Issue 23, 2023

Photoluminescence control by atomically precise surface metallization of C-centered hexagold(i) clusters using N-heterocyclic carbenes

Abstract

The properties of metal clusters are highly dependent on their molecular surface structure. The aim of this study is to precisely metallize and rationally control the photoluminescence properties of a carbon(C)-centered hexagold(I) cluster (CAuI6) using N-heterocyclic carbene (NHC) ligands with one pyridyl, or one or two picolyl pendants and a specific number of silver(I) ions at the cluster surface. The results suggest that the photoluminescence of the clusters depends highly on both the rigidity and coverage of the surface structure. In other words, the loss of structural rigidity significantly reduces the quantum yield (QY). The QY in CH2Cl2 is 0.04 for [(C)(AuI-BIPc)6AgI3(CH3CN)3](BF4)5 (BIPc = N-isopropyl-N′-2-picolylbenzimidazolylidene), a significant decrease from 0.86 for [(C)(AuI-BIPy)6AgI2](BF4)4 (BIPy = N-isopropyl-N′-2-pyridylbenzimidazolylidene). This is due to the lower structural rigidity of the ligand BIPc because it contains a methylene linker. Increasing the number of capping AgI ions, i.e., the coverage of the surface structure, increases the phosphorescence efficiency. The QY for [(C)(AuI-BIPc2)6AgI4(CH3CN)2](BF4)6 (BIPc2 = N,N′-di(2-pyridyl)benzimidazolylidene) recovers to 0.40, 10-times that of the cluster with BIPc. Further theoretical calculations confirm the roles of AgI and NHC in the electronic structures. This study reveals the atomic-level surface structure–property relationships of heterometallic clusters.

Graphical abstract: Photoluminescence control by atomically precise surface metallization of C-centered hexagold(i) clusters using N-heterocyclic carbenes

Supplementary files

Article information

Article type
Edge Article
Submitted
16 apr 2023
Accepted
28 apr 2023
First published
11 may 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 6207-6215

Photoluminescence control by atomically precise surface metallization of C-centered hexagold(I) clusters using N-heterocyclic carbenes

Z. Lei, P. Zhao, X. Pei, H. Ube, M. Ehara and M. Shionoya, Chem. Sci., 2023, 14, 6207 DOI: 10.1039/D3SC01976D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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