Assistant Professor

Telephone
+44 (0)131 451 4299
Email
s.mansell@hw.ac.uk
Address
Room 2.07
William Perkin Building
Heriot-Watt University
Stephen Mansell
Roles and responsibilities
  • EPS Induction Working Group
  • ICS Representative, EPS Early Career Network
  • Seminar coordinator
Research

Catalysis

My research focuses on the synthesis and development of new homogeneous catalysts. I use skills in synthetic main group chemistry to construct new ligands that include cooperative reaction sites to increase the potential for exciting new reactivity. Synthetic organometallic chemistry is exploited to form new transition metal and f-element catalysts for testing in challenging reactions such as dehydrocoupling and the catalytic functionalisation of dinitrogen.

1. Unconventional main group ligands

In order to access unusual reactivity, new classes of ligand are required so I target the synthesis of unconventional ligands for designing better catalysts. Examples include the synthesis and exploration of the chemistry of N-heterocyclic stannylenes, the tin analogues of extensively used N-heterocyclic carbenes (NHCs), which show bridging modes almost unknown for NHCs. Low-coordinate phosphorus compounds also show very different ligand behaviour compared to conventional phosphine ligands.

 

Figure 1. N-heterocyclic stannylene ligands bridging two iron tetracarbonyl moieties (left) and trimethylsilylphosphaalkyne (containg a phosphorus-carbon triple bond) bound side-on to a platinum centre (right).

2. Dinitrogen and hydrocarbon activation

I am interested in functionalising conventionally inert small molecules, such as dinitrogen and hydrocarbons. These compounds are often very cheap and abundant but difficult to convert selectively into useful and valuable products. Working with Prof. Polly Arnold (The University of Edinburgh), I have explored these reactions using highly reactive uranium compounds to bind dinitrogen and activate aromatic hydrocarbons allowing their selective C-H activation by borylation.

  

 Figure 2. The product from the direduction of benzene followed by C-H activation and borylation by 9-borabicyclononane mediated by uranium.

 

Selected publications
  1. "Uranium(IV) amido-borohydrides as highly active diene polymerisation catalysts". S. M. Mansell, F. Bonnet, M. Visseaux and P. L. Arnold, Dalton Trans., 2013, 42, 9033.
  2. "Spontaneous reduction and C–H borylation of arenes mediated by uranium(III) disproportionation". P. L. Arnold, S. M. Mansell, L. Maron and D. McKay, Nature Chem., 2012, 4, 668.
  3. "Coordination chemistry of trimethylsilylphosphaalkyne: a phosphaalkyne bearing a reactive substituent". S. M. Mansell, M. Green and C. A. Russell, Dalton Trans., 2012, 41, 14360
  4. "Small Molecule Activation by Uranium Tris(aryloxides): Experimental and Computational Studies of Binding of N2, Coupling of CO, and Deoxygenation Insertion of CO2 under Ambient Conditions". S. M. Mansell, Nikolas Kaltsoyannis and Polly L. Arnold, J. Am. Chem. Soc., 2011, 133, 9036.
  5. "Coordination Chemistry of N-Heterocyclic Stannylenes: A Combined Synthetic and Mössbauer Spectroscopy Study". S. M. Mansell, R. H. Herber, I. Nowik, D. H. Ross, C. A. Russell and D. F. Wass, Inorg. Chem., 2011, 50, 2252

 

Further information

http://www.mansellresearch.org.uk

3-D Laboratory tour of the Mansell Lab