TY - JOUR
T1 - Dicobalt-μ-oxo polyoxometalate compound, [(α2-P 2W17O61Co)2O]14-
T2 - A potent species for water oxidation, C-H bond activation, and oxygen transfer
AU - Barats-Damatov, Delina
AU - Shimon, Linda J.W.
AU - Weiner, Lev
AU - Schreiber, Roy E.
AU - Jiménez-Lozano, Pablo
AU - Poblet, Josep M.
AU - De Graaf, Coen
AU - Neumann, Ronny
PY - 2014/2/3
Y1 - 2014/2/3
N2 - High-valent oxo compounds of transition metals are often implicated as active species in oxygenation of hydrocarbons through carbon-hydrogen bond activation or oxygen transfer and also in water oxidation. Recently, several examples of cobalt-catalyzed water oxidation have been reported, and cobalt(IV) species have been suggested as active intermediates. A reactive species, formally a dicobalt(IV)-μ-oxo polyoxometalate compound [(α2- P2W17O61Co)2O]14-, [(POMCo)2O], has now been isolated and characterized by the oxidation of a monomeric [α2-P2W17O 61CoII(H2O)]8-, [POMCo IIH2O], with ozone in water. The crystal structure shows a nearly linear Co-O-Co moiety with a Co-O bond length of ∼1.77 Å. In aqueous solution [(POMCo)2O] was identified by 31P NMR, Raman, and UV-vis spectroscopy. Reactivity studies showed that [(POMCo) 2O]2O] is an active compound for the oxidation of H 2O to O2, direct oxygen transfer to water-soluble sulfoxides and phosphines, indirect epoxidation of alkenes via a Mn porphyrin, and the selective oxidation of alcohols by carbon-hydrogen bond activation. The latter appears to occur via a hydrogen atom transfer mechanism. Density functional and CASSCF calculations strongly indicate that the electronic structure of [(POMCo)2O]2O] is best defined as a compound having two cobalt(III) atoms with two oxidized oxygen atoms.
AB - High-valent oxo compounds of transition metals are often implicated as active species in oxygenation of hydrocarbons through carbon-hydrogen bond activation or oxygen transfer and also in water oxidation. Recently, several examples of cobalt-catalyzed water oxidation have been reported, and cobalt(IV) species have been suggested as active intermediates. A reactive species, formally a dicobalt(IV)-μ-oxo polyoxometalate compound [(α2- P2W17O61Co)2O]14-, [(POMCo)2O], has now been isolated and characterized by the oxidation of a monomeric [α2-P2W17O 61CoII(H2O)]8-, [POMCo IIH2O], with ozone in water. The crystal structure shows a nearly linear Co-O-Co moiety with a Co-O bond length of ∼1.77 Å. In aqueous solution [(POMCo)2O] was identified by 31P NMR, Raman, and UV-vis spectroscopy. Reactivity studies showed that [(POMCo) 2O]2O] is an active compound for the oxidation of H 2O to O2, direct oxygen transfer to water-soluble sulfoxides and phosphines, indirect epoxidation of alkenes via a Mn porphyrin, and the selective oxidation of alcohols by carbon-hydrogen bond activation. The latter appears to occur via a hydrogen atom transfer mechanism. Density functional and CASSCF calculations strongly indicate that the electronic structure of [(POMCo)2O]2O] is best defined as a compound having two cobalt(III) atoms with two oxidized oxygen atoms.
UR - http://www.scopus.com/inward/record.url?scp=84893313708&partnerID=8YFLogxK
U2 - 10.1021/ic402962c
DO - 10.1021/ic402962c
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 24437566
AN - SCOPUS:84893313708
SN - 0020-1669
VL - 53
SP - 1779
EP - 1787
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 3
ER -