The average price for iridium in 2023 was nearly 4,700 U.S. dollars per troy ounce, an increase compared to the previous year. This figure was still lower than the peak of 5,100 U.S. dollars recorded in 2021. Iridium is a transition metal and a platinum group metal. It is one of the most corrosion-resistant metals and is also one of the rarest elements in the Earth's crust.
The average annual price for iridium in 2020 was 2,550 U.S. dollars per troy ounce. The price of iridium dramatically increased in March 2021, to 6,000 U.S. dollars per troy ounce as a result of supply shortages combined with its prospective use to produce green hydrogen.
Iridium is a transition metal and a platinum group metal. It is one of the most corrosion-resistant metals and is also one of the rarest elements in the Earth's crust.
Gold and silver prices increased over the course of 2021, but these did not grow as fast as the prices of iridium and, especially, rhodium. According to a comparison of price indices, the price for rhodium - a precious metal similar to platinum and used especially in catalytic converters of cars - was ten times higher in April 2021 than it was in January 2019. The price hike for rhodium was apparently caused by coronavirus-related lockdowns implemented in South Africa, where mining companies had to close for several weeks.
Rhodium is a precious metal that removes pollutants from vehicle exhaust fumes. In February 2020, the price of rhodium was 11,665 U.S. dollars per troy ounce. By May 2020, the price decreased to below 8,000 U.S. dollars per ounce. In April 2021, the price rose to a new high of 28,775 U.S dollars, before decreasing throughout 2022 and early 2023. By December 2024, the average price significantly decreased, reaching around 4,575 U.S. dollars per troy ounce. In comparison, the price for an ounce of rhodium was approximately 5,905 U.S. dollars in August 2022. The rarest metal: Rhodium Rhodium is a rare and precious metal that belongs to the platinum group metals (PGMs), along with platinum, palladium, osmium, iridium, and ruthenium. Due to its scarcity, it is one of the most valuable metals in the world, often exceeding the price of gold. Rhodium is extensively used in the automotive industry to manufacture catalytic converters that reduce harmful emissions. Over the last few years, even with a steady supply, Rhodium demand has risen significantly, exceeding supply due to stricter emission regulations and advancements in the automobile industry. The significance of PGMs in South Africa South Africa is rich in various natural resources, such as metals and minerals. For example, almost all of the total global reserves of PGMs are in South Africa. In 2023, PGMs generated the highest revenue share in the South African mining sector compared to other commodities, amounting to 370 billion rands.
https://dataintelo.com/privacy-and-policyhttps://dataintelo.com/privacy-and-policy
The global market size of Iridium Catalyst is $XX million in 2018 with XX CAGR from 2014 to 2018, and it is expected to reach $XX million by the end of 2024 with a CAGR of XX% from 2019 to 2024.
Global Iridium Catalyst Market Report 2019 - Market Size, Share, Price, Trend and Forecast is a professional and in-depth study on the current state of the global Iridium Catalyst industry. The key insights of the report:
1.The report provides key statistics on the market status of the Iridium Catalyst manufacturers and is a valuable source of guidance and direction for companies and individuals interested in the industry.
2.The report provides a basic overview of the industry including its definition, applications and manufacturing technology.
3.The report presents the company profile, product specifications, capacity, production value, and 2013-2018 market shares for key vendors.
4.The total market is further divided by company, by country, and by application/type for the competitive landscape analysis.
5.The report estimates 2019-2024 market development trends of Iridium Catalyst industry.
6.Analysis of upstream raw materials, downstream demand, and current market dynamics is also carried out
7.The report makes some important proposals for a new project of Iridium Catalyst Industry before evaluating its feasibility.
There are 4 key segments covered in this report: competitor segment, product type segment, end use/application segment and geography segment.
For competitor segment, the report includes global key players of Iridium Catalyst as well as some small players. At least 12 companies are included:
* BASF
* Evonik
* Johnson Matthey
* Heraeus
* Stanford Advanced Materials
* Vineeth Chemicals
For complete companies list, please ask for sample pages.
The information for each competitor includes:
* Company Profile
* Main Business Information
* SWOT Analysis
* Sales, Revenue, Price and Gross Margin
* Market Share
For product type segment, this report listed main product type of Iridium Catalyst market
* Particle
* Powder
For end use/application segment, this report focuses on the status and outlook for key applications. End users sre also listed.
