The crystal structures of p-halo-N-(p-cyanobenzylidene)aniline and p-cyano-N-(p-halobenzylidene)aniline (halo = bromo and chloro)

Abstract

p-Bromo-N-(p-cyanobenzylidene)aniline is triclinic, has space group P $\overline 1$, at 173 K, with a = 7.3892(15), b = 12.087(2), c = 7.0283(14) Å, α = 105.24(2), β = 98.11(2), γ = 98.89(2)°, Z = 2, V = 587.4(2) ų. p-Chloro-N-(p-cyanobenzylidene)aniline is triclinic, space group P $\overline 1$, at 173 K, with a = 7.317(2), b = 12.165(3), c = 6.990(2) Å, α = 104.02(2), β = 100.96(2), γ = 100.76(2)°, Z = 2, V = 574.7(3) ų. p-Cyano-N-(p-bromobenzylidene)aniline is orthorhombic, has space group P2₁2₁2₁, at 173 K, with a = 10.333(3), b = 4.732(3), c = 23.526(5) Å, Z = 4, V = 1150.3(8) ų. p-Cyano-N-(p-chlorobenzylidene)aniline is orthorhombic, has space group P2₁2₁2₁, at 173 K, with a = 10.161(2), b = 4.713(2), c = 23.509(5) Å, Z = 4, V = 1125.8(4) ų. In the two cyanobenzylidene compounds there are chains of molecules held together by CN······X interactions. The chains form two-dimensional sheets similar to those in the iodo analog, but with a different stacking arrangement between the sheets. In the two halobenzylidene compounds there are no CN······X contacts; rather there are short X······X and C–H······NC contacts.