Evolution of all-carboxylate-protected superatomic Ag clusters confined in Ti-organic cages

In this study, the size of the titanium organic cage was controlled to achieve the restricted growth from a single Ag(I) atom (Ag@Ti-5) to rare all-carboxylate-protected superatomic Ag cluster (Ag-6@Ti-6). The classical octahedral Ag-6(4+) cluster with two delocalized electrons (2e) has been encapsulated in a Ti-6 organic cage, which shows high stability in air and dimethyformamide (DMF). Furthermore, larger 2e nested double-tetrahedra Ag clusters (Ag-8(6+) and Ag-9(7+)) protected using a tetrahedral hollow metalloligand framework (Ag-8@Ti-4 and Ag-9@Ti-4) were obtained. Electrospray ionization mass spectrometry (ESI-MS) and density functional theory (DFT) calculations confirmed that there are two delocalized electrons on these small Ag clusters. This study provides a new form of protection for superatomic Ag clusters and provides a feasible strategy for the development of stable Ag clusters.

Automated summary

This study controlled the size of the titanium organic cage to achieve restricted growth from a single Ag(I) atom to a rare all-carboxylate-protected superatomic Ag cluster. The study provides a new form of protection for superatomic Ag clusters and a feasible strategy for the development of stable Ag clusters.