Elongated Dihydrogen versus Compressed Dihydride in Osmium Complexes

Eguillor, Beatriz; Esteruelas, Miguel A.; Lezáun, Virginia; Oliván, Montserrat; Oñate, Enrique

doi:10.1002/chem.201605843

Cited by 28 publications

(29 citation statements)

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“…In the search for new molecular heteroleptic iridium(III) emitters, we decided to replace one of the phenyl substituents in 2,6‐diphenylpyridine by carbazol‐9‐yl and phenoxy groups (Figure ) to prepare [5t+4t′] complexes with one six‐membered heterometallacycle in their structure. 9‐(6‐Phenylpyridin‐2‐yl)‐9 H ‐carbazole (PhpyCzH) was prepared by Kim and Yoon and co‐workers in 2011, although its reactivity with metals has not been studied, whereas 2‐phenoxy‐6‐phenylpyridine (PhpyOPh) was described by Luo and Hu and co‐workers in 2013 and has proved to favor nonclassical interactions in the chemistry of transition‐metal polyhydrides . During the preparation of the target compounds we discovered novel η 1 ‐arene intermediates involving the carbazolyl and phenoxy substituents of the pyridines.…”

Section: Introductionmentioning

confidence: 99%

“…9-(6-Phenylpyridin-2-yl)-9H-carbazole (PhpyCzH) was prepared by Kim and Yoon and co-workers in 2011, [21] although its reactivity with metals has not been studied, whereas 2-phenoxy-6-phenylpyridine (PhpyOPh)w as described by Luo and Hu and co-workers in 2013 [22] andh as proved to favor nonclassical interactions in the chemistry of transition-metal polyhydrides. [23] During the preparation of the target compounds we discoveredn ovel h 1 -arene intermediates involving the carbazolyl and phenoxy substituents of the pyridines. In this paper we report the characterization of these intermediates, demonstrate that the coordination of the carbon atom to the metal cation produces at ransfer of electrophilicity from the metal to the IrÀCH hydrogen atom, and describe the photophysical properties of novel [5t + 4t']i ridium complexes.…”

Section: Introductionmentioning

confidence: 99%

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η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Esteruelas

Gómez-Bautista

López

et al. 2017

Chemistry A European J

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Molecular phosphorescent heteroleptic bis-tridentate iridium(III) emitters have been prepared via η -arene intermediates. In the presence of 4.0 mol of AgOTf, the complex [(IrCl{κ -N,C,N-(pyC HMe py)})(μ-Cl)] (1; pyC H Me py=1,3-di(2-pyridyl)-4,6-dimethylbenzene) reacted with 9-(6-phenylpyridin-2-yl)-9H-carbazole (PhpyCzH) and 2-phenoxy-6-phenylpyridine (PhpyOPh) to give [Ir{κ -N,C,N-(pyC HMe py)}{κ -C,N,C'-(C H pyCzH)}]OTf (2) and [Ir{κ -N,C,N-(pyC HMe py)}{κ -C,N,C'-(C H pyOPh)}]OTf (3). The X-ray diffraction structures of 2 and 3 reveal that the carbazolyl and phenoxy substituents of the C,N,C' ligand coordinate to the metal center to form an η -arene π bond. Treatment of 2 and 3 with KOtBu led to the deprotonation of the coordinated carbon atom of the η -arene group to afford the molecular phosphorescent [5t+4t'] heteroleptic iridium(III) complexes [Ir{κ -N,C,N-(pyC HMe py)}{κ -C,N,C'-(C H pyCz)}] (4) and [Ir{κ -N,C,N-(pyC HMe py)}{κ -C,N,C'-(C H pyOC H )}] (5). These complexes are green emitters that display short lifetimes and high quantum yields of 0.73 (4) and 0.87 (5) in the solid state.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Esteruelas

