Received 27 September 2008
The title compound, C39H26F6N2O2, showed two melting transitions 477.4 and 506.5 K in a differential scanning calorimetry (DSC) study. The first of these can be attributed to a melting phase transition arising from the rotation of two trifluoromethyl groups. In the crystal structure, both trifluoromethyl groups are disordered over two sites with occupancy factors of 0.660 (17) and 0.340 (17) for the major and minor orientations, respectively. The introduction of trifluoromethyl groups inhibits -stacking between the diazafluorene (cyclopenta[2,1-b:3,4-b']dipyridine) units. Three short FO contacts between 2.80 (3) and 2.95 (1) Å are observed in the crystal structure.
The synthesis and thermal properties of the title compound were reported by Ono et al. (2007). For related literature on molecular and crystal structures, including the 4,5-diazafluorene system, see: Ono & Saito (2008).
Data collection: CrystalClear (Rigaku/MSC, 2001); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003) and Mercury (Macrae et al., 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB2809 ).
This work was supported by a Grant-in-Aid for Scientific Research (grant No. 19550034) from the Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors thank the Instrument Center of the Institute for Molecular Science for the X-ray structure analysis.
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