Research Article: (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

Date Published: May 01, 2012

Publisher: International Union of Crystallography

Author(s): Gregory T. McCandless, Andrzej Sygula, Peter W. Rabideau, Steven F. Watkins, Frank R. Fronczek.


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.

Partial Text

For the synthesis of fullerene fragments, see the following recent reviews: Tsefrikas & Scott (2006 ▶); Wu & Siegel (2006 ▶); Sygula (2011 ▶). For structurally related compounds, see also: Abdourazak et al. (1994 ▶); Sygula et al. (1997 ▶); Mehta et al. (1999 ▶); Kilway et al. (2004 ▶). For a description of the Cambridge Crystallographic Database, see: Allen (2002 ▶). For tables of van der Waals radii, see: Bondi (1964 ▶). For inter­molecular carbonyl group inter­actions, see: Allen et al. (1998 ▶).