A monoclinic modification of propane-1,3-diyl bis­(pyridine-3-carboxyl­ate)

In the title compound, C(15)H(14)N(2)O(4), (I), the mol­ecule lies on a twofold rotation axis which passes through the central C atom of the aliphatic chain, giving one half-mol­ecule per asymmetric unit. The structure is a monoclinic polymorph of the triclinic structure previously reported [Brito, Vallejos, Bolte & López-Rodríguez (2010). Acta Cryst. E66, o792], (II). The most obvious difference between them is the O/C/C/C—O/C/C/C torsion angle [58.2 (7)° in (I) and 173.4 (3)/70.2 (3)° in (II) for GG and TG conformations, respectively]. Another important difference is observed in the dihedral angle between the planes of the aromatic rings [86.49 (7)° for (I) and 76.4 (3)° for (II)]. The crystal structure features a weak π–π inter­action [centroid–centroid distance = 4.1397 (10)Å]; this latter kind of inter­action is not evident in the triclinic polymorph.