Diethyl 2,2′-bi­pyridine-4,4′-di­carboxyl­ate

The title bi­pyridine derivative, C16H16N2O4, crystallized with two half mol­ecules in the asymmetric unit. The whole mol­ecules (A and B) are generated by inversion symmetry with the mid-points of the bridging C—C bonds of the bi­pyridine units being located on crystallographic inversion centers. In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds, forming sheets parallel to (120). The sheets are linked by C—H⋯N hydrogen bonds, forming a three-dimensional framework.