Pargyline-phosphine copper(I) clusters with tunable emission for light-emitting devices.

Three pargyline-phosphine copper(I) clusters, [Cu 4 (CC-C 9 H 12 N) 3 (PPh 3 ) 4 ](PF 6 ) (1) and [Cu 6 (CC-C 9 H 12 N) 4 (dppy) 4 ](X) 2 (dppy = diphenyl-2-pyridylphosphine; X = PF 6 for 2 and X = ClO 4 for 3), were synthesized. Their structures were fully characterized using various spectroscopic methods and X-ray crystallography, which showed that the stoichiometry and nature of pargyline and phosphine ligands play an important role in tuning the structure and photophysical features of Cu(I) clusters. Interestingly, clusters 1, 2 and 3 exhibited red, orange and yellow phosphorescence with high quantum yields of 88.5%, 22.0% and 40.2%, respectively, at room temperature. Moreover, clusters 1-3 show distinct temperature-dependent emissions. The excellent luminescence performance of 1 and 3 was designed and employed for the construction of monochrome and white light-emitting devices (LEDs).