2026-04-17T13:54:53Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1631232025-12-05T14:29:02Zcom_2072_1057col_2072_478917col_2072_478923

00925njm 22002777a 4500 dc Prohens López, Rafael author Portell Bueso, Anna author Vallcorba, Oriol author Font Bardia, Ma. Mercedes author Bauzá, Antonio author Frontera, Antonio author 2020-05-29T14:19:36Z 2020-05-29T14:19:36Z 2018 2020-05-29T14:19:37Z We 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). Polimorfisme (Cristal·lografia) Química supramolecular Polymorphism (Crystallography) Supramolecular chemistry Polymorphism in secondary squaramides: on the importance of π-interactions involving the four membered ring