Cationic iridium (III) complexes bearing fluorinated Ar-BIAN ligands: Synthesis, structure, electronic, and electrochemical properties

Abstract

Three cationic iridium (III) complexes, [(ppy)2Ir(4-FPhBIAN)]PF6 (Ir1), [(ppy)2Ir(3,4-F,FPhBIAN)]PF6 (Ir2), [(ppy)2Ir(4-CF3PhBIAN)]PF6 (Ir3) were synthesized from 2-phenylpyridine (Hppy) as cyclometalating ligand and N,N′-bis(aryl)acenaphthene as ancillary ligand. All the complexes were characterized by FT-IR, 1H, 13C and 19F NMR spectroscopies, and elemental analysis. The molecular structures of the complexes were determined by X-ray crystallography. These complexes were crystalized as greenish-black needles in the triclinic P1 space group for complexes Ir1 and Ir3, while Ir2 was crystalized in the orthorhombic P212121 space group. Electrochemical properties were studied by cyclic voltammetry analysis. All the complexes showed quasi-reversible oxidation and reduction peaks, and reversibility increased by scan rate. Electronic properties were studied by UV-visible spectroscopy, and intense absorption band below 300 nm was obtained compared to intense absorption bands between 300 ~ 530 nm. Density functional theory (DFT) calculations were employed to get better understanding of electrochemical properties.