Application of Iridium Catalysts in the Fine Chemicals Industry

Blaser, Hans‐Ulrich

doi:10.1002/9783527623075.ch1

Cited by 4 publications

(3 citation statements)

References 48 publications

(15 reference statements)

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“…Transition-metal hydride complexes are almost ubiquitous in organometallic catalysis and energy conversion and storage paradigms . In particular, those of iridium promote or mediate catalytic transformations of actual or potential industrial importance, , such as hydrogenations , and C–H bond functionalizations. − Behind this singular reactivity are factors such as the exceptional mobility of metal-bonded hydrogen atoms, which enables different facile inner- and outer-sphere migrations, , and their strong σ-donor character and trans influence as ligands, which often also determine the structures. The latter, however, become less decisive when other strong σ-donor ligands are present, as observed, for example, in hydride complexes with silyl-donor (PSiP) or boryl-donor (PBP) pincers .…”

Section: Introductionmentioning

confidence: 99%

Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers

et al. 2017

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This work describes synthetic routes from the known precursor [IrClH{κP,P,Si-Si(Me)(CH-2-PiPr)}] (1) to new hydride and polyhydride derivatives. Substituting the chloride ligand with triflate leads to the five-coordinate complex [IrH{κO-OS(CF)}{κP,P,Si-Si(Me)(CH-2-PiPr)}] (2), which can undergo reversible coordination of water (HO) or dihydrogen (H) to generate respectively the cationic derivative [IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}(OH)](CFSO) (3) or the neutral trans-hydride-dihydrogen [IrH{κO-OS(CF)}{κP,P,Si-Si(Me)(CH-2-PiPr)}(η-H)] (6) in equilibrium. The use of acetonitrile or carbon monoxide (CO) excess instead of water produces stable analogues of 3 (complexes 4 or 5, respectively). The reaction between 1 and NaBH affords the tetrahydroborate derivative [IrH{κH-HBH}{κP,P,Si-Si(Me)(CH-2-PiPr)}] (7), which can be protonated with triflic acid to form 2 or with HBF to give the dinuclear cationic derivative [(μ:κH,κH-BH)[IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}]](BF) (8). The reactions of 7 with alcohols afford either the dihydride-carbonyl [IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}(CO)] (9) or the known tetrahydride [IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}] (10), depending on the ease of alcohol decarbonylation. NMR observations and density functional theory calculations on the fluxional behavior of 10 indicate that the spatial contour of the mer PSiP framework conditions hydride-ligand exchanges. Complex 10 reacts with NaH in tetrahydrofuran to form the anionic trihydride [IrH{κP,P,Si-Si(Me)(CH-2-PiPr)}]Na (11), which exists as a mixture of fac and mer isomers in equilibrium.

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Section: Introductionmentioning

confidence: 99%

Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers

et al. 2017

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“…With this unique electronic configuration iridium shows various unique properties, that explores it broad area applications i.e. industrial, medical and catalysis [4,5,6,7]. Key process in photosynthesis is the photolysis of water means breaking of water molecules in hydrogen and oxygen [8,9].…”

Section: Iridium Chemistrymentioning

confidence: 99%

Iridium Chemistry and Its Catalytic Applications: A Brief

Singh

2016

gctl

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Iridium is very important element among the all transition metals with highest reported oxidation state i.e. +9 in gas phase existing species IrO4+. Instead of its less reactivity, it forms number of compounds having oxidation states between -3 to +9. It is second known densest element after osmium. Till now its toxicity and environmental impact is not much more reported and thus it may be use as green element in various fields of its application. Reason behinds it’s less toxicity and environmental impact may be due to its less reactivity and solubility. Corrosion and heat resistant properties of Iridium makes it much more useful element for alloying purpose. Iridium is the member of platinum family and used as catalyst due to its variable oxidation states. Iridium(III) complexes show great catalytic activity in both the acidic and basic medium for various organic as well as inorganic chemical transformations. Catalyst may be defined as the substance which can increases the rate of reaction of a specific chemical reaction without changing its own composition. Iridium is only one reported catalyst which is able to capture the sunlight and convert it into the chemical energy. Thus, it may be used in artificial photosynthesis process to solve our future food problem. Instead of these advantage, Iridium chemistry and its catalytic activity is not much reviewed till date, therefore, present review includes a brief introduction about chemistry and catalytic application of Iridium, which proof itself a boon for beginners to start their research career in the field of Iridium chemistry.

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“…The transition metal iridium (Ir) has been increasingly used in the industry due to its physical properties, including high mechanical strength, low oxidation at ambient conditions, corrosion resistant, large work function, high melting point, and high electrical conductivity. It has been widely applied in thermocouples and as an encapsulating material to stabilize and provide mechanical protection to radioisotopes used as nuclear fuels [1], in microelectronics for designing and implementing dynamic-and ferroelectric-random access memory electrodes [2], as gate electrodes in metal-oxide-semiconductor field-effect transistors [3], and as ohmic contact in diamond-based electronic devices [4], as coatings in spatial instrumentation to protect against ultraviolet radiation [5], in gas sensors [6] and catalytic processes [7,8]. In addition, Ir has been implicated in the design and characterization of metallic photonic-band-gap crystals [9].…”

Section: Introductionmentioning

confidence: 99%

Optical, Charge Transport, Thermal, Magnetic, Plasmonic, and Quantum Mechanical Properties of Iridium

Vargas¹,

Hernández-Jiménez²,

Quirós-Cordero³

et al. 2022

Recent Prog Mater

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Spectrophotometry has been widely used to retrieve the dielectric function of a bulk iridium sample using an extended version of the Drude–Lorentz model. The parameters of the model are optimized using a spectral-projected-gradient-method-assisted acceptance-probability-controlled simulated annealing approach. Furthermore, optimized values of Drude parameters corresponding to the optical response of electrons and holes (scattering frequency of electrons, the ratio between scattering frequencies of holes and electrons, the ratio between effective masses of electrons and holes, the ratio between the number densities of holes and electrons, and electron volume plasma frequency) are used to evaluate charge transport and magnetic properties. These include static and dynamic conductivities, intrinsic mean free paths, the effective mass of charge carriers and their number densities, Fermi velocities and energies, densities of states at Fermi energies, mobilities, specific heats, Hall’s coefficient, thermal conductivities, charge carrier coupling constant, paramagnetic and diamagnetic susceptibilities, and the number of Bohr magnetons. In addition, optimized resonance energy values of the Lorentz contribution to the dielectric function were compared with the background information provided by density-functional-theory calculations for iridium. A decomposition of the energy loss function was used as the starting point to calculate the effective numbers of bound electrons involved in interband transitions, as well as the densities of states at the final energies of the sets of transitions considered. The Drude–Lorentz model involves charge carrier parameters for both electrons and holes, as well as the resonance energies correlating with the energies associated with quantum transitions. To a large extent, several physical quantities calculated from optimized parameters exhibit values close to those obtained from measurements or by applying other models, including quantum mechanics formulations.

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Application of Iridium Catalysts in the Fine Chemicals Industry

Cited by 4 publications

References 48 publications

Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers

Cationic, Neutral, and Anionic Hydrides of Iridium with PSiP Pincers

Iridium Chemistry and Its Catalytic Applications: A Brief

Optical, Charge Transport, Thermal, Magnetic, Plasmonic, and Quantum Mechanical Properties of Iridium

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