These include the stereochemistry of organic reactions, organic host-guest chemistry and crystal packing, protein folding and structure, DNA and RNA base stacking, protein-nucleic acid recognition, drug design, and asphaltene (heavy crude oil) aggregation and fouling.
We have used isotopic labelling and neutron diffraction to measure the structure in two archetypal aromatic liquids: benzene and toluene. Our results call for a significant rethink of the way we model π-orbital interactions. We have found that the so-called ‘T-shaped’ arrangement between aromatic groups, which had previously been proposed as a dominant motif in π – π interactions, is in fact absent in our liquids. Instead, we have observed an entirely new geometry, which we have christened ‘Y-shaped’.In this configuration molecules direct hydrogen atoms towards the π-orbitals themselves, rather than towards the centre of the aromatic ring.
TF Headen, CA Howard, NT Skipper, MA Wilkinson (University College London), DT Bowron, AK Soper (ISIS)
Research date: January 2008
Contact: CA Howard, email@example.com
Further reading: TF Headen et al., J Am Chem Soc 132 (2010) 5735