Alkoxy/siloxy group exchange in the system vinyltrialkoxysilane–iridium(<scp>i</scp>) siloxide complex

Kownacki, Ireneusz; Marciniec, Bogdan; Kubicki, Maciej

doi:10.1039/b208603b

Cited by 9 publications

(4 citation statements)

References 14 publications

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“…As in complex 1, the four-membered ring "IrNIrN" of complex 2 shows a folded conformation; the dihedral angle between the coordination planes defined by N(1)-Ir(1)-N(2) and N(1)-Ir(2)-N(2) is 119.2(4)8, and consequently, a relatively short metal-metal distance of 2.8146(3) was observed. This value, shorter than that found in the related [26] is close to the mean value found in dinuclear Ir compounds involving two bridging N atoms (2.584-2.968 , mean value 2.781(12) ). [27] In fact a deeper analysis of these "IrNIrN" central cores revealed a direct relationship between the intermetallic distance and the four-membered-ring folding (similar to that observed for "RhORhO" fragments).…”

Section: Resultssupporting

confidence: 70%

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Mena

Jaseer

Garcı́a-Orduña

et al. 2013

Chemistry A European J

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The ready availability of rare parent amido d(8) complexes of the type [{M(μ-NH2)(cod)}2] (M=Rh (1), Ir (2); cod=1,5-cyclooctadiene) through the direct use of gaseous ammonia has allowed the study of their reactivity. Both complexes 1 and 2 exchanged the di-olefines by carbon monoxide to give the dinuclear tetracarbonyl derivatives [{M(μ-NH2)(CO)2}2 ] (M=Rh or Ir). The diiridium(I) complex 2 reacted with chloroalkanes such as CH2Cl2 or CHCl3, giving the diiridium(II) products [(Cl)(cod)Ir(μ-NH2)2Ir(cod)(R)] (R=CH2Cl or CHCl2) as a result of a two-center oxidative addition and concomitant metal-metal bond formation. However, reaction with ClCH2CH2Cl afforded the symmetrical adduct [{Ir(μ-NH2)(Cl)(cod)}2] upon release of ethylene. We found that the rhodium complex 1 exchanged the di-olefines stepwise upon addition of selected phosphanes (PPh3, PMePh2, PMe2Ph) without splitting of the amido bridges, allowing the detection of mixed COD/phosphane dinuclear complexes [(cod)Rh(μ-NH2)2Rh(PR3)2], and finally the isolation of the respective tetraphosphanes [{Rh(μ-NH2)(PR3)2}2]. On the other hand, the iridium complex 2 reacted with PMe2 Ph by splitting the amido bridges and leading to the very rare terminal amido complex [Ir(cod)(NH2)(PMePh2)2]. This compound was found to be very reactive towards traces of water, giving the more stable terminal hydroxo complex [Ir(cod)(OH)(PMePh2)2]. The heterocyclic carbene IPr (IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) also split the amido bridges in complexes 1 and 2, allowing in the case of iridium to characterize in situ the terminal amido complex [Ir(cod)(IPr)(NH2)]. However, when rhodium was involved, the known hydroxo complex [Rh(cod)(IPr)(OH)] was isolated as final product. On the other hand, we tested complexes 1 and 2 as catalysts in the transfer hydrogenation of acetophenone with iPrOH without the use of any base or in the presence of Cs2CO3, finding that the iridium complex 2 is more active than the rhodium analogue 1.

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Section: Resultssupporting

confidence: 70%

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Mena

Jaseer

Garcı́a-Orduña

et al. 2013

Chemistry A European J

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“…The Ir–Ir distances are 2.7507(3)–2.8737(4) Å. These Ir–Ir distances are comparable to those reported for [(cod)Ir(μ-NH 2 )] 2 (2.8146(3) Å) and [(cod)Ir(μ-OEt)] 2 (2.8958(11) Å) . The Ir–O bond lengths (2.055(3)–2.086(3) Å) are at the longer side among the known Ir-oxo bond lengths (1.73–2.14 Å), ,− , reflecting the low metal oxidation state and small Ir–O multiple bond nature in 2 .…”

Section: Resultssupporting

confidence: 76%

Anionic Trinuclear Iridium(I) Oxo Complex: Synthesis and Reactivity as a Metal-Centered σ-Donor Ligand to Gold(I) and Silver(I)

