The face that gazes back at you from the mirror each morning is so familiar to you that it's easy to forget it's not really the one that your family and friends know, or that photographs capture.

It's of no great significance that the mirror reverses the left and right sides of your face. But mirror reversals do not always have trivial consequences, says Deakin University chemist Professor Dainis Dakternieks.

Professor Dakternieks, head of the Molecular Science Group in Deakin University's School of Biological and Chemical Sciences, says that in the multi-billion dollar international pharmaceutical industry the difference between left and right can literally mean the difference between life and death.

The chemical reactions used to produce many synthetic molecules, including drugs, yield a racemic mix - a mixture of right- and left-handed forms of the same molecule, called isomers or enantiomers

Professor Dakternieks and his colleagues are developing new catalysts, based on the humble element tin, that will selectively produce the "right" isomers, free of contamination by their potentially sinister alter-egos.

His research could lead to safer, cheaper drugs - the powerful US Food and Drug Administration (FDA) recently set guidelines which mean that pharmaceutical companies will not be able to sell drugs contaminated by unwanted isomers.

The FDA guidelines were prompted by several episodes involving drugs containing racemic mixes. While identical in composition, two isomers of the same molecule can have dramatically different effects in the body.

History's most tragic example was thalidomide, a drug that in its pure, right-handed form, is an effective, safe tranquiliser.

Professor Dakternieks says another well known drug with Jekyll-and-Hyde identities is the synthetic form of dopamine used to treat the tremors of Parkinson's disease. One isomer, L-dopa, acts on nerve cells to quell the patient's involuntary shaking; the other is actually toxic to nerve cells.

"Nature was very clever in designing enantiomeric compounds," says Professor Dakternieks. "Instead of wasting energy making or breaking a chemical bond, she just flips the three-dimensional arrangement of the same molecule, and leaves natural selection to choose the form that works.

But nature's frugality is the bane of pharmaceutical companies around the world. It is extremely expensive to purify drugs after inefficient synthesis reactions - it would be better not to make the unwanted isomers at all.

"Size and shape selectivity is the biggest prize in chemistry," Professor Dakternieks said. "It would be fantastic to be able to control which particular isomer emerges from a reaction."

The global market for patented, selective catalysts is huge, at around $40 billion a year. Virtually all classes of mass-produced pharmaceuticals have compounds with "switch" forms - cardiovascular, central nervous system, anti-inflammatory, anti-cancer and antibiotic drugs, hormones, antihistamines, and analgesics, and cold and 'flu remedies.

The ideal catalyst is one that can recognise a precursor compound and change it unerringly into the right isomer. One series of compounds Professor Dakternieks is working with, triorganoyl tin hydride (TTH), shows considerable promise.

TTH catalyses a range of reactions involving highly reactive molecules called free radicals - free-radical reactions are very common in the synthesis of drugs, as well as in plastics manufacture.

"Selectivity is the key to our approach - we're trying to 'tune' the basic TTH catalyst to develop a suite of highly selective reagents.

"The speed of the reaction is crucial, and TTH catalyses a very fast type reaction that reduces the time and energy required for synthesis reaction. We can perform reactions at moderate temperatures, and very quickly.

Tin is toxic to living cells, and Professor Dakternieks says special care is being taken to develop catalysts which will not leave tin as a contaminant in the final product - the very nature of a good catalyst is that it mediates a reaction between other compounds, but is not itself consumed by the reaction.

"We would make a tin-based reagent, fix it to a polymer support, and pour through the starter materials for the reaction. The last step involves a free radical reduction reaction that yields the pure product.

"Ideally, we would then be able to regenerate the tin reagent, still immobilised by the polymer support so that it cannot become toxic, and use it to synthesise further batches of the same compound.

Professor Dakternieks is working on another synthesis project, also based on tin compounds, in which size is just as important as speed.

He is synthesising compounds consisting of tiny clusters of tin oxide compounds that can be linked together, like Lego bricks, into progressively larger complexes, or nanoparticles,

Professor Dakternieks says that tin oxide is an opaque material in bulk, but in very thin layers, its optical properties change dramatically and it becomes transparent.

In a related project, the Deakin University team is developing tin oxide compounds as the basis of synthetic solid catalysts, similar to the zeolites widely used by the refining industry to convert crude oil into liquid fuels.

Zeolites occur widely in nature - they consist of highly ordered crystalline lattices that form parallel molecular channels that admit molecules of a particular size and shape and transform them into new compounds via catalytic reactions.

Zeolites work well for the low molecular weight hydrocarbons in light sweet crude oil, but as global oil reserves dwindle, refineries are being forced to refine heavier fractions in crude oil in which the molecules are too large to fit into the zeolite's channels.

Using similar 'Lego' techniqes, Professor Dakternieks and his team are planning to develop a range of synthetic solid catalysts with much larger channel sizes than zeolites.

In this case, they will use tin oxide compounds as tiny pillars to prop open channels in a special class of clays, called smectites.

The Deakin University researchers are collaborating with organic chemists at the University of Dortmund, in Germany, and Okayama University of Science, Japan.

"They're taking our materials and testing their ability to carry out selective, homogenous catalysis reactions," Professor Dakternieks said.

"In this way, we hope to internationalise our research - we'd like the research community and industries overseas to know about the innovative research we are doing here in Australia."