posted on 2014-08-06, 00:00authored byPere Alemany, Anthony D’Aléo, Michel Giorgi, Enric Canadell, Frédéric Fages
Molecules bearing the borondifluoride
unit represent an important class of dyes. We report the intriguing
occurrence of short H···B contacts in the crystal structure
of compounds featuring the BF2O2 fragment. Using
density functional theory-based calculations, we discovered that,
in contrast to what is suggested by the structural observation, the
driving force behind these short H···B contacts is
not a direct H···B interaction but it relies on the
existence of a combination of single, bifurcated, or trifurcated hydrogen
bond paths that are practically isoenergetic within a broad range
of C–H···B interaction orientations. The BF2O2 group as a whole displays a very isotropic hydrogen
bonding ability and, in turn, a strong adaptability to structural
requirements in the solid state.