Enhanced Understanding of Structure-Function Relationships for Oxomanganese(IV) Complexes
(2023) In Inorganic Chemistry 62(45). p.18357-18374- Abstract
A series of manganese(II) and oxomanganese(IV) complexes supported by neutral, pentadentate ligands with varied equatorial ligand-field strength (N3pyQ, N2py2I, and N4pyMe2) were synthesized and then characterized using structural and spectroscopic methods. On the basis of electronic absorption spectroscopy, the [MnIV(O)(N4pyMe2)]2+ complex has the weakest equatorial ligand field among a set of similar MnIV-oxo species. In contrast, [MnIV(O)(N2py2I)]2+ shows the strongest equatorial ligand-field strength for this same series. We examined the influence of these changes in electronic structure on the reactivity of the oxomanganese(IV) complexes using hydrocarbons and thioanisole as substrates. The [MnIV(O)(N3pyQ)]2+ complex, which... (More)
A series of manganese(II) and oxomanganese(IV) complexes supported by neutral, pentadentate ligands with varied equatorial ligand-field strength (N3pyQ, N2py2I, and N4pyMe2) were synthesized and then characterized using structural and spectroscopic methods. On the basis of electronic absorption spectroscopy, the [MnIV(O)(N4pyMe2)]2+ complex has the weakest equatorial ligand field among a set of similar MnIV-oxo species. In contrast, [MnIV(O)(N2py2I)]2+ shows the strongest equatorial ligand-field strength for this same series. We examined the influence of these changes in electronic structure on the reactivity of the oxomanganese(IV) complexes using hydrocarbons and thioanisole as substrates. The [MnIV(O)(N3pyQ)]2+ complex, which contains one quinoline and three pyridine donors in the equatorial plane, ranks among the fastest MnIV-oxo complexes in C-H bond and thioanisole oxidation. While a weak equatorial ligand field has been associated with high reactivity, the [MnIV(O)(N4pyMe2)]2+ complex is only a modest oxidant. Buried volume plots suggest that steric factors dampen the reactivity of this complex. Trends in reactivity were examined using density functional theory (DFT)-computed bond dissociation free energies (BDFEs) of the MnIIIO-H and MnIV ≡ O bonds. We observe an excellent correlation between MnIV≡O BDFEs and rates of thioanisole oxidation, but more scatter is observed between hydrocarbon oxidation rates and the MnIIIO-H BDFEs.
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- author
- Singh, Priya ; Lee, Yuri ; Mayfield, Jaycee R. ; Singh, Reena LU ; Denler, Melissa C. ; Jones, Shannon D. ; Day, Victor W. ; Nordlander, Ebbe LU and Jackson, Timothy A.
- organization
- publishing date
- 2023
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Inorganic Chemistry
- volume
- 62
- issue
- 45
- pages
- 18357 - 18374
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- pmid:37314463
- scopus:85163834233
- ISSN
- 0020-1669
- DOI
- 10.1021/acs.inorgchem.3c00600
- language
- English
- LU publication?
- yes
- id
- cf560361-f1da-431e-994d-4f15c6624501
- date added to LUP
- 2023-10-10 13:29:19
- date last changed
- 2024-04-19 02:11:33
@article{cf560361-f1da-431e-994d-4f15c6624501, abstract = {{<p>A series of manganese(II) and oxomanganese(IV) complexes supported by neutral, pentadentate ligands with varied equatorial ligand-field strength (N3pyQ, N2py2I, and N4pyMe2) were synthesized and then characterized using structural and spectroscopic methods. On the basis of electronic absorption spectroscopy, the [MnIV(O)(N4pyMe2)]2+ complex has the weakest equatorial ligand field among a set of similar MnIV-oxo species. In contrast, [MnIV(O)(N2py2I)]2+ shows the strongest equatorial ligand-field strength for this same series. We examined the influence of these changes in electronic structure on the reactivity of the oxomanganese(IV) complexes using hydrocarbons and thioanisole as substrates. The [MnIV(O)(N3pyQ)]2+ complex, which contains one quinoline and three pyridine donors in the equatorial plane, ranks among the fastest MnIV-oxo complexes in C-H bond and thioanisole oxidation. While a weak equatorial ligand field has been associated with high reactivity, the [MnIV(O)(N4pyMe2)]2+ complex is only a modest oxidant. Buried volume plots suggest that steric factors dampen the reactivity of this complex. Trends in reactivity were examined using density functional theory (DFT)-computed bond dissociation free energies (BDFEs) of the MnIIIO-H and MnIV ≡ O bonds. We observe an excellent correlation between MnIV≡O BDFEs and rates of thioanisole oxidation, but more scatter is observed between hydrocarbon oxidation rates and the MnIIIO-H BDFEs.</p>}}, author = {{Singh, Priya and Lee, Yuri and Mayfield, Jaycee R. and Singh, Reena and Denler, Melissa C. and Jones, Shannon D. and Day, Victor W. and Nordlander, Ebbe and Jackson, Timothy A.}}, issn = {{0020-1669}}, language = {{eng}}, number = {{45}}, pages = {{18357--18374}}, publisher = {{The American Chemical Society (ACS)}}, series = {{Inorganic Chemistry}}, title = {{Enhanced Understanding of Structure-Function Relationships for Oxomanganese(IV) Complexes}}, url = {{http://dx.doi.org/10.1021/acs.inorgchem.3c00600}}, doi = {{10.1021/acs.inorgchem.3c00600}}, volume = {{62}}, year = {{2023}}, }