Coordination of alkaline-earth metal cations to an inverted hexamethylcucurbit[3,3]uril in the presence of polychlorido cadmium(II) anions

Abstract The coordination of alkaline earth metal cations (AE2+ = Mg2+, Ca2+, Sr2+, Ba2+) with inverted hexamethylcucurbit[3,3]uril {iMe6Q[3,3]} has been investigated in the presence of polychlorido cadmium anions as structure directing agent. Single-crystal X-ray diffraction analysis has revealed that the interactions of iMe6Q[3,3] with AE2+ cations result in the formation of linear iMe6Q[3,3]-based coordination polymers from iMe6Q[3,3]-AECl2-CdCl2-HCl systems. Generally, Cd2+ cations can form [CdCl4]2− anions that serve as structure directing agent in the formation of iMe6Q[3,3]/AE2+-based coordination polymers. Moreover, iMe6Q[3,3]-AECl2-CdCl2-HCl systems exhibit high affinity for the heavier AE2+, such as Sr2+, and Ba2+.