Copper(II) defect-cubane water oxidation electrocatalysts: from molecular tetramers to oxidic nanostructures.

We report on the synthesis and spectroscopic evidence for a sequence of structural transformations of a new defect-cubane type copper complex, [Cu(pyalk)(OAc)](ClO)(HNEt), which acts as a pre-catalyst for water oxidation. and post-catalytic studies showed that the tetrameric complex undergoes a structural transformation into dimeric and monomeric species, induced by water molecules and carbonate anions, respectively. Further, the observed electrocatalytic water oxidation activity has been confirmed to arise from -generated Cu(II) oxidic nanostructures at the electrode interface.