title: Iridium(III) emitters based on 1,4-disubstituted-1H-1,2,3-triazoles as cyclometalating ligand: synthesis, characterization, and electroluminescent devices.
abstract: A series of blue and blue-green emitters based on neutral bis- and tris-cyclometalated Ir(III) complexes with 1-benzyl-4-(2,6-difluorophenyl)-1H-1,2,3-triazole (dfptrBn) as cyclometalating ligand is reported. The bis-cyclometalated complexes of the type [Ir(dfptrBn)(2)(L(^)X)] with different ancillary ligands, L(^)X = picolinate (pic) (2) or 2-(5-(perfluorophenyl)-2H-1,2,4-triazol-3-yl)pyridine (pytrF(5)) (3), are described and their photophysical properties compared with the analogous complexes containing the archetypal 2-(2,4-difluorophenyl)pyridinato (dfppy) as cyclometaled ligand (C(^)N). Complex 2 exhibits a marked solvatochromic behavior, from 475 nm in toluene to 534 nm in formamide, due to the strong MLCT character of its emissive excited state. Complex 3 displays a true-blue emission, narrower in the visible part than FIrpic. In addition, the homoleptic complex [Ir(dfprBn)(3)] (4) and the heteroleptic compounds with mixed arylpyridine/aryltriazole ligands, [Ir(dfptrBn)(2)(C(^)N)] (C(^)N = 2-phenylpyridinato (ppy) (5) or dfppy (6)), have been synthesized and fully characterized. The facial (fac) complex fac-4 is emissive at 77 K showing a deep-blue emission, but it is not luminescent in solution at room temperature similarly to their phenylpyrazole counterparts. However, the fac isomers, fac-5 and fac-6, are highly emissive in solution and thin films, reaching emission quantum yields of 76%, with emission colors in the blue to blue-green region. The photophysical properties for all complexes have been rationalized by means of quantum-chemical calculations. In addition, we constructed electroluminescent devices, organic light-emitting diodes (OLEDs) by sublimation of fac-6, and by solution processed polymer-based devices (PLEDs) using complexes fac-5 or fac-6 as dopants.
authors: Physikalisches Institut, Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, Heisenbergstrasse 11, 48149 Münster, Germany. jfern_01@uni-muenster.de
authors: Jesús M
authors: JM
authors: Fernández-Hernández
authors: Juan I
authors: JI
authors: Beltrán
authors: Vincent
authors: V
authors: Lemaur
authors: Maria-Dolores
authors: MD
authors: Gálvez-López
authors: Chen-Han
authors: CH
authors: Chien
authors: Federico
authors: F
authors: Polo
authors: Enrico
authors: E
authors: Orselli
authors: Roland
authors: R
authors: Fröhlich
authors: Jérôme
authors: J
authors: Cornil
authors: Luisa
authors: L
authors: De Cola
mesh_terms: D055664:Electrochemical Techniques; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D011789:Quantum Theory; D014230:Triazoles / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D014230:Triazoles; D007495:Iridium