An investigation of the influence of temperature on the adsorption of the chiral modifier, (S)-glutamic acid, on Ni{1Â 1Â 1}

α-Amino acids have been used successfully as chiral modifiers in the Ni catalysed heterogeneous enantioselective hydrogenation of β-keto esters. (S)-glutamic acid ((S)-GA) modified Ni catalysts are unique in exhibiting a switch in the preferred enantiomeric product dependent on the modification temperature. We investigate the adsorption of (S)-GA on Ni{1 1 1} using Reflection Absorption Infrared Spectroscopy (RAIRS) and Scanning Tunnelling Microscopy (STM) as functions of modifier coverage and adsorption temperature. We show that there are several potentially important differences between modification at 300 K and 350 K and discuss the relevance of our findings to enantioselective catalysis.