Synthesis, structures and luminescent properties of red emissive neutral copper(I) complexes with bisphosphino-substituted benzimidazole

Three neutral copper(I) complexes have been synthesized and characterized, based on two iminephosphine P boolean AND N boolean AND P and P boolean AND N ligands. X-ray crystallographic analysis reveals that the Cu(I) centers are chelated by the tridentate or bidentate ligands, forming distorted tetrahedron configurations. All the complexes show red emissions in powder at 293 K with moderate luminescent quantum yields of 11.8%, 1.2% and 16.6% for CuL1I, CuL1Br and (CuL2I)(2), respectively. CuL1I exhibits very good thermal stability, so vapor deposited OLED based on CuL1I has been fabricated. The device displays pure red emission at 645 nm with a maximal luminance of 1970 cd m(-2) and a maximum EQE of 2.68%.