Gómez-Bautista

López

et al. 2017

Chemistry A European J

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“…Like in the [OTf]case, the substitution produces the elongation of the elongated dihydrogen which is converted into a compressed dihydride. The resulting species (4) was isolated as a green solid in almost quantitative yield (Scheme 7). The compressed dihydride character of the OsH 2 -unit is supported by the 1 H NMR spectrum, in dichloromethane-d 2 , of the obtained solid, which contains a broad signal at -7.21 ppm.…”

Section: Scheme 5 Position Exchange Of the Hydrogen Atoms Coordinatementioning

confidence: 99%

“…Thus, for instance, we have recently shown that the compressed dihydride [OsH 2 (C 6 H 4 pyPh)(P i Pr 3 ) 2 ]BF 4 eliminates 2,6-diphenylpyridine in acetonitrile, while the elongated dihydrogen [Os(C 6 H 4 pyOPh(η 2 -H 2 )(P i Pr 3 ) 2 ]BF 4 is stable toward the release of 2-phenoxy-6-phenylpyridine, under the same conditions (Scheme 1). 4…”

Section: Introductionmentioning

confidence: 99%

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Tuning the Nature and Formation of Bis(dihydrogen)–Osmium Species

et al. 2018

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The influence of chelate ligands in the formation and nature of bis(dihydrogen) units of OsH 4-complexes has been studied. The classical trihydride OsH 3 {κ 2-C,N-(C 6 H 4-py)}(P i Pr 3) 2 (1) reacts with HBF 4 •OEt 2 to give the Kubas-type dihydrogenelongated dihydrogen derivative [Os{κ 2-C,N-(C 6 H 4-py)}(η 2-H 2) 2 (P i Pr 3) 2 ]BF 4 (2), as a result of the protonation of one of the hydride ligands. Triflate (OTf) displaces the Kubas-type dihydrogen and elongates the elongated dihydrogen ligand, which is converted into a compressed dihydride. Thus, the addition of one equiv of HOTf to 1 leads to Os(H•••H){κ 2-C,N-(C 6 H 4-py)}(OTf)(P i Pr 3) 2 (3). Similarly to [OTf]-, acetone reacts with 2 to afford the related compressed dihydride [Os(H•••H){κ 2-C,N-(C 6 H 4-py)}(κ 1-OCMe 2)(P i Pr 3) 2 ]BF 4 (4), whereas acetonitrile leads to a 1:8 mixture of the monohydride [OsH(CH 3 CN) 3 (P i Pr 3) 2 ]BF 4 (5) and the trihydride [OsH 3 (CH 3 CN) 2 (P i Pr 3) 2 ]BF 4 (6). Reactions of 2 with toluene and p-xylene yield the half-sandwich derivatives [Os{κ 2-C,N-(C 6 H 4-py)}(η 6-toluene)(P i Pr 3)]BF 4 (7) and [Os{κ 2-C,N-(C 6 H 4-py)}(η 6-p-xylene)(P i Pr 3)]BF 4 (8), respectively. The acyl oxygen atom of the C,C-chelate ligand of the trihydride OsH 3 {κ 2-C,C-[C(O)CH 2 ImMe]}(P i Pr 3) 2 (10; Im = imidazolylidene) provides reliable and effective protection of the hydride ligands against the protonation. Thus, the addition of HBF 4 •OEt 2 or HOTf to 10 leads to the trihydride-hydroxycarbene cation [OsH 3 {κ 2-C,C-[C(OH)CH 2 ImMe]}(P i Pr 3) 2 ] + (11). The hydroxycarbene-NHC ligand of the latter is unstable, undergoing an intramolecular 1,3-hydrogen shift, which produces the rupture of the chelate ligand and the formation of the cis-hydride dihydrogen (12a) and trans-hydride-dihydrogen (12b) derivatives [OsH(η 2-H 2)(CO)(Me 2 Im)(P i Pr 3) 2 ] + (12). The protonation of 11 with a second equiv of HOTf affords the transient bis(Kubas-type dihydrogen) [Os(η 2-H 2) 2 {κ 2-C,C-[C(OH)CH 2 ImMe]}(P i Pr 3) 2 ](OTf) 2 , which undergoes the displacement of a coordinated hydrogen molecule by a [OTf]anion to give the Kubas-type dihydrogen [Os(OTf)(η 2-H 2){κ 2-C,C-[C(OH)CH 2 ImMe]}(P i Pr 3) 2 ]OTf (13). The addition of MeOTf to 10 leads to [OsH 3 {κ 2-C,C-[C(OMe)CH 2 ImMe]}(P i Pr 3) 2 ]OTf (14) which, in contrast to 11, is stable. Similarly to the latter, the protonation of 14 with HOTf yields the Kubas-type dihydrogen complex [Os(OTf)(η 2-H 2){κ 2-C,C-[C(OMe)CH 2 ImMe]}(P i Pr 3) 2 ]OTf (15).

