A Simple Strategy to Obtain Synthetic Ca 2+ ‐Dependent Lectin Mimics

Many lectins require a Ca 2+ ion as structure directing co‐factor to function as carbohydrate binders. Such lectins are implicated in various important biological processes such as inflammation and infection, yet a simple strategy to mimic their function is lacking. Herein, a very simple dipyridyl ligand ( 6 ) is reported that can organize around a Pd 2+ ion to form the ring‐like complexes [PdCl 2 6 ] and [Pd 6 2 ] 2+ . In CD 2 Cl 2 with 5 % dmso‐ d 6 , ligand 6 does not associate with glycosides, while its Pd 2+ complexes selectively bind to β‐ n ‐octyl‐glycosides over α‐ n ‐octyl‐glycosides. The highest affinity ( K a 1:1 ≈116 M −1 ) was found between the dicationic [Pd 6 2 ] 2+ and n ‐octyl‐β‐D‐galactoside. Molecular modelling suggests a common binding motif with an important role of C−H⋅⋅⋅π interactions and two charge assisted bifurcated [N−H/C−H] + ⋅⋅⋅O hydrogen bonds. Ligand 6 and its metal complexes thus provide a proof‐of‐concept for a very simple strategy to mimicking Ca 2+ ‐dependent lectins.