2021 Fiscal Year Annual Research Report
Beyond thiols, beyond gold: Novel NHC-stabilized nanoclusters in catalysis
| Project/Area Number |
21H01949
|
|---|
| Allocation Type | Single-year Grants |
|---|
| Research Institution | Nagoya University |
|---|
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)
|
|---|
| Project Period (FY) |
2021-04-01 – 2025-03-31
|
| Keywords | nanocluster / gold / N-heterocyclic carbene / catalysis |
|---|
| Outline of Annual Research Achievements |
In FY 2022, we successfully synthesized gold nanoclusters stabilized by N-heterocyclic carbene (NHC) ligands in collaboration with the Tsukuda and Hakkinen group. We demonstrated that the use of chiral, BIANP-inspired NHCs to prepare chiral Au10 nanoclusters with a unique elongated central Au10 core. ESI-MS and single-crystal X-ray crystallography confirmed the molecular formula to be [Au10(bisNHC)4Br2]2+. The chiral Au10 nanocluster adopts a linear edge-shared tetrahedral geometry with a prolate shape. The UV-vis spectrum this cluster in CH2Cl2 displayed four prominent absorption bands at 291, 325, and 546 nm, which is a significant departure from the spectra of bis-NHC dinuclear Au(I) complexes. CD spectra demonstrate chirality transfer from the chiral bisNHC ligand to the inner Au10 nanocluster core. The reaction monitoring by ESI-MS and UV-vis spectroscopy indicated the formation of [Au9(bisNHC)4Br]2+ as a key intermediate.
In addition, we achieved the synthesis of a toroidal Au10 cluster stabilized by NHC bearing bulky 2,4,6-trimethylbenzyl units. The [Au10(NHC)6Br3]Br cluster readily undergoes conversion to form a biicosahedral Au25 cluster, while the corresponding Cl cluster showed no conversion. This facyt may be explained both by the steric environment imposed by the bulky mesityl-substituted NHC ligand, as well as steric and electronic factors introduced by the smaller chloride ligands.
|
| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
We have been able to make new examples of gold nanoclusters containing NHC ligands. These nanoclusters are the first example of isolable Au10-NHC clusters with chirality, which promise to be an important starting point for the development of new types of ligands for magic number clusters. In addition, we have clarified for the first time that the Au10 nanocluster is an important intermediate of Au25 nanocluster. This is a very important finding for understanding the formation process of gold clusters.
|
| 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. Focusing on the bulkiness of ligands, we aim to control the size of stable nanoclusters. Additionally, building on our synthetic method, the synthesis of new heterobimetallic clusters stabilized by NHC ligands will be examined. For application to catalysis, homogeneous electrochemical investigation of NHC-gold nanoclusters will be established.
|
-
-
-
-
-
-
[Journal Article] NHC-Stabilized Au10 Nanoclusters and Their Conversion to Au25 Nanoclusters2022
Author(s)
Lummis Paul A.、Osten Kimberly M.、Levchenko Tetyana I.、Sabooni Asre Hazer Maryam、Malola Sami、Owens-Baird Bryan、Veinot Alex J.、Albright Emily L.、Schatte Gabriele、Takano Shinjiro、Kovnir Kirill、Stamplecoskie Kevin G.、Tsukuda Tatsuya、Hakkinen Hannu、Nambo Masakazu、Crudden Cathleen M.
-
Journal Title
JACS Au
Volume: 2
Pages: 875～885
DOI
Peer Reviewed / Open Access / Int'l Joint Research
-
-
-
-
-
-
-
-
-
-
-
-
-