* Petrochemicals
* Medical
* Other
For geography segment, regional supply, application-wise and type-wise demand, major players, price is presented from 2013 to 2023. This report covers following regions:
* North America
* South America
* Asia & Pacific
* Europe
* MEA (Middle East and Africa)
The key countries in each region are taken into consideration as well, such as United States, China, Japan, India, Korea, ASEAN, Germany, France, UK, Italy, Spain, CIS, and Brazil etc.
Reasons to Purchase this Report:
* Analyzing the outlook of the market with the recent trends and SWOT analysis
* Market dynamics scenario, along with growth opportunities of the market in the years to come
* Market segmentation analysis including qualitative and quantitative research incorporating the impact of economic and non-economic aspects
* Regional and country level analysis integrating the demand and supply forces that are influencing the growth of the market.
* Market value (USD Million) and volume (Units Million) data for each segment and sub-segment
* Competitive landscape involving the market share of major players, along with the new projects and strategies adopted by players in the past five years
* Comprehensive company profiles covering the product offerings, key financial information, recent developments, SWOT analysis, and strategies employed by the major market players
* 1-year analyst support, along with the data support in excel format.
We also can offer customized report to fulfill special requirements of our clients. Regional and Countries report can be provided as well.
Attribution 4.0 (CC BY 4.0)https://creativecommons.org/licenses/by/4.0/
License information was derived automatically
Indium traded flat at 2,495 CNY/Kg on June 27, 2025. Over the past month, Indium's price has remained flat, but it is still 18.86% lower than a year ago, according to trading on a contract for difference (CFD) that tracks the benchmark market for this commodity. This dataset includes a chart with historical data for Indium.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
Organometallic compounds Cp*Ir(κ2-N,O)X and Ir(κ3-N,O,O)(1-κ-4,5-η2-C8H13)(MeOH) are effective catalysts for the oxidative splitting of water to O2 driven by Ce4+. They show similar TOFLT values (long-term TOF, 2.6–7.4 min–1) while TOFIN values (initial TOF) strongly depend on the catalyst (1 ≫ 2 > 3 > 4), reaching a maximum value of 287 min–1 (4.8 s–1) for 1a, which is the highest TOF value ever reported for an iridium catalyst. Voltammetric measurements indicate that the oxidative processes of compounds 1–4 are located at values substantially less positive than that of Cp*Ir(bzpy)NO3, taken as reference catalyst for water oxidation. In particular, compound 3, having a pendant −COOH moiety in close proximity to an iridium coordination site, as shown by the structure determined by single-crystal X-ray diffraction, exhibits several low-potential oxidation processes.
https://dataintelo.com/privacy-and-policyhttps://dataintelo.com/privacy-and-policy
The global Iridium 192 seeds source market size is projected to grow exponentially from USD 150 million in 2023 to an estimated USD 220 million by 2032, reflecting a Compound Annual Growth Rate (CAGR) of 4.2%. This growth is primarily driven by the rising demand for effective cancer treatment technologies and advancements in industrial radiography applications. Iridium 192, known for its high radioactivity and precision, is increasingly utilized in various sectors, offering significant benefits in terms of treatment efficacy and industrial inspection accuracy.
A significant growth factor for this market is the increasing prevalence of cancer worldwide, which has escalated the need for advanced brachytherapy solutions. Iridium 192 seeds are crucial in high dose rate (HDR) and low dose rate (LDR) brachytherapy, providing localized treatment that minimizes damage to surrounding healthy tissues. The growing aging population, which is more susceptible to cancer, further fuels the demand for these advanced treatment options. Additionally, technological advancements in radioactive isotopes and the development of new delivery methods are enhancing the effectiveness and safety of Iridium 192 seeds, making them more attractive to healthcare providers.
Another driving factor is the expanding application of Iridium 192 seeds in industrial radiography. Industries such as aerospace, automotive, and construction extensively use radiographic testing for non-destructive evaluation of components and structures. The high penetrating power and precision of Iridium 192 make it ideal for detecting internal flaws, ensuring the integrity and safety of critical components. With the global emphasis on quality and safety standards, industries are increasingly adopting Iridium 192-based radiographic technologies, thus contributing to market growth.
Furthermore, the growing investment in research and development activities pertaining to radioactive isotopes is another catalyst for market expansion. Numerous research institutes and organizations are focusing on exploring new applications and improving the existing technologies associated with Iridium 192. Government funding and private investments are also playing a crucial role in driving innovation in this field. The development of novel brachytherapy techniques and more efficient radiographic equipment is expected to open new avenues for market growth in the coming years.
