Akademik Veri Yönetim Sistemi
JOURNAL OF MOLECULAR STRUCTURE, cilt.526, ss.201-207, 2000 (SCI-Expanded)
Molecules of C12H4F8N2 crystallize in the orthorhombic space group P2(1)2(1)2(1) with cell constants a = 9.200(1), b = 10,896(1), c = 23.178(3) Angstrom and V = 2323.4(5) Angstrom(3). There are two molecules in the asymmetric unit which have D-2 symmetry. However these two molecules have C-2 symmetry in central C-C bonds, separately. Intramolecular steric repulsions between F atoms and N-H ... F hydrogen bonds have very much affected the molecular conformation. The mean dihedral angle between intramolecular phenyl rings is 119.2(1)degrees. The N-C bonds have lengths 1.363(4)-1.407(4) Angstrom with a mean of 1.388 Angstrom. This is shorter than the conventional C-N (1.47(1) Angstrom) bond length due to pi-electron delocalizations (F.H. Alien, O. Kennard, D.G. Watson, L. Brammer, A.G. Orpen, R. Taylor, J. Chem. Sec. Perkin Trans. II(1987) S1-S19).