Significantly enhanced NIR emission of solid-state clusters based on CuPt triggered with volatile organic compounds.

Near-infrared (NIR) emitting metal clusters, recognized for their low toxicity, large Stokes shift, and exceptional photostability, hold considerable promise as stimuli-responsive luminescent materials for applications including organic vapor sensing, pollutant detection, and photoluminescent thermometers. However, their limited quantum yield (QY) for NIR emission poses a challenge, highlighting the need for developing light-up sensors with NIR emitting metal clusters to broaden the scope of applications. Herein, the carbazole-alkyne ligand-incorporated novel bimetallic cluster, CuPt(CZ-PrA)(dppy)(PF) (CZ-Cu4Pt2, CZ-PrAH = 9-(Prop-2-yn-1-yl)-9-carbazole; dppy = diphenyl-2-pyridylphosphine), was synthesized, which exhibits NIR emission centered at 740 nm in the solid state and shows a significant blue shift compared to the previously reported analogues.