Preparation, Solid-State Characterization, and Computational Study of a Crown Ether Attached to a Squaramide

Crystals of a disecondary squaramide covalently linked to a crown ether presents a great variety of inter- and intramolecular nonbonded
interactions including C−H/π contacts, C−H···O and N−H···O hydrogen bonds, and π−π stacking between squaramide rings. Latter interaction,
the stacking between squaramide rings, can be considered as an experimental evidence for the proposed aromaticity of squaramide when it
is forming hydrogen bonds, either as acceptor or donor.