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π–π-Stacking and nitro–π-stacking interactions of 1-(4-nitrophenyl)-4-phenyl-2,4-bis(phenylethynyl)butadiene
Acta Cryst. (2003). E59, o227–o229
Bilal R. Kaafarani, Brigitte Wex, Allen G. Oliver, Jeanette A. Krause Bauer and Douglas C. Neckers
The X-ray structure and stacking of 1-(4-nitrophenyl)-4-phenyl-2,4-bis(phenyl-ethynyl)butadiene (4) is reported. This compound is a side product observed during the Sonogashira coupling reaction of β ,β -dibromo-p-nitrostyrene (1) and phenylacetylene to afford β ,β -bis(phenylethynyl)-4-nitrostyrene (2), a Y-enyne. Diynes, formed by reductive elimination, are classical side products in the course of the Sonogashira coupling reaction, in this case 1,4-diphenylbutadiyne (3). To the best of our knowledge, this is the first report of such a side product in the Sonogashira reaction. The nitro substitution induced π –π -stacking and nitro–π interactions in (4). The distance between the centroids of the phenyl rings in (4) alternates between 4.96 and 5.35 Å. The distance between the centers of the acetylene triple bonds is 3.28 Å. The scanning electron micrograph of (4) shows its crystal habit in the form of complex, cactus-like needles with a diameter of several micrometers.