title: Influence of ligand architecture on oxidation reactions by high-valent nonheme manganese oxo complexes using water as a source of oxygen.
abstract: Mononuclear nonheme Mn(IV)=O complexes with two isomers of a bispidine ligand have been synthesized and characterized by various spectroscopies and density functional theory (DFT). The Mn(IV)=O complexes show reactivity in oxidation reactions (hydrogen-atom abstraction and sulfoxidation). Interestingly, one of the isomers (L(1) ) is significantly more reactive than the other (L(2) ), while in the corresponding Fe(IV)=O based oxidation reactions the L(2) -based system was previously found to be more reactive than the L(1) -based catalyst. This inversion of reactivities is discussed on the basis of DFT and molecular mechanics (MM) model calculations, which indicate that the order of reactivities are primarily due to a switch of reaction channels (σ versus π) and concomitant steric effects.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Guwahati, Assam, 781039 (India).
authors.forename: Prasenjit
authors.initials: P
authors.lastname: Barman
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Vardhaman
authors.forename: Bodo
authors.initials: B
authors.lastname: Martin
authors.forename: Svenja J
authors.initials: SJ
authors.lastname: Wörner
authors.forename: Chivukula V
authors.initials: CV
authors.lastname: Sastri
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D007536:Isomerism; D008024:Ligands; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D056831:Coordination Complexes; D008024:Ligands; C495809:bispidine; D014867:Water; D008345:Manganese; D010100:Oxygen
keywords: density functional calculations; isomers; manganese; oxidation; structure elucidation