title: 2-{[(3-Fluorophenyl)amino]methylidene}-3-oxobutanenitrile and 5-{[(3-fluorophenyl)amino]methylidene}-2,2-dimethyl-1,3-dioxane-4,6-dione: X-ray and DFT studies.
abstract: In the crystal structures of the title compounds, C(11)H(9)FN(2)O, (I), and C(13)H(12)FNO(4), (II), the molecules are joined pairwise via different hydrogen bonds and the constituent pairs are crosslinked by weak C-H...O hydrogen bonds. The basic structural motif in (I), which is partially disordered, comprises pairs of molecules arranged in an antiparallel fashion which enables C-H...N[triple bond]C interactions. The pairs of molecules are crosslinked by two weak C-H...O hydrogen bonds. The constituent pair in (II) is formed by intramolecular bifurcated C-H...O/O' and combined inter- and intramolecular N-H...O hydrogen bonds. In both structures, F atoms form weak C-F...H-C interactions with the H atoms of the two neighbouring methyl groups, the H...F separations being 2.59/2.80 and 2.63/2.71 A in (I) and (II), respectively. The bond orders in the molecules, estimated using the natural bond orbitals (NBO) formalism, correlate with the changes in bond lengths. Deviations from the ideal molecular geometry are explained by the concept of non-equivalent hybrid orbitals. The existence of possible conformers of (I) and (II) is analysed by molecular calculations at the B3LYP/6-31+G** level of theory.
authors.affiliation: Environmental Inorganic Chemistry, Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden. langer@chalmers.se
authors.forename: Vratislav
authors.initials: V
authors.lastname: Langer
authors.forename: Pavol
authors.initials: P
authors.lastname: Mach
authors.forename: Lubomír
authors.initials: L
authors.lastname: Smrcok
authors.forename: Viktor
authors.initials: V
authors.lastname: Milata
authors.forename: Kristína
authors.initials: K
authors.lastname: Plevová
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004146:Dioxanes / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular
chemical_list: C552264:2-(((3-fluorophenyl)amino)methylidene)-3-oxobutanenitrile; C552265:5-(((3-fluorophenyl)amino)methylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione; D000814:Aniline Compounds; D004146:Dioxanes; D005030:Ethylenes