Mechanistic Insights on the Challenging Trifluoromethylation of Ni(II) DOI
Mathilde Rigoulet, Sebastian Wellig, Franziska Schoenebeck

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(10), P. 7456 - 7462

Published: April 29, 2024

While the transmetalation of Ni(II) intermediates constitutes a key elementary step, there are limited data and insights available on precise underlying mechanism transmetalation. This work describes our combined experimental computational study trifluoromethylation LnNi(II)–F complexes origins ligand effects in this process. Our studies reveal an ionic rebound to be favored with Me3SiCF3, which fluoride abstraction from by Me3SiCF3 takes place, followed CF3 anion intermediate ion pair. The steric shielding employed controls accessibility, was verified through successful synthesis isolation PMe3-bound Ni(II)−F3 complex. Alternative mechanisms LnNi(II)−CF3 synthesis, e.g., via difluorocarbene insertion, were also studied, although found feasible majority ligands, alternative Ni–P insertions seen for sterically most demanding ligands.

Language: Английский

Overview on Building Blocks and Applications of Efficient and Robust Extended Tight Binding DOI
Abylay Katbashev, Marcel Stahn, Thomas Rose

et al.

The Journal of Physical Chemistry A, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 27, 2025

The extended tight binding (xTB) family of methods opened many new possibilities in the field computational chemistry. Within just 5 years, GFN2-xTB parametrization for all elements up to Z = 86 enabled more than a thousand applications, which were previously not feasible with other electronic structure methods. xTB provide robust and efficient way apply quantum mechanics-based approaches obtaining molecular geometries, computing free energy corrections or describing noncovalent interactions found applicability targets. A crucial contribution success is availability within simulation packages frameworks, supported by open source development its program library packages. We present comprehensive summary applications capabilities different fields Moreover, we consider main software calculations, covering their current ecosystem, novel features, usage scientific community.

Language: Английский

Citations

0
Importance of Dynamic Effects in Isobutanol to Linear Butene Conversion Catalyzed by Acid Zeolites Assessed by AIMD DOI
Monika Gešvandtnerová, Pascal Raybaud, Céline Chizallet

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(10), P. 7478 - 7491

Published: April 29, 2024

Dehydration of alcohols into alkenes is a key reaction for the production fuels and chemicals from biomass. However, mechanism these reactions highly questionable, hindering rational optimization efficient catalysts. In present work, formation linear butenes starting isobutanol catalyzed by proton-exchanged zeolites unraveled ab initio molecular dynamics (AIMD). Comparison with static calculations done gas phase proton prototypical chabazite zeolite framework shows that AIMD estimations free energy barriers are significantly different ones. Moreover, common transition state (TS) found two competing reactions, namely, isomerization butan-2-ol (the dehydration latter yielding butenes) synchronous products related to in single step. The existence post-TS bifurcation prevents traditional estimation rates theory. To circumvent this problem, we quantify relative transmission coefficients using Bennett–Chandler theory, which clear tendency decrease frequency increase when switching 100 500 K. This work represents step forward accurate determination alcohol reactions.

Language: Английский

Citations

1
Trajectory-Based Time-Resolved Mechanism for Benzene Reductive Elimination from Cyclopentadienyl Mo/W Phenyl Hydride Complexes DOI

Joshua I. Wheeler,

Anthony J. Schaefer, Daniel H. Ess

et al.

The Journal of Physical Chemistry A, Journal Year: 2024, Volume and Issue: 128(24), P. 4775 - 4786

Published: June 5, 2024

Calculated potential energy structures and landscapes are very often used to define the sequence of reaction steps in an organometallic mechanism interpret kinetic isotope effect (KIE) measurements. Underlying most this structure-to-mechanism translation is use statistical rate theories without consideration atomic/molecular motion. Here we report direct dynamics simulations for benzene reductive elimination reaction, where nonstatistical intermediates dynamic-controlled pathways were identified. Specifically, single spin state as well mixed quasiclassical trajectories gas phase explicit solvent from Mo W bridged cyclopentadienyl phenyl hydride complexes ([Me

Language: Английский

Citations

1
Mechanistic Insights on the Challenging Trifluoromethylation of Ni(II) DOI
Mathilde Rigoulet, Sebastian Wellig, Franziska Schoenebeck

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(10), P. 7456 - 7462

Published: April 29, 2024

While the transmetalation of Ni(II) intermediates constitutes a key elementary step, there are limited data and insights available on precise underlying mechanism transmetalation. This work describes our combined experimental computational study trifluoromethylation LnNi(II)–F complexes origins ligand effects in this process. Our studies reveal an ionic rebound to be favored with Me3SiCF3, which fluoride abstraction from by Me3SiCF3 takes place, followed CF3 anion intermediate ion pair. The steric shielding employed controls accessibility, was verified through successful synthesis isolation PMe3-bound Ni(II)−F3 complex. Alternative mechanisms LnNi(II)−CF3 synthesis, e.g., via difluorocarbene insertion, were also studied, although found feasible majority ligands, alternative Ni–P insertions seen for sterically most demanding ligands.

Language: Английский

Citations

0