Paddle Ball Dynamics during Conversion of a Rh–Methyl Hydride Complex to a Rh–Methane σ-Complex through Reductive Coupling

Carlsen, Ryan; Jenkins, Jordan R.; Huang, Tsung-Chiang Johnny; Pugh, Samuel L.; Ess, Daniel H.

doi:10.1021/acs.organomet.8b00936

Cited by 10 publications

(7 citation statements)

References 64 publications

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“…We discuss this interaction in more detail in Section . In general, the calculated distances for the metal-methane interaction in 2 agree well with those of other σ-methane complexes. ,,,,− In the final part of the reaction coordinate, the dissociation of methane from 2 produces the dissociated state 3 , in which the metal center and the methane molecule no longer interact.…”

Section: Resultssupporting

confidence: 72%

Steric and Electronic Analyses of Ligand Effects on the Stability of σ-Methane Coordination Complexes: A DFT Study

et al. 2022

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Developing efficient catalysts for methane functionalization is a longstanding goal in inorganic chemistry. Here, we present theoretical calculations to support efforts to synthesize σmethane complexes that can be studied by NMR spectroscopy. The systems studied are osmium complexes of stoichiometry (C 5 R 5 )Os(diphosphine)(CH 3 )(H) + : when both cyclopentadienyl and diphosphine are relatively strong electron donors, the methyl/ hydride structure is in rapid equilibrium with its σ-methane tautomer at low temperatures, as shown experimentally some years ago. Here, using density functional theory, we examine how changing the steric and electronic properties of the ancillary cyclopentadienyl and diphosphine ligands affects the relative energies of the two tautomers, with the goal of identifying a ligand set for which the σ-methane structure, rather than the methyl/hydride form, is the predominant species in equilibrium. We also examine how varying the ancillary ligands affects the barrier for methane dissociation. The calculations suggest that osmium complexes bearing weakly donating and sterically undemanding ligands stabilize the σ-methane structure both relative to its methyl/hydride tautomer and toward dissociation of the methane ligand. More specifically, osmium σ-methane complexes of fluorinated diphosphines (CF 3 ) 2 PCH 2 P(CF 3 ) 2 and (CF 3 ) 2 PCF 2 P(CF 3 ) 2 are predicted to be stable enough to be observed by variable-temperature NMR spectroscopy.

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Section: Resultssupporting

confidence: 72%

Steric and Electronic Analyses of Ligand Effects on the Stability of σ-Methane Coordination Complexes: A DFT Study

et al. 2022

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“…Formation of this product occurred in less than 50 fs. Trajectories starting from TS 1 in the reverse (away from products) direction showed initial motion towards the singlet σ-coordination structure INT 2 but then quickly reverted to the forwards direction in a paddle ball type motion 43 and like the forward direction trajectories only resulted in formation of I (see ESI † ).…”

Section: Resultsmentioning

confidence: 97%

Dynamic-dependent selectivity in a bisphosphine iron spin crossover C–H insertion/π-coordination reaction

Davenport,

Kirkland,

Ess

2023

Chem. Sci.

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“…Consistent with experiment, quasiclassical trajectories started at the reductive coupling transition state showed that most trajectories (>90%) led to the Rh−methane σ-complex (Figure 9). 64 Less than 10% of trajectories did not sample this σ-complex structure and resulted in direct methane dissociation. This indicates that the σ-complex connected to the Rh-methyl hydride is not the result of methane rebounding back to the Rh metal center due to a solvent cage but is on the reactive trajectory pathway.…”

Section: One Step Two Steps or Something Inmentioning

confidence: 99%

Quasiclassical Direct Dynamics Trajectory Simulations of Organometallic Reactions

Ess

2021

Acc. Chem. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Homogeneous metal-mediated organometallic reactions represent a very large and diverse reaction class. Density functional theory calculations are now routinely carried out and reported for analyzing organometallic mechanisms and reaction pathways. While density functional theory calculations are extremely powerful to understand the energy and structure of organometallic reactions, there are several assumptions in their use and interpretation to define reaction mechanisms and to analyze reaction selectivity. Almost always it is assumed that potential energy structures calculated with density functional theory adequately describe mechanisms and selectivity within the framework of statistical theories, for example, transition state theory and RRKM theory. However, these static structures and corresponding energy landscapes do not provide atomic motion information during reactions that could reveal nonstatistical intermediates without complete intramolecular vibrational redistribution and nonintrinsic reaction coordinate (non-IRC) pathways. While nonstatistical intermediates and non-IRC reaction pathways are now relatively well established for organic reactions, these dynamic effects have heretofore been highly underexplored in organometallic reactions. Through a series of quasiclassical density functional theory direct dynamics trajectory studies, my group has recently demonstrated that dynamic effects occur in a variety of fundamental organometallic reactions, especially bond activation reactions. For example, in the C−H activation reaction between methane and [Cp*(PMe 3 )Ir III (CH 3 )] + , while the density functional theory energy landscape showed a two-step oxidative cleavage and reductive coupling mechanism, trajectories revealed a mixture of this two-step mechanism and a dynamic onestep mechanism that skipped the [Cp*(PMe 3 )Ir V (H)(CH 3 ) 2 ] + intermediate. This study also showed that despite a methane σcomplex being located on the density functional theory surface before oxidative cleavage and after reductive coupling, this intermediate is always skipped and should not be considered an intermediate during reactive trajectories. For non-IRC reaction pathways, quasiclassical direct dynamics trajectories showed that for the isomerization of [Tp(NO)(PMe 3 )W(η 2 -benzene)] to [Tp(NO)(PMe 3 )W(H)(Ph)], there are many dynamic reaction pathway connections due to a relatively flat energy landscape and π coordination is not necessary for C−H bond activation through oxidative cleavage. Trajectories also showed that dynamic effects are important in selectivity for ethylene C−H activation versus π coordination in reaction with Cp(PMe 3 ) 2 Re, and trajectories provide a more quantitative model of selectivity than transition state theory. Quasiclassical trajectories examining Au-catalyzed monoallylic diol cyclizations showed dynamic coupling of several reaction steps that include alkoxylation π bond addition, proton shuttling, and water elimination reaction steps. Over...

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Paddle Ball Dynamics during Conversion of a Rh–Methyl Hydride Complex to a Rh–Methane σ-Complex through Reductive Coupling

Cited by 10 publications

References 64 publications

Steric and Electronic Analyses of Ligand Effects on the Stability of σ-Methane Coordination Complexes: A DFT Study

Steric and Electronic Analyses of Ligand Effects on the Stability of σ-Methane Coordination Complexes: A DFT Study

Dynamic-dependent selectivity in a bisphosphine iron spin crossover C–H insertion/π-coordination reaction

Quasiclassical Direct Dynamics Trajectory Simulations of Organometallic Reactions

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