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Experimental demonstration of radicaloid character in a Ru(V)=O intermediate in catalytic water oxidation.

ABSTRACT: Water oxidation is the key half reaction in artificial photosynthesis. An absence of detailed mechanistic insight impedes design of new catalysts that are more reactive and more robust. A proposed paradigm leading to enhanced reactivity is the existence of oxyl radical intermediates capable of rapid water activation, but there is a dearth of experimental validation. Here, we show the radicaloid nature of an intermediate reactive toward formation of the O-O bond by assessing the spin density on the oxyl group by Electron Paramagnetic Resonance (EPR). In the study, an (17)O-labeled form of a highly oxidized, short-lived intermediate in the catalytic cycle of the water oxidation catalyst cis,cis-[(2,2-bipyridine)2(H2O)Ru(III)ORu(III)(OH2)(bpy)2](4+) was investigated. It contains Ru centers in oxidation states [4,5], has at least one Ru(V) = O unit, and shows

SUBMITTER: Moonshiram D

PROVIDER: S-EPMC3593827 | biostudies-other | 2013 Mar

REPOSITORIES: biostudies-other

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Experimental demonstration of ecological character displacement.

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