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

In the comproportionation reaction of Cu II X 2 and Cu 0 with isopropylacetylene (iPr−C≡C−H), the ethynediide species C 2 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 C 2 2− exhibits chameleon‐like templating behavior to form C 2 @Cu m ( m =6 ( 3 , 4 ), 7 ( 2 , 4 ), 8 ( 1 )) central structural units for successive formation of {C 2 2− ⊂Cu 24 } ( 1 , 2 ), {6 C 2 2− ⊂Cu 48 } ( 3 ), and {18 C 2 2− ⊂Cu 92 } ( 4 ) complexes. Bearing the highest C 2 2− content, complex 4 features an unprecedented nanoscale Cu 2 C 2 kernel. Furthermore, 1 – 3 exhibit structure‐controlled photoluminescence in the solid state.