Unexpected formation of a co-crystal containing the chalcone (E)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-2-en-1-one and the keto-enol tautomer (Z)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-1-en-1-ol.

Mahmoud Al-Refai,Armin Geyer,Klaus Harms,Basem F Ali,Michael Marsch

doi:10.1107/s2056989020002583

Abstract

The title crystal structure is assembled from the superposition of two mol-ecular structures, (E)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-2-en-1-one, C12H9ClOS2 (93%), and (Z)-1-(5-chloro-thio-phen-2-yl)-3-(3-methyl-thio-phen-2-yl)prop-1-en-1-ol, C12H11ClOS2 (7%), 0.93C12H9ClOS2·0.07C12H11ClOS2. Both were obtained from the reaction of 3-methyl-thio-phene-2-carbaldehyde and 1-(5-chloro-thio-phen-2-yl)ethanone. In the extended structure of the major chalcone component, mol-ecules are linked by a combination of C-H⋯O/S, Cl⋯Cl, Cl⋯π and π-π inter-actions, leading to a compact three-dimensional supra-molecular assembly.

Highlights

Chalcones exhibit a wide spectrum of pharmacological activities, including antibacterial (Tran et al, 2012), anticancer (Shin et al, 2013), antifungal (Lopez et al, 2001) and antiinflammatory properties (Fang et al, 2015)
As a part of our ongoing research in this area (Ibrahim et al, 2019), we report the crystal structure of a chalcone containing two terminal-substituted thiophene rings, namely (E)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-2-en-1-one, which crystallized as a co-crystal in an unexpected superposition with the keto–enol tautomer (Z)-1(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-1-en1-ol as a minor component
The crystal structure (Fig. 1) exhibits two superimposed molecules with occupancies of 93% and 7%: this was surprising since the formation of the minor component was quite unexpected

Summary

Chemical context

Chalcones exhibit a wide spectrum of pharmacological activities, including antibacterial (Tran et al, 2012), anticancer (Shin et al, 2013), antifungal (Lopez et al, 2001) and antiinflammatory properties (Fang et al, 2015). Combining thiophenes and chalcones could result in compounds with interesting new structures and properties: AlMaqtari et al (2015) reported the synthesis of thiophene– chalcones containing two thiophene rings and their antimicrobial and anticancer activities. One of their reported structures is (E)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-2-en-1-one. As a part of our ongoing research in this area (Ibrahim et al, 2019), we report the crystal structure of a chalcone containing two terminal-substituted thiophene rings, namely (E)-1-(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-2-en-1-one, which crystallized as a co-crystal in an unexpected superposition with the keto–enol tautomer (Z)-1(5-chlorothiophen-2-yl)-3-(3-methylthiophen-2-yl)prop-1-en1-ol as a minor component

Structural commentary

Supramolecular features

Database survey

Refinement