Calculating accurate barriers for olefin insertion and related reactions

Ehm, Christian; Budzelaar, Peter H. M.; Busico, Vincenzo

doi:10.1016/j.jorganchem.2014.10.019

Cited by 61 publications

(62 citation statements)

References 90 publications

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“…[115][116][117][120][121][122] Previous efforts from other research groups and ours have led to DFT calibration studies covering a few 4d and 5d transition metals, including group 4 (Zr), 120 group 7 (Re), 121 group 8 (Ru), 117,126-129 group 9 (Rh, Ir), 110,115,116,126,130 group 10 (Pd, Pt). 109,[111][112][113][114][115][116]123,131,132 and group 11 (Au). 108,115,122,124,125,133,134 Concerning group 6 metals, there are few available DFT calibration studies only on a specific oxo-transfer reaction catalyzed by DMSO reductase.…”

Section: Scheme 1 the Mo/w-mediated Reactions Studied In This Workmentioning

confidence: 99%

Assessment of DFT Methods for Computing Activation Energies of Mo/W-Mediated Reactions

Chen

2015

J. Chem. Theory Comput.

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Using high level ab initio coupled cluster calculations as reference, the performances of 15 commonly used density functionals (DFs) on activation energy calculations for typical Mo/W-mediated reactions have been systematically assessed for the first time in this work. The selected representative Mo/W-mediated reactions cover a wide range from enzymatic reactions to organometallic reactions, which include Mo-catalyzed aldehyde oxidation (aldehyde oxidoreductase), Mo-catalyzed dimethyl sulfoxide (DMSO) reduction (DMSO reductase), W-catalyzed acetylene hydration (acetylene hydratase), Mo/W-mediated olefin metathesis, Mo/W-mediated olefin epoxidation, W-mediated alkyne metathesis, and W-mediated C-H bond activation. Covering both Mo- and W-mediated reactions, four DFs of B2GP-PLYP, M06, B2-PLYP, and B3LYP are uniformly recommended with and without DFT empirical dispersion correction. Among these four DFs, B3LYP is notably improved in performance by DFT empirical dispersion correction. In addition to the absolute value of calculation error, if the trend of DFT results is also a consideration, B2GP-PLYP, B2-PLYP, and M06 keep better performance than other functionals tested and constitute our final recommendation of DFs for both Mo- and W-mediated reactions.

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Section: Scheme 1 the Mo/w-mediated Reactions Studied In This Workmentioning

confidence: 99%

Assessment of DFT Methods for Computing Activation Energies of Mo/W-Mediated Reactions

Chen

2015

J. Chem. Theory Comput.

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“…DFT appears to underestimate H transfer barriers,, and the models used are strongly simplified, so our results should be considered indicative at best and do not allow definitive assignment of the mechanism(s) responsible for rearrangement of the real complexes 2a , 3b and 3c , nor do they explain the absence of such rearrangements for 2b and 4b . However, the involvement of a low‐concentration pseudo‐catalytic anionic or radical species would be consistent with the somewhat capricious nature of the reaction.…”

Section: Resultsmentioning

confidence: 80%

Formation and Rearrangement of Reduced Diiminepyridine Complexes of Zr and Hf

2018

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Reduction of seven‐coordinate [(EtDIP)MCl4] {EtDIP = 2,6‐(2,6‐Et2–C6H3N=CMe)2C5H3N; M = Zr or Hf} produces formally divalent complexes [(EtDIP)MCl2] containing in reality a doubly reduced DIP ligand. The Hf complex is five‐coordinate, but the Zr analog crystallizes as a chloride‐bridged dimer with an unusual coordination geometry; the monomer‐dimer equilibrium is fast at room temperature. Reaction of [(EtDIP)HfCl2] with MeMgBr or LiCH2SiMe3 produced the corresponding dialkyls [(EtDIP)HfR2]. An unexpected ligand isomerization to an amido/enamido form was observed for [(EtDIP)ZrCl2], [(EtDIP)HfMe2] and [(EtDIP)TiMe2], and a mechanism is proposed based on DFT calculations.

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“…Our own results indicate that these complexes should produce high‐molecular‐weight polymers (predicted P n ≈ 25000 for Zr). We believe that the low‐MW predictions of Deng et al are due to the lack of dispersion corrections and to their use of the BP86 functional, both of which significantly affect the reliability of predictions for polymerization chemistry . Although their quantum mechanics/molecular mechanics (QM/MM) approach for the full model correctly predicts a high MW for Ti, their prediction for Zr ( P n ≈ 1.5) appears to be at odds with the later experimental findings mentioned above.…”

Section: Resultsmentioning

confidence: 90%

“…The computational protocol used in this paper was tested thoroughly for the type of chemistry considered here [vs. CCSD(T) and experimental data] as well as in several polymerization‐related problems and is expected to yield accurate transition‐state energies and relative isomer energies.…”

Section: Discussionmentioning

confidence: 99%

Tuning the Relative Energies of Propagation and Chain Termination Barriers in Polyolefin Catalysis through Electronic and Steric Effects

2017

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A computational exploration of the predicted molecular weights for Ti‐ and Zr‐catalyzed olefin polymerizations shows that there are considerable opportunities for electronic tuning. Ligand variation mainly affects the propagation rate, whereas chain transfer to the monomer is hardly affected by electronic factors. The results are analyzed in terms of the effects of ligand variation on the relative energies of “connected couples” of reactant local minima and the corresponding transition states on the basis of the Hammond postulate and the Curtin–Hammett principle. For the constrained‐geometry catalysts (CGCs) and bis(amido) systems studied, better donating ligands increase the preference for a “planar” metal environment and produce higher molecular weights.

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Calculating accurate barriers for olefin insertion and related reactions

Cited by 61 publications

References 90 publications

Assessment of DFT Methods for Computing Activation Energies of Mo/W-Mediated Reactions

Assessment of DFT Methods for Computing Activation Energies of Mo/W-Mediated Reactions

Formation and Rearrangement of Reduced Diiminepyridine Complexes of Zr and Hf

Tuning the Relative Energies of Propagation and Chain Termination Barriers in Polyolefin Catalysis through Electronic and Steric Effects

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