Long distance structural consequences of H-bonding: the case of complexes of para-substituted phenol derivatives


  • Dedicated to Dr Wiesław Szelejewski (Pharmaceutical Research Institute, Warsaw, Poland) on the occasion of his 65th birthday.


H-bonded complexes of p-X-PhOH/p-X-PhO with fluoride and hydrofluoric acid (X = OH, H, NO2) were subject of optimization (by means of B3LYP/6-311+G**) for gradually changed O···F distance from dO···F = 4.0 Å down to (i) the distance of the proton transfer from the hydroxyl group to fluoride leading to O···HF interaction and (ii) fully optimized system (O···HF type). In this way, we simulate gradual changes of H-bond strength estimating simultaneously the energy of interaction, Eint, energy of deformation, Edef, and the binding energy, Etot. The obtained geometrical parameters allow us to show that H-bond formation causes substantial changes in geometry, even at so distant parts of the system as the ring and bond length in para-substituents (OH and NO2). All these changes are monotonically dependent on interaction and deformation energies. Copyright © 2009 John Wiley & Sons, Ltd.