Metal coordination with an amide-functionalized axially chiral resorcinarene

The synthesis and characterization of an amide-functionalized axially chiral resorcinarene, 1(4),3(6),5(6),7(6)-tetra-2-oxo-2-(2-hydroxyethylamino)ethoxy-1(6),3(4),5(4),7(4)-tetramethoxy-2,4,6,8- tetrapropylresorcin[4]arene, is reported. Metal complexation with picrate salts gave crystalline products that could be structurally characterised for calcium, lanthanum, praseodymium, and ytterbium. While the details of these structures vary, the metal-ligand interactions are remarkably consistent, with coordination polymers formed through interaction between three of the amide O atoms, each binding to a different metal atom. No other potential donor atom of the macrocycle is bound to the metal atoms, with the coordination spheres completed by solvent or picrate donor O atoms.