Synthesis and Molecular Structure of the New Green Emitting Complex [Ir₂(μ₂‐oxamidato‐N,N′,O,O′)(2‐(p‐tolyl)pyridinato)₄]

Abstract

The reaction of the complex [{Ir(μ‐Cl)(ptpy)2}2] (1) with oxamide in methanol in the presence of sodium methylate as the base was investigated. During the reaction the new complex [Ir2(μ2‐oxamidato‐N,N′,O,O′)(ptpy)4] (2), ptpy = 2‐(p‐tolyl)pyridinato was obtained. The molecular structure of compound 2 was determined by an X‐ray diffraction study. 2 crystallized from dichloromethane/methanol as a dihydrate in the orthorhombic space group Pbcm. This new compound displays intense green phosphorescence, with φPL = 60 %, stemming from the lowest triplet state of the 3MLCT/LC character.

Synthesis, Diastereomer Separation, and Optoelectronic and Structural Properties of Dinuclear Cyclometalated Iridium(III) Complexes with Bridging Diarylhydrazide Ligands

“…5 Å. 23,26,27,32,34,40,47 (It is noteworthy that with [Ir(ppy) 2 µ-Cl] 2 -type complexes where the Ir-Ir distances are <4 Å only the less sterically congested rac ΔΔ/ɅɅ diastereomers have been reported to date [15][16][17][18]39,[48][49][50][51][52][53][54][55] ). For 13-16 the diastereomers were separated by fractional crystallization, silica column chromatography, or a combination of the two techniques.…”

Bimetallic Cyclometalated Iridium(III) Diastereomers with Non‐Innocent Bridging Ligands for High‐Efficiency Phosphorescent OLEDs

“…The peaks for the two different pyridine rings (A and B) and the two phenylene rings (C and D) were assigned with the aid of 1 H-1 H 2D COSY spectra ( Figure S2 and S4). Whereas studies [21,22,30] on the enantiomer separation of monoiridium complexes have been reported, the facile separation of diastereomers of a diiridium complex into their pure forms, such as complexes 3 and 4, has, to the best of our knowledge, not been demonstrated previously. The electrochemical properties of 3 and 4 were examined by cyclic voltammetry in dichloromethane (CH 2 Cl 2 ) solutions.…”

“…[1b, 3-5] Cyclometalated iridium(III) complexes are widely exploited because of their excited-state lifetimes on the microsecond time scale, high quantum yields, good thermal and chemical stability, and tunability of the emission color. [6][7][8][9][10] In this context, the prototype complex is fac-[Ir(ppy) 3 ] (ppy = 2-phenylpyridine).The photoluminescence quantum yields of dinuclear metal complexes [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] are usually considerably lower than those of their mononuclear analogues [12,14,23,24] (although there are exceptions), [25] leading to the established view that dinuclear complexes give poor device performance. [26,27] For example, the quantum yield of the bis(m-Cl) bridged dimer [{Ir(ppy) 2 Cl} 2 ] (1) is only 0.5 %, [11] whereas that of fac-[Ir(ppy) 3 ] is 40(AE0.1) % (both in toluene).…”

Bimetallic Cyclometalated Iridium(III) Diastereomers with Non‐Innocent Bridging Ligands for High‐Efficiency Phosphorescent OLEDs

“…The peaks for the two different pyridine rings (A and B) and the two phenylene rings (C and D) were assigned with the aid of 1 H– 1 H 2D COSY spectra (Figure S2 and S4). Whereas studies21, 22, 30 on the enantiomer separation of monoiridium complexes have been reported, the facile separation of diastereomers of a diiridium complex into their pure forms, such as complexes 3 and 4 , has, to the best of our knowledge, not been demonstrated previously.…”