Regionally, the market is witnessing significant growth across various geographies. North America holds a prominent share due to the high incidence of cancer and well-established healthcare infrastructure. Europe follows closely, with substantial investments in healthcare and industrial sectors. The Asia Pacific region is anticipated to showcase the highest growth rate due to increasing healthcare awareness, rising industrialization, and supportive government initiatives. Latin America and the Middle East & Africa are also expected to contribute to the market growth, driven by improving healthcare facilities and increasing adoption of advanced technologies.
The Iridium 192 seeds source market can be segmented based on product type into High Dose Rate (HDR) and Low Dose Rate (LDR) Iridium-192. Each of these segments plays a crucial role in different applications, catering to specific needs and requirements. High Dose Rate (HDR) Iridium-192 seeds are predominantly used in medical applications, particularly in brachytherapy for cancer treatment. This segment is witnessing significant growth due to the rising prevalence of cancer and the increasing adoption of HDR brachytherapy techniques. HDR brachytherapy allows for more precise delivery of radiation, reducing treatment times and minimizing side effects, making it a preferred choice among healthcare providers and patients.
Low Dose Rate (LDR) Iridium-192 seeds, on the other hand, are also used in medical applications but are more commonly employed in situations where continuous low-dose radiation treatment is required. This segment is seeing steady growth due to its effectiveness in treating certain types of cancer, such as prostate cancer. LDR brachytherapy offers the advantage of a one-time implant procedure, providing continuous treatment over a period of time, which can be more convenient for patients. Additionally, advancements in LDR seed technology, such as improved delivery systems and seed designs, are enhancing treatment outcomes and driving market growth.
In the industrial segment, both HDR and LDR Iridium-1
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
The catalytic activity of the iridium complexes involved in methanol carbonylation is significantly enhanced when the carbonyliodoplatinum dimer [PtI2(CO)]2 (10‘) is added to the reaction mixture. Under CO this complex readily affords the monomeric species PtI2(CO)2. The turnover frequency value, which is 1450 h-1 for iridium alone, reaches 2400 h-1 for a Pt/Ir = 3/7 molar ratio, under 30 bar of CO and at 190 °C. To get a deeper insight into the role of the platinum cocatalyst, model conditions (dinitrogen, ambient temperature, CH2Cl2, PPN+ as counterion) have been adopted. [PtI2(CO)]2 (10‘) interacts with [PPN]IrI3(CH3)(CO)2, affording the monoiodo-bridged anionic species [IrI2(CH3)(CO)2(μ-I)PtI2(CO)]- (11), which undergoes cleavage under CO to provide IrI2(CH3)(CO)3 and [PtI3(CO)]- (9). Although we have to take into account the possible iodide dissociation from 4 in the polar reaction medium (CH3COOH, CH3OH, CH3I, HI, H2O), which can be scavenged by platinum to give 9, we should not discard the intermediacy of 11, even under working catalytic conditions. The crystal structures of [PPN]IrI3(COCH3)(CO)2 and [PPN]PtI3(CO), which are both involved in the overall process, were determined by X-ray diffraction analysis. A catalytic cycle is herein proposed, in which the cooperative effect between the platinum promoter and the iridium catalyst is depicted.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
In this paper, three new iridium(III) complexes: [Ir(piq)2(DFIPP)]PF6 (piq = deprotonated 1-phenylisoquinoline, DFIPP = 3,4-difluoro-2-(1H-imidazo[4,5-f][1,10]phenenthrolin-2-yl)phenol, 3a), [Ir(bzq)2(DFIPP)]PF6 (bzq = deprotonated benzo[h]quinoline, 3b), and [Ir(ppy)2(DFIPP)]PF6 (ppy = deprotonated 1-phenylpyridine, 3c), were synthesized and characterized. The complexes were found to be nontoxic to tumor cells via 3-(4,5-dimethylthiazole-2-yl)-diphenyltetrazolium bromide (MTT) assay. Surprisingly, its liposome-entrapped complexes 3alip, 3blip, and 3clip on B16 cells showed strong cytotoxicity (IC50 = 13.6 ± 2.8, 9.6 ± 1.1, and 18.9 ± 2.1 μM). Entry of 3alip, 3blip, and 3clip into B16 cells decreases mitochondrial membrane potential, regulates Bcl-2 family proteins, releases cytochrome c, triggers caspase family cascade reaction, and induces apoptosis. In addition, we also found that 3alip, 3blip, and 3clip triggered ferroptosis and autophagy. In vivo studies demonstrated that 3blip inhibited melanoma growth in C57 mice with a high inhibitory rate of 83.95%, and no organic damage was found in C57 mice.
