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

摘要

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(Ag6@Ti_(6)).The classical octahedral Ag_(6)^(4+)cluster with two delocalized electrons(2e)has been encapsulated in a Ti6 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.