidence: 50%

C−H Bond Activation in Ru‐Catalyzed Reactions of Arenes with Olefins: Theoretical Insights into Hydroarylation and Oxidative Coupling Mechanisms

Efremenko

Martin

2023

Israel Journal of Chemistry

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“…Our group and others have reported catalysts for arene alkylation using molecular Pt, − Ru, − Ir, , and Ni complexes. , With the exception of the Ni-mediated chemistry, the selectivity for linear alkyl arenes using α-olefins is modest, and, in the case of some Pt catalysts, the arene alkylation reactions are selective for branched products (Scheme ). ,,,, Catalysis based on Ru, Pt, and Ir were proposed to have similar mechanisms that involve olefin insertion into a M–aryl bond, arene coordination, and arene C–H activation to release an alkyl arene product .…”

Section: Introductionmentioning

confidence: 96%

Highly Anti-Markovnikov Selective Oxidative Arene Alkenylation Using Ir(I) Catalyst Precursors and Cu(II) Carboxylates

Ketcham,

Zhu,

Gunnoe

2024

Organometallics

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The Ir(I) complex [Ir(μ-Cl)(coe) 2 ] 2 (coe = ciscyclooctene) is a catalyst precursor for benzene alkenylation using Cu(II) carboxylate salts. Using [Ir(μ-Cl)(coe) 2 ] 2 , propenylbenzenes are formed from the reaction of benzene, propylene, and CuX 2 (X = acetate, pivalate, or 2-ethylhexanoate). The Ir-catalyzed reactions selectively produce anti-Markovnikov products, trans-βmethylstyrene, cis-β-methylstyrene, and allylbenzene, along with minor amounts of the Markovnikov product, α-methylstyrene. The selectivity for the anti-Markovnikov products changed as the reaction progressed. For example, in a reaction that uses 240 equiv of Cu(OHex) 2 (related to Ir), the selectivity for the anti-Markovnikov products increases from 18:1 at 3 h to 42:1 at 42 h with 30 psig of propylene at 150 °C. Studies of product stability have revealed that the increase in the selectivity for anti-Markovnikov products is not the result of an isomerization process or the selective decomposition of specific products. Rather, the change in selectivity correlates with the ratio of Cu(II) to Cu(I) in the solution, which decreases as the reaction progresses. We propose that the identity of the active catalyst changes as Cu(I) is accumulated, resulting in the formation of an active catalyst that is more selective for anti-Markovnikov products. Using a 4:1 Cu(I)/Cu(II) ratio at the start of the reaction, a 65(3):1 anti-Markovnikov/ Markovnikov ratio is observed.

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Synthesis of Quinoline-Based Pt–Sb Complexes with L- or Z-Type Interaction: Ligand-Controlled Redox via Anion Transfer

Webber,

Kong,

Kumawat

et al. 2024

Organometallics

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A series of Pt–Sb complexes with two or three L-type quinoline side arms were prepared and studied. Two ligands, tri(8-quinolinyl)stibane (SbQ3, Q = 8-quinolinyl, 1) and 8,8′-(phenylstibanediyl)diquinoline (SbQ2Ph, 2), were used to synthesize the PtII–SbIII complexes (SbQ3)PtCl2 (3) and (SbQ2Ph)PtCl2 (4). Chloride abstraction with AgOAc provided the bis-acetate complexes (SbQ3)Pt(OAc)2 (5) and (SbQ2Ph)Pt(OAc)2 (6). To better understand the electronic effects of the Sb moiety, analogous bis-chloride complexes were oxidized to an overall formal oxidation state of +7 (i.e., Pt + Sb formal oxidation states = 7) using dichloro(phenyl)-λ3-iodane (PhICl2) and 3,4,5,6-tetrachloro-1,2-dibenzoquinone (o-chloranil) as two-electron oxidants. Depending on the oxidant, different conformational changes occur within the coordination sphere of Pt as confirmed by single-crystal X-ray diffraction and NMR spectroscopy. In addition, the nature of Pt–Sb interactions was evaluated via molecular and localized orbital calculations.

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Electron-Deficient Ru(II) Complexes as Catalyst Precursors for Ethylene Hydrophenylation

Cited by 3 publications

References 61 publications

C−H Bond Activation in Ru‐Catalyzed Reactions of Arenes with Olefins: Theoretical Insights into Hydroarylation and Oxidative Coupling Mechanisms

C−H Bond Activation in Ru‐Catalyzed Reactions of Arenes with Olefins: Theoretical Insights into Hydroarylation and Oxidative Coupling Mechanisms

Highly Anti-Markovnikov Selective Oxidative Arene Alkenylation Using Ir(I) Catalyst Precursors and Cu(II) Carboxylates

Synthesis of Quinoline-Based Pt–Sb Complexes with L- or Z-Type Interaction: Ligand-Controlled Redox via Anion Transfer

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