Synthesis, Host Properties and Structure of Phosphorylated Cavitands

Abstract

New supramolecular phosphorus receptors with conformationally rigid structures were investigated. Tetraphosphonate-calix[4]resorcinarenes with long chain substituents on the resorcinolarene unit were synthesized in fairly good yields. The all in (iiii) stereoisomer was preferentially obtained. The phosphacavitands exhibit an extremely large affinity for metallic and ammonium cations, which is due to the complementary positioning of a “soft” lipophilic cavity and “hard” phosphorylated binding sites, leading to cooperative binding interactions. The formation of a thio-phosphorylated hemicryptophane, bearing a phosphotrihydrazone moiety, is also reported. It forms stable complexes with neutral aromatic guests and provides a novel synthetic approach to the design of new metallo-receptors.

Keywords::

• phosphorus ligands
• cavitands
• cation complexation
• ditopic cavity