Molecular and Crystal Structure of C−(2-Phenoxy-1 -Vinyl)-N-n−Bromophenyl Nitrone and C−(2-Phenoxy-1 -Vinyl)-N-Phenyl Nitrone

Abstract

An X-ray study of the crystals of C−(2-phenoxy-1-vinyl)-N-n−bromophenyl nitrone (I) and C−(2-phenoxy-1-vinyl)-N−phenyl nitrone (II) has been performed. The main crystal data of I: C₁₅H₁₂NO₂Br, a=10.807(5) Å, b=10.275(5)Å, c= 15.415(7)Å, β=129.7(2)°, M = 318.14, V= 1525(2)ų, d _calc = 1.3S5(3)g/cm³, Space gr. P2₁/b, Z= 4. The main crystal data of II: C₁₅H₁₃NO₂, a = 12.760(4)Å, b = 19.784(6) Å, c = 9.805(4) Å, M = 239.64, V = 2475(1) ų, d _calc = 1.284(2) g/cm³, Space gr. Pbna, Z = 8.

The crystal packing of I and II is characterized by the presence of centrosymmetric dimer associates (CDA) existing due to stable intermolecular hydrogen bonds (IMHB). Such a crystalline structure of these nitrones accounts for the possibility of intermolecular proton transfer along the O → O coordinate to form a coloured quinoid product.