Capture of Cesium Ions with Nanoclusters: Effects on Inter- and Intramolecular Assembly

The
capture of cations with nanoclusters is a flourishing area
in the nanocluster science due to their effects on both molecular
chemistry and supramolecular chemistry. The capture of Cs+ is most concerned in this field for its capability of controlling
the synthesis and assembly of nanoclusters. However, the atomically
precise interaction between Cs+ ions and nanoclusters remains
mysterious. In this paper, we report the first X-ray crystal structure
of a Cs+-captured nanocluster, formulated as Cs3Ag29(SSR)12(DMF)x (x = 5, 6; SSR, 1,3-benzene dithiol). The capture
of Cs+ with Ag29(SSR)12(PPh3)4 peels the PPh3 ligands off from the nanocluster
surface, giving rise to Cs3Ag29(SSR)12(DMF)x. The Cs+–cluster
interactions not only alter the geometric structure of the Ag29(SSR)12 kernel but also assemble Ag29(SSR)12 clusters into one-dimensional, cluster-based lines.
Remarkable differences have been observed by comparing the optical
properties of the Cs3Ag29(SSR)12(DMF)x nanocluster in solutions or in crystallized
films. Overall, this work is of great significance for revealing both
the Cs+-induced intracluster transformation of nanocluster
structures and the Cs+-induced intercluster self-assembly.