Mechanistic Investigation of Improved Syntheses of Iridium(III)-Based OLED Phosphors

Lin, Chih‐Hsun; Chiu, Yuan-Chieh; Chi, Yun; Tao, Yu‐Tai; Liao, Liang‐Sheng; Tseng, Meu-Rurng; Lee, Gene‐Hsiang

doi:10.1021/om300325y

Cited by 33 publications

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References 45 publications

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“…The complex [Ir(tht) 3 Cl 3 ], tht=tetrahydrothiophene, was first reacted with an equal amount of 1,2‐bis(diphenylphosphino)benzene (dppBz) to afford [Ir(tht)(dppBz)Cl 3 ] ( 1 ). Its structure is akin to that of the di‐substitution product [Ir(tht)(PPh 3 ) 2 Cl 3 ] obtained from treatment of [Ir(tht) 3 Cl 3 ] with two equivalents of PPh 3 . The dppBz complex 1 possesses three chloride ligands arranged in meridional geometry.…”

Section: Resultsmentioning

confidence: 99%

“…Its structure is akin to that of the di-substitution product [Ir(tht)(PPh 3 ) 2 Cl 3 ]o btained from treatment of [Ir(tht) 3 Cl 3 ]w ith two equivalents of PPh 3 . [13] The dppBz complex 1 possesses three chloride ligands arranged in meridional geometry.T his structure is verified by NMR spectroscopies where peaks corresponding to a1 :1 ligand ratio of tht/dppBz are shown in the 1 HNMR spectrum and two set of doubletsa td = 15.43 and9 .85 (J PP = 2.9 Hz) for chemically distinct phosphorus atoms are present in the 31 PNMR spectrum.…”

Section: Syntheses and Characterizationsmentioning

confidence: 99%

“…In general,t he highere mission quantum yields (QY, F)a gainst those recorded in fluid states are caused by the rigide nvironments, which are expectedt or estrict the lengthening of Figure 6. Crystal structureo fc omplex 5 with thermalellipsoids shown at 30 %p robability level;only the ipso-carbons of four phenyl groups of dppBz chelates are shownfor clarity.Hydrogen atoms and solvates suchase thyl acetatea nd hexanem olecules are also omittedf or clarity.S electedb ond lengths:I r ÀN(1) = 2.113 (3), IrÀN(2) = 2.044 (3), IrÀN(5) = 2.056 (3), IrÀ N(6) = 2.096 (3), IrÀP(1) = 2.3007 (10), and IrÀP(2) = 2.2860(10) ;s elected angles:N (1)-Ir-N(2) = 77.65 (13), N(5)-Ir-N(6) = 85.53 (13), and P(1)-Ir-P(2) = 84.50(4)8. (3), IrÀP(1) = 2.2488 (9), IrÀP(2) = 2.2623 (9), IrÀ H = 1.43 (3), N(6)ÀH(6) = 0.75 (4), and N(3)···H(6) = 2.02(4) ;s elected angles: N(1)-Ir-N(2) = 74.94 (10),N(5)-Ir-H = 90.9(13), and P(1)-Ir-P(2) = 85.97 (3)8. Chem.…”

Section: Photophysical Propertiesmentioning

confidence: 99%

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Role of the Diphosphine Chelate in Emissive, Charge‐Neutral Iridium(III) Complexes

Liao

Devereux

Fox

et al. 2017

Chemistry A European J

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A class of neutral tris-bidentate Ir metal complexes incorporating a diphosphine as a chelate is prepared and characterized here for the first time. Treatment of [Ir(dppBz)(tht)Cl ] (1, dppBz=1,2-bis(diphenylphosphino)benzene, tht=tetrahydrothiophene) with fppzH (3-trifluoromethyl-5-(2'-pyridyl)-1H-pyrazole) afforded the dichloride complexes, trans-(Cl,Cl)[Ir(dppBz)(fppz)Cl ] (2) and cis-(Cl,Cl)[Ir(dppBz)(fppz)Cl ] (3). The reaction of 3 with the dianionic chelate precursor, 5,5'-di(trifluoromethyl)-3,3'-bipyrazole (bipzH ) or 5,5'-(1-methylethylidene)-bis(3-trifluoromethyl-1H-pyrazole) (mepzH ), in DMF gave the tris-bidentate complex [Ir(dppBz)(fppz)(bipz)] (4) or [Ir(dppBz)(fppz)(mepz)] (5), respectively. In contrast, a hydride complex [Ir(dppBz)(fppz)(bipzH)H] (6) was isolated instead of 4 in protic solvent, namely: diethylene glycol monomethyl ether (DGME). All complexes 2-6 are luminescent in powder form and thin films where the dichlorides (2, 3) emit with maxima at 590-627 nm (orange) and quantum yields (QYs) up to 90 % whereas the tris-bidentate (4, 5) and hydride (6) complexes emit at 455-458 nm (blue) with QYs up to 70 %. Hybrid (time-dependent) DFT calculations showed considerable metal-to-ligand charge transfer contribution to the orange-emitting 2 and 3 but substantial ligand-centered π-π* transition character in the blue-emitting 4-6. The dppBz does not participate in the radiative transitions in 4-6, but it provides the rigidity and steric bulk needed to promote the luminescence by suppressing the self-quenching in the solid state. Fabrication of an organic light-emitting diode (OLED) with dopant 5 gave a deep-blue CIE chromaticity of (0.16, 0.15). Superior blue emitters, which are vital in OLED applications, may be found in other neutral Ir complexes containing phosphine chelates.

