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EPSRC Reference: EP/C004655/1
Title: In situ STM imaging of selective and enantioselective heterogeneous catalysts: from adsorbed intermediates to reaction products.
Principal Investigator: Attard, Professor GA
Other Investigators:
Researcher Co-Investigators:
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Department: Chemistry
Organisation: Cardiff University
Scheme: Standard Research (Pre-FEC)
Starts: 02 November 2005 Ends: 01 May 2009 Value (£): 374,032
EPSRC Research Topic Classifications:
Catalysis & Applied Catalysis
EPSRC Industrial Sector Classifications:
No relevance to Underpinning Sectors
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Panel History:  
Summary on Grant Application Form
Many molecules exist in both a left- and a right- handed form. Each can only be distinguished by objects which themselves are either left- or right-handed. Your feet for example would recognise instantly if you had put your shoes on the wrong way around! Such chiral chemicals are extremely important in nature because in many instances, the recognition between, and behaviour of, biomolecules in living organisms is based on this simple idea of left- or right-handedness. Therefore it is no surprise that many of the pharmaceuticals, medicines, agrochemicals, fragrances, flavours etc from which we derive the benefits of modern life happen to be chiral. Large quantities of these chiral chemicals are manufactured every year worth billions of pounds to the world economy. However the central problem has always been: How to manufacture the left- or right-handed form exclusively? or in the jargon enantioselectively . This can be achieved using enantioselective catalysts . These materials have the property of favouring the formation of one or other of the chiral pairs during manufacture. The way that the catalyst does this is often not well understood. In the present proposal, we will try to discover how the solid surface of an enantioselective catalyst achieves this outcome. In that way, better catalysts could be designed based on knowledge of the fundamental molecular and chemical steps taking place. Previously we have shown that particular features of a metal surface ( kinks ) can also exist in left- or right-handed versions. Hence an enantioselective catalyst could be prepared for example either by blocking all of the right-handed kink sites on the surface (leaving behind exclusively only left-handed sites) or by generating an increase in the surface concentration of left-handed sites. Then, only the chemical reaction favoured by the left-handed kinks will take place and a chiral outcome is achieved. This and several other ideas concerning the way enantioselective catalysts work will be tested by actually visualising the position of molecules on the surface of the enantioselective catalyst under the ambient conditions used in the real catalytic process and monitoring simultaneously changes in the distribution of chemical products being formed. In the past it has only been possible to examine these important surface reactions under model conditions (utilising single crystals in vacuum), conditions far removed from commercial industrial processes. The question of whether or not such model studies yield information relevant to real heterogeneous catalytic reactions remains a vexed and difficult one. By carefully changing a number of parameters thought important to the enantioselective process (metal surface chirality, molecular shape, surface acidity, solvent type ( chiral modifying agents often adopt different molecular configurations of which only one configuration is thought to give rise to enantioselectivity), the availability of particular surface reaction sites (selective blocking of such sites using atoms including bismuth and sulphur can pin-point the active adsorption site crucial for enantioselectivity)), it may be possible to discover the optimal catalyst structure necesary to engender enantioselectivity.
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Organisation Website: http://www.cf.ac.uk