Temperature-Dependent Optical Absorption Properties of Monolayer-Protected Au<sub>25</sub> and Au<sub>38</sub> Clusters

Devadas, Mary Sajini; Bairu, Semere Ghebru; Hu, Qian; Sinn, Ekkehard; Jin, Rongchao; Ramakrishna, G.

doi:10.1021/jz2012897

Cited by 157 publications

(267 citation statements)

References 57 publications

(126 reference statements)

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“…The maximum MUE is 3.5 ppm for 13 C and 0.18 ppm for 1 H NMR. Thus we see that both 13 C and 1 H agree remarkably well with the known experimental results. Although small, we believe that the discrepancies arise from the fact that the experimental structure has six semi-rings with CH 2 CH 2 Ph as the functional group for all ligands whereas the QM/MM and full DFT models have two semi-rings with CH 2 CH 2 Ph as ligands and the rest replaced with CH 3 , so we are neglecting some of the electrostatic interactions that arise due to the difference in the structure.…”

Section: Resultssupporting

confidence: 89%

“…This is clearly the case if, in addition to quantum detail, finite temperature simulations are required. In fact, a number of studies have shown a marked dependence of optical and electrochemical properties on temperature [13,14,15]. Thus, to retain quantum detail and incorporate finite temperature motions it would certainly be advantageous to develop approaches that can combine these features with a reasonable computational cost.…”

Section: Introductionmentioning

confidence: 99%

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A QM/MM approach for the study of monolayer-protected gold clusters

Banerjee

Gascón

2012

J Mater Sci

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We report the development and implementation of hybrid methods that combine Quantum Mechanics (QM) with Molecular Mechanics (MM) to theoretically characterize thiolated gold clusters. We use, as training systems, structures such as Au 25 (SCH 2 -R) 18 and Au 38 (SCH 2 -R) 24 , which can be readily compared with recent crystallographic data. We envision that such an approach will lead to an accurate description of key structural and electronic signatures at a fraction of the cost of a full quantum chemical treatment. As an example, we demonstrate that calculations of the 1 H and 13 C NMR shielding constants with our proposed QM/MM model maintain the qualitative features of a full DFT calculation, with an order-of-magnitude increase in computational efficiency.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

A QM/MM approach for the study of monolayer-protected gold clusters

Banerjee

Gascón

2012

J Mater Sci

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“…Broad peaks were observed at 21.3, 26.3, 28.7, and 38.2 kDa. 119 The peaks at 21.3 and 28.7 kDa were attributed to the laser fragment products of the previously reported Au 102 (SR) 44 to clusters with undetermined chemical composition. These four clusters were separated by HPLC using reverse-phase columns.…”

Section: Chemical Compositionmentioning

confidence: 74%

“…Thiolate-protected gold clusters (Au n (SR) m ) 645 are stable compared with other metal clusters and are promising materials for use in a variety of applications. Extensive investigations have shown that Au n (SR) m clusters, such as Au 25 (SR) 18 , Au 38 (SR) 24 , Au 102 (SR) 44 , and Au 144 (SR) 60 (Figure 1), are particularly stable and have been referred to as magic clusters. 2,8,11,12,21,4658 These magic Au n (SR) m clusters can be synthesized precisely at the atomic level.…”

Section: Introductionmentioning

confidence: 99%

Toward the Creation of Functionalized Metal Nanoclusters and Highly Active Photocatalytic Materials Using Thiolate-Protected Magic Gold Clusters

Negishi

2013

Bulletin of the Chemical Society of Japan

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Advances in developments in nanotechnology have encouraged the creation of highly functionalized nanomaterials. Thiolate-protected gold clusters (Au n (SR) m ) less than 2 nm in size exhibit size-specific physical and chemical properties not observed in bulk metals. Therefore, they have attracted attention as functional units or building blocks in nanotechnology. The highly stable, magic Au n (SR) m clusters possess great potential as new nanomaterials. We are studying the following subjects related to magic Au n (SR) m clusters: (1) establishing methods to enhance their functionality, (2) developing high-resolution separation methods, and (3) utilizing the clusters as active sites in photocatalytic materials. Through these studies, we aim to create highly functional metal nanoclusters and apply them as highly active photocatalytic materials. The results of our efforts to date are summarized in this paper.

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“…The results were obtained owing to low-temperature measurements on ultrahomogeneous samples 32 and realistic quantum-theoretical 33 simulation (B2,500 active electrons). Our results call for fundamental re-evaluation of the perceived limits to 'quantum information content' of spectra in the crucial size range between 100 and 300 metal atoms, wherein the plasmonic response first emerges in the stable cluster materials actually employed in science and technology applications.…”

mentioning

confidence: 99%

Information on quantum states pervades the visible spectrum of the ubiquitous Au144(SR)60 gold nanocluster

et al. 2014

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Absorption spectra of very small metal clusters exhibit individual peaks that reflect the discreteness of their localized electronic states. With increasing size, these states develop into bands and the discrete absorption peaks give way to smooth spectra with, at most, a broad localized surface-plasmon resonance band. The widely accepted view over the last decades has been that clusters of more than a few dozen atoms are large enough to have necessarily smooth spectra. Here we show through theory and experiment that for the ubiquitous thiolate cluster compound Au 144 (SR) 60 this view has to be revised: clearly visible individual peaks pervade the full near-IR, VIS and near-UV ranges of low-temperature spectra, conveying information on quantum states in the cluster. The peaks develop well reproducibly with decreasing temperature, thereby highlighting the importance of temperature effects. Calculations using time-dependent density-functional theory indicate the contributions of different parts of the cluster-ligand compound to the spectra.

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Temperature-Dependent Optical Absorption Properties of Monolayer-Protected Au₂₅ and Au₃₈ Clusters

Cited by 157 publications

References 57 publications

A QM/MM approach for the study of monolayer-protected gold clusters

A QM/MM approach for the study of monolayer-protected gold clusters

Toward the Creation of Functionalized Metal Nanoclusters and Highly Active Photocatalytic Materials Using Thiolate-Protected Magic Gold Clusters

Information on quantum states pervades the visible spectrum of the ubiquitous Au144(SR)60 gold nanocluster

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Temperature-Dependent Optical Absorption Properties of Monolayer-Protected Au25 and Au38 Clusters

Cited by 157 publications

References 57 publications

A QM/MM approach for the study of monolayer-protected gold clusters

A QM/MM approach for the study of monolayer-protected gold clusters

Toward the Creation of Functionalized Metal Nanoclusters and Highly Active Photocatalytic Materials Using Thiolate-Protected Magic Gold Clusters

Information on quantum states pervades the visible spectrum of the ubiquitous Au144(SR)60 gold nanocluster

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Temperature-Dependent Optical Absorption Properties of Monolayer-Protected Au₂₅ and Au₃₈ Clusters