Senior Lecturer in Inorganic Chemistry.

B.Sc., (Sussex) Ph.D. (Cambridge).

Tel: 0116 252 2096

email: gas8@le.ac.uk 

Research Interests

The themes within our research programme fall into three general areas namely:

• Homogeneous Catalysis

• Organobimetallic Transformations

• New Inorganic Molecular-Based Material 

Homogeneous Catalysis

The direct synthesis of functionalised polyolefins presents an attractive challenge to the synthetic chemist, as such polymers may allow facile degradation and thereby limit environmental pollution. The advent of highly active (and atom efficient) late transition metal catalysts (e.g., Figure 1) for the polymerisation of olefins and the potential tolerance for polar momomers, offers an exciting means of preparing functionalised polyolefins. Furthermore, such catalysts may operate in aqueous media which has further environmental benefits.

 We are developing a broad based programme to develop well-defined catalysts for the synthesis of not only polyolefins but also polyesters and polyethers by employing late transition metal(s) and p-block metals supported by readily modifiable multidentate ligand sets. To support our programme we make use of various molecular modelling packages for catalyst design and a range of screening facilities, including a parallel screening reactor for rapid catalyst evaluation and a single-cell high pressure system for more in-depth studies.

Organobimetallic Transformations

The presence of two distinct metal centres fixed in close proximity offers considerable opportunities for the study of the relative reactivities of the two different metal sites, while cooperative interactions between the two different metal centres may lead to complexes exhibiting unique reactivity properties.

 We are looking at the reactivity patterns exhibited by M2 or MM' bimetallic species supported on the same ligand framework, whereby the metal centres are enforced into either remote (1) or closely located positions (2) (Figure 2), with a view to exploring their catalytic applications (e.g ., small molecule or polymerisation). The metal centres can be varied from early to late transition metals, first row through to third row metals, while the pre-designed binucleating ligand can be tuned to accommodate the specific requirements of each metal centre. Sometimes the ligand frame itself can participate in a transformation leading to new carbon-carbon and carbon-heteroatom bond forming reactions.  On the other hand the ligand can participate in a more subtle manner in which its electronic and/or steric attributes play a key role in the reactivity at each metal centre.

 New Inorganic Molecular-Based Materials

Strategies for the development of well-defined molecular-based magnets represents an on-going research area.  More recently we have teamed up with the Space Research Centre (SRC) in Leicester with the intent of developing inorganic materials for applications in X-ray polarimetry (e.g. Fig. 3). Such transition metal-based systems present a simple filter technology that could add polarimetry capability to future large effective area X-ray astronomical observatories.

Through a combination of theoretical studies and inorganic synthesis, single crystals are being evaluated for their dichroic response using various synchrotron facilities.

Methodology and Techniques

All of this work provides excellent opportunities for developing skills in inorganic and organic synthetic techniques, including the use of Schlenk-line and glove-box techniques. The characterisation of the new compounds, their reactivity and physical studies will be carried out using a combination of state of the art equipment.

Recent Publications

1. Factors affecting imine coordination in [imino-terpyridine]MX2; Synthesis, structures, DFT calculations and ethylene oligomerisation studies, Y.D.M. Champouret, J.-D. Maréchal, R.K. Chaggar, J. Fawcett, K. Singh, F. Maseras and G.A. Solan, New. J. Chem., 2007, 31, 75 - 85.
2. Probing the effect of binding site and metal centre variation in pentadentate oligopyridylimine-bearing bimetallic (Fe₂, Co₂, Ni₂) ethylene oligomerisation catalysts, Y.D.M. Champouret, K. Singh and G. A. Solan, Eur. J. Inorg. Chem., 2008, 4597-4607.
3. Iron and Cobalt-Based Olefin Polymerisation Catalysts, V.C. Gibson and G.A. Solan, in Topics in Organometallic Chemistry, Springer Berlin/Heidelberg, Z. Guan (Ed.) Volume 26, 2009, Chapter 4, p. 107-158.
4. Bis(imino)quaterpyridine-bearing multimetallic late transition metal complexes as ethylene oligomerisation catalysts, Q. Khamker, Y.D.M. Champouret, K. Singh and G.A. Solan, Dalton Trans., 2009, 8935 – 8944.
5. Simple transmissive filters to measure astrophysical X-ray polarisation, A. Martindale, N.P. Bannister, D. Cotton, G.W. Fraser, K.D.M. Harris, B. Kariuki, B. Palmer, S.P. Collins, G.A. Solan, A. Armitage, and M. Roy, SPIE Newsroom, 2009, DOI: 10.1117/2.1200904.1585.