2005 IRISH SCIENTIST YEAR BOOK

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National University of Ireland, Galway
Patrick O'Leary
Researching metal catalysts in the Department of Chemistry

In the body seemingly very similar molecules can have dramatically different effects. When a molecule has a mirror image that is different it is said to be 'chiral'. Chiral molecules are related in the same way as a right and left hand are mirror images. Our bodies are made from a huge variety of chiral species. How a chiral molecule in the body will act depends on the chiral species it meets. Examples of such different interactions in the body are numerous, one of the two mirror images (or stereoisomers) of limonene smells of oranges and the other of lemons, one stereoisomer of ibuprofen is an analgesic drug whereas the other is inactive and one stereoisomer of nicotine is more toxic than the other.

Pharmaceutical companies, on identifying a drug, need to check the activity of all the stereoisomers in the body and seek to synthesise only the required active ingredient. The preferential synthesis of one stereoisomer of a molecule can be a difficult task.

We are engaged in research seeking to generate techniques which are generally applicable to the preferential synthesis of one stereoisomer. This is achieved using a catalyst which controls the reaction. Typical catalysts consist of a metal component which becomes the centre where the reaction takes place and a molecule (or ligand) which surrounds the metal and gives control of the chirality of the product.


Our work concentrates on catalysts which contain copper and a bis(oxazoline) ligand, a system which can be used as a catalyst for a wide variety of reactions. As well as studying these reactions we have focused on making the catalysts easier to use and more economical. The bis(oxazoline) ligand is difficult and expensive to prepare. Both it and the copper are still reactive at the end of the reaction but they are normally destroyed in the removal of the product from the reaction. By sticking (or immobilizing) the copper and ligand to a silica particle, a material similar to fine sand, the catalyst can be removed by filtering after the reaction and reused. A new method for this immobilization opened this area of research. The attachment is now achieved by a similar attraction to that which you get when you rub a balloon vigorously and then stick it to the wall. This 'electrostatic immobilisation' is simpler to perform than previous methods and the catalyst still has the same properties.




Contact: Dr Patrick O'Leary,
Department of Chemistry, NUI Galway;
Tel: +353 (0)91 492476; E-mail: [email protected]