Phosphorylated macrocycles: structures, complexing properties, and molecular recognition

Procedures were developed for functionalization of macrocycles by introducing a phosphonic group either directly linked to the aromatic rings (in the case of cyclophanes or calixarenes) or as a pendant arm. For these compounds to be used as artificial receptors for amino alcohols and amino acids, the host molecule must possess not only negative charges arising from the phosphonate moieties but also a hydrophobic binding site, such as electron-rich aromatic residues. We designed inter alia new dissymmetric macrocycles capable of being involved in three binding modes with guest molecules, viz., hydrogen bonding, electrostatic attraction, and pi-cation interactions. The NMR characterization of the macrocycles, their stereochemistry in solution and in the solid state, and the use as chiral receptors for biologically relevant molecules are described.