9,9-Dibutyl-9H-fluorene-2-carbonitrile

The fluorene fragment of the title compound, C22H25N, is essentially planar, with an r.m.s deviation of the five-membered ring of 0.005 (2) Å. The dihedral angle between this ring and the outer benzene rings are 1.5 (2) and 0.7 (2)° while that between the benzene rings is 2.1 (2)°. The cyano group makes an angle of 0.3 (2)° with the attached benzene ring.

The fluorene fragment of the title compound, C 22 H 25 N, is essentially planar, with an r.m.s deviation of the fivemembered ring of 0.005 (2) Å . The dihedral angle between this ring and the outer benzene rings are 1.5 (2) and 0.7 (2) while that between the benzene rings is 2.1 (2) . The cyano group makes an angle of 0.3 (2) with the attached benzene ring.

Comment
The title compound, 2-cyano-9,9-dibutylfluorene, is an important compound which can be used in many fields such as a substrate in the synthesis of organic light-emitting materials (Jiang et al., 2012). We report here the crystal structure of the title compound, (I).
The molecular structure of (I) is shown in Fig. 1. Bond lengths are within normal ranges (Allen et al., 1987).

Experimental
The title compound,(I) was prepared according to the literature method (Omer et al., 2010). Yellow block-shaped crystals were obtained by dissolving (I) (0.5 g, 1.04 mmol) in a mixed solution (10 ml petroleum ether and 1 ml EtOAc) and evaporating the solvent slowly at room temperature for about 5 d.

Refinement
All hydrogen atoms were positioned geometrically, with C-H = 0.93 Å for aromatic H, and constrained to ride on their parent atoms, with U iso (H) = xU eq (C), where x = 1.2 for aromatic H, and x = 1.5 for other H.  The molecular structure of (I) with displacement ellipsoids drawn at the 30% probability level.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq N −0.2377 (4)