C-H•••F, C-H•••O interactions in the crystal structure of 2-(2-nitrophenyl)-3-pentafluorophenyl-oxirane and 2-pentafluorophenyl-3-phenyl-1-(p-tosyl)-aziridine

Existence and nature of C-H center dot center dot center dot F, C-H center dot center dot center dot O interactions in 2-(2-nitrophenyl)-3-pentafluorophenyl-oxirane (1) and 2-pentafluorophenyl-3-phenyl-1-(p-tosyl)-aziridine (2) are discussed. In compound 1 with a linear molecule, C-H center dot center dot center dot F, C-H center dot center dot center dot O hydrogen bonds assemble adjacent molecules into the two-dimensional layers, F center dot center dot center dot F, O center dot center dot center dot F interactions connect adjacent layers into three-dimensional supramolecular networks. Owing to the inductive effect of nitro group, the C-H acidity of nitrophenyl increases and the numbers of C-H center dot center dot center dot F, C-H center dot center dot center dot O hydrogen bonds also increase, C-H center dot center dot center dot F, C-H center dot center dot center dot O interactions become stronger and more important. 1D ribbons of compound 2 are stabilized by C-H center dot center dot center dot F, C-H center dot center dot center dot O intermolecular interactions. Nonplanar tritopic molecule would demand the formation of a pi center dot center dot center dot pi packing interactions between benzene rings and pentafluorobenzene rings in 2. (C) 2011 Published by Elsevier B.V.