2-(2,2,2-Trifluoroethyl)isoindoline-1,3-dione

In the title compound, C10H6F3NO2, the isoindole ring system is planar, the maximum atomic deviation being 0.012 (2) Å. The C—C bond of the trifluoroethyl group is twisted with respect to the isoindole ring by a dihedral angle of 62.58 (17)°. Weak intermolecular C—H⋯O and C—H⋯F hydrogen bonding is present in the crystal structure.

In the title compound, C 10 H 6 F 3 NO 2 , the isoindole ring system is planar, the maximum atomic deviation being 0.012 (2) Å . The C-C bond of the trifluoroethyl group is twisted with respect to the isoindole ring by a dihedral angle of 62.58 (17) . Weak intermolecular C-HÁ Á ÁO and C-HÁ Á ÁF hydrogen bonding is present in the crystal structure.

Comment
The title compound, I, is a key intermediate in the synthesis of organic electro-luminescent materials. The emission of light by organic molecules exposed to an electric field has been widely investigated in both an academic and industrial context. (Han & Kay, 2005).
The molecular structure of the title compound is illustrated in Fig. 1. The isoindole ring system is planar, the maximum atomic deviation being 0.012 (2) Å (for the N1 atom). The C9-C10 bond of the trifluoroethyl group is twisted with respect to the isoindole ring by a dihedral angle of 62.58 (17)°, which is similar to the angle 60.3 (5)° found in the related compound 2-(2-iodoethyl)isoindole-1,3-dione (Valkonen et al. 2007). Weak intermolecular C-H···O and and C-H···F hydrogen bonding is present in the crystal structure, Table 1, Fig. 2.

Refinement
H atoms were positioned geometrically and refined as riding with C-H = 0.95 or 0.99 Å, and U iso (H) = 1.2U eq (C).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.