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

Abstract

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.