2018

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The diiridium(I) μ-hydroxo complex [Ir(μ-OH)(cod)] 2 (1; cod = 1,5-cyclooctadiene) readily reacted with aqueous NaOH in DMSO-d 6 or NaN(SiMe 3 ) 2 in THF to give the anionic trinuclear iridium oxo complex Na[{Ir(cod)) upon recrystallization from THF−hexane. Reactions of 2 with group 11 metal electrophiles (AuCl(PPh 3 ), AgCl(PPh 3 ), and AgCl) afforded iridium−gold and −silver mixed-metal cluster complexes [{Ir(cod)} 3 (μ 3 -O) 2 M(PPh 3 )] (3a: M = Au; 3b: M = Ag) and [Na(dmso) 3 (μ-dmso)] 2 [{Ir(cod)} 3 (μ 3 -O) 2 Ag(μ-Cl)] 2 (4) containing Ir(I) → Au(I)/Ag(I) dative interactions as revealed by DFT and NBO analysis. These results demonstrate the ability of 2 to act as an iridium(I)-centered σ-donor ligands to the group 11 metal centers. Single-crystal X-ray structures of 2•(THF) 2 (H 2 O), 3a, 3b, and 4 are presented.

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“…The Ir–O distance in 3 (1.935 Å) is consistent with a bridging oxo ligand, which range from 1.902 to 2.139 Å, as opposed to Ir 2 (μ-hydroxo) , and Ir 2 (μ-alkoxo) ligands which range from 2.059 to 2.145 Å and 2.078 to 2.160 Å respectively.…”

Section: Results and Discussionmentioning

confidence: 82%

Oxyfunctionalization with Cp*Ir^III(NHC)(Me)(Cl) with O₂: Identification of a Rare Bimetallic Ir^IV μ-Oxo Intermediate

et al. 2015

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Methanol formation from [Cp*Ir(III)(NHC)Me(CD2Cl2)](+) occurs quantitatively at room temperature with air (O2) as the oxidant and ethanol as a proton source. A rare example of a diiridium bimetallic complex, [(Cp*Ir(NHC)Me)2(μ-O)][(BAr(F)4)2], 3, was isolated and shown to be an intermediate in this reaction. The electronic absorption spectrum of 3 features a broad observation at ∼660 nm, which is primarily responsible for its blue color. In addition, 3 is diamagnetic and can be characterized by NMR spectroscopy. Complex 3 was also characterized by X-ray crystallography and contains an Ir(IV)-O-Ir(IV) core in which two d(5) Ir(IV) centers are bridged by an oxo ligand. DFT and MCSCF calculations reveal several important features of the electronic structure of 3, most notably, that the μ-oxo bridge facilitates communication between the two Ir centers, and σ/π mixing yields a nonlinear arrangement of the μ-oxo core (Ir-O-Ir ∼ 150°) to facilitate oxygen atom transfer. The formation of 3 results from an Ir oxo/oxyl intermediate that may be described by two competing bonding models, which are close in energy and have formal Ir-O bond orders of 2 but differ markedly in their electronic structures. The radical traps TEMPO and 1,4-cyclohexadiene do not inhibit the formation of 3; however, methanol formation from 3 is inhibited by TEMPO. Isotope labeling studies confirmed the origin of the methyl group in the methanol product is the iridium-methyl bond in the [Cp*Ir(NHC)Me(CD2Cl2)][BAr(F)4] starting material. Isolation of the diiridium-containing product [(Cp*Ir(NHC)Cl)2][(BAr(F)4)2], 4, in high yields at the end of the reaction suggests that the Cp* and NHC ligands remain bound to the iridium and are not significantly degraded under reaction conditions.

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Alkoxy/siloxy group exchange in the system vinyltrialkoxysilane–iridium(i) siloxide complex

Cited by 9 publications

References 14 publications

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Anionic Trinuclear Iridium(I) Oxo Complex: Synthesis and Reactivity as a Metal-Centered σ-Donor Ligand to Gold(I) and Silver(I)

Oxyfunctionalization with Cp*Ir^III(NHC)(Me)(Cl) with O₂: Identification of a Rare Bimetallic Ir^IV μ-Oxo Intermediate

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Alkoxy/siloxy group exchange in the system vinyltrialkoxysilane–iridium(i) siloxide complex

Cited by 9 publications

References 14 publications

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Terminal and Bridging Parent Amido 1,5‐Cyclooctadiene Complexes of Rhodium and Iridium

Anionic Trinuclear Iridium(I) Oxo Complex: Synthesis and Reactivity as a Metal-Centered σ-Donor Ligand to Gold(I) and Silver(I)

Oxyfunctionalization with Cp*IrIII(NHC)(Me)(Cl) with O2: Identification of a Rare Bimetallic IrIV μ-Oxo Intermediate

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Oxyfunctionalization with Cp*Ir^III(NHC)(Me)(Cl) with O₂: Identification of a Rare Bimetallic Ir^IV μ-Oxo Intermediate