Open AccessManganese–Cobalt Oxido Cubanes Relevant to Manganese-Doped Water Oxidation Catalysts
Author(s) -
Andy I. Nguyen,
Daniel L. M. Suess,
Lucy E. Darago,
Paul H. Oyala,
Daniel S. Levine,
Micah S. Ziegler,
R. David Britt,
T. Don Tilley
Publication year - 2017
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.7b01792
Subject(s) - cubane , chemistry , cobalt , manganese , inorganic chemistry , redox , pyridine , catalysis , electron paramagnetic resonance , ligand (biochemistry) , polyoxometalate , crystallography , medicinal chemistry , crystal structure , organic chemistry , biochemistry , physics , receptor , nuclear magnetic resonance
Incorporation of Mn into an established water oxidation catalyst based on a Co(III) 4 O 4 cubane was achieved by a simple and efficient assembly of permanganate, cobalt(II) acetate, and pyridine to form the cubane oxo cluster MnCo 3 O 4 (OAc) 5 py 3 (OAc = acetate, py = pyridine) (1-OAc) in good yield. This allows characterization of electronic and chemical properties for a manganese center in a cobalt oxide environment, and provides a molecular model for Mn-doped cobalt oxides. The electronic properties of the cubane are readily tuned by exchange of the OAc - ligand for Cl - (1-Cl), NO 3 - (1-NO 3 ), and pyridine ([1-py] + ). EPR spectroscopy, SQUID magnetometry, and DFT calculations thoroughly characterized the valence assignment of the cubane as [Mn IV Co III 3 ]. These cubanes are redox-active, and calculations reveal that the Co ions behave as the reservoir for electrons, but their redox potentials are tuned by the choice of ligand at Mn. This MnCo 3 O 4 cubane system represents a new class of easily prepared, versatile, and redox-active oxido clusters that should contribute to an understanding of mixed-metal, Mn-containing oxides.