High-Nuclear Organometallic Copper(I)-Alkynide Clusters: Thermochromic Near-Infrared Luminescence and Solution Stability.

Cu(CF COO) reacts with tert-butylacetylene (tBuC≡CH) in methanol in the presence of metallic copper powder to give two air-stable clusters, [Cu (tBuC≡C) (CF COO) ]⋅tBuC≡CH (1) and [Cu (tBuC≡C) (CF COO) (CH OH) ] (2). The assembly process involves in situ comproportionation reaction between Cu and Cu and the formation of two different clusters is controlled by reactants concentration. The clusters consist of Cu and Cu cores co-stabilized by strong by σ- and π-bonded tert-butylethynide and CF COO (together with methanol molecule in 2).