Synthesis of novel luminescent copper nanoclusters with substituent driven self-assembly and aggregation induced emission (AIE)

We demonstrate a novel strategy to synthesize highly stable luminescent mercaptoimidazole-capped copper nanoclusters (CuNCs). Herein we depict that a simple modification of substituents on the mercaptoimidazole ligand dictates the self-assembly and photophysical properties of the clusters. These CuNCs showed aggregation induced emission (AIE) with a large Stokes shift (Δλ > 200 nm), and the formation of clusters corresponding to Cu4L3 was confirmed by MALDI-TOF mass spectrometric analyses. Interestingly, these nanoclusters effectively internalize into mammalian cells while retaining their fluorescent properties and exhibit negligible toxicity.