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
Journal article, 2010

In the crystal structures of the title compounds, C11H9FN2O, (I), and C13H12FNO4, (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≡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 Å 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.


quantum chemistry calculations

resonance structure

weak hydrogen interactions


Vratislav Langer

Chalmers, Chemical and Biological Engineering, Environmental Inorganic Chemistry

Pavel Mach

Slovak Academy of Sciences

Lubomir Smrcok

Slovak Academy of Sciences

Viktor Milata

Slovak University of Technology Bratislava

Kristína Plevová

Slovak University of Technology Bratislava

Acta Crystallographica Section C: Crystal Structure Communications

0108-2701 (ISSN) 1600-5759 (eISSN)

Vol. C66 8 o392-o395

Subject Categories

Inorganic Chemistry

Theoretical Chemistry

Organic Chemistry



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9/6/2018 1