https://dataintelo.com/privacy-and-policyhttps://dataintelo.com/privacy-and-policy
The global iridium recycling market is estimated to have a market size of USD 1.5 billion in 2023 and is projected to reach USD 2.8 billion by 2032, growing at a CAGR of 7.1% during the forecast period. The growth of this market is driven by the increasing scarcity of iridium, a rare and valuable metal, coupled with the rising demand for iridium in various industries such as electronics, automotive, and chemical manufacturing.
One of the major growth factors in the iridium recycling market is the increasing awareness and emphasis on sustainable practices. With the global focus shifting towards reducing carbon footprints and enhancing resource efficiency, industries are recognizing the importance of recycling rare metals like iridium. Recycling not only conserves natural resources but also reduces the environmental impact associated with mining and refining raw iridium. This growing environmental consciousness is expected to propel the demand for iridium recycling over the coming years.
Another significant driver boosting the iridium recycling market is the escalating demand for iridium in high-tech applications. Iridium's exceptional properties, such as high melting point, corrosion resistance, and excellent electrical conductivity, make it indispensable in various high-tech applications, including electronics, automotive catalysts, and chemical processing. As the demand for advanced electronic devices and efficient automotive catalysts continues to rise, the need for recycled iridium is expected to follow suit, thereby driving market growth.
The advancements in recycling technologies also play a pivotal role in the growth of the iridium recycling market. Innovations in pyrometallurgical and hydrometallurgical processes have significantly improved the efficiency and yield of iridium recovery from various waste sources. These technological advancements not only enhance the economic viability of iridium recycling but also ensure that the process is more environmentally friendly. As recycling technologies continue to evolve, the cost-effectiveness and sustainability of iridium recycling are expected to improve, further driving market growth.
Platinum Group Metals Recycling is an integral part of the broader recycling landscape, encompassing not only iridium but also other valuable metals such as platinum, palladium, and rhodium. These metals are crucial in various industrial applications, including automotive catalytic converters, electronics, and chemical processing. The recycling of these metals is driven by their scarcity and high economic value, making it essential to recover and reuse them efficiently. By recycling platinum group metals, industries can significantly reduce their reliance on mining, thereby conserving natural resources and minimizing environmental impact. This practice not only supports sustainable development but also ensures a steady supply of these critical materials for future technological advancements.
Regionally, the Asia Pacific region is anticipated to witness substantial growth in the iridium recycling market. Countries like China, Japan, and South Korea are notable producers and consumers of electronic devices and automotive components, which are significant sources of iridium. The presence of well-established recycling infrastructure and favorable government policies supporting resource recovery and sustainable practices are expected to bolster the market growth in this region. Additionally, the rapid industrialization and urbanization in these countries are likely to create ample opportunities for iridium recycling in the coming years.
In the iridium recycling market, sources of iridium can be broadly categorized into industrial waste, electronic scrap, automotive catalysts, and others. Each of these sources holds a significant share in the market and contributes uniquely to the recycling process. Industrial waste, for instance, is a primary source of iridium as it is often a byproduct of various manufacturing processes. Recycling iridium from industrial waste not only mitigates environmental pollution but also provides a cost-effective means of reclaiming this valuable metal.
