T-Butyl 3-azido- and 3-amino-2,3-dideoxy-α-d-arabino-hexopyranosides: a concise protocol of structural and chemical profiles to identify metal ion binding modes

Abstract

The metal cations-polysaccharides complexes play crucial roles in the process of immune cell recognitions. Here, we create simpler biomimetic ligands, which emulate binding of carbohydrates in living organisms. We present a detailed study on the interactions of Cu2+, Ni2+ and VO2+ ions with t-butyl 3-azido- and 3-amino-2,3-dideoxy-α-d -arabino-hexopyranosides. NMR, IR and UV–Vis spectroscopies as well as single crystal X-ray diffraction were used for the ligand structure determinations and showed their binding affinity of ions selected. The formation of stable complexes of Cu(II), Ni(II), VO(IV) ions and saccharides with 1:1, 1:2 and 1:3 molar ratios was proved. The coordination sites proposed are N-donor (amino or azido groups), O-donor (hydroxyl group) and endo-oxygen atoms. Additionally, parameters like shape, charge density distribution, and sites of chemical reactivity of the sugars studied were obtained by mapping electron density isosurface with electrostatic potential (MESP).