Oxygen activation at a dicobalt centre of a dipyridylethane naphthyridine complex

Casey N. Brodsky, Guillaume Passard, Andrew M. Ullman, David E. Jaramillo, Eric D. Bloch, Michael Huynh, David Gygi, Cyrille Costentin, Daniel G. Nocera

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

The mechanism of oxygen activation at a dicobalt bis-μ-hydroxo core is probed by the implementation of synthetic methods to isolate reaction intermediates. Reduction of a dicobalt(iii,iii) core ligated by the polypyridyl ligand dipyridylethane naphthyridine (DPEN) by two electrons and subsequent protonation result in the release of one water moiety to furnish a dicobalt(ii,ii) center with an open binding site. This reduced core may be independently isolated by chemical reduction. Variable-temperature 1H NMR and SQUID magnetometry reveal the reduced dicobalt(ii,ii) intermediate to consist of two low spin Co(ii) centers coupled antiferromagnetically. Binding of O2 to the open coordination site of the dicobalt(ii,ii) core results in the production of an oxygen adduct, which is proposed to be a dicobalt(iii,iii) peroxo. Electrochemical studies show that the addition of two electrons results in cleavage of the O-O bond.

Original languageEnglish
Pages (from-to)11903-11908
Number of pages6
JournalDalton Transactions
Volume47
Issue number34
DOIs
StatePublished - 2018
Externally publishedYes

Funding

This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0017619. C. N. B. acknowledges the National Science Foundation’s Graduate Research Fellowship Program. We are grateful to Chris Lemon for guidance with VT NMR, Robert Halbach for assistance in crystal structure refinement, Ryan Cowley for help with resonance Raman, and Professor Kit Cummins for helpful discussions. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0017619. C. N. B. acknowledges the National Science Foundation's Graduate Research Fellowship Program. We are grateful to Chris Lemon for guidance with VT NMR, Robert Halbach for assistance in crystal structure refinement, Ryan Cowley for help with resonance Raman, and Professor Kit Cummins for helpful discussions.

FundersFunder number
Office of Basic Energy SciencesDE-SC0017619
U.S. Department of Energy Office of Science
National Science Foundation
U.S. Department of Energy
Office of Science

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