Abstract
In the title paper, Vetere et al. reported a computational investigation of the mechanism of H2 oxidation/proton reduction using a model of nickel-based electrocatalysts that incorporates pendant amines in cyclic phosphorus ligands. These catalysts are attracting considerable attention owing to their high turnover rates and relatively low overpotentials. These authors interpreted the results of their calculations as evidence for a symmetric bond cleavage of H2 leading directly to two protonated amines in concert with a two-electron reduction of the Ni(II) site to form a Ni(0) diproton state. Proton reduction would involve a reverse symmetric bond formation. We report here an analysis that refutes the interpretation by these authors. We give, for the same model system, the structure of a heterolytic cleavage transition state consistent with the presence of the Ni(II) center acting as a Lewis acid and the pendant amines acting as Lewis bases. We present the associated intrinsic reaction coordinate (IRC) pathway connecting the dihydrogen (ν2- H2) adduct and a hydride-proton state. We report also the transition state and associated IRC for the proton rearrangement from a hydride-proton state to a diproton state. Finally, we complete the characterization of the transition state reported by Vetere et al. through a determination of the corresponding IRC. In summary, H2 oxidation/proton reduction with this class of catalysts involves a heterolytic bond breaking/formation.
| Original language | English |
|---|---|
| Pages (from-to) | 4861-4865 |
| Number of pages | 5 |
| Journal | Journal of Physical Chemistry A |
| Volume | 115 |
| Issue number | 18 |
| DOIs | |
| Publication status | Published - May 12 2011 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
Cite this
Comment on "new Insights in the Electrocatalytic Proton Reduction and Hydrogen Oxidation by Bioinspired Catalysts : A DFT Investigation". / Dupuis, Michel; Chen, Shentan; Raugei, Simone; DuBois, Daniel L; Bullock, R Morris.
In: Journal of Physical Chemistry A, Vol. 115, No. 18, 12.05.2011, p. 4861-4865.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Comment on "new Insights in the Electrocatalytic Proton Reduction and Hydrogen Oxidation by Bioinspired Catalysts
T2 - A DFT Investigation"
AU - Dupuis, Michel
AU - Chen, Shentan
AU - Raugei, Simone
AU - DuBois, Daniel L
AU - Bullock, R Morris
PY - 2011/5/12
Y1 - 2011/5/12
N2 - In the title paper, Vetere et al. reported a computational investigation of the mechanism of H2 oxidation/proton reduction using a model of nickel-based electrocatalysts that incorporates pendant amines in cyclic phosphorus ligands. These catalysts are attracting considerable attention owing to their high turnover rates and relatively low overpotentials. These authors interpreted the results of their calculations as evidence for a symmetric bond cleavage of H2 leading directly to two protonated amines in concert with a two-electron reduction of the Ni(II) site to form a Ni(0) diproton state. Proton reduction would involve a reverse symmetric bond formation. We report here an analysis that refutes the interpretation by these authors. We give, for the same model system, the structure of a heterolytic cleavage transition state consistent with the presence of the Ni(II) center acting as a Lewis acid and the pendant amines acting as Lewis bases. We present the associated intrinsic reaction coordinate (IRC) pathway connecting the dihydrogen (ν2- H2) adduct and a hydride-proton state. We report also the transition state and associated IRC for the proton rearrangement from a hydride-proton state to a diproton state. Finally, we complete the characterization of the transition state reported by Vetere et al. through a determination of the corresponding IRC. In summary, H2 oxidation/proton reduction with this class of catalysts involves a heterolytic bond breaking/formation.
AB - In the title paper, Vetere et al. reported a computational investigation of the mechanism of H2 oxidation/proton reduction using a model of nickel-based electrocatalysts that incorporates pendant amines in cyclic phosphorus ligands. These catalysts are attracting considerable attention owing to their high turnover rates and relatively low overpotentials. These authors interpreted the results of their calculations as evidence for a symmetric bond cleavage of H2 leading directly to two protonated amines in concert with a two-electron reduction of the Ni(II) site to form a Ni(0) diproton state. Proton reduction would involve a reverse symmetric bond formation. We report here an analysis that refutes the interpretation by these authors. We give, for the same model system, the structure of a heterolytic cleavage transition state consistent with the presence of the Ni(II) center acting as a Lewis acid and the pendant amines acting as Lewis bases. We present the associated intrinsic reaction coordinate (IRC) pathway connecting the dihydrogen (ν2- H2) adduct and a hydride-proton state. We report also the transition state and associated IRC for the proton rearrangement from a hydride-proton state to a diproton state. Finally, we complete the characterization of the transition state reported by Vetere et al. through a determination of the corresponding IRC. In summary, H2 oxidation/proton reduction with this class of catalysts involves a heterolytic bond breaking/formation.
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U2 - 10.1021/jp111479z
DO - 10.1021/jp111479z
M3 - Article
VL - 115
SP - 4861
EP - 4865
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
SN - 1089-5639
IS - 18
ER -