Cooperativity-Driven Reactivity of a Dinuclear Copper Dimethylglyoxime Complex.

In this report, we present the dinuclear copper(II) dimethylglyoxime (H dmg) complex [Cu (H dmg)(Hdmg)(dmg)] (1), which, in contrast to its mononuclear analogue [Cu(Hdmg) ] (2), is subject to a cooperativity-driven hydrolysis. The combined Lewis acidity of both copper centers increases the electrophilicity of the carbon atom in the bridging μ -O-N=C-group of H dmg and thus, facilitates the nucleophilic attack of H O. This hydrolysis yields butane-2,3-dione monoxime (3) and NH OH that, depending on the solvent, is then either oxidized or reduced. In ethanol, NH OH is reduced to NH , yielding acetaldehyde as the oxidation product. In contrast, in CH CN, NH OH is oxidized by Cu to form N O and [Cu(CH CN) ] . Herein are presented the combined synthetic, theoretical, spectroscopic and spectrometric methods that indicate and establish the reaction pathway of this solvent-dependent reaction.