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Alkanes and xenon as ligands: NMR studies of photolytically generated, short-lived complexes. Graham E. Ball School of Chemistry, University of New South Wales, Sydney 2052, AUSTRALIA We have been studying the binding of unusual ligands, namely alkanes and xenon, to transition metal centres using NMR spectroscopy.1-5 Complexes containing intact alkane and xenon ligands have long been seen as key reactive intermediates in organometallic chemistry. Owing to the poor nature of these ligands, such complexes are highly unstable and usually have only fleeting existences even at low temperatures. Hence, the observation of alkane and xenon complexes has been mostly restricted to using “fast” spectroscopies such as UV and IR. This talk will describe our studies on complexes of the type Cp’Re(CO)(L)(alkane) (1) and Cp’Re(CO)(PF3)(Xe) (2) (Cp’ = Cp, iPrCp; L = CO, PF3), the first organometallic alkane and xenon complexes observed using NMR. These complexes are formed photolytically inside the spectrometer at low temperatures to stabilize them sufficiently to allow their characterization. Bonding in these molecules, stability, ligand exchange processes, binding preferences amongst different alkane sites, oxidative cleavage of bound alkanes and NMR techniques employed will be discussed. 1. Lawes, D.J.; Geftakis, S.; Ball, G.E. J. Am. Chem. Soc. 2005, 127, 4134. 2. Geftakis, S.; Ball, G. E. J. Am. Chem. Soc. 1998, 120, 9953. 3. Lawes, D.J.; Darwish, T.A.; Clark, T.; Harper, J.B.; Ball, G.E. Angew. Chem. Int. Ed. Engl. 2006, 45, 4486. 4. Ball, G.E.; Brookes, C.M.; Cowan, A.J.; Darwish, T.A; George, M.W.; Kawanami, H.K.; Portius, P.; Rourke, J.P. Proc. Natl. Acad. Sci. USA., 2007, 104, 6927. 5. Ball, G.E.; Darwish, T.A; Geftakis, S.; George, M.W.; Lawes, D.J.; Portius, P.; Rourke, J.P. Proc. Natl. Acad. Sci. USA. 2005, 102, 1853.