Professor Martin A. Bennett

Organotransition Metal Chemistry

Research School of Chemistry

I am interested in the synthesis and reactivity of unusual organometallic molecules, including the complexes of short-lived organic molecules such as small ring acetylenes. My Group made for the first time very reactive complexes of zerovalent nickel with benzyne (C₆H₄) and naphthalyne (C₁₀H₆), such as Ni([eta]²-C₁₀H₆)(PEt₃)₂ (I), and studied their behaviour with molecules such as CO, alkynes and alkenes. In collaboration with a Group at the University of Pisa, we are studying the chemistry of a labile hexahapto-naphthalene complex of zerovalent ruthenium and have isolated for the first time species such as II in which only four [pi]-electrons of the naphthalene are involved in binding to the metal; these are believed to be involved as intermediates in the catalytic behaviour of the original compound.

I am also interested in the redox behaviour of organo-metallic compounds, especially those containing oxygen-donor ligands. In this context, we have made novel alkene, alkyne and acyl complexes (stabilised by chelation) of paramagnetic trivalent ruthenium bearing two O-donor acetylacetonate groups as the supporting ligands.

In the long term, it may be possible to develop homogeneously catalysed processes, based on organo-metallic intermediates, either in water or involving water as one of the reactive partners. We now have examples of the intramolecular transfer of hydroxide ion to coordinated alkenes and alkynes in tertiary phosphine-stabilised platinum(II) complexes.

Selected Publications

Bennett, M.A., Jin, H., Li, S., Rendina, L.M., and Willis, A.C.
cis-Hydroxyplatination of Dimethyl Maleate: Modeling the Intermediates in a Catalytic Alkene-Hydration Cycle with Organoplatinum(II)-Hydroxo complexes.
J. Am. Chem. Soc. 1995, 117, 8335-8340
erratum: J. Am. Chem. Soc. 1996, 118, 6528

Bennett, M. A., Goh, L. Y., and Willis, A. C.
Base-induced Fragmentation of a Macrocyclic Thioether at an (Arene)ruthenium Center. Generation of η¹-(S)-Ethenethiolate and η²-(C,S)-Thioacetaldehyde.
J. Am. Chem. Soc. 1996, 118, 4984-4992

Bennett, M. A., Heath, G. A., Hockless, D. C. R., Kovacik, I., and Willis, A. C.
Alkene Complexes of Divalent and Trivalent Ruthenium Stabilized by Chelation. Dependence of Coordinated Alkene Orientation on Metal Oxidation State.
J. Am. Chem. Soc. 1998, 120, 932-941

Bennett, M. A., Lu, Z. Wang, X., Bown, M., and Hockless, D. C. R.
Ligand-induced Ring Slippage of η⁶- to η⁴-Naphthalene. Preparation and Structural Characterization of Ru(η⁴-C₁₀H₈)(η⁴-1,5-C₈H₁₂)(L) [L = PMe₃, PEt₃, P(OMe)₃)] and of Derived Binuclear Complexes Containing Bridging Naphthalene, Ru₂(μ-η⁶:η⁴-C₁₀H₈)(η⁴-1,5-C₈H₁₂)₂(L) [L = PEt₃, P(OMe)₃].
J. Am. Chem. Soc. 1998, 120, 10409-10415

Retbøll, M., Edwards, A. J., Rae, A. D., Willis, A. C., Bennett, M. A., and Wenger, E.
Preparation of Benzyne Complexes of Group 10 Metals by Intramolecular Suzuki Coupling of ortho-Metalated Phenylboronic Esters: Molecular Structure of the First Benzyne-Palladium(0) Complex.
J. Am. Chem. Soc. 2002, 124, 8348-8360

Martin Bennett, a graduate of the Imperial College of Science, London, is a Fellow of the Australian Academy of Science and of the Royal Australian Chemical Institute. He has received the H.G. Smith Medal of the RACI, the Royal Society of Chemistry Award for Chemistry and Electrochemistry of the Transition Metals, the Royal Society of Chemistry's Nyholm Medal and the G.J. Burrows Award of the RACI Inorganic Division. He has been an invited lecturer at the Institute for Molecular Science, Okazaki, at Texas A & M University and at the University of Victoria, BC, Canada.