Highly-efficient blue neutral mononuclear copper(I) halide complexes containing bi- and mono-dentate phosphine ligands

Highly emissive copper halide complexes with a bidentate phosphine ligand have been paid much attention. Here, a series of four-coordinate mononuclear copper(I) halide complexes containing bi- and mono-dentate phosphine ligands, [CuX (dpmb)(PPh 3 )] (dpmb = 1,2-bis(diphenylphosphino)–4,5-dimethylbenzene, X = I ( 1 ), Br ( 2 ) and Cl ( 3 )), were synthesized, and their molecular structures and photophysical properties were investigated. These complexes exhibit intense blue emission in the solid state at room temperature and have peak emission wavelengths at 464–479   nm with microsecond lifetimes ( τ = 3.5−4.9   μs; Φ = 0.23−0.52). The emission of the complexes 1–3 mainly originates from MLCT, XLCT and intraligand transitions. Three complexes display moderate thermal stability.