DFT/TDDFT studies of electronic structures and spectral properties of Cu(I) complexes containing pyridine-imidazole ligand tethered with fluorene moiety

摘要

Copper (I) complexes have received significant attention because of their potential applications in a broad range of fields, including organic light emitting diodes (OLED), bioimages, sensors, and photocatalysis. A Cu(I) complexes, [Cu(POP){(Py-Imidazole)(CH_2)_2(2-Fluorene)]~+ (1), where Py-Imidazole)(CH_2)_2(2-Fluorene) = 5-(2-(9H-fluoren-2-yl)ethyl)-2-(1H-imidazol-2-yl) pyridine, POP= bis[2-diphenylphosphino]-phenyl]ether, was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The optimized ground structures show that the fluorene ring is parallel to the imidazole ring. The HOMO is π character, while the LUMO is π~* orbitals of the Py-imidazole ligands. The lowest lying absorption band of the complexes has the HOMO-1 → LUMO transition configurations resulting in the MLCT/LLCT characters.