Solution structure of R2Sn(IV)-β-N-acetyl-neuraminate (R = Me, Bu) complexes in D2O and DMSO-d6: Experimental NMR and DFT computational study

Two diorganotin(IV)–NANA complexes (NANA (1) = β-N-acetyl-Neuraminic Acid = 5-amino-3,5-dideoxy-D-glycero-β-D-galactononulosic acid) with formula Me2Sn(IV)NANA (2) and Bu2Sn(IV)NANA (3) were synthesized and characterized by 1H, 13C and 119Sn NMR spectroscopy, both in D2O and DMSO-d6 solutions. The experimental data in DMSO suggested the monosaccharide bidentate chelation via O1 carboxylate and vicinal O2 alkoxide atoms, which, in D2O, can be dynamically extended to a third binding site (O8 atom) of the pendant chain. Coordination at the tin atom is discussed on the basis of experimental NMR data and DFT calculation.