2-(2-Pyridyl)pyridinium bis(pyridine-2,6-dicarboxylato-κ3O,N,O′)aluminate(III) trihydrate

Abstract

The title compound, (C10H9N2)[Al(C7H3NO4)2]·3H2O or (2,2′-bipyH)[Al(pydc)2]·3H2O (where 2,2′-bipy is 2,2′-bipyridine and pydcH2 is pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of aluminium(III) nitrate nonahydrate with pyridine-2,6-dicarboxylic acid and 2,2′-bipyridine in a 1:2:4 molar ratio in aqueous solution. This compound is composed of an anionic complex, [Al(pydc)2]−, a protonated 2,2′-bipyridine molecule as a counter-ion, (2,2′-bipyH)+, and three uncoordinated water molecules. The anion is a six-coordinate complex, with the AlIII atom in a distorted octahedral geometry coordinated by two tridentate pyridine-2,6-dicarboxylate groups. In the crystal structure, intermolecular O—H...O, N—H...O, N—H...N and C—H...O hydrogen bonds, π–π stacking between two aromatic rings [centroid–centroid distance = 3.827 (10) Å], and C=O...π stacking [with distances of 3.2311 (13), 3.4924 (14) and 3.5731 (13) Å], connect the various components to form a supramolecular structure.