Halogen as Template to Modulate the Structures of the Nanocage-Based Silver(I)-Thiolate Coordination Polymers

By the reaction of AgNO₃, 2-methyl-2-propanethiol (HS<i>t</i>Bu), with various-sized halogen ions as templates, three multi-nuclear silver-thiolate cluster-based chain-like coordination polymers, [Ag₆(<i>μ</i>-SBu)₆]_n (<b>USC-CP-2</b>), [Ag₆(<i>μ</i>-S<i>t</i>Bu)₅Br]_n (<b>USC-CP-4</b>) and [Ag₁₄(<i>μ</i>-S<i>t</i>Bu)₁₂I₂]_n (<b>USC-CP-3</b>) constructed by different Ag(I)-nanocages, have been synthesized and characterized by X-ray diffraction analyses. With F^-, Cl^- or without template, <b>USC-CP-2</b> exhibits a one-dimensional structure composed of detached Ag₆-cages, absent of fluoride or chloridion. While with Br^- and I^-, <b>USC-CP-4</b> and <b>USC-CP-3</b>, two distinct halogen-templating multi-sliver cages-based chain-like polymeric structures have been observed, which are a mono-Br^- encapsulated Ag₈-cage, or a dual-I^- embedded Ag₁₆-cage, respectively. In these three compounds, the multi-Ag(I) cages were self-assembled by Ag-S bonds through bridged <i>μ</i>₂-S<i>t</i>Bu ligands, and stabilized argentophilic interactions between neighboring silver atoms. This study demonstrates that the halide anions of varying sizes play a critical role in inducing the nucleation and structural evolution of the silver-thiolate clusters.