Recycling of Platinum Group Metals is gaining momentum as industries recognize the importa
As of May 2025, it was estimated that the global supply of rhodium stood at approximately 691,000 ounces. Rhodium is considered one of the rarest and most valuable metals in the world. Rhodium: the rare PGM Rhodium is a silver-colored platinum group metal (PGM) that is highly reflective and resistant to corrosion and oxidation. Platinum group metals include rhodium, platinum, ruthenium, iridium, osmium, and palladium. Rhodium is the rarest metal in the platinum family and occurs in the Earth’s crust at a rate of around one part per 200 million. It is primarily used in catalytic converters to clean motor emissions or as a finishing metal for jewelry. Despite having a stable supply globally, the demand for rhodium has been increasing over time. Platinum-group metals: expensive precious metals Platinum-group metal mine production has been stable in recent years. Platinum is one of the most expensive metals to produce due to its low concentration within the ore from which it is mined. The price of production varies greatly between the countries in which it is produced, with South Africa having the highest cost of production for platinum. The world’s leading producer of platinum as of 2019 was Anglo American Platinum Ltd.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
Novel mixed-ligand Ir(III) complexes, [Ir(L)(N∧C)X]n+ (L = N∧C∧N or N∧N∧N; X = Cl, Br, I, CN, CH3CN, or −CCPh; n = 0 or 1), were synthesized, where N∧C∧N = bis(N-methylbenzimidazolyl)benzene (Mebib) and bis(N-phenylbenzimidazolyl)benzene (Phbib), N∧N∧N = bis(N-methylbenzimidazolyl)pyridine (Mebip), and N∧C = phenylpyridine (ppy) derivatives. The X-ray crystal structures of [Ir(Phbib)(ppy)Cl] and [Ir(Mebib)(mppy)Cl] [mppy = 5-methyl-2-(2‘-pyridyl)phenyl] indicate that the nitrogen atom of the ppy ligand is located trans to the coordinating carbon atom in Me- or Phbib, while the coordinating carbon atom in ppy occupies the trans position of Cl. [Ir(Mebip)(ppy)Cl]+ showed a quasireversible Ir(III/IV) oxidation wave at +1.05 V, while the Ir complexes, [Ir(Mebib)(ppy)Cl], were oxidized at +0.42 V versus Fc/Fc+. The introduction of an Ir−C bond in [Ir(Mebib)(ppy)Cl] induces a large potential shift of 0.63 V in a negative direction. Further, the oxidation potential of [Ir(Mebib)(Rppy)X] was altered by the substitution of R, R‘, and X groups. Compared to the oxidation potential, the first reduction potential revealed an almost constant value at −2.36 to −2.46 V for Ir(L)(ppy)Cl and −1.52 V for [Ir(Mebip)(ppy)Cl. The UV−vis spectra of [Ir(Mebib)(R-ppy)X] show a clear singlet metal-to-ligand charge-transfer transition around 407∼425 nm and a triplet metal-to-ligand charge-transfer transition at 498∼523 nm. [Ir(Mebip)(ppy)Cl]+ emits at 610 nm with a luminescent quantum yield of Φ = 0.16 at room temperature. The phosphorescence of [Ir(Mebib)(ppy)X] was observed at 526 nm for X = CN and 555 nm for X = Cl with the high luminescent quantum yields, Φ = 0.77∼0.86, at room temperature. [Ir(Phbib)(ppy)Cl] shows the emission at 559 nm with a luminescent quantum yield of Φ = 0.95, which is an unprecedentedly high value compared to those of other emissive metal complexes. Compared to the luminescent quantum yields of the Ir(ppy)2(L) derivatives and [Ir(Mebip)(ppy)Cl]+, the neutral Ir complexes, Ir(L)(R-ppy)X, reveal very high quantum yields and large radiative rate constants (kr) ranging from 3.4 × 105 to 5.5 × 105 s-1. The density functional theory calculation suggests that these Ir complexes possess dominantly metal-to-ligand charge-transfer and halide-to-ligand charge-transfer excited states. The mechanism for a high phosphorescence yield in [Ir(bib)(ppy)X] is discussed herein from the perspective of the theoretical consideration of radiative rate constants using perturbation theory and a one-center spin−orbit coupling approximation.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
The diiron vinyliminium complexes [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(3-C5H4N)CHCN(R)(Me)}]CF3SO3 (Cp = η5-C5H5; R = 2,6-C6H3Me2 = Xyl, 2a, R = Me, 2b) reacted with IrCp*(Phpy)Cl and AgCF3SO3 to afford the bis-cationic iron–iridium conjugates [Fe2Cp2(CO)(μ-CO){μ-η1:η3-C(3-C5H4NIrCp*Phpy)CHCN(Me)(R)}][CF3SO3]2 (4a–b), in nearly quantitative yields. Similarly, the reaction of the ferracyclic compound FeCp(CO){CN(Me)(Xyl)CHC(3-C5H4N)C(O)} with [IrCp*(Phpy)Cl]/AgNO3 led to the monocationic species [FeCp(CO){CN(Me)(Xyl)CHC(3-C5H4NIrCp*Phpy)C((O)}]NO3 (5a, 70% yield). The new complexes 4a–b and 5a were characterized by mass spectrometry, IR and 1H and 13C NMR spectroscopy. NMR and DFT analyses indicate that they exist as pairs of diastereoisomers due to the chirality centers in the iron and iridium scaffolds, and that the coordination strength of the pyridyl ligand to iridium is comparable to that observed in the iridium-pyridine adduct IrCp*(py)(Phpy). The cytotoxicity of 4a–b and 5a was evaluated on cancer (A2780, A549, U87) and noncancerous (MRC-5) cell lines, with 5a exhibiting superior activity compared to cisplatin and Irpy, along with a tendency toward selectivity. The activity of 4a–b and 5a, which is significantly higher compared to their iron precursors, is associated with enhanced iridium uptake in cancer cells (aligning with lipophilicity, determined as Log Pow values), suppression of oxygen consumption rate and elevated ROS production.
