Chiral Separation of Copper Sulfide [S–Cu₃₆] Nanocluster Using a Chiral Adaptive Counterion

This work presents a new strategy to achieve the growth of copper sulfide nanoclusters with high nuclearity. Through a phosphine-assisted C–S reductive cleavage approach, an intrinsically chiral [Cu4] cluster passes through a [S–Cu9] cluster and transforms into a higher-nuclearity [S–Cu36] cluster, which features a core–shell structure with a [Cu4]4+ core encapsulated by a chiral [Cu20S12] shell. Interestingly, the spiral arrangement of the bidental ligands on the surface of the [S–Cu36] cluster leads to the L-/R-enantiomeric configurations. Moreover, by utilization of [Na(THF)6]+ as a chiral adaptive counterion, [S–Cu36] can be interlocked separately, thus enabling the isolation of homochiral clusters. Theoretical calculation suggests that the configuration transition between two enantiomeric [Na(THF)6]+ species is favorable at room temperature, thereby promoting the cocrystallization of resulting chiral products. This study introduces a novel perspective on the synthesis of chiral copper sulfide nanoclusters and presents an innovative approach to achieving the chiral separation of nanoclusters.