High‐Nuclearity Heterometallic tert‐Butylethynide Clusters Assembled with tert‐Butylphosphonate

tert‐Butylphosphonic acid and lanthanide precursors were employed to construct two high‐nuclearity hybrid silver(I)–ytterbium(III) phosphonate clusters: compound 1 consists of a Ag16 ethynide cluster fused with a trinuclear hydroxoytterbium phosphonate cluster, whereas compound 2 is composed of two Ag16 ethynide clusters bridged by a hexanuclear oxo/hydroxoytterbium phosphonate cluster. Using transition‐metal‐substituted lacunary polyoxotungstates in place of the lanthanide reactant, new phosphonate‐functionalized silver(I)–copper(II) ethynide clusters [Ag34Cu6 (3) and Ag37Cu6 (4)] and silver(I) ethynide clusters [Ag51 (5) and Ag72 (6)] were obtained. The structures of complexes 3–6 feature core–shell arrangements, in which silver(I)–copper(II) or silver(I) ethynide cluster shells stabilized by peripheral phosphonate ligands enclose different kinds of tungstate core templates. Time to shell out: Phosphonate‐functionalized silver(I)–ytterbium(III) clusters (Ag16Yb3 and Ag32Yb6), silver(I)–copper(II) ethynide clusters (Ag34Cu6 and Ag37Cu6), and silver(I) ethynide clusters (Ag51 and Ag72) are obtained. The figure shows the outer Ag34Cu6 shell that encapsulates the inner anionic [SiW9O34]10− template.