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Mn IV -Oxo complex of a bis(benzimidazolyl)-containing N5 ligand reveals different reactivity trends for Mn IV -oxo than Fe IV -oxo species

Denler, Melissa C.; Massie, Allyssa A.; Singh, Reena LU ; Stewart-Jones, Eleanor; Sinha, Arup LU ; Day, Victor W.; Nordlander, Ebbe LU and Jackson, Timothy A. (2019) In Dalton Transactions 48(15). p.5007-5021
Abstract


Using the pentadentate ligand (N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine, 2pyN2B), presenting two pyridyl and two (N-methyl)benzimidazolyl donor moieties in addition to a central tertiary amine, new Mn
II
and Mn
IV
-oxo complexes were generated and characterized. The [Mn
IV
... (More)


Using the pentadentate ligand (N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine, 2pyN2B), presenting two pyridyl and two (N-methyl)benzimidazolyl donor moieties in addition to a central tertiary amine, new Mn
II
and Mn
IV
-oxo complexes were generated and characterized. The [Mn
IV
(O)(2pyN2B)]
2+
complex showed spectroscopic signatures (i.e., electronic absorption band maxima and intensities, EPR signals, and Mn K-edge X-ray absorption edge and near-edge data) similar to those observed for other Mn
IV
-oxo complexes with neutral, pentadentate N
5
supporting ligands. The near-IR electronic absorption band maximum of [Mn
IV
(O)(2pyN2B)]
2+
, as well as DFT-computed metric parameters, are consistent with the equatorial (N-methyl)benzimidazolyl ligands being stronger donors to the Mn
IV
center than the pyridyl and quinolinyl ligands found in analogous Mn
IV
-oxo complexes. The hydrogen- and oxygen-atom transfer reactivities of [Mn
IV
(O)(2pyN2B)]
2+
were assessed through reactions with hydrocarbons and thioanisole, respectively. When compared with related Mn
IV
-oxo adducts, [Mn
IV
(O)(2pyN2B)]
2+
showed muted reactivity in hydrogen-atom transfer reactions with hydrocarbons. This result stands in contrast to observations for the analogous Fe
IV
-oxo complexes, where [Fe
IV
(O)(2pyN2B)]
2+
was found to be one of the more reactive members of its class.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Dalton Transactions
volume
48
issue
15
pages
15 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85064170452
ISSN
1477-9226
DOI
10.1039/c9dt00308h
language
English
LU publication?
yes
id
4958a518-d50f-4e87-87d8-2ca1b26c072d
date added to LUP
2019-05-08 12:38:52
date last changed
2019-09-15 05:16:41
@article{4958a518-d50f-4e87-87d8-2ca1b26c072d,
  abstract     = {<p><br>
                                                         Using the pentadentate ligand (N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine, 2pyN2B), presenting two pyridyl and two (N-methyl)benzimidazolyl donor moieties in addition to a central tertiary amine, new Mn                             <br>
                            <sup>II</sup><br>
                                                          and Mn                             <br>
                            <sup>IV</sup><br>
                                                         -oxo complexes were generated and characterized. The [Mn                             <br>
                            <sup>IV</sup><br>
                                                         (O)(2pyN2B)]                             <br>
                            <sup>2+</sup><br>
                                                          complex showed spectroscopic signatures (i.e., electronic absorption band maxima and intensities, EPR signals, and Mn K-edge X-ray absorption edge and near-edge data) similar to those observed for other Mn                             <br>
                            <sup>IV</sup><br>
                                                         -oxo complexes with neutral, pentadentate N                             <br>
                            <sub>5</sub><br>
                                                          supporting ligands. The near-IR electronic absorption band maximum of [Mn                             <br>
                            <sup>IV</sup><br>
                                                         (O)(2pyN2B)]                             <br>
                            <sup>2+</sup><br>
                                                         , as well as DFT-computed metric parameters, are consistent with the equatorial (N-methyl)benzimidazolyl ligands being stronger donors to the Mn                             <br>
                            <sup>IV</sup><br>
                                                          center than the pyridyl and quinolinyl ligands found in analogous Mn                             <br>
                            <sup>IV</sup><br>
                                                         -oxo complexes. The hydrogen- and oxygen-atom transfer reactivities of [Mn                             <br>
                            <sup>IV</sup><br>
                                                         (O)(2pyN2B)]                             <br>
                            <sup>2+</sup><br>
                                                          were assessed through reactions with hydrocarbons and thioanisole, respectively. When compared with related Mn                             <br>
                            <sup>IV</sup><br>
                                                         -oxo adducts, [Mn                             <br>
                            <sup>IV</sup><br>
                                                         (O)(2pyN2B)]                             <br>
                            <sup>2+</sup><br>
                                                          showed muted reactivity in hydrogen-atom transfer reactions with hydrocarbons. This result stands in contrast to observations for the analogous Fe                             <br>
                            <sup>IV</sup><br>
                                                         -oxo complexes, where [Fe                             <br>
                            <sup>IV</sup><br>
                                                         (O)(2pyN2B)]                             <br>
                            <sup>2+</sup><br>
                                                          was found to be one of the more reactive members of its class.                         <br>
                        </p>},
  author       = {Denler, Melissa C. and Massie, Allyssa A. and Singh, Reena and Stewart-Jones, Eleanor and Sinha, Arup and Day, Victor W. and Nordlander, Ebbe and Jackson, Timothy A.},
  issn         = {1477-9226},
  language     = {eng},
  number       = {15},
  pages        = {5007--5021},
  publisher    = {Royal Society of Chemistry},
  series       = {Dalton Transactions},
  title        = {Mn                         
                        <sup>IV</sup>
                                                 -Oxo complex of a bis(benzimidazolyl)-containing N5 ligand reveals different reactivity trends for Mn                         
                        <sup>IV</sup>
                                                 -oxo than Fe                         
                        <sup>IV</sup>
                                                 -oxo species},
  url          = {http://dx.doi.org/10.1039/c9dt00308h},
  volume       = {48},
  year         = {2019},
}