Assembly of air-stable copper(I) alkynide nanoclusters assisted by tripodal polydentate phosphoramide ligands

Copper(I) nanoclusters are attractive due to their potential applications, but their synthesis remains challenging due to susceptibility to oxidation and the lack of mature synthetic methods. Here, by introducing a bifunctional phosphoramide ligand, N,N′,N′-tris(2-pyridinyl)phosphoric triamide [PO(NHPy)₃], into the Cu/RC≡CH assembly system, we construct two high-nuclearity Cu(I) nanoclusters (Cu62 and Cu12). Single-crystal X-ray structural analysis reveals that multidentate phosphoramide ligands enhance the stability of Cu(I) nanoclusters through cooperation of hydrogen and coordination bonding. Cu62 is a four-layered (C₂)@Cu₈@(C₂)₁₂@Cu₅₄ core, where acetylenediide (C₂²⁻) ions from alkynol ligands are inserted betwen two Cu shells (inner Cu₈ and outer Cu₅₄ shells). By changing alkynol to another cycloalkyl alkyne lacking the OH group, Cu12 without C₂²⁻ ion was isolated, demonstrating the promotion of C₂²⁻ release by hydroxyl group in the above assembly system. We show the universality of the synthetic method by isolating two additional nanoclusters (Cu32 and Cu24). Cu62 exhibits good degradation performance for various dyes due to the generation of reactive oxygen species (·OH). This work presents a generalized strategy for constructing high-nuclearity Cu(I) alkynyl nanoclusters at room temperature.