Two 9-[(E)-nitrophenylvinyl]-9H-carbazoles

Abstract

The crystal structures of 9-[(E)-(4-nitrophenyl)vinyl]-9H-carbazole and 9-[(E)-(3-nitrophenyl)vinyl]-9H-carbazole, both C20H14N2O2, are determined mainly by van der Waals forces and pi-pi interactions between the carbazole and benzene systems. However, the packing modes are different. In the 4-nitro derivative, the molecules in the weakly bound stack are related by a unit-cell translation, while in the 3-nitro derivative there are centrosymmetric pairs of molecules joined by pi-pi interactions and also pairs of molecules, related by another centre of symmetry, connected by eight relatively short C-H...O interactions.