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C-H Bond Oxidation by MnIV-Oxo Complexes : Hydrogen-Atom Tunneling and Multistate Reactivity

Singh, Priya ; Massie, Allyssa A. ; Denler, Melissa C. ; Lee, Yuri ; Mayfield, Jaycee R. ; Lomax, Markell J.A. ; Singh, Reena LU ; Nordlander, Ebbe LU and Jackson, Timothy A. (2024) In Inorganic Chemistry
Abstract

The reactivity of six MnIV-oxo complexes in C-H bond oxidation has been examined using a combination of kinetic experiments and computational methods. Variable-temperature studies of the oxidation of 9,10-dihydroanthracene (DHA) and ethylbenzene by these MnIV-oxo complexes yielded activation parameters suitable for evaluating electronic structure computations. Complementary kinetic experiments of the oxidation of deuterated DHA provided evidence for hydrogen-atom tunneling in C-H bond oxidation for all MnIV-oxo complexes. These results are in accordance with the Bell model, where tunneling occurs near the top of the transition-state barrier. Density functional theory (DFT) and DLPNO-CCSD(T1)... (More)

The reactivity of six MnIV-oxo complexes in C-H bond oxidation has been examined using a combination of kinetic experiments and computational methods. Variable-temperature studies of the oxidation of 9,10-dihydroanthracene (DHA) and ethylbenzene by these MnIV-oxo complexes yielded activation parameters suitable for evaluating electronic structure computations. Complementary kinetic experiments of the oxidation of deuterated DHA provided evidence for hydrogen-atom tunneling in C-H bond oxidation for all MnIV-oxo complexes. These results are in accordance with the Bell model, where tunneling occurs near the top of the transition-state barrier. Density functional theory (DFT) and DLPNO-CCSD(T1) computations were performed for three of the six MnIV-oxo complexes to probe a previously predicted multistate reactivity model. The DFT computations predicted a thermal crossing from the 4B1 ground state to a 4E state along the C-H bond oxidation reaction coordinate. DLPNO-CCSD(T1) calculations further confirm that the 4E transition state offers a lower energy barrier, reinforcing the multistate reactivity model for these complexes. We discuss how this multistate model can be reconciled with recent computations that revealed that the kinetics of C-H bond oxidation by this set of MnIV-oxo complexes can be well-predicted on the basis of the thermodynamic driving force for these reactions.

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Contribution to journal
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in press
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Inorganic Chemistry
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85190726514
  • pmid:38625043
ISSN
0020-1669
DOI
10.1021/acs.inorgchem.4c00186
language
English
LU publication?
yes
id
c7306085-dc05-4a95-82cc-794064f2cf7d
date added to LUP
2024-04-29 08:44:31
date last changed
2024-05-13 10:04:08
@article{c7306085-dc05-4a95-82cc-794064f2cf7d,
  abstract     = {{<p>The reactivity of six Mn<sup>IV</sup>-oxo complexes in C-H bond oxidation has been examined using a combination of kinetic experiments and computational methods. Variable-temperature studies of the oxidation of 9,10-dihydroanthracene (DHA) and ethylbenzene by these Mn<sup>IV</sup>-oxo complexes yielded activation parameters suitable for evaluating electronic structure computations. Complementary kinetic experiments of the oxidation of deuterated DHA provided evidence for hydrogen-atom tunneling in C-H bond oxidation for all Mn<sup>IV</sup>-oxo complexes. These results are in accordance with the Bell model, where tunneling occurs near the top of the transition-state barrier. Density functional theory (DFT) and DLPNO-CCSD(T<sub>1</sub>) computations were performed for three of the six Mn<sup>IV</sup>-oxo complexes to probe a previously predicted multistate reactivity model. The DFT computations predicted a thermal crossing from the <sup>4</sup>B<sub>1</sub> ground state to a <sup>4</sup>E state along the C-H bond oxidation reaction coordinate. DLPNO-CCSD(T<sub>1</sub>) calculations further confirm that the <sup>4</sup>E transition state offers a lower energy barrier, reinforcing the multistate reactivity model for these complexes. We discuss how this multistate model can be reconciled with recent computations that revealed that the kinetics of C-H bond oxidation by this set of Mn<sup>IV</sup>-oxo complexes can be well-predicted on the basis of the thermodynamic driving force for these reactions.</p>}},
  author       = {{Singh, Priya and Massie, Allyssa A. and Denler, Melissa C. and Lee, Yuri and Mayfield, Jaycee R. and Lomax, Markell J.A. and Singh, Reena and Nordlander, Ebbe and Jackson, Timothy A.}},
  issn         = {{0020-1669}},
  language     = {{eng}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Inorganic Chemistry}},
  title        = {{C-H Bond Oxidation by Mn<sup>IV</sup>-Oxo Complexes : Hydrogen-Atom Tunneling and Multistate Reactivity}},
  url          = {{http://dx.doi.org/10.1021/acs.inorgchem.4c00186}},
  doi          = {{10.1021/acs.inorgchem.4c00186}},
  year         = {{2024}},
}