Self-assembly of pyrrole-2-carboxylates: Substituent effect on the synthon conversion

The substituent effect on the solid state self-assemblies of three pyrrole-2-carboxylate compounds, 2–4, with N–H⋯O hydrogen bonds have been studied by X-ray crystallography. Although just one group different in structure, the self-assemblies of 2–4 varied greatly. The phenyl substituted compound 2 assembled into corrugated tape structure through a R22(10) type dimer synthon and the benzyl substituted compound 3 assembled into 2-D layer structure through a C(5) type catemer synthon, whereas the butyl substituted compound 4 assembled into 2-D layer through both type synthons.