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Liu Z, Li Y, Kahng E, Xue S, Du X, Li S, Jin R. Tailoring the Electron-Phonon Interaction in Au 25(SR) 18 Nanoclusters via Ligand Engineering and Insight into Luminescence. ACS Nano 2022; 16:18448-18458. [PMID: 36252530 DOI: 10.1021/acsnano.2c06586] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Understanding the electron-phonon interaction in Au nanoclusters (NCs) is essential for enhancing and tuning their photoluminescence (PL) properties. Among all the methods, ligand engineering is the most straightforward and facile one to design Au NCs with the desired PL properties. However, a systematic understanding of the ligand effects toward electron-phonon interactions in Au NCs is still missing. Herein, we synthesized four Au25(SR)18- NCs protected by different -SR ligands and carefully examined their temperature-dependent band-gap renormalization behavior. Data analysis by a Bose-Einstein two-oscillator model revealed a suppression of high-frequency optical phonons in aromatic-ligand-protected Au25 NCs. Meanwhile, a low-frequency breathing mode and a quadrupolar mode are attributed as the main contributors to the phonon-assisted nonradiative relaxation pathway in aromatic-ligand-protected Au25 NCs, which is in contrast with non-aromatic-ligand-protected Au25 NCs, in which tangential and radial modes play the key roles. The PL measurements of the four Au25 NCs showed that the suppression of optical phonons led to higher quantum yields in aromatic-ligand-protected Au25 NCs. Cryogenic PL measurements provide insights into the nonradiative energy relaxation, which should be further investigated for a full understanding of the PL mechanism in Au25 NCs.
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Affiliation(s)
- Zhongyu Liu
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Yingwei Li
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Ellen Kahng
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Shan Xue
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Xiangsha Du
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Site Li
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, PittsburghPennsylvania15213, United States
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Dainese T, Antonello S, Bogialli S, Fei W, Venzo A, Maran F. Gold Fusion: From Au 25(SR) 18 to Au 38(SR) 24, the Most Unexpected Transformation of a Very Stable Nanocluster. ACS Nano 2018; 12:7057-7066. [PMID: 29957935 DOI: 10.1021/acsnano.8b02780] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The study of the molecular cluster Au25(SR)18 has provided a wealth of fundamental insights into the properties of clusters protected by thiolated ligands (SR). This is also because this cluster has been particularly stable under a number of experimental conditions. Very unexpectedly, we found that paramagnetic Au25(SR)180 undergoes a spontaneous bimolecular fusion to form another benchmark gold nanocluster, Au38(SR)24. We tested this reaction with a series of Au25 clusters. The fusion was confirmed and characterized by UV-vis absorption spectroscopy, ESI mass spectrometry, 1H and 13C NMR spectroscopy, and electrochemistry. NMR evidences the presence of four types of ligand and, for the same proton type, double signals caused by the diastereotopicity arising from the chirality of the capping shell. This effect propagates up to the third carbon atom along the ligand chain. Electrochemistry provides a particularly convenient way to study the evolution process and determine the fusion rate constant, which decreases as the ligand length increases. No reaction is observed for the anionic clusters, whereas the radical nature of Au25(SR)180 appears to play an important role. This transformation of a stable cluster into a larger stable cluster without addition of any co-reagent also features the bottom-up assembly of the Au13 building block in solution. This very unexpected result could modify our view of the relative stability of molecular gold nanoclusters.
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Affiliation(s)
| | | | | | | | | | - Flavio Maran
- Department of Chemistry , University of Connecticut , 55 North Eagleville Road , Storrs , Connecticut 06269 , United States
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Li G, Abroshan H, Liu C, Zhuo S, Li Z, Xie Y, Kim HJ, Rosi NL, Jin R. Tailoring the Electronic and Catalytic Properties of Au25 Nanoclusters via Ligand Engineering. ACS Nano 2016; 10:7998-8005. [PMID: 27442235 DOI: 10.1021/acsnano.6b03964] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To explore the electronic and catalytic properties of nanoclusters, here we report an aromatic-thiolate-protected gold nanocluster, [Au25(SNap)18](-) [TOA](+), where SNap = 1-naphthalenethiolate and TOA = tetraoctylammonium. It exhibits distinct differences in electronic and catalytic properties in comparison with the previously reported [Au25(SCH2CH2Ph)18](-), albeit their skeletons (i.e., Au25S18 framework) are similar. A red shift by ∼10 nm in the HOMO-LUMO electronic absorption peak wavelength is observed for the aromatic-thiolate-protected nanocluster, which is attributed to its dilated Au13 kernel. The unsupported [Au25(SNap)18](-) nanoclusters show high thermal and antioxidation stabilities (e.g., at 80 °C in the present of O2, excess H2O2, or TBHP) due to the effects of aromatic ligands on stabilization of the nanocluster's frontier orbitals (HOMO and LUMO). Furthermore, the catalytic activity of the supported Au25(SR)18/CeO2 (R = Nap, Ph, CH2CH2Ph, and n-C6H13) is examined in the Ullmann heterocoupling reaction between 4-methyl-iodobenzene and 4-nitro-iodobenzene. Results show that the activity and selectivity of the catalysts are largely influenced by the chemical nature of the protecting thiolate ligands. This study highlights that the aromatic ligands not only lead to a higher conversion in catalytic reaction but also markedly increase the yield of the heterocoupling product (4-methyl-4'-nitro-1,1'-biphenyl). Through a combined approach of experiment and theory, this study sheds light on the structure-activity relationships of the Au25 nanoclusters and also offers guidelines for tailoring nanocluster properties by ligand engineering for specific applications.
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Affiliation(s)
- Gao Li
- Gold Catalysis Research Centre, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China
| | - Hadi Abroshan
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Chong Liu
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Shuo Zhuo
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Zhimin Li
- Gold Catalysis Research Centre, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China
| | - Yan Xie
- Gold Catalysis Research Centre, State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023, China
| | - Hyung J Kim
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
- School of Computational Sciences, Korea Institute for Advanced Study , Seoul 02455, Korea
| | - Nathaniel L Rosi
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
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Abstract
The atomic arrangement of Au and Ag atoms in Au25-xAgx(SR)18 was determined by X-ray crystallography. Ag atoms were selectively incorporated in the 12 vertices of the icosahedral core. The central atom and the metal atoms in the six [-SR-Au-SR-Au-SR-] units were exclusively gold, with 100% Au occupancy. The composition of the crystals determined by X-ray crystallography was Au18.3Ag6.7(SCH2CH2Ph)18. This composition is in reasonable agreement with the composition Au18.8Ag6.2(SCH2CH2Ph)18 measured by electrospray mass spectrometry. The structure can be described in terms of shells as Au1@Au5.3Ag6.7@6×[-SR-Au-SR-Au-SR-]. Density functional theory calculations show that the electronic structure and optical absorption spectra are sensitive to the silver atom arrangement within the nanocluster.
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Affiliation(s)
- Chanaka Kumara
- †Department of Chemistry and Biochemistry, University of Mississippi, Oxford, Mississippi 38677, United States
| | - Christine M Aikens
- §Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Amala Dass
- †Department of Chemistry and Biochemistry, University of Mississippi, Oxford, Mississippi 38677, United States
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