Alkynyl-Stabilized Superatomic Silver Clusters Showing Circularly Polarized Luminescence

We report a new enantiomeric pair of superatomic silver clusters, R/S-Ag-17, prepared from chiral alkynyl ligands. R-Ag-17 and S-Ag-17 possess C3 symmetry and emit near-infrared (NIR) light with a quantum yield (QY) of 8.0% under ambient condition as well as NIR circularly polarized luminescence (CPL) as a result of the chirality of the excited states. Both experiments and theoretical calculations indicate for the first time that the CPL originates from transitions between superatomic 1P(z) (along the C-3 axis) and 1S orbitals. This work opens a new avenue for CPL-active metal nanoclusters by utilizing chiral alkynyl ligands and enlightens the chirality transfer from chiral protecting ligands to superatomic states in metal clusters.

Automated summary

This study introduces a new enantiomeric pair of superatomic silver clusters, R/S-Ag-17, prepared from chiral alkynyl ligands, which exhibit near-infrared emission and circularly polarized luminescence. Experimental and theoretical evidence suggest that the CPL originates from transitions between superatomic 1P(z) and 1S orbitals. This work paves the way for the development of CPL-active metal nanoclusters utilizing chiral ligands and demonstrates the transfer of chirality from protecting ligands to superatomic states in metal clusters.