On the flexibility of the gold–thiolate interface: racemization of the Au40(SR)24 cluster

Abstract

The two enantiomers of the Au₄₀(2-PET)₂₄ cluster were collected using HPLC and analyzed by MALDI-TOF mass spectrometry, UV-vis- and CD-spectroscopy. The flexibility of the cluster surface allows racemization of the intrinsically chiral cluster at elevated temperatures (80–130 °C) which was monitored following the optical activity. The determined activation energy (25 kcal mol⁻¹) lies in the range of previously reported values for Au₃₈ nanoclusters whereas the activation entropy deviates significantly from the one in Au₃₈. The latter may indicate that the racemization can take place via different mechanisms.