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Section: Resultsmentioning

confidence: 99%

Section: Syntheses and Characterizationsmentioning

confidence: 99%

Section: Photophysical Propertiesmentioning

confidence: 99%

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Role of the Diphosphine Chelate in Emissive, Charge‐Neutral Iridium(III) Complexes

Liao

Devereux

Fox

et al. 2017

Chemistry A European J

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“…Notably, there are numerous examples of phosphine-directed CÀH activation of analogous substrates by iridium complexes in the literature to support the feasibility of these intermediates. [32][33][34][35] The proposed catalytically active complex is a bisboryl iridium(III) complex (F), rather than the generally accepted trisboryl complex due to the bidentate ligand serving as an LX-type ligand. [36] Since one of the boryl substituents is replaced by a carbon-based X ligand, the coordination of a second phosphine does not lead to a coordinatively saturated iridium complex.…”

Section: Tertiaryphosphineshaveplayedaprominentroleinthefieldmentioning

confidence: 99%

Phosphine‐Directed CH Borylation Reactions: Facile and Selective Access to Ambiphilic Phosphine Boronate Esters

et al. 2014

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Ambiphilic ligands have received considerable attention over the last two decades due to their unique reactivity as organocatalysts and ligands. The iridium-catalyzed CÀH borylation of phosphines is described in which the phosphine is used as a directing group to provide selective formation of arylboronate esters with unique scaffolds of ambiphilic compounds. A variety of aryl and benzylic phosphines were subjected to the reaction conditions, selectively providing stable, isolable boronate esters upon protection of the phosphine as the borane complex. After purification, the phosphine-substituted boronate esters could be deprotected and isolated in pure form.

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“…It is also mentioned that replacement of IrH 5 (PPr i 3 ) 2 with [IrCl 3 (tht) 3 ] allowed synthesis of unsaturated dichloro complex [Ir(k 2 -N,C-(qui-C 6 H 4 ))(PPr i 3 )Cl 2 ] (35), [31] which is related to the saturated analogue [Ir(dfppy)(PPh 3 )Cl 2 (tht)] (36) bearing an extra tht coordination ligand as reported earlier (Scheme 13). [32] Complex 36 was employed as versatile starting material for preparation of a range of blue-emitting Ir(III) metal phosphors by removal of both tht and PPh 3 , attributed to their weakly coordination character. Furthermore, the unsaturated character of 35 was confirmed by means of the X-ray diffraction analysis.…”

Section: Introductionmentioning

confidence: 99%

Emissive Iridium(III) Complexes with Phosphorous‐Containing Ancillary

Chi

Wang

Ganesan

2018

The Chemical Record

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Ir(III) metal complexes and related emitters bearing all kind of cyclometalated chromophoric chelates and non-chromophoric ancillary are extensively studied during the past three decades. Many of them have been found to display bright room temperature phosphorescence from triplet excited states in both solution and solid states, offering a possible application in contemporary optoelectronic technologies, including organic light emitting diodes, electrochemiluminescence, biological imaging and chemical sensing. Among reported materials, there are Ir(III) complexes with at least one phosphorus (P)-containing ligand and/or ancillary chelate, together with cyclometalates or equivalents that are in control of the actual emission energy. Particularly, possession of P-based donor can lead to divergent structural and photophysical properties compared to the traditional designs. This review aims to provide a literature overview as well as the authors' personal account to the development of relevant Ir(III) based phosphors bearing these P-donors. To the readers' convenience, the contents are subdivided into six sessions, according to whether or not they are charge natural, or with mono-or dianionic electronic character, and in accordance to their divergent bonding modes, i. e. monodentate, bidentate and tripodal coordination. In many cases, the P-based ancillaries offer an easy accessible route to the formation of efficient sky-blue and true-blue emitters due to their p-accepting property, together with enlarged emission energy gap and destabilized upper lying quenching state. . Emitters Bearing Monodentate P Donor Neutral Ir(III) metal complex [Ir(ppy) 2 (PBu n 3 )Cl] (5) depicted in Scheme 3, had been synthesized from treatment of dimer [Ir(ppy) 2 (m-Cl)] 2 with stoichiometric amount of P(n-Bu) 3 in CH 2 Cl 2 at RT. [8] It showed mixed 3 MLCT and pp* based emission profile with peak max. at 492 nm. Its emission is blue-shifted with respect to that of parent [Ir(ppy) 3 ], indicating the higher ligand field strength of phosphine and increased HOMO-LUMO energy gap. . His current research interests involve the design and evaluation of transition-metal based true-blue and NIR phosphors and thermally activated delay fluorescence materials for organic light emitting diodes (OLEDs). He has coauthored over 340 scientific articles with overall H-index > 61 and held over 50 patents worldwide. Scheme 1. Structural drawings of Os(II) complexes 1 and 2. Scheme 2. Structural drawings of Pt(II) complexes 3 and 4.

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Mechanistic Investigation of Improved Syntheses of Iridium(III)-Based OLED Phosphors

Cited by 33 publications

References 45 publications

Role of the Diphosphine Chelate in Emissive, Charge‐Neutral Iridium(III) Complexes

Role of the Diphosphine Chelate in Emissive, Charge‐Neutral Iridium(III) Complexes

Phosphine‐Directed CH Borylation Reactions: Facile and Selective Access to Ambiphilic Phosphine Boronate Esters

Emissive Iridium(III) Complexes with Phosphorous‐Containing Ancillary

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