Hydrogen bonding in C-substituted nitroanilines: molecular ladders in 2-trifluoromethyl-4-nitroaniline and sheets of Rand Rrings in 3-trifluoromethyl-4-nitroaniline

In 2-trifluoromethyl-4-nitroaniline, C7H5F3N2O2, (I), the molecules lie across a mirror plane in space group Pnma. The molecules are linked by paired N-H...O hydrogen bonds to form a C(8)[R-2(2)(6)] chain of rings, pairs of which are linked into a molecular ladder by a single C-H...O hydrogen bond. The isomeric 3-trifluoromethyl-4-nitroaniline, (II), has Z' = 2 in space group P2(1)/c. Each molecule is linked to four others by N-H...O hydrogen bonds to form sheets built from alternating R-4(4)(12) and R-4(4)(32) rings.