Phenylpyridine Ir

Once again, the most recent developments have been in the area of green phosphorescent materials where phenomenal efficiencies are now beginning to be coupled with good device lifetimes. The prototypical emitter of this type is iridium-tris-2-phenylpyridine (Ir(ppy)3) used as a dopant (Scheme 3.98), usually diluted into a carbazole type host, because it is prone to serious self-quenching problems. 

Tiis(2-phenylpyridine)Ir(in) iV,iV-di(4-tert-butylphenyl)-4-(2-pyridyl) green 100,115... 

More recently, 2-bromothiazoles and 2-benzothiazoles reacted with unactivated olefins, rmder the action of the photocatalyst c-iridium tris(2-phenylpyridine) [Ir(ppy)3], in the presence of a tertiary amine, to... 

Fig. 4 Structures of fac and mer fluorinated 2-phenylpyridine Ir(III) complexes and their computed UV-Visible spectra from TD-DFT calculations. (Reproduced by permission from Eur. J. Inorg. Chem., 2011, 2517). 

Reactions of IrCL/I I2C) with 2-(/>-tolyl)pyridine(ptpy) and 3-methyl-2-phenylpyridine(mppy) gave [Ir(ptpy)2Cl]2 and [Ir(mppy)2Cl]2, respectively.323 Treatment with bpy afforded [Ir (ptpy)2-bpy]Cl and [Ir(mppy)2bpy]Cl. All complexes were characterized by UV-vis, emission spectroscopy, and cyclic voltammetry. 

The donor-acceptor complexes [Ir(/r-dmpz)(CO)(PPh2 0(CH2)2R )]2 exhibit photo-induced electron-transfer rate constants of 1012s—1 and charge recombination rates slower than 2 x 10los-1 when R = pyridine and 4-phenylpyridine.534 Further studies on these complexes revealed that recombination reactions were temperature dependent and slower for the deuterated acceptors.535... 

A variety of transition metal complexes including organometallics was subjected to an ac electrolysis in a simple undivided electrochemical cell, containing only two current-carrying platinum electrodes. The compounds (A) are reduced and oxidized at the same electrode. If the excitation energy of these compounds is smaller than the potential difference of the reduced (A ) and oxidized (A ) forms, back electron transfer may regenerate the complexes in an electronically excited state (A+ + A A + A). Under favorable conditions an electrochemiluminescence (eel) is then observed (A A + hv). A weak eel appeared upon electrolysis o t]jie following complexes Ir(III)-(2-phenylpyridine-C, N ) [Cu(I)(pyridine)i],... 

With regard to transition metal complexes thg+majority of eel studies have been carried out with RuCbipy) and its derivatives (11, 20-33). Recently, King, Spellane, and Watts reported on the mission properties of Ir(ppy) with ppy = 2-phenylpyridine-C, N (41 ) which can be gonsidered to be an organometallic counterpart of Ru(bipy) ... 

The first iridium complex used in PHOLED devices was fac tris(2-phenylpyridine) iridium Ir(ppy)3 complex [282]. It has a short triplet lifetime ( 1 ps) and high phosphorescent efficiency (p = 40% at room temperature in solution) [283]. However, in the solid state, most iridium complexes showed very low phosphorescent QE due to aggregate quenching. In most cases, the complexes have to be diluted in host materials to avoid reducing the... 

PHOLEDs also show excellent stability under display drive conditions. First generation phosphorscent dopants such as PtOEP, fac tris(2-phenylpyridine)iridium (Ir(ppy)3), and iridium(III)/Vv(2-phcnylquinolyl-jV,C2)acetylacetonate (PQ2Ir(acac)) have demonstrated lifetimes of several thousands of hours [60,96], Recent PHOLEDs have shown lifetimes in excess of 30,000 h at display brightnesses [97]. 

Another efficient material introduced by the same group is the green emitting /ac-tris(2-phenylpyridine)iridium [Ir(ppy)3, 67] [38], A suitable host for this phosphorescent emitter is CBP (10). The triplet lifetime is rather short, the experimentally determined value being 500 ns in the CBP matrix. Another iridium complex was shown to emit in the red with high efficiency due to the short phosphorescence lifetime in comparison with PtOEP [165]. 

Metal ions such as Rh(III), Ir(III), Pd(II), Pt(II) and Pt(IV) may be used, although pyridyl-type ligands are less appropriate in these cases since they do not provide the required orbital energy levels. In such cases, combinations of pyridyl and N—C carbanion ligands, such as deprotonated 2-phenylpyridine, are beginning to prove useful. 

Neutral Ir complexes were obtained by an orthometalation reaction with ligands that contain a benzene ring attached to a functional group containing a donor atom such as 2-phenylpyridine (ppy) and benzo[h]-quinoline (bzq) [93]. The coordination of ppy and bzq ligands to metal is analogous to... 

The tuning aspects of phosphorescence colors in anionic Ir complexes are illustrated using the following representative complexes The (C4H9)4N[Ir(2-phenylpyridine)2 (CN)2] (46), (C4H9)4N[Ir(2-phenyl)-4-dimethylaminopyr-idine)2(CN)2] (47), (C4H9)4N[Ir(2-(2,4-difluorophenyl)-pyridine)2(CN)2]... 

To investigate the electroluminescence properties of the cationic complex 45 [Ir(2-phenylpyridine)2 (4,4/-dimethylamino-2,2/-bipyridine)]PF6, LECs were fabricated in a nitrogen atmosphere glovebox [82]. They consisted of a 100 nm spin-coated layer of pristine 45 sandwiched between an ITO and an evaporated... 

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