Search results for "Iridium"

Easy preparation of Cp*-functionalized N-heterocyclic carbenes and their coordination to rhodium and iridium

2010

A simple high-yielding method for the preparation of a tetramethylcyclopentadienyl-NHC ligand is described. This ligand has been successfully coordinated to Rh and Ir. A related Cp*-NHC ligand with a -CH(2)CMePh- linker between the Cp* and the NHC is also described, together with its coordination to Rh and Ir. This latter ligand, affords the orthocyclometallation of the phenyl ring yielding a constrained structure in which the ligand is tridentate. All the complexes have been fully characterized and their crystal structures are described. Preliminary catalytic results on the beta-alkylation of secondary alcohols and N-alkylation of aniline with primary alcohols are also reported.

Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization an…

2016

The synthesis and characterization of twenty new pentamethylcyclopentadienyl-rhodium and iridium complexes containing N^N and N^O-chelating chloroquine analogue ligands are described. The in vitro antimalarial activity of the new ligands as well as the complexes was evaluated against the chloroquine sensitive (CQS) NF54 and the chloroquine resistant (CQR) Dd2 strains of Plasmodium falciparum. The antimalarial activity was found to be good to moderate; although all complexes are less active than artesunate, some of the ligands and complexes showed better activity than chloroquine (CQ). In particular, rhodium complexes were found to be considerably more active than iridium complexes against t…

2015

AbstractThe synthesis, characterization and evaluation in solid-state devices of a series of 8 cationic iridium complexes bearing different numbers of methoxy groups on the cyclometallating ligands are reported. The optoelectronic characterization showed a dramatic red shift in the absorption and the emission and a reduction of the electrochemical gap of the complexes when a methoxy group was introduced para to the Ir-C bond. The addition of a second or third methoxy group did not lead to a significant further red shift in these spectra. Emission maxima over the series ranged from 595 to 730 nm. All complexes possessing a motif with a methoxy group at the 3-position of the cyclometalating l…

Dumbbell-Shaped Dinuclear Iridium Complexes and Their Application to Light-Emitting Electrochemical Cells

2010

A novel family of dumbbell- shaped dinuclear complexes in which an oligophenyleneethynylene spacer is linked to two heteroleptic iridiumA complexes is presented. The synthesis, as well as the electrochemical and pho- tophysical characterization of the new complexes, is reported. The experimen- tal results are interpreted with the help of density functional theory calcula- tions. From these studies we conclude that the lowest triplet excited state cor- responds to a 3 p-p* state located on the conjugated spacer. The presence of this state below the 3 MLCT/ 3 LLCT emitting states of the end-capping Ir III complexes explains the low quantum yields observed for the dinuclear com- plexes (one or…

Phosphorescent hybrid organic-inorganic light-emitting diodes.

2010

Efficient deep-red light-emitting electrochemical cells based on a perylenediimide-iridium-complex dyad

2009

A two-layer light-emitting electrochemical cell device based on a new perylenediimide-iridium-complex dyad is presented emitting in the deep-red region with high external quantum efficiencies (3.27%). Costa Riquelme, Ruben Dario, Ruben.Costa@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es ; Bolink, Henk, Henk.Bolink@uv.es ; Gierschner, Johannes, Johannes.Gierschner@uv.es

Efficient orange light-emitting electrochemical cells

2012

We report the first bis-cyclometalated cationic iridium(III) complex with N-aryl-substituted 1H-imidazo [4,5-f][1,10]phenanthroline. The complex emits yellow-orange phosphorescence with a maximum at 583 nm, a quantum yield of 43%, and an excited-state lifetime of 910 ns in argon-saturated dichloromethane. Optimized orange light-emitting electrochemical cells with the new Ir(III) complex exhibit fast turn-on, a peak luminance of 684 cd m(-2) and a peak efficacy of 6.5 cd A(-1); in 850 h of continuous operation their luminance and efficacy decrease only by 20%.

Dual Luminescence, Interligand Decay, and Nonradiative Electronic Relaxation of Cyclometalated Iridium Complexes in Solution

2016

Femtosecond broadband photoluminescence studies are presented for Ir(ppy)3 (Ir1), Ir(ppy)2(pic) (Ir2), Ir(ppy)2(bpy)(PF6) (Ir3), Ir(ppz)3 (Ir4), and Ir(ppz)2dipy (Ir5) (where ppy = 2-phenylpyridine, pic = picolinate, bpy = 2,2′-bipyridine, ppz = 1-phenylpyrazole, and dipy = 5-phenyldipyrrinato) in solution. Upon 400-nm excitation of Ir1–Ir3, we observed a prompt population of the lowest MLCT states. The higher states decay on an ultrafast time scale (3MLCT state undergoes further vibrational relaxation on a 1-ps time scale. In Ir3, this relaxation is accompanied by an interligand decay from the ppy to the bpy ligand in ∼1.5 ps. For the ppy-containing complexes (Ir1 and Ir2), we found that, …

Thiphenylmethane based structural fragments as building blocks towards solution-processable heteroleptic iridium(iii) complexes for OLED use

2019

A novel structural approach to solution-processable heteroleptic iridium(III) complexes is presented. On the basis of 2-arylbenzo[d]thiazole cyclometalating main ligands and picolinic acid (pic) and acetylacetone (acac) ancillary ligands six new yellow or orange emitting materials were obtained using attached 1,1,1-triphenylmethylpentane substituents as aggregation preventing and solubility enhancing functional fragments. The obtained compounds show high photoluminescence quantum yield values in the range of 0.64 to 0.90. OLEDs with a spin-coated emissive layer were successfully prepared, with the highest achieved external quantum efficiency of 7.9%, current efficiency of 12.4 cd A−1 and po…

Fine‐Tuning of Photophysical and Electronic Properties of Materials for Photonic Devices Through Remote Functionalization

2012

We report four new iridium(III) complexes of the type [Ir(ppy)2(N?N)][PF6] in which N?N is a 4,6-diphenyl-2,2`-bipyridine and the 4-phenyl ring is substituted at either the para or meta positions [4-Me, N?N = 1; 4-Br, N?N = 2; 3,5-Br2, N?N = 3; 3,5-(C6H4-4-NPh2)2, N?N = 4]. The complexes have been fully characterized, and single-crystal diffraction analyses of [Ir(ppy)2(N?N)][PF6] (N?N = 13) confirmed that each [Ir(ppy)2(N?N)]+ cation exhibits face-to-face p-stacking between the pendant phenyl substituent of the N?N ligand and the cyclometallated phenyl ring of an adjacent [ppy] ligand. In solution, the complexes are short-lived emitters; the emission maxima for [Ir(ppy)2(1)][PF6], [Ir(ppy)…