| 研究実績の概要 |
We set out to investigate whether chiral bis-benzimidazolylidene ligands based on the highly successful DIOP phosphine ligand would also generate chiral NHC-stabilized nanoclusters. We synthesized a chiral Au13 cluster stabilized by a chiral dioxolane-linked bisNHC. The resulting clusters were characterized by electrospray ionization mass spectrometry (ESI-MS), UV-vis spectroscopy, nuclear magnetic resonance (NMR) spectroscopy. We examined the CD spectra of the two enantiomers. As expected, the spectra are perfect mirror images for the two enantiomers. Unfortunately, we could not confirm the exact structure of clusters by XRD analysis, but we performed DFT calculations to explain the experimental observations and give insight into the structural details and their effects on the optical properties and chirality.
Electrochemical and thermal analyses were conducted to probe the reactivity and stability of this cluster, and its behavior as a catalyst for the electrocatalytic reduction of CO2 to CO was examined. The headspace above the reaction mixture in an H-cell was analyzed by gas chromatography equipped with a thermal conductivity detector (GC-TCD), which confirmed the production of 136 equiv of CO relative to cluster with a 74% Faradaic efficiency.
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| 今後の研究の推進方策 |
Future work will entail the synthesis of new series of gold nanoclusters by using designed NHC ligands to control size and shape of gold core. In particular, we focused on the synthesis of new heterobimetallic clusters stabilized by NHC ligands. For application to catalysis, homogeneous electrochemical investigation of NHC-gold nanoclusters will be established.
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