https://www.wiseguyreports.com/pages/privacy-policyhttps://www.wiseguyreports.com/pages/privacy-policy
BASE YEAR | 2024 |
HISTORICAL DATA | 2019 - 2024 |
REPORT COVERAGE | Revenue Forecast, Competitive Landscape, Growth Factors, and Trends |
MARKET SIZE 2023 | 4.64(USD Billion) |
MARKET SIZE 2024 | 4.94(USD Billion) |
MARKET SIZE 2032 | 8.2(USD Billion) |
SEGMENTS COVERED | Platform ,Connectivity Type ,Application ,Frequency Band ,Data Rate ,Regional |
COUNTRIES COVERED | North America, Europe, APAC, South America, MEA |
KEY MARKET DYNAMICS | Growing demand Technological advancements Government initiatives Increasing adoption in defense Expanding applications in commercial sectors |
MARKET FORECAST UNITS | USD Billion |
KEY COMPANIES PROFILED | Iridium Communications Inc. ,Hughes Network Systems, LLC ,Comtech Telecommunications Corp. ,General Dynamics Mission Systems ,Thuraya Telecommunications Company ,Orbital Satellite Communications ,Airbus Defence and Space ,Rohde & Schwarz GmbH & Co. KG ,L3Harris Technologies ,SSL (Maxar Technologies) ,Cobham SATCOM ,Kymeta ,Boeing Defense, Space & Security ,Inmarsat ,KVH Industries, Inc. |
MARKET FORECAST PERIOD | 2024 - 2032 |
KEY MARKET OPPORTUNITIES | 1 Maritime Connectivity 2 Government and Defense Expansion 3 Disaster Response and Emergency Communications 4 IOT and Industrial Applications 5 Commercial Aviation |
COMPOUND ANNUAL GROWTH RATE (CAGR) | 6.54% (2024 - 2032) |
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
The first general catalytic approach to effecting transfer hydrogenation (TH) of unactivated alkenes using ethanol as the hydrogen source is described. A new NCP-type pincer iridium complex (BQ-NCOP)IrHCl containing a rigid benzoquinoline backbone has been developed for efficient, mild TH of unactivated C–C multiple bonds with ethanol, forming ethyl acetate as the sole byproduct. A wide variety of alkenes, including multisubstituted alkyl alkenes, aryl alkenes, and heteroatom-substituted alkenes, as well as O- or N-containing heteroarenes and internal alkynes, are suitable substrates. Importantly, the (BQ-NCOP)Ir/EtOH system exhibits high chemoselectivity for alkene hydrogenation in the presence of reactive functional groups, such as ketones and carboxylic acids. Furthermore, the reaction with C2D5OD provides a convenient route to deuterium-labeled compounds. Detailed kinetic and mechanistic studies have revealed that monosubstituted alkenes (e.g., 1-octene, styrene) and multisubstituted alkenes (e.g., cyclooctene (COE)) exhibit fundamental mechanistic difference. The OH group of ethanol displays a normal kinetic isotope effect (KIE) in the reaction of styrene, but a substantial inverse KIE in the case of COE. The catalysis of styrene or 1-octene with relatively strong binding affinity to the Ir(I) center has (BQ-NCOP)IrI(alkene) adduct as an off-cycle catalyst resting state, and the rate law shows a positive order in EtOH, inverse first-order in styrene, and first-order in the catalyst. In contrast, the catalysis of COE has an off-cycle catalyst resting state of (BQ-NCOP)IrIII(H)[O(Et)···HO(Et)···HOEt] that features a six-membered iridacycle consisting of two hydrogen-bonds between one EtO ligand and two EtOH molecules, one of which is coordinated to the Ir(III) center. The rate law shows a negative order in EtOH, zeroth-order in COE, and first-order in the catalyst. The observed inverse KIE corresponds to an inverse equilibrium isotope effect for the pre-equilibrium formation of (BQ-NCOP)IrIII(H)(OEt) from the catalyst resting state via ethanol dissociation. Regardless of the substrate, ethanol dehydrogenation is the slow segment of the catalytic cycle, while alkene hydrogenation occurs readily following the rate-determining step, that is, β-hydride elimination of (BQ-NCOP)Ir(H)(OEt) to form (BQ-NCOP)Ir(H)2 and acetaldehyde. The latter is effectively converted to innocent ethyl acetate under the catalytic conditions, thus avoiding the catalyst poisoning via iridium-mediated decarbonylation of acetaldehyde.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
