Structural Investigation of Weak Intermolecular Interactions (Hydrogen and Halogen Bonds) in Fluorine-Substituted Benzimidazoles

The structures of five fluorinated benzimidazoles and one intermediate (an open double amide) have been determined by X-ray crystallography. In the analysis of these heterocycles, particular attention has been paid to N–H···H hydrogen bonds and to fluorine–fluorine intermolecular contacts. Thus, one of the shortest F···F distances ever reported, 2.596(3) Å, has been observed in 4,5,6,7-tetrafluoro-1 H -benzimidazole-2(3 H )-one. The 13 C, 15 N, and 19 F solid-state NMR data for all benzimidazoles are also given.