Exploring activity differences between the hydroformylation catalysts: Insights from theory

Dangat, Yuvraj; Rizvi, Masood Ahmad; Pandey, Pippalad; Vanka, Kumar

doi:10.1016/j.jorganchem.2015.10.015

Cited by 9 publications

(8 citation statements)

References 83 publications

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“…It was ensured that the obtained transition state structures possessed only one imaginary frequency corresponding to the correct normal mode. The translational entropy term in the calculated structures was corrected through a free volume correction introduced by Mammen et al This procedure of correcting the translational entropy term has also been followed by other groups …”

Section: Experimental Sectionmentioning

confidence: 99%

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway

et al. 2016

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Pincer-based ( R2 POCN R ′ 2 )PdCl complexes along with CuI cocatalyst catalyze the arylation of azoles with aryl iodides to give the 2-arylated azole products. Herein, we report an extensive mechanistic investigation for the direct arylation of azoles involving a well-defined and highly efficient ( iPr2 POCN Et2 )PdCl (2a) catalyst, which emphasizes a rare Pd II −Pd IV −Pd II redox catalytic pathway. Kinetic studies and deuterium labeling experiments indicate that the C−H bond cleavage on azoles occurs via two distinct routes in a reversible manner. Controlled reactivity of the catalyst 2a underlines the iodo derivative ( iPr2 POCN Et2 )PdI (3a) to be the resting state of the catalyst. The intermediate species ( iPr2 POCN Et2 )Pd-benzothiazolyl (4a) has been isolated and structurally characterized. A determination of reaction rates of compound 4a with electronically different aryl iodides has revealed the kinetic significance of the oxidative addition of the C(sp 2 )−X electrophile, aryl iodide, to complex 4a. Furthermore, the reactivity behavior of 4a suggests that the arylation of benzothiazole proceeds via an oxidative addition/ reductive elimination pathway involving a ( iPr2 POCN Et2 )Pd IV (benzothiazolyl)(Ar)I species, which is strongly supported by DFT calculations.

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Section: Experimental Sectionmentioning

confidence: 99%

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway

et al. 2016

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“…This is a reasonable assumption as a real transition state with a much higher energy than the reactants is often improbable for coordination reactions. Moreover, such reactions are generally considered to be nonactivated. ,− , Although a small activation energy is possible for ethylene coordination on certain catalysts, DFT calculations have indicated that the reaction is essentially nonactivated on a PPh 3 -modified Rh catalyst . Additionally, it is beneficial to assume the coordination reactions are nonactivated when the activation energy can be expected to be very small in order to reduce the total number of parameters and lead to a more accurate estimation of the other parameters.…”

Section: Kinetic Model Developmentmentioning

confidence: 99%

Kinetics Assessment of the Homogeneously Catalyzed Hydroformylation of Ethylene on an Rh Catalyst

Siradze

Poissonnier

Frøseth

et al. 2021

Ind. Eng. Chem. Res.

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The homogeneously catalyzed hydroformylation of ethylene to propanal using an Rh(H)(PPh 3 ) 3 (CO) catalyst has been assessed experimentally in a gas−liquid batch reactor and via microkinetic modeling, based on Wilkinson's dissociative mechanism. A higher reaction rate was observed with increasing temperature, up to 100 °C. Even higher temperatures resulted in catalyst deactivation, which was also attributed to lower total pressures and PPh 3 /rhodium molar ratios. The model and its parameters were statistically significant and could be used to simulate the trends observed in the experimental data. Activation energies for the insertion of ethylene and the oxidative addition of H 2 of 42 and 48 kJ mol −1 , respectively, were obtained. Ethylene insertion and oxidative addition of H 2 were identified as the most kinetically relevant steps in the reaction mechanism.

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“…The coordination number can also impact the hydroformylation activity. , The addition of excessive amounts of phosphine ligands can experimentally inhibit the hydroformylation of formaldehyde, indicating that the coordination number of phosphine ligands indeed delivers an effect on the reaction outcomes. , The comparison of the difference between mono- and bisubstituted PPh 3 ligands in the olefin hydroformylation showed the energy barrier of the single coordination reaction (24.5 kcal/mol) was lower than that of the double coordination reaction (28.9 kcal/mol) . van Leeuwen et al explored the influence of 12 bidentate ligands on the hydroformylation reaction and proposed that the product selectivity was dominated by the electronic properties of ligands, while the spatial properties showed less influence.…”

Section: Introductionmentioning

confidence: 99%

Computational Insight into the Ligand Effect on the Original Activity of Rh-Catalyzed Formaldehyde Hydroformylation

Wei

Ding

et al. 2021

J. Phys. Chem. C

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This study performs a computational examination of the effect of the ligand nature on the Rh–L interaction and of the formaldehyde hydroformylation for substituted rhodium–carbonyl catalysts using a range of realistic mono- and bidentate ligands (CO, P(OMe)3, PPh3, DMI, and DPPE). The energy decomposition analysis of the Rh–L bond suggests the bidentate ligand, DPPE, shows the strongest interaction with Rh. The π-accepting capacity of monodentate ligands follows the sequence CO > P(OMe)3 > PPh3 > DMI. Analysis of the potential energy surface reveals the σ-donor ligands serve to increase the energy of the active anionic complex [Rh(CO)3L]−. No clear correlation has been found between the CO insertion/hydrogenolysis energy barrier and electronic properties of ligands, while the H2 oxidative addition barrier increases with increasing the ligand’s electron donating capacity. The investigation on the effect of the ligand (PPh3) coordination number demonstrates that the three-coordinated catalyst exhibits the highest energy barrier, and the influence of ligand steric hindrance on the H2 oxidative addition can be ignorable.

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Exploring activity differences between the hydroformylation catalysts: Insights from theory

Cited by 9 publications

References 83 publications

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway

Kinetics Assessment of the Homogeneously Catalyzed Hydroformylation of Ethylene on an Rh Catalyst

Computational Insight into the Ligand Effect on the Original Activity of Rh-Catalyzed Formaldehyde Hydroformylation

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Exploring activity differences between the hydroformylation catalysts: Insights from theory

Cited by 9 publications

References 83 publications

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a PdII–PdIV–PdII Pathway

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a PdII–PdIV–PdII Pathway

Kinetics Assessment of the Homogeneously Catalyzed Hydroformylation of Ethylene on an Rh Catalyst

Computational Insight into the Ligand Effect on the Original Activity of Rh-Catalyzed Formaldehyde Hydroformylation

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Product

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About

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway

Mechanistic Insights into Pincer-Ligated Palladium-Catalyzed Arylation of Azoles with Aryl Iodides: Evidence of a Pd^II–Pd^IV–Pd^II Pathway