Coordination and supramolecular assemblies of mono-hydroxylated octamethylcucurbit[6]uril with alkali and alkaline earth metal ions in the presence of polychloride cadmium anions

Abstract

The interactions of alkali metal (A⁺ = Na⁺, K⁺, Rb⁺, Cs⁺) and alkaline earth metal cations (AE²⁺ = Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺) with mono-hydroxylated octamethylcucurbit[6]uril {(OH)OMeQ[6]} have been investigated in the presence of polychloride cadmium anions as structure-directing agents. Single-crystal X-ray diffraction analysis has revealed that the interactions of (OH)OMeQ[6] with A⁺ or AE²⁺ cations results in the formation of (OH)OMeQ[6]-based coordination complexes from (OH)OMeQ[6]–ACl or AECl₂–CdCl₂–HCl systems, in which Cd²⁺ cations form [Cd₂Cl₈]⁴⁻ or [CdCl₄]²⁻ anions that serve as structure-directing agents in the formation of (OH)OMeQ[6]/A⁺ or AE²⁺-based supramolecular assemblies.