The two key principles discovered in this work are: first, scalable synthesis of copper nanocluster with aggregation induced emission (AIE); second, the successful development of a scalable synthesis approach for defective Cu NCs. AIE phenomenon was discovered first time in thiolate capped Cu NCs, namely, Cu15 using 2-phenylethanethiol and triphenylphosphine, and extensive investigations have been conducted to elucidate the underlying reasons for this behavior. These AIE-active Cu NCs hold great promise in applications such as sensing and imaging.

The catalytic potential of defective nanoclusters is substantial owing to the presence of highly reactive active sites. The newly synthesized defective NCs, namely, Cu28 using o-thiocresol and triphenylphosphine, demonstrated remarkable reaction yields of up to 80% and exceptional selectivity, as evidenced by the absence of byproducts in the Sonogashira C-C coupling reaction. Mechanistic studies and Density Functional Theory (DFT) analyses were employed to thoroughly examine the structure-properties relationship of the defective nanoclusters. These findings pave the way to obtain new smart materials by ligand-engineering approach. The outcomes of this research lay a solid foundation for the development of advanced smart materials through the strategic manipulation of ligands.