PYRAMIDALIZATION IN A HEXACHLORONORBORNADIENE DERIVATIVE

7,8,9,10,11,11-Hexachloro-7,10-dihydro-7,10-methanofluoranthene, (1), C17H6Cl6, M(r) = 422.95, monoclinic, P2(1)/c, a = 14.814 (8), b = 8.623 (2), c = 14.206 (4) angstrom, beta = 111.22 (3)degrees, V = 1691.6 (9) angstrom3, Z = 4, D(x) = 1.660 g cm-3, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 10.16 cm-1, F(000) = 840, T = 295 K, R = 0.0488 for 3186 reflections. The molecule is composed of a naphthalene ring system joined to a hexachloronorbornadiene molecule forming an acenaphthylene moiety. The acenaphthylene system is planar (0.005 angstrom r.m.s. deviation); however, the C(sp2) atoms of the two double bonds in norbornadiene are pyramidalized with substituents bent away from the methano bridge in the endo direction. The C(sp2) atoms associated with the naphthalene ring fusion exhibit pyramidalization angles of 5.1 (3)-degrees while the C(sp2) atoms substituted by Cl have pyramidalization angles of 2.4 (4)-degrees.