EXPERIMENTAL CHARGE DENSITIES IN STRONGLY HYDROGEN-BONDED AROMATICS

Ross O. Piltz,^a David E. Hibbs,^b Jacob Overgaard^b and Peter Williams^c

^aBragg Institute, ANSTO, Lucas Heights, NSW 2234, Australia; ^bSchool of Chemistry, University of Sydney, Sydney, NSW 2006, Australia; ^cBiostructural and Biomolecular Research Group, University of Western Sydney, Parramatta, NSW 2150, Australia (rop@ansto.gov.au)

Conventional strong hydrogen bonds such as O – H …O, N – H …O and O – H …N are clearly important in the areas of supramolecular chemistry, crystal engineering and the study of biological activity. Unfortunately the position of such hydrogen atoms cannot be located unambiguously in conventional charge density work using X-ray diffraction techniques. To overcome this limitation combined X-ray/neutron diffraction studies have been performed using the facilities of ANSTO, Lucas Heights and the University of Sydney on a set of hydrogen-bonded aromatics, including (Z)-N-methyl-C-phenylnitrone and 1-(2-hydroxy-5-nitro-phenyl)-ethanone. The results of these, and other more recent studies, will be presented.