We report highly active iridium precatalysts, [Cp*Ir(N,N)Cl]Cl (1–4), for water oxidation that are supported by recently designed dihydroxybipyridine (dhbp) ligands. These ligands can readily be deprotonated in situ to alter the electronic properties at the metal; thus, these catalyst precursors have switchable properties that are pH-dependent. The pKa values in water of the iridium complexes are 4.6(1) and 4.4(2) with (N,N) = 6,6′-dhbp and 4,4′-dhbp, respectively, as measured by UV–vis spectroscopy. For homogeneous water oxidation catalysis, the sacrificial oxidant NaIO4 was found to be superior (relative to CAN) and allowed for catalysis to occur at higher pH values. With NaIO4 as the oxidant at pH 5.6, water oxidation occurred most rapidly with (N,N) = 4,4′-dhbp, and activity decreased in the order 4,4′-dhbp (3) > 6,6′-dhbp (2) ≫ 4,4′-dimethoxybipyridine (4) > bipy (1). Furthermore, initial rate studies at pH 3–6 showed that the rate enhancement with dhbp complexes at high pH is due to ligand deprotonation rather than the pH alone accelerating water oxidation. Thus, the protic groups in dhbp improve the catalytic activity by tuning the complexes’ electronic properties upon deprotonation. Mechanistic studies show that the rate law is first-order in an iridium precatalyst, and dynamic light scattering studies indicate that catalysis appears to be homogeneous. It appears that a higher pH facilitates oxidation of precatalysts 2 and 3 and their [B(ArF)4]− salt analogues 5 and 6. Both 2 and 5 were crystallographically characterized.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
Oxotrimesityliridium(V), (mes)3IrO (mes = 2,4,6-trimethylphenyl), and trimesityliridium(III), (mes)3Ir, undergo extremely rapid degenerate intermetal oxygen atom transfer at room temperature. At low temperatures, the two complexes conproportionate to form (mes)3IrOIr(mes)3, the 2,6-dimethylphenyl analogue of which has been characterized crystallographically. Variable-temperature NMR measurements of the rate of dissociation of the μ-oxo dimer combined with measurements of the conproportionation equilibrium by low-temperature optical spectroscopy indicate that oxygen atom exchange between iridium(V) and iridium(III) occurs with a rate constant, extrapolated to 20 °C, of 5 × 107 M-1 s-1. The oxotris(imido)osmium(VIII) complex (ArN)3OsO (Ar = 2,6-diisopropylphenyl) also undergoes degenerate intermetal atom transfer to its deoxy partner, (ArN)3Os. However, despite the fact that its metal−oxygen bond strength and reactivity toward triphenylphosphine are nearly identical to those of (mes)3IrO, the osmium complex (ArN)3OsO transfers its oxygen atom 12 orders of magnitude more slowly to (ArN)3Os than (mes)3IrO does to (mes)3Ir (kOsOs = 1.8 × 10-5 M-1 s-1 at 20 °C). Iridium−osmium cross-exchange takes place at an intermediate rate, in quantitative agreement with a Marcus-type cross relation. The enormous difference between the iridium−iridium and osmium−osmium exchange rates can be rationalized by an analogue of the inner-sphere reorganization energy. Both Ir(III) and Ir(V) are pyramidal and can form pyramidal iridium(IV) with little energetic cost in an orbitally allowed linear approach. Conversely, pyramidalization of the planar tris(imido)osmium(VI) fragment requires placing a pair of electrons in an antibonding orbital. The unique propensity of (mes)3IrO to undergo intermetal oxygen atom transfer allows it to serve as an activator of dioxygen in cocatalyzed oxidations, for example, acting with osmium tetroxide to catalyze the aerobic dihydroxylation of monosubstituted olefins and selective oxidation of allyl and benzyl alcohols.
