6,6'-(Pyridine-2,6-di-yl)bis-(pyrrolo-[3,4-b]pyridine-5,7-dione).
The title compound, C(19)H(9)N(5)O(4), has crystallographically imposed twofold rotational symmetry. The asymmetric unit contains one half-mol-ecule. The crystal structure is stabilized by π-π stacking of inversion-related pyrrolo-[3,4-b]pyridine rings, with a centroid-centroid distance between stacked pyridines of 3.6960 (8) Å. The dihedral angle between the central pyridine ring and the pyrrolo-pyridine side rings is 77.86 (2)° while the angle between the two side chains is 60.87 (2)°.
Department of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300,  South Africa.
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Van der Berg
Hendrik G
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Visser
Andreas
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Roodt