Jahn–Teller effects in Au25(SR)18

Abstract

The relationship between oxidation state, structure, and magnetism in many molecules is well described by first-order Jahn–Teller distortions. This relationship is not yet well defined for ligated nanoclusters and nanoparticles, especially the nano-technologically relevant gold-thiolate protected metal clusters. Here we interrogate the relationships between structure, magnetism, and oxidation state for the three stable oxidation states, 1, 0 and +1 of the thiolate protected nanocluster Au25(SR)18. We present the single crystal X-ray structures of the previously undetermined charge state Au25(SR)18+1, as well as a higher quality single crystal structure of the neutral compound Au25(SR)180 . Structural data combined with SQUID magnetometry and DFT theory enable a complete description of the optical and magnetic properties of Au25(SR)18 in the three oxidation states. In aggregate the data suggests a first-order Jahn– Teller distortion in this compound. The high quality single crystal X-ray structure enables an analysis of the ligand–ligand and ligand–cluster packing interactions that underlie single-crystal formation in thiolate protected metal clusters.