Equatorial Ligand Perturbations Influence the Reactivity of Manganese(IV)-Oxo Complexes
(2017) In Angewandte Chemie (International edition) 56(15). p.4178-4182- Abstract
Manganese(IV)-oxo complexes are often invoked as intermediates in Mn-catalyzed C-H bond activation reactions. While many synthetic MnIV-oxo species are mild oxidants, other members of this class can attack strong C-H bonds. The basis for these reactivity differences is not well understood. Here we describe a series of MnIV-oxo complexes with N5 pentadentate ligands that modulate the equatorial ligand field of the MnIV center, as assessed by electronic absorption, electron paramagnetic resonance, and Mn K-edge X-ray absorption methods. Kinetic experiments show dramatic rate variations in hydrogen-atom and oxygen-atom transfer reactions, with faster rates corresponding to weaker equatorial ligand fields.... (More)
Manganese(IV)-oxo complexes are often invoked as intermediates in Mn-catalyzed C-H bond activation reactions. While many synthetic MnIV-oxo species are mild oxidants, other members of this class can attack strong C-H bonds. The basis for these reactivity differences is not well understood. Here we describe a series of MnIV-oxo complexes with N5 pentadentate ligands that modulate the equatorial ligand field of the MnIV center, as assessed by electronic absorption, electron paramagnetic resonance, and Mn K-edge X-ray absorption methods. Kinetic experiments show dramatic rate variations in hydrogen-atom and oxygen-atom transfer reactions, with faster rates corresponding to weaker equatorial ligand fields. For these MnIV-oxo complexes, the rate enhancements are correlated with both 1)the energy of a low-lying 4E excited state, which has been postulated to be involved in a two-state reactivity model, and 2)the MnIII/IV reduction potentials.
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- author
- Massie, Allyssa A. ; Denler, Melissa C. ; Cardoso, Luísa Thiara ; Walker, Ashlie N. ; Hossain, Kamal LU ; Day, Victor W. ; Nordlander, Ebbe LU and Jackson, Timothy A.
- organization
- publishing date
- 2017
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- C-H activation, Hydrogen atom transfer, Kinetics, Manganese, Metal-oxo compounds
- in
- Angewandte Chemie (International edition)
- volume
- 56
- issue
- 15
- pages
- 4178 - 4182
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- scopus:85015179485
- pmid:28300349
- wos:000397599500014
- ISSN
- 1433-7851
- DOI
- 10.1002/anie.201612309
- language
- English
- LU publication?
- yes
- id
- 45cc51d7-dd37-4dd5-8f7c-430330430cb9
- date added to LUP
- 2017-03-30 09:53:29
- date last changed
- 2025-01-07 10:34:41
@article{45cc51d7-dd37-4dd5-8f7c-430330430cb9, abstract = {{<p>Manganese(IV)-oxo complexes are often invoked as intermediates in Mn-catalyzed C-H bond activation reactions. While many synthetic Mn<sup>IV</sup>-oxo species are mild oxidants, other members of this class can attack strong C-H bonds. The basis for these reactivity differences is not well understood. Here we describe a series of Mn<sup>IV</sup>-oxo complexes with N5 pentadentate ligands that modulate the equatorial ligand field of the Mn<sup>IV</sup> center, as assessed by electronic absorption, electron paramagnetic resonance, and Mn K-edge X-ray absorption methods. Kinetic experiments show dramatic rate variations in hydrogen-atom and oxygen-atom transfer reactions, with faster rates corresponding to weaker equatorial ligand fields. For these Mn<sup>IV</sup>-oxo complexes, the rate enhancements are correlated with both 1)the energy of a low-lying <sup>4</sup>E excited state, which has been postulated to be involved in a two-state reactivity model, and 2)the Mn<sup>III/IV</sup> reduction potentials.</p>}}, author = {{Massie, Allyssa A. and Denler, Melissa C. and Cardoso, Luísa Thiara and Walker, Ashlie N. and Hossain, Kamal and Day, Victor W. and Nordlander, Ebbe and Jackson, Timothy A.}}, issn = {{1433-7851}}, keywords = {{C-H activation; Hydrogen atom transfer; Kinetics; Manganese; Metal-oxo compounds}}, language = {{eng}}, number = {{15}}, pages = {{4178--4182}}, publisher = {{John Wiley & Sons Inc.}}, series = {{Angewandte Chemie (International edition)}}, title = {{Equatorial Ligand Perturbations Influence the Reactivity of Manganese(IV)-Oxo Complexes}}, url = {{http://dx.doi.org/10.1002/anie.201612309}}, doi = {{10.1002/anie.201612309}}, volume = {{56}}, year = {{2017}}, }