Calix[4]arenes with carboxamide and sulfonamide groups and their complexation with transition metal salts

Calix[4]arene derivatives functionalized by ester and carboxamide groups on the lower rim and sulfonamide groups on the upper rim were synthesized, and their complexing properties toward transition metal salts (Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺) were studied by extraction in chloroform-water system. The presence of carboxamide and sulfonamide fragments in the ligand was shown to considerably enhance binding of transition metal cations.