LAUSR

Abstract The three Cu(I) complexes [Cu(POP)(N^N)]PF6, N^N = 2-(1H-imidazol-2-yl)-5-(p-tolylethynyl)pyridine (P1), 2-(1H-imidazol-2-yl)-5-((4-methoxyphenyl)ethynyl)pyridine (P2), 4-((6-(1H-imidazol-2-yl)pyridin-3-yl)ethynyl)-N,N-diphenylaniline (P3), were prepared and characterized. The different electron-donating groups such as methylphenyl, methoxyphenyl, and diphenylamine substituents were functionalized onto the pyridine ring part of the diimine ligands through an acetylide linker to enhance the light-absorption abilities, giving the larger light-absorption ability and red-shifted absorption bands for the investigated Cu(I) complexes. Yellow emissions in the range of 579–590 nm with quantum yields of 8.40–15.1% can be observed for all complexes at room temperature. The photophysical properties were further explained by DFT and TDDFT methods.