Prohens López, RafaelPortell Bueso, AnnaVallcorba, OriolFont Bardia, Ma. MercedesBauzá, AntonioFrontera, Antonio2020-05-292020-05-2920181466-8033https://hdl.handle.net/2445/163123We report the X-ray solid state structures of four new squaric acid derivatives, i.e. three polymorphs of 3,4-bisIJ(2-(dimethylamino)ethyl)amino)cyclobut-3-ene-1,2-dione (1a-c) and a co-crystal of compound 1 and resorcinol (2). All structures form interesting supramolecular assemblies in the solid state which have been analyzed using high level DFT calculations and molecular electrostatic potential (MEP) surface calculations. A combination of H-bonding and π-π stacking interactions of the cyclobutenedione rings are crucial for the formation of the supramolecular assemblies in the solid state. Moreover, unusual antiparallel CO⋯CO interactions observed in the X-ray structure of one of the polymorphs of 1 and the lp-π interactions between one oxygen atom of resorcinol and the squaramide ring in 2 have been characterized using Bader's theory of 'atoms-in-molecules' (AIM).29 p.application/pdfeng(c) Prohens López, Rafael et al., 2018Polimorfisme (Cristal·lografia)Química supramolecularPolymorphism (Crystallography)Supramolecular chemistryinfo:eu-repo/semantics/article6930582020-05-29info:eu-repo/semantics/openAccess