Creating chiral architectures at metal surfaces

The adsorption of complex organic molecules at a metal surface provides a means of introducing the ultimate selectivity function of chirality to a metal surface. Here, the adsorption of R , R -tartaric acid ( R standing for rectus), which possesses two chiral centres, on a Cu(110) surface is reviewed. Using a combination of vibrational, surface diffraction, and scanning probe microscopy techniques, a detailed molecular picture of the organic/metal interface has been constructed. This reveals that a number of different phases can be created which vary in terms of the local chemistry and bonding of the organic unit and in terms of the long-range-ordered architectures that are created. Of the various phases created, two possess the special quality of extended chirality, where a truly chiral surface which is non-superimposable on its mirror image, is created. Three constraints are shown to be important for sustaining a single chiral domain across the entire surface: local chirality of the adsorbate, a rigid and defined adsorption geometry, and the presence of anisotropic lateral interactions.