(E)-3,3′,4,4′,7,7′,8,8′-Octamethyl-2H,2′H-1,1′-bi(cyclopenta[fg]acenaphthylenylidene)-2,2′,5,5′,6,6′-hexaone dichloromethane monosolvate

Abstract

The title compound, C36H24O6·CH2Cl2, is a dimer of two essentially planar (r.m.s., deviations of fitted plane of 14 pyracene C atoms = 0.0539 and 0.0543 Å) tetracyclic pyracene frameworks (each with four methyl groups and three carbonyl groups on the peripheral carbon atoms) twisted along a central C=C bond with an angle of 50.78 (3)° at 90 K. There are notably long Csp2—Csp2 bonds associated with the carbonyl groups, the longest being 1.601 (3) Å between two carbonyl C atoms. There are also intermolecular carbonyl...carbonyl interactions of both parallel and antiparallel types, with C...O distances in the range 3.041 (3) to 3.431 (2) Å. This compound is of interest with respect to the synthesis of fullerene fragments, such as corannulene and semibuckminsterfullerene derivatives (or `buckybowls'), and is a side product of the previously reported oxidation reaction. Structural details, such as planarity analysis of fused rings, out-of-plane deviation of substituents, intermolecular interactions, and longer than typical bond lengths, will be discussed as well as comparisons to structurally related compounds.