title: Ligand redox non-innocence in the stoichiometric oxidation of Mn2(2,5-dioxidoterephthalate) (Mn-MOF-74).
abstract: Unsaturated metal sites within the nodes of metal-organic frameworks (MOFs) can be interrogated by redox reagents common to small molecule chemistry. We show, for the first time, that an analogue of the iconic M2(2,5-dioxidoterephthalate) (M2DOBDC, MOF-74) class of materials can be stoichiometrically oxidized by one electron per metal center. The reaction of Mn2DOBDC with C6H5ICl2 produces the oxidized material Cl2Mn2DOBDC, which retains crystallinity and porosity. Surprisingly, magnetic measurements, X-ray absorption, and infrared spectroscopic data indicate that the Mn ions maintain a formal oxidation state of +2, suggesting instead the oxidation of the DOBDC(4-) ligand to the quinone DOBDC(2-). These results describe the first example of ligand redox non-innocence in a MOF and a rare instance of stoichiometric electron transfer involving the metal nodes. The methods described herein offer a synthetic toolkit that will be of general use for further explorations of the redox reactivity of MOF nodes.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Cozzolino
authors.forename: Carl K
authors.initials: CK
authors.lastname: Brozek
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Palmer
authors.forename: Junko
authors.initials: J
authors.lastname: Yano
authors.forename: Minyuan
authors.initials: M
authors.lastname: Li
authors.forename: Mircea
authors.initials: M
authors.lastname: Dincă
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010795:Phthalic Acids / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; C000592849:Mn2(2,5-dioxidoterephthalate); D010795:Phthalic Acids; C011363:terephthalic acid