Dispiro[indene-2,5 '-indeno[2,1-a]-fluorene-6 ',2 '-indene]-1,1 '',3,3 '',11 ',12 '-hexaone: a three-dimensional hydrogen-bonded framework

The title compound, C36H16O6, (I), was obtained as a new and unexpected oxidation product of 1,2'-biindene-1',3,3'(2H)-trione. The molecules of (I) exhibit approximate, but noncrystallographic, twofold rotation symmetry and the central ring of the fused pentacyclic portion is distinctly puckered, with a conformation intermediate between half-chair and screw-boat. Six independent C - H center dot center dot center dot O hydrogen bonds link the molecules into a three-dimensional framework structure of considerable complexity. Comparisons are drawn between the crystal structure of (I) and those of several simpler analogues, which show wide variation in their patterns of supramolecular aggregation.