(IUCr) Crystallography Journals Online

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Acta Cryst. (2012). E68, o3079-o3080
[ doi:10.1107/S1600536812041396 ]

2-Cyano-5-({4-[N-methyl-N-(2-hydroxyethyl)amino] phenyl}diazenyl)pyridine

R. Centore and V. Piccialli

Abstract: In the title compound, C₁₅H₁₅N₅O, the benzene and pyridine rings make a dihedral angle of 30.86 (7)°. In the crystal, chains of molecules are wrapped around the screw axes into compressed helices, through hydrogen bonding between the hydroxy and cyano groups. The chains are linked by weak C-HN and C-HO interactions. The [pi] conjugated unit of the molecule is almost perpendicular to the helix axis, and the formation of the helix is allowed by a gauche-type torsion angle in the hydroxyethyl tail. In this way, consecutive chromophore units along the chain are placed in a strict antiparallel arrangement, and this is energetically favoured because of the high dipole moment of the molecule.