Amplification of enantiomeric excess by dynamic inversion of enantiomers in deracemization of Au<sub>38</sub> clusters.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32917885.
- Also identified by DOI 10.1038/s41467-020-18357-0 and PMC identifier 7486404.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Symmetry breaking and amplification processes have likely played a fundamental role in the development of homochirality on earth. Such processes have not been much studied for inorganic matter at the nanoscale. Here, we show that the balance between left- and right-handed intrinsically chiral metal clusters can be broken by adsorbing a small amount of a chiral molecule in its ligand shell. We studied the amplification of enantiomeric excess of the Au<sub>38</sub>(2-PET)<sub>24</sub> cluster (2-PET = 2-phenylethylthiolate). By exchanging a small fraction of the achiral 2-PET ligand by chiral R-1,1'-binaphthyl-2,2'-dithiol (R-BINAS), a mixture of species is obtained composed of anticlockwise (A) and clockwise (C) versions of Au<sub>38</sub>(2-PET)<sub>24</sub> and Au<sub>38</sub>(2-PET)<sub>22</sub>(R-BINAS)<sub>1</sub>. At 70 °C, the system evolves towards the anticlockwise clusters at the expense of the clockwise antipode. It is shown that the interplay between the diastereospecific ligand exchange, which introduces selectivity but does not change the A/C ratio, and the fast racemization of the Au<sub>38</sub>(2-PET)<sub>24</sub> is at the origin of this observation.