Development of non-closed silver clusters by transition-metal-coordination-cluster substituted polyoxometalate templates

Abstract

Nature seems to favor the formation of closed anion-templated silver clusters. How precisely to create non-closed sliver clusters remains an interesting challenge. In this work, we propose that the use of transition-metal-coordination-cluster substituted polyoxometalates (TMCC-substituted POMs) as templates is an effective synthetic strategy for creating the non-closed silver clusters, as demonstrated by the obtainment of four types of rare non-closed silver cluster species of Ag₃₈-TM (TM = Co, Ni or Zn), Ag₃₇-Zn, {Ag₃₇-Zn}_∞ and Ag₃₆-TM (TM = Co, Ni). The idea of the strategy is to employ the TMCC-substituted POMs containing cluster modules with different bond interactions with Ag⁺ ions as templates to guide the formation of the non-closed silver clusters. For example, TMCC-substituted POM clusters are used as templates in this work, which contain POM modules that can coordinate with the Ag⁺ ions and TMCC moieties that are difficult to coordinate with the Ag⁺ ions, leading to the Ag⁺ ions being unable to form closed clusters around TMCC-substituted POM templates. The work demonstrates a promising approach to developing intriguing and unexplored non-closed silver clusters.