2026-04-17T05:54:46Zhttps://recercat.cat/oai/request

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

Polymorphism in secondary squaramides: on the importance of π-interactions involving the four membered ring Prohens López, Rafael Portell Bueso, Anna Vallcorba, Oriol Font Bardia, Ma. Mercedes Bauzá, Antonio Frontera, Antonio Polimorfisme (Cristal·lografia) Química supramolecular Polymorphism (Crystallography) Supramolecular chemistry 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). 2020-05-29T14:19:36Z 2020-05-29T14:19:36Z 2018 2020-05-29T14:19:37Z info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Versió postprint del document publicat a: https://doi.org/10.1039/c7ce01945a Crystengcomm, 2018, vol. 20, num. 2, p. 237-244 https://doi.org/10.1039/c7ce01945a (c) Prohens López, Rafael et al., 2018 info:eu-repo/semantics/openAccess Royal Society of Chemistry Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)