A Semiconductor Nanocluster Platform with Four Structural Configurations: An Ionic Pair with Tunable Chirality

In chemistry, a cluster refers to an ensemble of a certain
number
of atoms that exhibit distinct physicochemical properties as a unified
entity. Isostructural clusters, with subtle variations in structure
or composition, can display opposite charges, behaving like monatomic
ions to undergo classical reaction processes like disproportionation.
Herein, we report that the semiconductor nanoclusters can be obtained
in the form of a co-crystallized ionic pair, [Cu56S12(SAdm)20(PP)10]+[S@Cu56S12(SAdm)20(PP)10]− (abbreviated as [S-Cu56]·[S@S-Cu56] hereafter).
This bi-nanocluster system is a derivative of a neutral copper sulfide
nanocluster [S-Cu56] with an interesting onion-like structural
configuration containing multiple shells. It consists of two nearly
isostructural copper sulfide nanoclusters with opposite charges that
differ only by the presence of a S2– ion at the
center of the cluster assembly. This represents an interesting ionic
bi-nanocluster system within the p-type copper sulfide semiconductor
family, offering the potential to exhibit electrical properties not
observed in the individual component nanoclusters. Notably, by utilizing
different chiral carboxylate ligands, chirality can be concurrently
imparted to the inorganic cores of both ionic clusters, thereby enabling
distinct chiroptical responses as revealed by circular dichroism spectroscopy.
This eventually results in four different structural configurations
based on this onion-like semiconductor nanocluster platform.