Absolute configuration retention of a configurationally labile ligand during dynamic processes of thiolate protected gold clusters

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-07-21
Major/Subject
Mcode
Degree programme
Language
en
Pages
7
9413–9419
Series
Chemical Science, Volume 12, issue 27
Abstract
Monolayer protected metal clusters are dynamic nanoscale objects. For example, the chiral Au-38(2-PET)(24) cluster (2-PET: 2-phenylethylthiolate) racemizes at moderate temperature. In addition, ligands and metal atoms can easily exchange between clusters. Such processes are important for applications of monolayer protected metal clusters; however, the mechanistic study of such processes turns out to be challenging. Here we use a configurationally labile, axially chiral ligand, biphenyl-2,2 '-dithiol (R/S-BiDi), as a probe to study dynamic cluster processes. It is shown that the ligand exchange of free R/S-BiDi on a chiral Au-38(2-PET)(24) cluster is diastereospecific. Using chiral chromatography, isolated single diastereomers of the type anticlockwise/clockwise-Au-38(2-PET)(22)(R/S-BiDi)(1) could be isolated. Upon heating, the cluster framework racemizes, while the R/S-BiDi ligand does not. These findings demonstrate that during cluster racemization and/or ligand exchange between clusters, the R/S-BiDi ligandis sufficiently confined, thus preventing its racemization, and exclude the possibility that the ligand desorbs from the cluster surface.
Description
Keywords
CIRCULAR-DICHROISM, EXCHANGE REACTIONS, AU-25 NANOCLUSTERS, MONOLAYER, NANOPARTICLE, AU-38, AU-38(SR)(24), SPECTROSCOPY, REACTIVITY, MECHANISM
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Citation
Wang , Y , Makkonen , E , Chen , X & Burgi , T 2021 , ' Absolute configuration retention of a configurationally labile ligand during dynamic processes of thiolate protected gold clusters ' , Chemical Science , vol. 12 , no. 27 , pp. 9413–9419 . https://doi.org/10.1039/d1sc01702k