Synthesis, crystal structure and Hirshfeld analysis of <em>N</em>-ethyl-2-{3-methyl-2-[(2Z)-pent-2-en-1-yl]cyclopent-2-en-1-ylidene}hydrazinecarbothioamide

Abstract

The title compound (C₁₄H₂₃N₃S, common name: <em>cis</em>-jasmone 4-ethylthiosemicarbazone) was synthesized by the equimolar reaction of <em>cis</em>-jasmone and 4-ethylthiosemicarbazide in ethanol facilitated by acid catalysis. There is one crystallographically independent molecule in the asymmetric unit, which shows disorder of the terminal ethyl group of the jasmone carbon chain [site-occupancy ratio = 0.911 (5):0.089 (5)]. The thiosemicarbazone entity [N—N—C(=S)—N] is approximately planar, with the maximum deviation of the mean plane through the N/N/C/S/N atoms being 0.0331 (8) Å, while the maximum deviation of the mean plane through the five-membered ring of the jasmone fragment amounts to −0.0337 (8) Å. The dihedral angle between the two planes is 4.98 (7)°. The molecule is not planar due to this structural feature and the <em>sp</em>³-hybridized atoms of the jasmone carbon chain. Additionally, one H&sdot;&sdot;&sdot;N intramolecular interaction is observed, with graph-set motif <em>S</em>(5). In the crystal, the molecules are connected through pairs of H&sdot;&sdot;&sdot;S interactions with R²₂(8) and R²₁(7) graph-set motifs into centrosymmetric dimers. The dimers are further connected by H&sdot;&sdot;&sdot;N interactions with graph-set motif <em>R</em>²₂(12), which are related by an inversion centre, forming a mono-periodic hydrogen-bonded ribbon parallel to the <em>b</em>-axis. The crystal structure and the supramolecular assembly of the title compound are compared with four known <em>cis</em>-jasmone thiosemicarbazone derivatives (two crystalline modifications of the non-substituted form, the 4-methyl and the 4-phenyl derivatives). A Hirshfeld surface analysis indicates that the major contributions for the crystal cohesion are from H&sdot;&sdot;&sdot;H (70.7%), H&sdot;&sdot;&sdot;S/S&sdot;&sdot;&sdot;H (13.5%), H&sdot;&sdot;&sdot;C/C&sdot;&sdot;&sdot;H (8.8%), and H&sdot;&sdot;&sdot;N/N&sdot;&sdot;&sdot;H (6.6%) interfaces (only the disordered atoms with the highest s.o.f. were considered for the evaluation).