title: 5,5-Bis(4-methoxy-phen-yl)-2,8-bis-[3-(trifluoro-meth-yl)phen-yl]-5H-cyclo-penta-[2,1-b:3,4-b']dipyridine.
abstract: The title compound, C(39)H(26)F(6)N(2)O(2), 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 trifluoro-methyl groups. In the crystal structure, both trifluoro-methyl 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 trifluoro-methyl groups inhibits π-stacking between the diaza-fluorene (cyclo-penta-[2,1-b:3,4-b']dipyridine) units. Three short F⋯O contacts between 2.80 (3) and 2.95 (1) Å are observed in the crystal structure.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Ono
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tomura
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Saito