Investigating the structure and dynamics of small molecules in solution is key to understanding their behaviour, reactivity and potential applications. In collaboration with other groups in the School we have applied state-of-the-art liquid state NMR methods to probe a variety of fascinating systems. Highlights of some recent results are shown below.

Unusual organometallic complexes

In the laboratory of Dr J. Robin Fulton (currently at Victoria University of Wellington) a number of novel compounds comprising main group metals and the β-diketiminate ligand been prepared recently. We have employed variable temperature ¹H and ¹⁹⁹Hg NMR understand the ligand binding modes and to compare solution structure with solid state X-ray crystallographic data.

• L. Ferro, M. P. Coles, I. J. Day and J. R. Fulton. Taking advantage of Hg-C bonds: synthesis of the first homoleptic bis-β-diketiminate complex bound through the γ-carbons Organometallics, 29(13):2911-2915, 2010

Dialkyl calcium complex

Dr Martyn Coles (now at the Victoria University of Wellington) is interested in small organometallic complexes as polymerisation catalysts. We have recently investigated a novel ether-free dialkyl calcium (II) complex synthesised in the Coles group. This is a rare example of a calcium (II) complex which does not contain a coordinating solvent molecule. A series of detailed variable temperature measurements have demonstrated that the metallocycle is transiently open in toluene.

• M. P. Coles, S. E. Sozerli, J. D. Smith, P. B. Hitchcock, and I. J. Day. An ether-free, internally coordinated dialkylcalcium(II) complex. Organometallics, 28(5):1579-1581, 2009

Small molecule structure elucidation

The meta-photocycloaddition to generate a fenestrane

In collaboration with Dr Clive Penkett we have been involved in determining the solution structure of a variety of novel small molecules. These compounds have been formed in only a small number of synthetic operations using photochemical methods, specifically the meta-photocycloaddition reaction, which yield molecules with high degrees of structural complexity. Modern 2-dimensional NMR techniques have been applied alongside X-ray crystallography to determine the structures of these fenestrane structures.

• C. S. Penkett, J. Woolford, I. J. Day, and M. P. Coles. The double [3+2] photocycloaddition reaction. J. Am. Chem. Soc., 132(1):4-5, 2010

Reactions of organo-uranium compounds with small molecules

Work in the group of Prof. Geoff Cloke FRS is concerned with organometallic uranium complexes and their reactions with small molecules such as CO, CO₂ etc. We undertook some detailed NMR studies of the mechanisms of these reactions, particularly the formation of an ynediolate complex bridging two uranium centres.

• A. S. Frey, F. G. N. Cloke, P. B. Hitchcock, I. J. Day, J. C. Green, and G. Aitken. Mechanistic studies on the reductive cyclooligomerisation of CO by U(III) mixed sandwich complexes; the molecular structure of [(U(η-C₈H₆{SiⁱPr₃-1,4}₂)(η-Cp*)]₂(μ-η¹:η¹-C₂O₂). J. Am. Chem. Soc., 130(42):13816-13817, 2008