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Collaborative work involving Garry McIntyre and Paul Waddell from the Institute, and led by Jacqui Cole's group at the Cavendish Laboratory in Cambridge, is featured this week on the cover of Organometallics.
Organoaluminum complexes are of interest for catalysis and synergic base chemistry. The exact nature of ligand bridging between the two metals requires elucidation since this has an impact on their chemical reactivity.
The cover article provides such clarity via the neutron structure of an organoaluminum polymer which evidences C–H···Li agostic interactions, three-center-two-electron interactions; these are revealed in the bridging methyl groups and serve to stabilize the alkali metal.
The bridging methyl groups run down the center of the structure shown in the cover graphic, with cartoons of the agostic interactions alongside. This study is the first to use neutrons to evidence C–H···Li agostic interactions in a lithium aluminate species.
Neutron diffraction is ideally suited to determine these types of interactions, given the significant neutron scattering cross section of hydrogen. The study is nonetheless challenging owing to the substantial neutron absorption cross section of lithium.
The full reference is "Neutron Diffraction Characterization of C–H···Li Interactions in a Lithium Aluminate Polymer", J. M. Cole, P. G. Waddell, A. E. H. Wheatley, G. J. McIntyre, A. J. Peel, C. W. Tate, and D. J. Linton , Organometallics 11, 3919-4156 (2014).