Crystal and molecular structures of 2′-nitro-4-aminobiphenyl and 2-amino-7-nitrofluorene

Abstract

2′-nitro-4-aminobiphenyl (5), C₁₂H₁₀N₂O₂, crystallizes in the monoclinic space groupP2₁/c:a = 6.043(2),b =15.795(3),c = 11.577(2) Å, β = 103.42(8) °;D _c = 1.324 g cm⁻³ forZ = 4. 2-amino-7-nitrofluorene (3), C₁₃H₁₀N₂O₂, crystallizes in the monoclinic space groupP2₁ n:a = 10.765(2),b = 7.454(4),c = 12.959(2) Å, β = 95.44(1) °;D _c = 1.451 g cm⁻³ forZ = 4. Three-dimensional CuKα intensity data were measured with a computer-controlled diffractometer, and the initial phases were obtained by direct methods. The two structures were refined by the full-matrix least-squares method, which gave finalR values for 5 and 3 of 0.045 and 0.043, respectively. Bond lengths in the compounds are normal, apart from slight shortening of the phenyl-phenyl C-C bond and some distortion of the phenyl rings caused by the amino and nitro groups. In 5, the two phenyl rings are twisted by 57.1 °, and the nitro group is twisted by 34.6 ° from the plane of its phenyl group. The carbon backbone of 3 is nearly planar with the two phenyl groups tilted by 4.0 ° to each other. The nitro group in 3 is twisted 5.7 ° from the plane of its phenyl group. There is amino hydrogen to nitro oxygen intermolecular hydrogen bonding in each structure.