Biomedical subjects
Publications and source records attributed to Kevin R Lawson.
A supramolecular approach has been used to investigate the free energies of intermolecular aromatic stacking interactions. Chemical double mutant cycles have been used to measure the effect of a range of substituents on face-to-face stacking interactions with phenyl and pentafluorophenyl rings. Electrostatic effects dominate the trends in interaction energy.
Chemical double mutant cycles have been used to quantify the interactions of halogens with the faces of aromatic rings in chloroform. The halogens are forced over the face of an aromatic ring by an array of hydrogen-bonding interactions that lock the complexes in a single, well-defined conformation. These interactions can also be engineered into the crystal structures of simpler model compounds, but experiments in solution show that the halogen-aromatic interactions observed in the solid state are all unfavourable, regardless of whether the aromatic rings contain electron-withdrawing or electron-donating substituents. The halogen-aromatic interactions are repulsive by 1-3 kJ mol(-1). The interactions with fluorine are slightly less favourable than with chlorine and bromine.