Acta Crystallographica Section C

Crystal Structure Communications

Volume 63, Part 4 (April 2007)

organic compounds

fa3067 scheme

Acta Cryst. (2007). C63, o207-o211 [ doi:10.1107/S0108270107006233 ]

Isomeric Schiff bases related by dual imino-group reversals

W. H. Ojala, T. M. Arola, N. Herrera, B. Balidemaj and C. R. Ojala

Abstract: Two isomeric pairs of Schiff bases, N,N'-bis(2-methoxybenzylidene)-p-phenylenediamine, C₂₂H₂₀N₂O₂, (I), and 2,2'-dimethoxy-N,N-(p-phenylenedimethylene)dianiline, C₂₂H₂₀N₂O₂, (II), and (E,E)-1,4-bis(3-iodophenyl)-2,3-diazabuta-1,3-diene (alternative name: 3-iodobenzaldehyde azine), C₁₄H₁₀I₂N₂, (III), and N,N'-bis(3-iodophenyl)ethylenediimine, C₁₄H₁₀I₂N₂ [JAYFEV; Cho, Moore & Wilson (2005). Acta Cryst. E61, o3773-o3774], differ pairwise only in the orientation of their imino linkages and in all four individual cases occupy inversion centers in the crystal, yet all four compounds are found to assume unique packing arrangements. Compounds (I) and (II) differ substantially in molecular conformation, possessing angles between their ring planes of 12.10 (15) and 46.29 (9)°, respectively. Compound (III) and JAYFEV are similar to each other in conformation, with angles between their imino linkages and benzene rings of 11.57 (15) and 7.4 (3)°, respectively. The crystal structures are distinguished from each other by different packing motifs involving the functional groups. Intermolecular contacts between methoxy groups define an R₂²(6) motif in (I) but a C(3) motif in (II). Intermolecular contacts are of the II type in (III), but they are of the NI type in JAYFEV.

Formula: C₂₂H₂₀N₂O₂ and C₁₄H₁₀I₂N₂


	Structure factor file (CIF format) (76.1 kbytes) [ doi:10.1107/S0108270107006233/fa3067Isup2.hkl ] Contains datablock I

	Structure factor file (CIF format) (78.1 kbytes) [ doi:10.1107/S0108270107006233/fa3067IIsup3.hkl ] Contains datablock II

	Structure factor file (CIF format) (79.6 kbytes) [ doi:10.1107/S0108270107006233/fa3067IIIsup4.hkl ] Contains datablock III

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