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Metathesis between E−C(spⁿ) and H−C(sp³) σ‐Bonds (E=Si, Ge; n=2, 3) on an Osmium‐Polyhydride

et al. 2022

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The silylation of a phosphine of OsH 6 (P i Pr 3 ) 2 is performed via net-metathesis between SiÀ C(sp n ) and HÀ C(sp 3 ) σ-bonds (n = 2, 3). Complex OsH 6 (P i Pr 3 ) 2 activates the SiÀ H bond of Et 3 SiH and Ph 3 SiH to give OsH 5 (SiR 3 )(P i Pr 3 ) 2 , which yield OsH 4 {k 1 -P,η 2 -SiH-[ i Pr 2 PCH(Me)CH 2 SiR 2 H]}(P i Pr 3 ) and RÀ H (R = Et, Ph), by displacement of a silyl substituent with a methyl group of a phosphine. Such displacement is a first-order process, with activation entropy consistent with a rate determining step occurring via a highly ordered transition state. It displays selectivity, releasing the hydrocarbon resulting from the rupture of the weakest Si-substituent bond, when the silyl ligand bears different substituents. Accordingly, reactions of OsH 6 (P i Pr 3 ) 2 with dimethylphenylsilane, and 1,1,1,3,5,5,5-heptamethyltrisiloxane afford OsH 5 (SiR 2 R')(P i Pr 3 ) 2 , which evolve into OsH 4 {k 1 -P,η 2 -GeH-[ i Pr 2 PCH(Me)CH 2 SiR 2 H]}(P i Pr 3 ) (R = Me, OSiMe 3 ) and R'À H (R' = Ph, Me). Exchange reaction is extended to Et 3 GeH. The latter reacts with OsH 6 (P i Pr 3 ) 2 to give OsH 5 (GeEt 3 )(P i Pr 3 ) 2 , which loses ethane to form OsH 4 {k 1 -P,η 2 -GeH-[ i Pr 2 PCH(Me)CH 2 GeEt 2 H]}(P i Pr 3 ).

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Elongated Dihydrogen versus Compressed Dihydride in Osmium Complexes

Cited by 28 publications

References 42 publications

η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Tuning the Nature and Formation of Bis(dihydrogen)–Osmium Species

Metathesis between E−C(spⁿ) and H−C(sp³) σ‐Bonds (E=Si, Ge; n=2, 3) on an Osmium‐Polyhydride

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Elongated Dihydrogen versus Compressed Dihydride in Osmium Complexes

Cited by 28 publications

References 42 publications

η1‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

η1‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Tuning the Nature and Formation of Bis(dihydrogen)–Osmium Species

Metathesis between E−C(spn) and H−C(sp3) σ‐Bonds (E=Si, Ge; n=2, 3) on an Osmium‐Polyhydride

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η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

η¹‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Metathesis between E−C(spⁿ) and H−C(sp³) σ‐Bonds (E=Si, Ge; n=2, 3) on an Osmium‐Polyhydride