Related Experiment Video
Updated: Jul 6, 2026
09:11
Synthesis of Near-Infrared Emitting Gold Nanoclusters for Biological Applications
Published on: March 22, 2020
On the structure of thiolate-protected Au25
Jaakko Akola1, Michael Walter, Robert L Whetten
1Department of Physics, Nanoscience Center, FIN-40014 University of Jyväskylä, Finland.
Journal of the American Chemical Society
|March 7, 2008
Summary
This study reveals the preferred structure of gold nanoclusters Au25(RS)18, featuring an icosahedral core. Enhanced stability as an anion arises from a closed electron shell, matching experimental data.
Area of Science:
- Computational Chemistry
- Materials Science
- Nanotechnology
Background:
- Gold nanoclusters are of significant interest due to their unique properties.
- Understanding the precise atomic structure of these clusters is crucial for predicting their behavior.
Purpose of the Study:
- To elucidate the preferred atomic structure of the gold nanocluster Au25(RS)18.
- To investigate the origin of enhanced stability in its anionic form.
Main Methods:
- Density Functional Theory (DFT) calculations were employed to explore various structural configurations.
- Theoretical X-ray Diffraction (XRD) patterns and optical spectra were computed.
Main Results:
- The most stable structure identified features an icosahedral Au13 core surrounded by six RS-Au-RS-Au-RS units.
- The anionic form exhibits enhanced stability due to the closure of an eight-electron shell for delocalized Au(6s) electrons.
- Calculated XRD patterns and optical spectra align well with experimental observations.
Conclusions:
- The study provides a detailed structural model for Au25(RS)18.
- The electronic structure explains the enhanced stability of the anionic cluster.
- The findings support experimental characterization and offer insights for designing novel gold nanoclusters.
More Related Videos
Related Concept Videos
02:33Preparation and Reactions of Thiols
Thiols are prepared using the hydrosulfide anion as a nucleophile in a nucleophilic substitution reaction with alkyl halides. For instance, bromobutane reacts with sodium hydrosulfide to give butanethiol.
02:17Structure and Nomenclature of Thiols and Sulfides
Thiols and sulfides are sulfur analogs of alcohols and ethers, respectively, where the sulfur atom takes the place of the oxygen atom. Thus, thiols are generally represented as RSH, where R is an alkyl substituent and —SH is the functional group. On the other hand, in sulfides, the central sulfur atom is bonded to two hydrocarbon groups on either side. Depending upon the type of group, sulfides can be either symmetrical or asymmetrical. Both thiols and sulfides display a bent geometry, similar...
01:24Acetals and Thioacetals as Protecting Groups for Aldehydes and Ketones
Acetals are formed by reacting two equivalents of alcohol with carbonyl compounds like aldehydes or ketones. Acetals are unaffected by bases, nucleophiles, oxidizing agents, and reducing agents. They serve as protecting groups for aldehydes and ketones. Acetals can be easily formed and also easily removed via mild acid hydrolysis.
In the presence of multiple functional groups, when selective reduction of one group over the other is desired, groups like aldehydes and ketones that form acetals...
In the presence of multiple functional groups, when selective reduction of one group over the other is desired, groups like aldehydes and ketones that form acetals...
02:26Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
01:19Structure of Amines
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...
02:31Protection of Alcohols
This lesson delves into the concept of protection and deprotection of a functional group fundamental to synthetic organic chemistry. These phenomena are explained in the context of aliphatic and aromatic alcohols.
Protection
It defines a protecting group as the masking agent to make the more reactive species inert to a given set of conditions. This concept is depicted via the illustration of liquid flow through different outlets in an assembly of pipes. The analogy helps to understand the role...
Protection
It defines a protecting group as the masking agent to make the more reactive species inert to a given set of conditions. This concept is depicted via the illustration of liquid flow through different outlets in an assembly of pipes. The analogy helps to understand the role...