Temperature-Mediated Template Release: Facile Growth of Copper(I) Mixed Ethynediide/Isopropylethynide Nanoclusters

In the comproportionation reaction of Cu^II X₂ and Cu⁰ with isopropylacetylene (iPr-C≡C-H), the ethynediide species C₂^2- is generated via concomitant C-H/C-C bond cleavage of the iPr-C≡C-H precursor under moderate temperature to direct the formation of Cu^I mixed ethynediide/isopropylethynide nanoclusters (potentially explosive). The active ethynediide dianion C₂^2- exhibits chameleon-like templating behavior to form C₂ @Cu_m (m=6 (3, 4), 7 (2, 4), 8 (1)) central structural units for successive formation of {C₂^2- ⊂Cu₂₄ } (1, 2), {6 C₂^2- ⊂Cu₄₈ } (3), and {18 C₂^2- ⊂Cu₉₂ } (4) complexes. Bearing the highest C₂^2- content, complex 4 features an unprecedented nanoscale Cu₂ C₂ kernel. Furthermore, 1-3 exhibit structure-controlled photoluminescence in the solid state.