High efficiency copper(i) halide complexes containing rigid diphosphine ligands have attracted much attention. However, rigid bidentate phosphine ligands have been rarely reported so far. Here, an electron-rich heteroaryl ring grafted with two electron donating methyl groups was first included to construct a rigid bidentate phosphine ligand, three four-coordinate dinuclear copper(i) halide complexes, [CuX(dpmt)]2 (dpmt = 3,4-bis(diphenylphosphino)-2,5-dimethylthiophene, X = I (1), Br (2) and Cl (3)), were synthesized, and their molecular structures and photophysical properties were investigated. The structural analysis reveals that two copper(i) centers are bridged by two halogen ligands to form a dinuclear structure with a four-membered Cu2X2 ring. These complexes exhibit intense bluish green to yellow green emission in the solid state at room temperature and have peak emission wavelengths at 490-543 nm with microsecond lifetimes (τave = 3.9-13.6 μs, Φ = 0.26-0.35). The emission of complex 1 mainly originates from MLCT and ligand-centered transitions. Similar emissive behaviors for complexes 2 and 3 are possibly due to ligand-centered transition. The solution-processed devices of complex 3 exhibit stable yellow emission with CIE(x, y) of (0.42, 0.52) for doped and nondoped devices.
ASJC Scopus subject areas
- Materials Chemistry