Evaluating Binuclear Copper(II) Complexes for Glycoside Hydrolysis

Three binuclear copper(II) complexes were characterized as solids by X-ray diffraction and in solution by UV/vis spectrophotometric titration, and subsequently evaluated for their glycosidase-like activity. The structure analysis revealed comparable intermetallic Cu···Cu distances (∼3.5 Å) for the complexes 2 and 3. Despite this similarity, the composition of the complexes differs significantly in aqueous solution as revealed by spectrophotometric titrations. The hydrolysis of selected nitrophenylglycopyranosides is up to 11,000-fold accelerated over background in the presence of the copper(II) complexes in 3-(cyclohexylamino)-1-propanesulfonic acid (CAPS) buffer at pH 10.5 and 30 °C.