A Sugar's Choice:  Coordination to a Mononuclear or a Dinuclear Copper(II) Complex?

Abstract

We proposed a decisive role of the number of metal ions at the sugar binding site for carbohydrate-coordinating copper(II) complexes. To verify this hypothesis, we studied the binding of the representatively chosen carbohydrates D-ribose (7), D-mannose (8), D-glucose (9), and D-maltose (10) to structurally related mono- and dinuclear copper(II) complexes in alkaline solution. All carbohydrates coordinate to the metal complexes in a 1:1 molar ratio. Coordination of 7 or 8 to the dinuclear copper(II) complex 1 is about 0.5 order of magnitude stronger than the complex formation with related mononuclear complexes. On contrast, 9, which is an epimer of 8, coordinates stronger to either one of the mononuclear copper(II) complexes in alkaline aqueous solution.

Study of potential binding of biologically important sugars with a dinuclear cobalt(II) complex

“…40 The dinuclear cobalt(II) complex 1 reacts with substrate at pH 12.5 to give 1:1 complex/substrate-bound product, resulting in two-state systems, a result that is consistent with several previously investigated mononuclear and dinuclear copper(II) complexes. 35,36 The representative UV-vis spectra obtained during the titration of complex 1 with D-glucose, D-xylose, and D-mannose are shown in Figures 3, 4 and 5, respectively. Clearly, the UV-vis spectra show a blue-shift of the absorption maximum of complex 1 (k max (1) = 550 nm) upon D-glucose binding (k max = 542 nm, Fig.…”

“…However, the binding modes of various carbohydrates with previously investigated mono-and dinuclear copper(II) complexes have been reported. 35,36 Based on the results obtained from FTIR measurements, UV-vis titrations, and 1:1 binding studies, we therefore have proposed the binding modes and equilibrium chemical structures of substrate-bound dinuclear cobalt(II) complexes with D-glucose, D-xylose, and D-mannose (Fig. 9).…”

Progress in biomimetic carbohydrate recognition

“…[81]. Synthetic receptors which exploit this approach have been developed by Striegler and coworkers [82][83][84]. Instead of Ca 2?…”

Human pharmacokinetic study of tutin in honey; a plant-derived neurotoxin

“…The ligands employed in this work are presented in Scheme 1 and were synthesized as described previously [15,16,17].…”