Design and Synthesis of Heteroleptic Cyclometalated Iridium(III) Complexes Containing Quinoline-Type Ligands that Exhibit Dual Phosphorescence

• Published in: Inorganic chemistry Vol. 55; no. 8; pp. 3829 - 3843
• Main Authors: Kumar, Sarvendra, Hisamatsu, Yosuke, Tamaki, Yusuke, Ishitani, Osamu, Aoki, Shin
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18.04.2016
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.5b02872

The design and synthesis of some cyclometalated iridium­(III) complexes containing quinoline-type ligands as ancillary ligands are reported. The emission spectra of Ir­(III) complexes containing a quinolinolate (6, 8, 10) moiety exhibit a single emission peak at ca. 590 nm, resulting in a red colored emission. However, Ir­(III) complexes containing 8-sulfonamidoquinoline ligands (11, 13–21) exhibit two different emission peaks (dual emission) at ca. 500 nm and ca. 600 nm upon excitation at 366 nm, resulting in a red-colored emission for 11 and a pale yellow-colored emission for 14–18 at 298 K. Especially, a white emission was observed for 19 at 298 and 77 K in dimethyl sulfoxide. The mechanistic studies based on time-dependent density functional theory calculations and time-resolved emission spectroscopy suggest that this dual emission originates from two independent emission states.