title: Series of new cationic iridium(III) complexes with tunable emission wavelength and excited state properties: structures, theoretical calculations, and photophysical and electrochemical properties.
abstract: A series of new cationic iridium(III) complexes [Ir(piq)2(N/\N)]+PF6- (1-6) (piq =1-phenyl-isoquinoline) containing N/\N ligands with different conjugated lengths were synthesized, where the six N/\N ligands were bipyridine, phenanthroline, 2-pyridyl-quinoline, 2,2'-biquinoline, 1,1'-biisoquinoline, and 2-(2-quniolinyl)quinoxaline. Single-crystal X-ray diffraction spectra of three complexes were studied, and the iridium(III) centers were found to adopt a distorted octahedral coordination geometry with cis metalated carbons and trans nitrogen atoms. UV-vis, photoluminescence, cyclic voltammetry, and theoretical calculations were employed for studying the photophysical and electrochemical properties. And the excited-state properties were investigated in detail. The excited state of complexes is complicated and contains triplet metal-to-ligand charge transfer (3MLCT), triplet ligand-to-ligand charge transfer (3LLCT), and ligand-centered (cyclometalated) (3LC) transitions simultaneously. Importantly, the emission wavelength can be tuned significantly from 586 to 732 nm by changing the conjugated length of N/\N ligands.
authors.affiliation: Department of Chemistry & Laboratory of Advanced Materials, Fudan University, Shanghai 200433, P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Shujuan
authors.initials: S
authors.lastname: Liu
authors.forename: Mei
authors.initials: M
authors.lastname: Shi
authors.forename: Chuanming
authors.initials: C
authors.lastname: Wang
authors.forename: Mengxiao
authors.initials: M
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Fuyou
authors.initials: F
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Yi
authors.forename: Chunhui
authors.initials: C
authors.lastname: Huang