Molecular capsules based on methyl-substituted cucurbit[5]urils and strontium-capped

Four molecular capsules based on three methyl-substituted cucurbit[5]urils, which are α,β,δ-hexamethyl cucurbit[5]uril (α,β,δ-HMeQ[5]), decamethylcucurbit[5]uril (Me10Q[5]) and a pentamethylcucurbit[5]uril constructed of a monomethyl-glycouril (PMeQ[5]), were synthesized and structurally characterized by single crystal X-ray diffractions. They are {[α,β,δ-HMeQ[5]@Cl][Sr(H2O)2]2}3+3·Cl−·13(H2O) (1), {[α,β,δ-HMeQ[5]@(NO3)][Sr(NO3)(H2O)]2}+[NO3]−HNO3·4(H2O) (2), {[Me10Q[5]@(NO3)][Sr(NO3)(H2O)]2}+(NO3)−8(H2O) (3) and {[PMeQ[5]@Cl][Sr(H2O)2]2}3+3·Cl−·22(H2O) (4). In the crystal structure of these compounds, molecular capsules included a Cl− or a NO3- anion and lidded with strontium cations were observed.