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
Artikel i vetenskaplig tidskrift, 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.

weak hydrogen interactions

quantum chemistry calculations


resonance structure


Vratislav Langer

Chalmers, Kemi- och bioteknik, Oorganisk miljökemi

Pavel Mach

Slovak Academy of Sciences

Lubomir Smrcok

Slovak Academy of Sciences

Viktor Milata

Slovak University of Technology in Bratislava

Kristína Plevová

Slovak University of Technology in Bratislava

Acta Crystallographica Section C: Crystal Structure Communications

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

Vol. C66 o392-o395


Oorganisk kemi

Teoretisk kemi

Organisk kemi