TRIFLUOROMETHYL GROUP DISORDER IN CRYSTALLINE 2,8-BIS(TRIFLUOROMETHYL)-4-HYDROXYMETHYLQUINOLINE

The title compound crystallized in space group Pna2(1) with lattice co nstants a = 13.406(1), b = 18.799 (4), and c = 4.785(1). The molecule is essentially flat with only fluorine atoms, methylene hydrogen atoms , and the hydroxyl hydrogen atom out of the plane of the quinoline rin g. Only one of the trifluoromethyl groups of the title compound is dis ordered following a pattern observed in other crystal structures. Quan tum chemical calculations at the AM1 level are consistent with this ph enomenon. Although the carbon atom of the fixed trifluoromethyl group is further from the quinoline nitrogen atom than the carbon atom of th e disordered trifluoromethyl group, the fluorine atoms of the fixed tr ifluoromethyl group more closely approach the quinoline nitrogen atom by 0.3 Angstrom if the C(8)-C(10) bond in the crystal structure is fre ely rotated.