Iridium dioxygen complexes in the oxidation of substrates: kinetics, mechanism, and steric and electronic effects in the oxidation of carbon monoxide, carbon dioxide, triphenylphosphine, and sulfur dioxide by RIr(O2)(CO)L2 (R = methyl, phenyl, neopentyl; L = tri-p-tolylphosphine, triphenylphosphine, methyldiphenylphosphine, tri-p-anisylphosphine)

Lawson, Holly J.; Atwood, Jim D.

doi:10.1021/ja00198a037

Cited by 40 publications

(33 citation statements)

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“…The 1 H NMR spectrum for reaction of H 2 SO 4 with trans-Ir(CO)(Cl)(TPPTS) 2 in H 2 O showed two hydrides, one of these (-15.8 (t) ppm) corresponds to the HCl addition product Ir(CO)(Cl) 2 (H)(TPPTS) 2 (7) prepared independently and, in combination with the 31 P NMR data, confirms the presence of this complex. 3 The chemical shifts in the 31 P NMR (7.5 (s) ppm) and the IR spectra (ν CO = 2060 cm -1) suggest that the other hydride complex (-14.8 (t) ppm, J P-H = 11 Hz) is the six-coordinate cation, Ir(CO)(Cl)(H)(OH 2 )(TPPTS) 2 ] + HSO 4 -. There was no evidence for formation of a sulfate complex.…”

Section: Resultsmentioning

confidence: 99%

“…One of the main advantages of these complexes is that triphenylphosphine can be easily substituted by a different phosphine ligand and thus the effect of changing the electronic and steric environment around the metal center can be monitored. For example, studies on O 2 binding have increased the understanding of steric and electronic factors in dioxygen coordination (4). In addition the recent development of water-soluble phosphines such as the trisulfonated triphenylphosphine derivative, TPPTS (TPPTS = P(m-C 6 H 4 SO 3 Na) 3 ), means that watersoluble square-planar metal complexes can be made and hence the effect of carrying out these reactions in water can be investigated.…”

Section: Introductionmentioning

confidence: 99%

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Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

Bowden¹,

Atwood²

2001

Can. J. Chem.

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Reaction of SO 2 with trans-Ir(CO)(Cl)(TPPTS) 2 in water mirrors the nature of SO 2 dissolved in water. At low pH (pH = 1) where SO 2 exists as the hydrated species SO 2 ·H 2 O, only Ir(CO)(Cl)(SO 2 )(TPPTS) 2 forms. At higher pH (pH = 6) where HSO 3 -dominates, no SO 2 complex is observed and a hydride, Ir(CO)(Cl)(H)(OH)(TPPTS) 2 , is the primary product. A mixture of SO 2 and O 2 does not lead to an iridium sulfate or show any evidence of the dioxygen adduct upon reaction in water with trans-Ir(CO)(Cl)(TPPTS) 2 , in contrast to the analogous reaction in organic solvents. In water, only the SO 2 complex, Ir(CO)(Cl)(SO 2 )(TPPTS) 2 , is observed prior to decomposition. The contrasts to the PPh 3 analogues in organic solvents provide further insight to water as a solvent for organometallic complexes.Résumé : La réaction du SO 2 avec le trans-Ir(CO)(Cl)(TPPTS) 2 dans l'eau est un miroir de la nature du SO 2 dissous dans l'eau. À faible pH (pH = 1), alors que le SO 2 existe sous la forme d'espèces hydratées SO 2 ·H 2 O, il ne se forme que du Ir(CO)(Cl)(SO 2 )(TPPTS) 2 . À des pH plus élevés (pH = 6), alors que l'anion HSO 3 -prédomine, on n'observe pas de formation de complexe avec le SO 2 et le produit primaire est un hydrure, Ir(CO)(Cl)(H)(OH)(TPPTS) 2 . Un mé-lange de SO 2 et de O 2 ne conduit pas à la formation d'un sulfate d'iridium; de plus, on ne détecte aucune indication de formation d'un adduit avec le dioxygène lors de la réaction dans l'eau du trans-Ir(CO)(Cl)(TPPTS) 2 et ceci est en opposition avec la réaction analogue dans les solvants organiques. Dans l'eau, on n'observe que la formation du complexe avec le SO 2 , Ir(CO)(Cl)(SO 2 )(TPPTS) 2 , avant sa décomposition. Le contraste avec les analogues PPh 3 dans les solvants organiques permet de comprendre le mécanisme d'action de l'eau comme solvant pour les complexes organométalliques.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

Bowden¹,

Atwood²

2001

Can. J. Chem.

