Approach to 10-Unit “Bracelet” Frameworks Based on Coordination of Alkyl-Substituted Cucurbit[5]urils and Potassium Ions.

The formation of 3D fused 10-membered “bracelet” frameworks derived from the alkyl-substituted curcurbit[5]urils (SQ[5]s), 1,2,4-hexamethylcucurbit[5]uril (1,2,4-HMeQ[5]), and pentacyclopentanocucurbit[5]uril (PCyHQ[5]) and K誉 is described. These remarkable catenated structures feature trigonal-planar branching units involving three SQ[5]s connected via their bound K誉 in a triangular manner in which the coordination of each K誉 to the five portal carbonyl oxygen atoms of one SQ[5] as well as to a bridging portal carbonyl oxygen from an adjacent SQ[5] draws the edges of three portals into close proximity. The corresponding offset angle at each junction provides the basis for the 3D assembly of the observed fused 10-membered SQ[5] bracelet frameworks. [ABSTRACT FROM AUTHOR]