Luminescence properties iridium complexes

Watts and coworkers reported the luminescence properties of cyclometalated iridium(III) and rhodium(III) complexes (see Cyclometalation). The dichloro-bridged dimers [M2(N C)4Cl2] (M = Ir, Rh HN C = Hppy, Hbzq) displayed intense emission with structural features in EtOH/MeOH/CH2Cl2 (4 1 1 v v) glass at 77 K. The emission of the rhodium(III) dimers was assigned to an lE excited state... 

Iridium(III) complexes have been widely explored in the past few decades because of their outstanding photophysical properties and superior photo- and chemical stability (123-129). Much effort has been devoted to both neutral and cationic luminescent iridium complexes in which fine-timing of the energy of their long-lived excited state can be achieved by proper choice of the coordinated ligands (130-136). 

Polystyrenes have also been used to support chromophores useful in organic light-emitting diodes (OLEDs). Week and coworkers have attached tris(2-phenylpyridine) iridium complexes to aminomethylated polystyrene using a Schiff base reaction, 4 [21]. There was no major diminution of the desirable luminescence properties of the iridium complexes (high emission quantum yields of 0.23 and lifetimes of about a microsecond). Similar results have been reported for aluminum and boron 8-hydroxy quinoline complexes tethered to polystyrene using Schiff base condensation [22]. 

A Comparative Study of Some Luminescence Properties of Homo- and Hetero-Bischelated Complexes of Iridium(III)... 

The complex ion, cw-dichlorobis-4,7-dimethyl-l,10-phenanthroline iridium (III) chloride [IrCl2(4,7-mephen)2]Cl, has luminescence properties which are intermediate between the aforementioned homo-bischelated complexes (23). The emitting levels of this complex are best classified as nearly equal admixtures of cItt and tttt configurations. The luminescence lifetime at 77 °K ranges from 208 to 22 fisec as the solvent polarity is decreased. The quantum yield of 0.62 in ethanol-methanol glass at 77°K indicates an intrinsic radiative lifetime of 35 /msec under these conditions. The number of equilibrated levels responsible for the emission of this complex as in the previous case, has not been determined. 

Abstract Considerable studies have been made on iridium complexes during the past 10 years, due to their high quantum efficiency, color tenability, and potential applications in various areas. In this chapter, we review the synthesis, structure, and photophysical properties of luminescent Ir complexes, as well as their applications in organic light-emitting diodes (OLEDs), biological labeling, sensitizers of luminescence, and chemosensors. 

Iridium metal compounds have shown some remarkable effects recently for luminescent properties such as very high photoluminescent quantum yields [27, 29, 44] and high stability [46]. Two reviews [2, 4] have recently reported on phosphorescent heavy-metal complexes (Re, Ru, Os, Ir, and Rh) as bioimaging probes, including their photophysical properties, cytotoxicity, and cellular uptake mechanisms [2], and on transition metals (Ir, Re, Ru) in fluorescent cell imaging applications such as uptake and toxicity [4], respectively. 

Research in the chemistry of rhodium and iridium Af-heterocyclic carbene (NHC) complexes has extraordinarily evolved since 2000. A quick search for rhodiimi-NHC and iridiimi-NHC complexes in the SCl-expanded database, with a 2005-2013 timespan, results in more than 360 hits for rhodium, and more than 340 for iridiiun, which gives a good idea on the interest that rhodium and iridium NHC-based chemistry have achieved in the last few years. It is important to note that a nimiber of reviews and book chapters specifically concerning the chemistry of NHC-based compounds of rhodium and iridiiun have recently appeared [1]. This chapter will deal with all new aspects of the NHC-M (M = Rh, Ir) chemistry not reviewed before, and therefore is mainly restricted to the last 4-5 years. The chapter is classified into two main sections, the first of which deals with relevant structural and electronic features of Rh-NHC and Ir-NHC complexes, and the second with the catalytic applications of these compounds. While not pretending to be completely comprehensive, we have tried to describe the most relevant examples assigned to each section. Some other relevant applications of these complexes have not been considered, such as the emerging biochemical applications, mostly referred to Rh-NHC complexes [2], and the luminescent properties of some Ir-NHC complexes, mostly used for the fabrication of electro-optical devices [3]. 

Photo active iridium complexes are of potential in the organic EL device, which was also studied [83-86]. The introduction of the cationic luminescent iridium(III) complexes into negatively charged P(Glu) as a polymeric scaffold is allowed to perform the tuning of the emission properties in an aqueous media (Fig. 4.33) [87]. Increasing the ratio of the Glu unit of P(Glu) to the cationic cyclometalated... 

Abstract Pressure-sensitive paint (PSP) is applied to the areodynamics measurement. PSP is optical sensor based on the luminescence of dye probe molecules quenching by oxygen gas. Many PSPs are composed of probe dye molecules, such as polycyclic aromatic hydrocarbons (pyrene, pyrene derivative etc.), transition metal complexes (ruthenium(II), osumium(II), iridium(III) etc.), and metalloporphyrins (platinum (II), palladium(II), etc.) immobilized in oxygen permeable polymer (silicone, polystyrene, fluorinated polymer, cellulose derivative, etc.) film. Dye probe molecules adsorbed layer based PSPs such as pyrene derivative and porphyrins directly adsorbed onto anodic oxidised aluminium plat substrate also developed. In this section the properties of various oxygen permeable polymer for matrix and various dye probes for PSP are described. 

In the following sections, luminescent organometallic rhenium(I) and iridium(III) polypyridine complexes relying on the labelling or binding strategies mentioned above will be described. We focus on the molecular structures, spectroscopic and photophysical properties of the complexes, and the emissive behaviour and potential applications of the labelled bioconjugates. 

Luminescent cyclometallated iridium(III) complexes containing an extended planar diimine ligand, [Ir(ppy)2(NAN)]+ (27) (NAN = dpq, dpqa, dppz, dppn), have been synthesised and their photophysical properties studied [66], The complexes display long-lived green to orange 3MLCT (dTi(Ir) —> ji (NaN)) luminescence under ambient conditions but do not emit in aqueous solution. The binding of these complexes to... 

ES tuning effects on photophysical properties are quite evident in the luminescence spectrum of the iridium(III) complex ion Ir(Mephen)2ClJ (Mephen = 5,6-dimethyl-1,10-phenanthroline) in ambient-temperature dimethylformamide. This displays dual emission from thermally equilibrated MLCT and LF states. Increased pressure (300 MPa) leads to enhanced MLGT emission (550 nm) at the expense of the LF emission (720 nm) with little or no shift of peak maxima (Fig. 

Luminescent bioconjugates obtained by inserting two biotin residues in iridium (III) complexes (Scheme 11.7) exhibited interesting photophysical properties that are based on the jr-accepting properties of the bpy ligands [113]. They can be... 

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