UNIGE document Doctoral Thesis
previous document  unige:26350  next document
add to browser collection
Title

On the stereochemistry of atomically defined gold clusters: synthesis, size-selection and stereochemical characterization of thiolate-protected gold clusters

Author
Director
Defense Thèse de doctorat : Univ. Genève, 2012 - Sc. 4491 - 2012/11/23
Abstract The thesis describes the synthesis of chiral thiolate-protected gold clusters. Au25(SR)18 clusters were protected with chiral thiolate ligands and the induced Cotton effects are ligand-dependent. A chromatography method was developed to isolate Au38(SR)24 and Au40(SR)24 clusters. Both clusters were separated into their enantiomers using HPLC. This predicts chirality for Au40(SR)24. The first CD spectra of intrinsically chiral gold clusters were measured and the activation barrier for racemization of Au38(SR)24 was determined. Ligand exchange experiments show that - using 1,1'-binaphthyl-2,2'-dithiol (BINAS) - the exchange is regio-selective. The data can be used to predict structural features in Au40(SR)24. The ligand exchange reaction between racemic Au38(SCH2CH2Ph)24 and R-BINAS shows a clear preference for the left-handed enantiomer of Au38. First experiments suggest a significant, but minor influence of the chiral ligand on the CD spectra and a drastically enhanced stability against thermally induced inversion compared to Au38(SCH2CH2Ph)24, making the BINAS-substituted Au38 cluster a suitable canditate for catalytic applications.
Keywords Gold ChemistryStereochemistryChiralityGold ClustersThiolatesCircular DichroismNanochemistry
Identifiers
URN: urn:nbn:ch:unige-263506
Full text
Thesis (7.4 MB) - public document Free access
Structures
Citation
(ISO format)
KNOPPE, Stefan. On the stereochemistry of atomically defined gold clusters: synthesis, size-selection and stereochemical characterization of thiolate-protected gold clusters. Université de Genève. Thèse, 2012. https://archive-ouverte.unige.ch/unige:26350

328 hits

1111 downloads

Update

Deposited on : 2013-02-11

Export document
Format :
Citation style :