2023 Fiscal Year Annual Research Report
Beyond thiols, beyond gold: Novel NHC-stabilized nanoclusters in catalysis
| Project/Area Number |
21H01949
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| Allocation Type | Single-year Grants |
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| Research Institution | Nagoya University |
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Principal Investigator |
CRUDDEN Cathleen 名古屋大学, トランスフォーマティブ生命分子研究所, 客員教授 (10721029)
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| Project Period (FY) |
2021-04-01 – 2025-03-31
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| Keywords | nanocluster / gold / N-heterocyclic carbene / chirality / electrocatalysis |
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| Outline of Annual Research Achievements |
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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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
We have demonstrated that employing chiral NHC-based ligands to stabilize nanoclusters offers a practical and controllable method for the preparation of highly stable, enantiopure chiral clusters. And cluster displayed high selectivity for the catalytic reduction of CO2 to CO. This result is published in Chem. Mater.
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| Strategy for Future Research Activity |
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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