Selective Synthesis and Photophysical Properties of Phosphorescent Heteroleptic Iridium(III) Complexes with Two Different Bidentate Groups and Two Different Monodentate Ligands

Esteruelas, Miguel A.; Oñate, Enrique; Palacios, Adrián

doi:10.1021/acs.organomet.7b00108

Cited by 24 publications

(13 citation statements)

References 95 publications

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“…The d 4 pentahydride IrH 5 (P i Pr 3 ) 2 displays an ability similar to that of the d 2 hexahydride OsH 6 (P i Pr 3 ) 2 to activate C–H bonds. , Polyhydride-promoted C–H bond activation reactions have been revealed as useful procedures to prepare phosphorescent emitters of both osmium and iridium . Our interest in σ bond activation reactions, and in the influence of the bite angles of the pincer ligands on the chemistry and the photophysical properties of their complexes, prompted us to study the reactivity of IrH 5 (P i Pr 3 ) 2 toward 2,6-diphenylpyridine and 2-phenoxy-6-phenylpyridine and to compare the emissive properties of the resulting iridium(III) hydride complexes with those of the compressed osmium(IV) dihydride compounds A and B shown in Scheme .…”

Section: Introductionsupporting

confidence: 81%

Influence of the Bite Angle of Dianionic C,N,C-Pincer Ligands on the Chemical and Photophysical Properties of Iridium(III) and Osmium(IV) Hydride Complexes

et al. 2019

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The study of the reactions of IrH 5 (P i Pr 3) 2 (1) with 2,6-diphenylpyridine and 2-phenoxy-6-phenylpyridine and the photophysical characterization of some of the resulting compounds, as well as their osmium-counterparts, reveal that the bite angle of dianionic C,N,C-pincer ligands has a marked influence on the chemical and photophysical properties of iridium(III)-and osmium(IV)-hydride complexes. Complex 1 promotes a double o-CH bond activation of both disubstituted pyridines. The reaction with 2,6-diphenylpyridine directly leads to IrH{κ 3-C,N,C-(C 6 H 4-py-C 6 H 4)}(P i Pr 3) 2 (2), whereas the activation of 2-phenoxy-6phenylpyridine is sequential and slower. Initially, the phenyl activation gives IrH 2 {κ 2-C,N-(C 6 H 4-py-OPh)}(P i Pr 3) 2 (3), which subsequently evolves to IrH{κ 3-C,N,C-(C 6 H 4-py-OC 6 H 4)}(P i Pr 3) 2 (4). Complexes 2 and 4 are Brønsted bases, which react with HBF 4 •OEt 2. The protonation of the hydride position is elusive; the proton of the acid is selectively added to one of the metalated substituents. Thus, the reaction with 2 affords [IrH{κ 3-C,N,(C-H)-(C 6 H 4-py-Ph)}(P i Pr 3) 2 ]BF 4 (5), in which the formed C-H bond remains coordinated. The protonation of 4 selectively occurs at the phenoxy substituent to give the five-coordinate cationic complex [IrH{κ 2-C,N-(C 6 H 4-py-OPh)}(P i Pr 3) 2 ]BF 4 (6) bearing a free OPh group. In contrast to 5, complex 6 inserts acetylene and phenylacetylene into the Ir-H bond to yield [Ir{(E)-CH=CHR}{κ 2-C,N-(C 6 H 4-py-OPh)}(P i Pr 3) 2 ]BF 4 (R = H (7), Ph (8)). Complexes 2 and 4 and their osmium(IV)-counterparts OsH 2 {κ 3-C,N,C-(C 6 H 4-py-C 6 H 4)}(P i Pr 3) 2 (A) and OsH 2 {κ 3-C,N,C-(C 6 H 4-py-OC 6 H 4)}(P i Pr 3) 2 (B) are phosphorescent emitters, which display emission wavelengths between 473 nm and 619 nm and quantum yields between 0.03 and 0.96 depending upon the metal center and the presence or absence of the oxygen atom in the pincer ligand. RESULTS AND DISCUSSION C-H Bond Activation Reactions. Pentahydride IrH 5 (P i Pr 3) 2 (1) promotes the o-CH bond activation of both substituents of 2,6-diphenylpyridine and 2-phenoxy-6-phenylpyridine. Interestingly, the rate of the C-H rupture depends upon the substituent. Thus, the phenyl activation is much faster than that of the phenoxide group. The reaction of 1 with 2,6-diphenylpyridine in toluene under reflux leads to the monohydride-iridium(III) derivative IrH{κ 3-C,N,C-(C 6 H 4-py-C 6 H 4)}(P i Pr 3) 2 (2), which was isolated as a yellow solid in 52%, after 14 h (Scheme 3), and characterized by X-ray diffraction analysis. Figure 1 shows a view of the structure, which proves the formation of the C,N,C-pincer

