On the flexibility of the gold–thiolate interface: racemization of the Au40(SR)24 cluster

Varnholt, Birte; Dolamic, Igor; Knoppe, Stefan; Bürgi, Thomas

doi:10.1039/c3nr03389a

Cited by 31 publications

(51 citation statements)

References 27 publications

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“…The Au-S vibrational modes have been identified below 400 cm −1 . [37,74] The vibrations of the metal core have been predicted below 200 cm −1 , Au-S-C bending in a range of 200-215 cm −1 , and a Au-S stretching mode at 242 cm −1 . [75] Experimental counterpart vibrational analysis on small Au NPs [3,75] have shown Raman bands at 300 and 270 cm −1 assigned to Au-S stretching mode for the reduced and the neutral form, respectively.…”

Section: Bands In the Range 200-300 CM −1 Corresponding To Au-cysteinmentioning

confidence: 96%

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Rodríguez‐Zamora

Salazar-Angeles

Buendía

et al. 2019

J Raman Spectroscopy

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Understanding the physical mechanisms of thiolated molecules adsorption on metal surfaces has required copious research, particularly on Au–cysteine systems due to the affinity of sulfur molecules to gold surfaces, as well as the interesting structural modifications that this strong interaction induces and the peculiar optical, chiroptical, and electronic properties of Au(SR) systems. Here, we present vibrational experimental data on the adsorption of L‐ and D‐cysteine on small gold nanoparticles (<2 nm) by means of Raman spectroscopy. L‐ and D‐cysteine molecules adopt the same strained conformation upon adsorption on colloidal gold nanoparticles, regaining structure due to the stabilization that the gold nanoparticle induces on the cysteine, reflected in the recuperation of vibrational bands from their polymorphically distinctive crystalline forms. Through the analysis of Raman vibrational modifications after adsorption, we found experimental evidence that confirms a stabilized cysteine conformation locating the carboxyl group in the antiposition (PC isomeric rotamer) for both molecules. This result is supported by extensive density functional theory (DFT) calculations and simulated Raman spectra, considering zwitterionic cysteine adsorbed on a Au34 cluster, emulating experimental nanoparticle sizes. Our Raman spectroscopy experimental and DFT results determine one of the oxygen atoms of the carboxyl group as a second adsorption site after the sulfur atom, confirming that independent of its polymorphism and enantiomerism, zwitterionic cysteine interacts with gold nanoparticles through the thiol group and the carboxyl group as adsorption sites.

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Section: Bands In the Range 200-300 CM −1 Corresponding To Au-cysteinmentioning

confidence: 96%

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Rodríguez‐Zamora

Salazar-Angeles

Buendía

et al. 2019

J Raman Spectroscopy

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“…In these structures, the small gold core is protected by mono and dimeric protecting units called “staple motifs” such as linear RS‐Au(I)‐SR and V‐shaped RS‐Au(I)‐SR‐Au(I)‐SR. Many distinct thiolate‐stabilized gold nanoclusters have been synthesized and identified . Chiral thiolate‐stabilized gold NPs have gained significant interest over recent years.…”

Section: Chiral Thiolate‐stabilized Gold Npsmentioning

confidence: 99%

“…Intrinsically chiral gold clusters include the Au 28 (SR) 20 , Au 38 (SR) 24 , Au 40 (SR) 24 , and Au 102 (SR) 44 systems . The CD spectra of their enantiomers are perfect mirror images.…”

Section: Chiral Thiolate‐stabilized Gold Npsmentioning

confidence: 99%

“…The next larger gold cluster that is intrinsically chiral is Au 40 (2‐PET) 24 . Enantiomers of this cluster were separated via high‐performance liquid chromatography.…”

Section: Chiral Thiolate‐stabilized Gold Npsmentioning

confidence: 99%

“…Enantiomers of this cluster were separated via high‐performance liquid chromatography. The collected fractions exhibit strong chiroptical activity with a mirror‐image relationship . In 2015, the crystal structure of the related Au 40 ( o ‐MBT) 24 ( o ‐MBT = ortho ‐methylbenzenethiolate) cluster was determined ( Figure ), and this structure was found to be chiral due to a chiral arrangement of the AuS staple motifs around an achiral core; both enantiomers were found in the crystal structure .…”

Section: Chiral Thiolate‐stabilized Gold Npsmentioning

confidence: 99%

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Karimova

Aikens

2019

Part & Part Syst Charact

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The origins of chirality and chiroptical properties in ligand‐protected gold and silver nanoparticles (NPs) are considered herein. Current conceptual models including the chiral core model, dissymmetric field model, and chiral footprint model are described as mechanisms that contribute to the understanding of chirality in these systems. Then, recent studies on thiolate‐stabilized gold NPs, phosphine‐stabilized gold NPs, multi‐ligand‐stabilized silver NPs, and DNA‐stabilized silver NPs are discussed. Insights into the origin of chiroptical properties including reasons for large Cotton effects in circular dichroism spectra are considered using both experimental and theoretical data available. Theoretical calculations using density functional theory (DFT) and time‐dependent DFT methods are found to be extremely useful for providing insights into the origin of chirality. The origin of chirality in ligand‐protected gold and silver NPs can be considered to be a complex phenomenon, arising from a combination of the three conceptual models.

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Gold Nanoparticles

Panikkanvalappil¹,

Khatun²,

Pradeep³

2019

Kirk-Othmer Encyclopedia of Chemical Technology

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Gold nanoparticles (GNPs) have been the most extensively studied colloidal systems in the area of nanoscience and nanotechnology owing to their fascinating physical and chemical properties. Nanoscience and nanotechnology are often inseparable from advances in GNPs. Diversity in the modes of preparation, unique properties, unusual stability in comparison to related materials make GNPs ideal for a vast array of applications in chemistry, biology, engineering, and medicine. This article gives an overview of the fascinating area of GNPs. The rich history of GNPs is briefly reviewed in the beginning of the article followed by a concise description of various pioneering synthetic strategies and their properties. An overview of novel anisotropic gold nanostructures is described in the subsequent section. Because of the importance of assembled nanostructures in tuning the collective properties of nanomaterials, assemblies of diverse GNPs are briefly described. Furthermore, a few interesting aspects of supported GNPs have also been outlined. Toward the end of the article, we have highlighted important applications of GNPs and have given a special mention of a new category of ultra‐small materials of gold known as atomically precise clusters. The article ends with the new directions of GNPs and outlines the prospects of future applications.

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On the flexibility of the gold–thiolate interface: racemization of the Au40(SR)24 cluster

Cited by 31 publications

References 27 publications

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Revisiting the conformational adsorption of L‐ and D‐cysteine on Au nanoparticles by Raman spectroscopy

Chiral Noble Metal Nanoparticles and Nanostructures

Gold Nanoparticles

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