Two novel bis‐azomethines derived from quinoxaline‐2‐carbaldehyde

The Schiff base compounds N,N′‐bis(E)‐quinoxalin‐2‐ylmethylidene]propane‐1,3‐diamine, C₂₁H₁₈N₆, (I), and N,N′‐bis(E)‐quinoxalin‐2‐ylmethylidene]butane‐1,4‐diamine, C₂₂H₂₀N₆, (II), crystallize in the monoclinic crystal system. These molecules have crystallographically imposed symmetry. Compound (I) is located on a crystallographic twofold axis and (II) is located on an inversion centre. The molecular conformations of these crystal structures are stabilized by aromatic π–π stacking interactions.