Park, K.-M.; Oh, H.; Kang, Y.
Acta Crystallographica. Section e Structure Reports Online 70(Part 2): O185
The title compound, C34H34, systematic name 9,9,9',9'-tetra-ethyl-2,2'-bi(9H-fluorene), crystallized with two crystallographically independent mol-ecules (A and B) in the asymmetric unit. These differ mainly in the orientation of the lateral ethyl chains: in mol-ecule A, they are both on the same side of the mol-ecule whereas in mol-ecule B, one di-ethyl-fluorene moiety has undergone a 180° rotation such that the two pairs of ethyl residues appear on opposite sides of the mol-ecule. The fluorene ring systems subtend dihedral angles of 31.37 (4) and 43.18 (3)° in mol-ecules A and B, respectively. Hence the two fluorene moieties are tilted slightly toward one another. This may be due to the presence of inter-molecular C-H⋯π inter-actions between neighboring mol-ecules. The lateral ethyl chains (excluding H atoms) are also almost planar, with each pair almost perpendicular to the plane of the fluorene system to which they are attached with dihedral angles between the ethyl and fluorene planes in the range 86.04 (8)-89.5 (1)°.