Shedding light on chiral substrates

Shedding light on chiral substrates. Most biological molecules naturally occur as either left-handed (S) or right-handed (R) nonidentical mirror images known as chiral enantiomers. Many drugs come in chiral pairs; therefore, pharmaceutical companies are keen to produce chirally pure medicines that bind to their intended target without subjecting the body to the other, unwanted, and in some cases harmful, enantiomer. One novel technique for separating drug mixtures is to pass them over a chiral substrate, typically a metal oxide, that selectively adsorbs specific enantiomers. But in order for researchers to understand the adsorption dynamics, they must first elucidate the substrate’s chiral orientation. Low-energy electron diffraction techniques can be used, but they cannot easily distinguish orientation if the unit cell of the surface is itself achiral. Now, researchers at the Australian Synchrotron, La Trobe University, and the University of Newcastle have shown that chiral orientation can be identified by photoemission techniques....