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
Phosphorescence studies of a series of facial homoleptic cyclometalated iridium(III) complexes have been carried out. The complexes studied have the general structure Ir(III)(C−N)3, where (C−N) is a monoanionic cyclometalating ligand: 2-(5-methylthiophen-2-yl)pyridinato, 2-(thiophen-2-yl)-5-trifluoromethylpyridinato, 2,5-di(thiophen-2-yl)pyridinato, 2,5-di(5-methylthiophen-2-yl)pyridinato, 2-(benzo[b]thiophen-2-yl)pyridinato, 2-(9,9-dimethyl-9H-fluoren-2-yl)pyridinato, 1-phenylisoquinolinato, 1-(thiophen-2-yl)isoquinolinato, or 1-(9,9-dimethyl-9H-fluoren-2-yl)isoquinolinato. Luminescence properties of all the complexes at 298 K in toluene are as follows: quantum yields of phosphorescence Φp = 0.08−0.29, emission peaks λmax = 558−652 nm, and emission lifetimes τ = 0.74−4.7 μs. Bathochromic shifts of the Ir(thpy)3 family [the complexes with 2-(thiophen-2-yl)pyridine derivatives] are observed by introducing appropriate substituents, e.g., methyl, trifluoromethyl, or thiophen-2-yl. However, Φp of the red emissive complexes (λmax > 600 nm) becomes small, caused by a significant decrease of the radiative rate constant, kr. In contrast, the complexes with the 1-arylisoquinoline ligands are found to have marked red shifts of λmax and very high Φp (0.19−0.26). These complexes are found to possess dominantly 3MLCT (metal-to-ligand charge transfer) excited states and have kr values approximately 1 order of magnitude larger than those of the Ir(thpy)3 family. An organic light-emitting diode (OLED) device that uses Ir(1-phenylisoquinolinato)3 as a phosphorescent dopant produces very high efficiency (external quantum efficiency ηex = 10.3% and power efficiency 8.0 lm/W at 100 cd/m2) and pure-red emission with 1931 CIE (Commission Internationale de L'Eclairage) chromaticity coordinates (x = 0.68, y = 0.32).
Attribution-NonCommercial 4.0 (CC BY-NC 4.0)https://creativecommons.org/licenses/by-nc/4.0/
License information was derived automatically
A series of novel emissive Ir(III) complexes having the coordination environments of [Ir(N∧N∧N)2]3+, [Ir(N∧N∧N)(N∧N)Cl]2+, and [Ir(N∧N∧N)(N∧C∧N)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, N∧N∧N), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, N∧C∧N), 4‘-(4-methylphenyl)-2,2‘:6‘,2‘ ‘-terpyridine (ttpy, N∧N∧N), and 2,2‘-bipyridine (bpy, N∧N) have been synthesized and their photophysical and electrochemical properties studied. The Ir(III) complexes exhibited phosphorescent emissions in the 500−600 nm region, with lifetimes ranging from approximately 1−10 μs at 295 K. Analysis of the 0−0 energies and the redox potentials indicated that the lowest excited state of [Ir(L1)(L2)]2+ possessed the highest contribution of 3MLCT (MLCT = metal-to-ligand charge transfer) among the Ir(III) complexes, reflecting the σ-donating ability of the tridentate ligand, ttpy < L1 < L2. The emission quantum yields (Φ) of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest Φ value (0.19) was obtained for [Ir(L1)(bpy)Cl]2+. Radiative rate constants (kr) were 1.2 × 104 s-1 for [Ir(ttpy)2]3+, 3.7 × 104 s-1 for [Ir(L1)(bpy)Cl]2+, 3.8 × 104 s-1 for [Ir(ttpy)(bpy)Cl]2+, 3.9 × 104 s-1 for [Ir(L1)2]3+, and 6.6 × 104 s-1 for [Ir(L1)(L2)]2+. The highest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of the singlet−triplet mixing induced by spin−orbit coupling of 5d electrons in the MLCT electronic configurations.
The average price for iridium in 2023 was nearly 4,700 U.S. dollars per troy ounce, an increase compared to the previous year. This figure was still lower than the peak of 5,100 U.S. dollars recorded in 2021. Iridium is a transition metal and a platinum group metal. It is one of the most corrosion-resistant metals and is also one of the rarest elements in the Earth's crust.