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Section: Introductionsupporting

confidence: 81%

Influence of the Bite Angle of Dianionic C,N,C-Pincer Ligands on the Chemical and Photophysical Properties of Iridium(III) and Osmium(IV) Hydride Complexes

et al. 2019

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“…Coherent synthetic methods for the preparation of phosphorescent heteroleptic iridium(III) emitters of the class [3b + 3b' + 2 m + 1 m'], based on 2-phenylquinoline and acetylacetonate (acac), with controlled stereochemistry, have also been developed starting from the pentahydride 51 (Scheme 15 and Scheme 16). [40] Complex 51 activates an ortho-CH bond of the phenyl substituent of 2-phenylquinoline to give the dihydride derivative 55. This compound acts as a Brønsted base.…”

Section: Iridium(iii) Emittersmentioning

confidence: 99%

Recent Advances in Synthesis of Molecular Heteroleptic Osmium and Iridium Phosphorescent Emitters

2021

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The application of new procedures of organometallic synthesis based on alternative starting complexes has given rise to a significant enhancement in the preparation of osmium(IV), osmium(II), and iridium(III) emitters, since 2012. The choice of the precursors should be done taking into account its ligands, since they may cooperate in the emitter synthesis. Three different functions are clearly pointed out in the revised procedures: the ligands of the starting compounds can direct the selectivity of competitive ruptures of σ-bonds of the chromophores, without having direct participation in the activation; on the contrary, they can directly participate in the generation of a ligand, being a part of the new coordinated group; and the ligands can also act as internal base in σ-bond heterolytic activation reactions. In addition, the ability of the polyhydrides OsH 6 (P i Pr 3 ) 2 and IrH 5 (P i Pr 3 ) 2 to activate CÀ H bonds is pointed out as one of the determining factors of the success in many cases.

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“…Acetylene and terminal alkynes react with Ir complex 153 to produce five-coordinate styryl derivatives 154 ( Scheme 80 ). The short-lived yellow-orange six-coordinate vinyl complexes are emissive upon photoexcitation [ 187 ].…”

Section: Acetylene In Organic Synthesismentioning

confidence: 99%

Acetylene in Organic Synthesis: Recent Progress and New Uses

et al. 2018

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Recent progress in the leading synthetic applications of acetylene is discussed from the prospect of rapid development and novel opportunities. A diversity of reactions involving the acetylene molecule to carry out vinylation processes, cross-coupling reactions, synthesis of substituted alkynes, preparation of heterocycles and the construction of a number of functionalized molecules with different levels of molecular complexity were recently studied. Of particular importance is the utilization of acetylene in the synthesis of pharmaceutical substances and drugs. The increasing interest in acetylene and its involvement in organic transformations highlights a fascinating renaissance of this simplest alkyne molecule.

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Selective Synthesis and Photophysical Properties of Phosphorescent Heteroleptic Iridium(III) Complexes with Two Different Bidentate Groups and Two Different Monodentate Ligands

Abstract: Rational synthetic procedures for the preparation of phosphorescent heteroleptic iridium(III) complexes, with con-

Cited by 24 publications

References 95 publications

Influence of the Bite Angle of Dianionic C,N,C-Pincer Ligands on the Chemical and Photophysical Properties of Iridium(III) and Osmium(IV) Hydride Complexes

Influence of the Bite Angle of Dianionic C,N,C-Pincer Ligands on the Chemical and Photophysical Properties of Iridium(III) and Osmium(IV) Hydride Complexes

Recent Advances in Synthesis of Molecular Heteroleptic Osmium and Iridium Phosphorescent Emitters

Acetylene in Organic Synthesis: Recent Progress and New Uses

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