title: Pushing Single-Oxygen-Atom-Bridged Bimetallic Systems to the Right: A Cryptand-Encapsulated Co-O-Co Unit.
abstract: A dicobalt(II) complex, [Co2(mBDCA-5t)](2-) (1), demonstrates a cofacial arrangement of trigonal monopyramidal Co(II) ions with an inter-metal separation of 6.2710(6) Å. Reaction of 1 with potassium superoxide generates an encapsulated Co-O-Co core in the dianionic complex, [Co2O(mBDCA-5t)](2-) (2); to form the linear Co-O-Co core, the inter-metal distance has diminished to 3.994(3) Å. Co K-edge X-ray absorption spectroscopy data are consistent with a +2 oxidation state assignment for Co in both 1 and 2. Multireference complete active space calculations followed by second-order perturbation theory support this assignment, with hole equivalents residing on the bridging O-atom and on the cryptand ligand for the case of 2. Complex 2 acts as a 2-e(-) oxidant toward substrates including CO and H2, in both cases efficiently regenerating 1 in what represent net oxygen-atom-transfer reactions. This dicobalt system also functions as a catalase upon treatment with H2O2.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Stauber
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.|Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Bloch
authors.affiliation: Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Konstantinos D
authors.initials: KD
authors.lastname: Vogiatzis
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Shao-Liang
authors.initials: SL
authors.lastname: Zheng
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Hadt
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Dugan
authors.initials: D
authors.lastname: Hayes
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Lin X
authors.initials: LX
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Chemical Theory Center, and Supercomputing Institute, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Laura
authors.initials: L
authors.lastname: Gagliardi
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Nocera
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Cummins