ja035561f_si_001.pdf (222.69 kB)
Download file

A Sugar Discriminating Binuclear Copper(II) Complex

Download (222.69 kB)
journal contribution
posted on 30.08.2003, 00:00 by Susanne Striegler, Michael Dittel
We investigated the complex formation between various underivatized carbohydrates and the binuclear copper(II) complex 1, Cu2(bpdpo). A combined approach of UV/vis and CD spectroscopic investigations shows a large discrimination ability of 1 for structurally closely related monosaccharides in alkaline solution. The dominating form of the binuclear copper(II) complex consists of a [Cu2L-H(OH)2]+ species between pH 11 and 13, as determined from pH-dependent spectrophotometric titration experiments. The binding strengths of the 1:1 sugar−1 complexes, derived from the biologically important monosaccharides d-mannose (3) and d-glucose (5), is about 1.5 orders of magnitude different at pH 12.40. Moreover, a blue- or a red-shift of the absorption maximum of 1 accompanies the sugar binding and highlights the ability of 1 to discriminate carbohydrates. This phenomenon is due to the number of hydroxyl groups of the particular monosaccharide involved in chelation to the binuclear metal complex.