Acta Cryst. (2001). E57, o964-o965  [ doi:10.1107/S1600536801015203 ]

Monoclinic form of 2-{5,5-dimethyl-3-[2-(2,4,6-trimethoxyphenyl)vinyl]cyclohex-2-enylidene}malononitrile

T. Kolev, Z. Glavcheva, M. Schürmann, D.-C. Kleb, H. Preut and P. Bleckmann

Abstract: On slow evaporation of an ethyl acetate solution, the title compound, C₂₂H₂₄N₂O₃, crystallizes simultaneously in two crystalline forms, differing in colour, size and shape. The molecule in the violet plate-like monoclinic crystal reported here is almost planar with the exception of the dimethylcyclohexene moiety, which has a twisted conformation. The red triclinic crystals [see Kolev et al. (2001a), Acta Cryst. E57, o966-o967] are built of the same molecules with similar geometry; however, the cyclohexene fragment in the triclinic crystal has a more symmetric sofa conformation. Another difference between the structures is the existence of a non-classical hydrogen bond involving one of the nitrile groups in the triclinic form. The molecules in the monoclinic form are held together by van der Waals interactions.

Online 29 September 2001

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