Comproportionation Synthesis of Copper(I) Alkynyl Complexes Encapsulating Polyoxomolybdate Templates: Bowl-Shaped Cu₃₃ and Peanut-Shaped Cu₆₂ Nanoclusters

Comproportionation reaction of Cu(II) salt and copper metallic powder in the presence of tert-butylacetylene (tBuC≡CH) in methanol at room temperature yielded discrete Cu(I) tert-butylethynide clusters whose identity depended on the particular co-existing anion employed. Introduction of polyoxomolybdate to the reaction system afforded two new core-shell nanoclusters, [Cu33(tBuC≡C)24(Mo4O16)]·BF4 (3) and [Cu62(tBuC≡C)34(Mo5O19)2(MoO4)2(OTf)2(OH)4]·(OTf)2 (4). Complexes 3 and 4 represent the first examples of high-nuclearity Cu(I) clusters that encapsulate polyoxometalate templates, and the latter features the largest Cu(I) alkynyl cluster known to date. The present study not only demonstrates a new paradigm for the designed synthesis of Cu(I) alkynyl clusters but also opens the door to understanding Cu(I) alkynyl structural chemistry.