In this study, a series of four formyl-substituted chloro-bridged iridium(iii) dimers were prepared. Their absorption, photophysical and electrochemical properties were studied in dichloromethane solution. It was found that as the formyl content increased on the cyclometalating ligands, emission unexpectedly became brighter. Organic light-emitting diodes (OLEDs) were fabricated using each of these iridium dimers as the emitter. The OLED fabricated using the brightest of the series, 2b, as the dopant afforded a decent external quantum efficiency (EQE) of 2.6%. This suggests that chloro-bridged iridium dimers are potential candidates as solid-state emitters.
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http://dx.doi.org/10.1039/c4dt03127j | DOI Listing |
Inorg Chem
October 2024
N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia.
Reactions of iridium trichloride hydrate with bulky 2-(9-anthracenyl)-1-phenyl-benzimidazole (anbi) in the presence of N-donor ligands afforded a number of unique noncyclometalated complexes, while attempts to prepare a common μ-chloro-bridged bis-cyclometalated dimer systematically gave a monocyclometalated complex -[Ir(,-anbi)(-anbi)Cl] instead. The obtained complexes were characterized by H NMR, high-resolution mass spectrometry, single-crystal and powder X-ray diffraction, UV-vis spectroscopy, and cyclic voltammetry. The noncyclometalated complexes -[Ir(-anbi)(N^N)Cl)], where N^N are 4,4'-disubstituted 2,2'-bipyridines, are octahedral and contain the anthracene and 2,2'-bipyridine units in a close cofacial arrangement.
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March 2023
Department of Chemistry, University of Houston, 3585 Cullen Blvd., Room 112, Houston, TX, 77204-5003, USA.
Four luminescent ratiometric oxygen sensors, pairing phosphorescent cyclometalated iridium with coumarin or BODIPY fluorophores, are presented here. These compounds realize three key improvements over our previous designs, namely higher phosphorescence quantum yields, the ability to access intermediate dynamic ranges better suited for typical atmospheric O levels, and the possibility of using visible excitation instead of UV. These ratiometric sensors are accessed very simple, 1-step syntheses involving direct reaction of the chloro-bridged cyclometalated iridium dimer with the pyridyl-substituted fluorophore.
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May 2022
N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Leninskii pr. 31, 119991 Moscow, Russia.
Though 2-arylperimidines have never been used in iridium(III) chemistry, the present study on structural, electronic and optical properties of -unsubstituted and -methylated 2-(2-thienyl)perimidines, supported by DFT/TDDFT calculations, has shown that these ligands are promising candidates for construction of light-harvesting iridium(III) complexes. In contrast to -H perimidine, the -methylated ligand gave the expected cyclometalated μ-chloro-bridged iridium(III) dimer which was readily converted to a cationic heteroleptic complex with 4,4'-dicarboxy-2,2'-bipyridine. The resulting iridium(III) dye exhibited panchromatic absorption up to 1000 nm and was tested in a dye-sensitized solar cell.
View Article and Find Full Text PDFInorg Chem
July 2020
Faculty of Chemistry, Adam Mickiewicz University in Poznań, St. Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
We present the results of our research on the use of microwaves as an unconventional heat source for the acceleration of iridium(III) chloro-bridged dimer preparation. The results enabled us to revise and improve known guidelines for the very quick and highly efficient synthesis of iridium(III) dimeric complexes in a very simple isolation manner. According to the developed methodology, the already known dimers containing ligands based on the 2-phenylpyridinato motif, as well as new ones stabilized with functionalized benzo[]quinolinato and 2-phenoxypyridinato-based ligands, were efficiently synthesized.
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November 2016
MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), LASCAMM CR-INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, I-87036 Arcavacata di Rende, CS, Italy. and Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia - Nanotec, UOS di Cosenza, Ponte Pietro Bucci Cubo 31/C, 87036 Rende, CS, Italy.
The synthesis and photophysical characterization of a new family of luminescent water-soluble ionic iridium(iii) complexes of the general formula [(ppy)Ir(bpy)]X are reported. The Ir(iii) complexes incorporate a cyclometalated 2-phenylpyridine (ppy), the ancillary ligand 2,2'-bipyridyl (bpy) and different counterions (X = EtO, OH, EtOCHCO, MeOCHCO). These complexes were obtained starting from the cyclometalated Ir(iii) chloro-bridged dimer [(ppy)Ir(μ-Cl)], for the first time synthesized through a new microwave assisted synthetic procedure, and subsequently converted into the corresponding hydroxy-bridged dimer [(ppy)Ir(μ-OH)].
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