skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Equatorial Ligand Perturbations Influence the Reactivity of Manganese(IV)‐Oxo Complexes

Journal Article · · Angewandte Chemie
 [1];  [1];  [1];  [1];  [2];  [1];  [2];  [1]
  1. Department of Chemistry University of Kansas Lawrence KS USA
  2. Chemical Physics Department of Chemistry Lund University Box 124 22100 Lund Sweden

Abstract Manganese(IV)‐oxo complexes are often invoked as intermediates in Mn‐catalyzed C−H bond activation reactions. While many synthetic Mn IV ‐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 IV ‐oxo complexes with N5 pentadentate ligands that modulate the equatorial ligand field of the Mn IV 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 IV ‐oxo complexes, the rate enhancements are correlated with both 1) the energy of a low‐lying 4 E excited state, which has been postulated to be involved in a two‐state reactivity model, and 2) the Mn III/IV reduction potentials.

Sponsoring Organization:
USDOE
Grant/Contract Number:
SC0016359
OSTI ID:
1401072
Journal Information:
Angewandte Chemie, Journal Name: Angewandte Chemie Vol. 129 Journal Issue: 15; ISSN 0044-8249
Publisher:
Wiley Blackwell (John Wiley & Sons)Copyright Statement
Country of Publication:
Germany
Language:
English

References (36)

Evidence for a Precursor Complex in CH Hydrogen Atom Transfer Reactions Mediated by a Manganese(IV) Oxo Complex journal April 2011
Hydrogen-Atom Abstraction Reactions by Manganese(V)- and Manganese(IV)-Oxo Porphyrin Complexes in Aqueous Solution journal October 2009
X-Band Electron Paramagnetic Resonance Comparison of Mononuclear Mn IV -oxo and Mn IV -hydroxo Complexes and Quantum Chemical Investigation of Mn IV Zero-Field Splitting journal March 2016
Evidence for an Alternative to the Oxygen Rebound Mechanism in C–H Bond Activation by Non-Heme Fe IV O Complexes journal December 2012
Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp 2 )−H Bonds by Carbene Insertion journal April 2016
Peroxo and oxo intermediates in mononuclear nonheme iron enzymes and related active sites journal February 2009
Origin of the Zero-Field Splitting in Mononuclear Octahedral Mn IV Complexes: A Combined Experimental and Theoretical Investigation journal January 2016
The pentadentate ligands 2PyN2Q and N4Py, and their Cu(II) and Zn(II) complexes: A synthetic, spectroscopic and crystallographic structural study journal February 2015
Distinct Reactivity Differences of Metal Oxo and Its Corresponding Hydroxo Moieties in Oxidations: Implications from a Manganese(IV) Complex Having Dihydroxide Ligand journal June 2011
Spectroscopic properties and reactivity of a mononuclear oxomanganese(iv) complex journal January 2013
To rebound or dissociate? This is the mechanistic question in C–H hydroxylation by heme and nonheme metal–oxo complexes journal January 2016
A Mononuclear Non-Heme Manganese(IV)–Oxo Complex Binding Redox-Inactive Metal Ions journal January 2013
Bioinspired oxidations of aliphatic C–H groups with H2O2 in the presence of manganese complexes journal September 2015
Manganese Catalyzed C–H Halogenation journal May 2015
Metal complex assembly controlled by surface ligand distribution on mesoporous silica: Quantification using refractive index matching and impact on catalysis journal March 2016
Modeling TauD- J : A High-Spin Nonheme Oxoiron(IV) Complex with High Reactivity toward C–H Bonds journal February 2015
Spectroscopic and Computational Investigations of a Mononuclear Manganese(IV)-Oxo Complex Reveal Electronic Structure Contributions to Reactivity journal November 2016
Toward the Synthesis of More Reactive S = 2 Non-Heme Oxoiron(IV) Complexes journal July 2015
C−H Bond Cleavage with Reductants: Re-Investigating the Reactivity of Monomeric Mn III/IV −Oxo Complexes and the Role of Oxo Ligand Basicity journal March 2009
A Highly Reactive Mononuclear Non-Heme Manganese(IV)–Oxo Complex That Can Activate the Strong C–H Bonds of Alkanes journal December 2011
Mn K-Edge X-ray Absorption Studies of Oxo- and Hydroxo-manganese(IV) Complexes: Experimental and Theoretical Insights into Pre-Edge Properties journal May 2014
A nonheme manganese( iv )–oxo species generated in photocatalytic reaction using water as an oxygen source journal January 2015
Iron and Manganese Catalysts for the Selective Functionalization of Arene C(sp 2 )−H Bonds by Carbene Insertion journal April 2016
Mechanistic elucidation of C–H oxidation by electron rich non-heme iron( iv )–oxo at room temperature journal January 2015
Distinct Reactivity Differences of Metal Oxo and Its Corresponding Hydroxo Moieties in Oxidations: Implications from a Manganese(IV) Complex Having Dihydroxide Ligand journal June 2011
Lessons from nature: unraveling biological CH bond activation journal February 2009
Reactive Intermediates in Cytochrome P450 Catalysis journal April 2013
Status of Reactive Non-Heme Metal–Oxygen Intermediates in Chemical and Enzymatic Reactions journal August 2014
Mononuclear nonheme iron( iv )–oxo and manganese( iv )–oxo complexes in oxidation reactions: experimental results prove theoretical prediction journal January 2015
Oxidative Reactivity Difference among the Metal Oxo and Metal Hydroxo Moieties: pH Dependent Hydrogen Abstraction by a Manganese(IV) Complex Having Two Hydroxide Ligands journal December 2008
Theoretical Investigations into C–H Bond Activation Reaction by Nonheme Mn IV O Complexes: Multistate Reactivity with No Oxygen Rebound journal September 2012
Preparation and Properties of a Monomeric Mn IV −Oxo Complex journal July 2006
A Balancing Act: Stability versus Reactivity of Mn(O) Complexes journal September 2015
Enantioselective Epoxidations of Olefins with Various Oxidants on Bioinspired Mn Complexes: Evidence for Different Mechanisms and Chiral Additive Amplification journal January 2016
Evidence for a Precursor Complex in CH Hydrogen Atom Transfer Reactions Mediated by a Manganese(IV) Oxo Complex journal April 2011
Factors Controlling the Chemoselectivity in the Oxidation of Olefins by Nonheme Manganese(IV)-Oxo Complexes journal August 2016

Related Subjects