Cooperativity‐driven reactivity of a dinuclear copper dimethylglyoxime complex

In this report, we present the dinuclear copper(II) dimethylglyoxime (H2dmg) complex [Cu2(H2dmg)(Hdmg)(dmg)]+ (1) that, in contrast to its mononuclear analogue [Cu(Hdmg)2] (2), is subject to a cooperativity-driven hydrolysis. The combined Lewis acidity of both copper centers increase the electrophilicity of the carbon atom in the bridging µ2-O-N=C-group of H2dmg and thus, facilitates the nucleophilic attack of H2O. This hydrolysis yields 2,3-butanedione monoxime (3) and NH2OH that depending on the solvent is then either oxidized or reduced. In ethanol, NH2OH is reduced to NH4+, yielding acetaldehyde as oxidation product. In contrast, in CH3CN, NH2OH is oxidized by CuII to form N2O and [Cu(CH3CN)4]+. Herein are presented the combined synthetic, theoretical, spectroscopic and spectrometric methods that indicate and establish the reaction pathway of this solvent-dependent reaction.