Emissive Iridium(III) Complexes with Phosphorous‐Containing Ancillary

Abstract

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.

Acetylides for the Preparation of Phosphorescent Iridium(III) Complexes: Iridaoxazoles and Their Transformation into Hydroxycarbenes and N,C(sp3),C(sp2),O-Tetradentate Ligands

“…A recent review about some advances in synthesis of molecular heteroleptic osmium and iridium phosphorescent emitters has pointed out that improvements in the field would come over as a consequence of the development of new procedures of organometallic synthesis, 10 for which the handling of alternative starting complexes is crucial. Dimers trans -[Ir(μ-Cl)(3b) 2 ] 2 have been traditionally the usual starting point for the preparation of heteroleptic emitters of classes [3b + 3b + 3b′] 11 and [3b + 3b + 2m + 1m′] 12 (2m = 2e donor monodentate, 1m = 1e donor monodentate). A handicap of these dimers, which appears to be responsible for the lack of structural diversity between the resulting emitters, is the retention of the stereochemistry of their mononuclear half during the emitter preparation process.…”

Multifunctional Heterometallic IrIII−AuI Probes as Promising Anticancer and Antiangiogenic Agents

“… [30] Therefore, this emission is assigned mainly to a 3 MLCT rather than 3 LC transitions, which contrapose other iridium complexes containing diphosphine ligands. [ 29 , 31 , 32 ] The main difference in this particular case is the highly constricted iridium coordination sphere, due to the small chelate P−Ir−P angle, together with the nature of the anionic Ph 2 PCHPPh 2 − bifunctional ligand. Such effects might be the reason for the prevalence of the 3 MLCT character over that of 3 LC.…”

“…5, 131.9, 131.7, 131.1, 130.5, 130.3, 130.0, 129.8, 129.3, 129.0, 128.8, 128.7, 124.9, 123.5, 123.4, 122.9, 122.3, 120.3, 118.7, 34.4 ppm. 31 P NMR (162 MHz, CD 2 Cl 2 ): δ = À 56.85 ppm. IR: ν(AuÀ Cl): 335 cm À 1 ).…”

Copper-Catalyzed Radical Hydrazono-Phosphorylation of Alkenes

“…Organophosphorus compounds are valuable chemicals with wide applications in areas such as agriculture, medicine, and materials . As a result, there is a continued demand for the development of practical methods for constructing a carbon–phosphorus bond in an economical manner.…”