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“…The oxidation of carbon dioxide to peroxocarbonates has also been reported. This was achieved by reaction of [Ir(CH 3 ){P(p‐tolyl) 3 } 2 (CO)(O 2 )] with CO 2 , which leads quantitatively to [Ir(CH 3 ){P( p ‐tolyl) 3 } 2 (CO){OOC(O)O}] 31. Mechanistic studies seem to suggest that the oxidation happens without previous coordination of the CO 2 molecule to the metal center.…”

Section: Coordination Chemistry and Reactivitymentioning

confidence: 99%

CO₂ Activation and Catalysis Driven by Iridium Complexes

et al. 2013

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Recent reports on homogeneous catalytic transformation of carbon dioxide by iridium complexes have prompted us to review the area. Progress on new iridium catalysts for carbon dioxide transformations should take into account the interaction of carbon dioxide with the iridium center, which seems to be governed by the oxidation state of iridium and the nature of the carbon dioxide molecule. Most examples of iridium catalyzed carbon dioxide reductions are based on IrIII centers. These reactions take place through outer‐sphere mechanisms, by means of nucleophilic attack on the carbon atom. In all the reported systems, the nucleophile is always a hydrido ligand coordinated to a IrIII center. Future challenges on iridium catalyzed functionalization of carbon dioxide include the development of efficient electrophiles, compatible with the inclusion of appropriate nucleophiles, which would allow the preparation of value‐added organic molecules using CO2 as C1 feedstock.

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“…(It should be noted that 9′ is isoelectronic with known Ir(III) dioxygen complexes. 33 ) A transition state for dioxygen loss from 9′ (TS9′; see the SI) was located 7.6 kcal/mol above 9′, showing that formation of 9′ and water would be rate-limiting.…”

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confidence: 94%

Dihydrogen Trioxide (HOOOH) Photoelimination from a Platinum(IV) Hydroperoxo-Hydroxo Complex

Wickramasinghe

Sharp

2014

J. Am. Chem. Soc.

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Photolysis (380 nm) of trans-Pt(PEt3)2(Cl)(OH)(OOH)(4-trifluoromethylphenyl) (1) at -78 °C in acetone-d6 or toluene-d8 yields HOOOH (16-20%) and trans-Pt(PEt3)2(Cl)(4-trifluoromethylphenyl) (2). Also observed in acetone-d6 are H2O2, (CD3)2C(OH)(OOH), and (CD3)2C(OOH)2. Thermal decomposition or room-temperature photolysis of 1 gives O2, water, and 2. Computational modeling (DFT) suggests two intramolecular hydrogen-bonding-dependent triplet pathways for the photolysis and two possible pathways for the thermolysis, one involving proton transfer from the OOH to the OH ligand and the other homolysis of the Pt-OOH bond, abstraction of the OH ligand, and decomposition of the resulting H2O3. Trapping studies suggest the latter pathway.

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Cited by 40 publications

References 1 publication

Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

CO₂ Activation and Catalysis Driven by Iridium Complexes

Dihydrogen Trioxide (HOOOH) Photoelimination from a Platinum(IV) Hydroperoxo-Hydroxo Complex

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Cited by 40 publications

References 1 publication

Reactions of SO2 with trans-Ir(CO)(Cl)(TPPTS)2 in water

Reactions of SO2 with trans-Ir(CO)(Cl)(TPPTS)2 in water

CO2 Activation and Catalysis Driven by Iridium Complexes

Dihydrogen Trioxide (HOOOH) Photoelimination from a Platinum(IV) Hydroperoxo-Hydroxo Complex

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Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

Reactions of SO₂ with trans-Ir(CO)(Cl)(TPPTS)₂ in water

CO₂ Activation and Catalysis Driven by Iridium Complexes