Proton Transfer in Host–Guest Complexation between a Difunctional Pillar[5]arene and Alkyldiamines

Host–guest
complexation between a novel difunctional pillar[5]­arene-based
host H and alkyldiamines was fully investigated in both
solution and the solid state. Proton transfer from the carboxylic
acid groups to the amine units occurred in the principle by undergoing
an acid–base reaction. Driven by the cooperativity of electrostatic
interactions, multiple C–H···π interactions,
and H-bonds, the guests penetrated into the cavity of H to form pseudorotaxane-type inclusion complexes with relatively
high binding affinities.