Molecular Capsules Based on Cucurbit[5]uril Encapsulating “Naked” Anion Chlorine

Four barrel-shaped artificial molecular capsules based on cucurbit[5]uril, [K 4 (C 30 H 30 N 20 O 10 ) 2 (HCONH 2 ) 2 (H 2 O) 2 Cl 2 ]Cl 2 ·CH 3 OH·17.5H 2 O ( 1 ), {[Ba 2 (C 30 H 30 N 20 O 10 )Cl](NO 3 )(H 2 O) 5 }Cl 2 ·2H 2 O ( 2 ), [Cd(C 30 H 30 N 20 O 10 )Cl 2 ](H 3 O) 2 2+ CdCl 4 2- ·2CH 3 OH 2 ·4H 2 O ( 3 ), and {[La(C 30 H 30 N 20 O 10 )Cl]LaCl(H 2 O) 9 }Cl 4 ·HCl·7H 2 O ( 4 ) were synthesized and structurally characterized by single-crystal X-ray diffractions. The crystal structure of these compounds show that chlorine anions were encapsulated in cucurbit[5]uril to form open or closed molecular capsules. 1 forms a novel one-dimensional (1D) polycationic chain in the solid state and the other three molecular capsules crystallize in isolated molecules.