Solvent‐dependent polymorphism in isomeric N ‐(nitrobenzylidene)iodoanilines

Three of the nine isomeric N ‐(nitrobenzylidene)iodoanilines, C 13 H 9 IN 2 O 2 , have been found, when crystallized from acetone, to yield polymorphs which differ from those obtained upon crystallization from ethanol. In the second polymorph of 2‐iodo‐ N ‐(2‐nitrobenzylidene)aniline, the molecules are disordered across inversion centres in space group C 2/ c , but there are no direction‐specific interactions between the molecules. In the second polymorph of 2‐iodo‐ N ‐(3‐nitrobenzylidene)aniline, the molecules adopt a different conformation from those in the first polymorph, and they are linked into sheets by a combination of a three‐centre iodo–nitro interaction and an aromatic π–π stacking interaction, both of which are absent from the supramolecular structure of the first polymorph. The second polymorph of 3‐iodo‐ N ‐(2‐nitrobenzylidene)aniline crystallizes with Z ′ = 2 in space group P 2 1 , and the molecules are linked into sheets by one C—H⋯O hydrogen bond and two C—H⋯π(arene) hydrogen bonds.