2-Phenylethanethiolate (PET) and 4-tert-butylbenzenethiolate (TBBT) are the most frequently used ligands in the study of thiolate (SR)-protected metal clusters. However, the effect of difference in the functional group between these ligands on the fundamental properties of the clusters has not been clarified. We synthesized [Au24Pt(TBBT)18]0, which has the same number of metal atoms, number of ligands, and framework structure as [Au24Pt(PET)18]0, by replacing ligands of [Au24Pt(PET)18]0 with TBBT. It was found that this ligand exchange is reversible unlike the case of other metal-core clusters. A comparison of the geometrical/electronic structure and stability of the clusters between [Au24Pt(PET)18]0 and [Au24Pt(TBBT)18]0 revealed three things with regard to the effect of ligand change from PET to TBBT on [Au24Pt(SR)18]0: (1) the induction of metal-core contraction and Au-S bond elongation, (2) no substantial effect on the HOMO-LUMO gap but a clear difference in optical absorption in the visible region, and (3) the decrease of stabilities against degradation in solution and under laser irradiation. By using these two clusters as model clusters, it is expected that the effects of the structural difference of ligand functional-groups on the physical properties and functions of clusters, such as catalytic ability and photoluminescence, would be clarified.
Bibliographical noteFunding Information:
We thank Prof. Shohei Tashiro (The University of Tokyo), Mr Kosuke Wakamatsu, and Ms Sayaka Hashimoto (Tokyo University of Science) for technical assistance. This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant numbers JP16H04099 and 16K21402), Scientific Research on Innovative Areas “Coordination Asymmetry” (grant number 17H05385), and Scientific Research on Innovative Areas “Innovations for Light-Energy Conversion” (grant number 18H05178). Funding from the Takahashi Industrial and Economic Research Foundation, Futaba Electronics Memorial Foundation, Iwatani Naoji Foundation, and Asahi Glass Foundation is also gratefully acknowledged. D. L. acknowledges support by the Korea CCS R&D Center (KCRC) grant (NRF-2014M1A8A1074219) and NRF grants NRF-2017R1A2B3006651 and NRF-2018M3D1A1089380.
© 2019 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Materials Science(all)