Assembly of Heterometallic Silver(I)–Copper(I) Alkyl-1,3-diynyl Clusters via Inner-Core Expansion

New tetranuclear supramolecular precursors [(RCCCC)­Ag]4 (R = iPr, tBu, and chx) are employed to construct a series of heterometallic silver­(I)–copper­(I) alkyl-1,3-diynyl cluster complexes (1–9) that bear a common CuAg3 core (normally trigonal-planar, but can be distorted to pyramidal) consolidated by cupro-argentophilic interaction under 3.12 Å, as found in 1 and 2. The photophysical properties of the multinuclear supramolecular precursors and selected complexes have been investigated. The present results strongly suggest that the assembly of medium-nuclearity clusters 3 to 9 is initiated by accretion of additional Ag­(I) ions by the ubiquitous CuAg3 template through argentophilic (9. To our knowledge, the present study provides the first report of conversion of a Group 11 homonuclear cluster into a heteronuclear one of higher nuclearity via inner-core expansion.