Polymorphism and configurational isomerism in 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one

In this study, 3-(9-anthryl)-1-(3-hydroxyphenyl)prop-2-en-1-one was synthesized and formed two cis isomers (alpha and beta polymorphs) and one trans isomer under different crystallization conditions. Single crystal X-ray diffraction revealed that all the three crystals exhibit the similar crystal structures, in which the two adjacent chalcone molecules form dimers through intermolecular H-bonds between the phenolic hydroxyl and carbonyl groups, and all of the dimers stack parallel to construct their 3D structures. In order to rationalize the configurational phenomenon and investigate the stability of the three crystals, Hirshfeld surface analyses, theoretical calculation and grinding experiments were performed. The results revealed that the coexistence of H-bonds and C-H center dot center dot center dot pi interactions around the two hydrogen atoms on the C=C double bond may be crucial for formation of the cis configuration, and the trans isomer is more stable than the other two cis isomers. Moreover, the optical-physical properties of these crystals were also investigated. Due to the similar crystal structures, the similar fluorescence bands were observed in their spectra. (C) 2019 Published by Elsevier B.V.