Pd-Mediated Synthesis of Ag Chiral Nanocluster with Core-Shell Structure in T Point Group.

We report a Pd-mediated synthesis and crystal structure of a new chiral Ag(SCHCHPh)(PPh) nanocluster with an open shell electronic structure. The single-crystal X-ray structure reveals that the kernel of the cluster comprises a keplerate Ag icosahedron core with one Ag atom in the center and a shell framework of AgSP block. The AgSP shell framework is fully arranged by helical -S-Ag-S- staples along four Ag-P bonds involved C3 axis, which endows the kernel structure of the nanocluster chirality and symmetry in the T point group. The geometry and chirality of the Ag nanocluster are further confirmed by nuclear magnetic resonance (NMR), electronic circular dichroism (ECD) spectra, and time-dependent density functional theory calculations. Our results show that the formation of the new chiral Ag nanocluster is strongly dependent on the presence of Pd regent with the form of Pd(PPh) functioning in the synthesis. This work not only presents a novel chiral structure of the silver nanocluster but also provides a new strategy for the development of a novel nanocluster.