Boosting Effect of Sterically Protected Glucosyl Substituents in Formic Acid Dehydrogenation by Iridium(III) 2‐Pyridineamidate Catalysts

ChemSusChem, Journal Year: 2024, Volume and Issue: 17(20)

Published: May 15, 2024

[Cp*Ir(R-pica)Cl] (Cp*=pentamethylcyclopentadienyl anion, pica=2-picolineamidate) complexes bearing carbohydrate substituents on the amide nitrogen atom (R=methyl-β-D-gluco-pyranosid-2-yl, 1; methyl-3,4,6-tri-O-acetyl-β-D-glucopyranosid-2-yl, 2) were tested as catalysts for formic acid dehydrogenation in water. TOF

Language: Английский

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Electrochemical NADH Regeneration Mediated by Pyridine Amidate Iridium Complexes Interconverting 1,4- and 1,6-NADH

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(13), P. 10334 - 10343

Published: June 25, 2024

Although there is a huge interest in redox mediators for the selective electrochemical regeneration of 1,4-NADH, only class rhodium compounds with bipyridine ligands, initially introduced by pioneering work Wienkamp and Steckhan (Wienkamp, R.; Steckhan, E. Angew. Chem. Int. Ed. Engl. 1982, 21, 782−783, 10.1002/anie.198207822), has been developed over last few decades. Here we report first two progenitors indirect NADH regeneration, namely [Cp*Ir(R′-pica)Cl] {pica = R′-picolinamidate κ2-R′-pyridine-2-carboxamide ion (−1), 1 R′ H 2 Me}, which exhibit high TOF values (0.51 1.34 s–1 2, respectively), production rate up to 3 μmol h–1 cm–2, faradaic efficiency 99% both complexes 0.1 M phosphate buffer (pH 7, 298 K). The reaction exclusively leads mixture desired product, 1,6-NADH always 91:9 molar ratio, independently mediator, degree conversion, applied potential. 1H EXSY NMR unequivocally shows that rapid equilibrium establishes between 1,4-NADH (Keq 10.1, ΔG0 −1.4 kcal mol–1, K), presence suggesting latter are capable rapidly interconverting regioisomers NADH, thus allowing utilization totality regenerated NADH.

Language: Английский

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Chiral Polymeric Diamine Ligands for Iridium-Catalyzed Asymmetric Transfer Hydrogenation

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 25, 2024

A series of polymeric chiral diamine ligands are developed by diboron-templated asymmetric reductive couplings, and their iridium complexes Ir-polydiamines efficient recyclable catalysts for transfer hydrogenation (ATH) functionalized ketones, affording a optically active secondary alcohols in excellent enantioselectivities (up to 99% ee) unprecedentedly high total TONs (12,000, six cycles). Ir-polydiamine with longer chains offered higher reactivities, providing plausible deactivation mechanism practical solutions ATH vitamin B5 phenylephrine.

Language: Английский

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Beyond Metal-Arenes: Monocarbonyl Ruthenium(II) Catalysts for Transfer Hydrogenation Reactions in Water and in Cells

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(16), P. 10798 - 10823

Published: Aug. 1, 2023

With the aim to design water-soluble organometallic Ru(II) complexes acting as anticancer agents catalyzing transfer hydrogenation (TH) reactions with biomolecules, we have synthesized four monocarbonyl (1–4), featuring 1,4-bis(diphenylphosphino)butane (dppb) ligand and different bidentate nitrogen (N∧N) ligands, of general formula [Ru(OAc)CO(dppb)(N∧N)]n (n = +1, 0; OAc acetate). The compounds been characterized by methods, including 1H 31P NMR spectroscopies, electrochemistry, well single-crystal X-ray diffraction in case 1 4. also studied for their hydrolysis an aqueous environment catalytic regioselective reduction nicotinamide adenine dinucleotide (NAD+) 1,4-dihydronicotinamide (1,4-NADH) solution sodium formate a hydride source. Moreover, stoichiometric oxidation 1,4-NADH investigated UV–visible spectrophotometry spectroscopy. results suggest that cycle can start directly from intact compound or its aquo/hydroxo species (in 1–3) afford ruthenium complex. Overall, initial structure–activity relationships could be inferred which point toward influence extension aromatic N∧N cationic 1–3 on TH both reduction/oxidation processes. While complex 3 is most active NADH O2, neutral 4, picolinamidate ligand, stands out catalyst NAD+, while being completely inactive oxidation. convert pyruvate into lactate presence formate, albeit scarce efficiency. In any case, all compounds, intermediates observed even isolated 1–3. Together, insights kinetic electrochemical characterization that, 1–3, sees H-transfer rate-limiting step, whereas NAD+ H-donor, step substrate, suggested density functional theory (DFT) calculations. Compound stable respect solution, appears operate via mechanism other derivatives. Finally, activity ability form reactive oxygen (ROS) cancerous nontumorigenic cells vitro. Noteworthy, conversion aldehydes alcohols achieved three catalysts living cells, assessed fluorescence microscopy. Furthermore, formation intermediate upon treatment cancer cell extracts has detected this study paves way application non-arene-based biological environment.

Language: Английский

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Asymmetric Reductive Amination of α-Keto Acids Using Ir-Based Hydrogen Transfer Catalysts: An Access to Unprotected Unnatural α-Amino Acids

Organic Letters, Journal Year: 2024, Volume and Issue: 26(7), P. 1426 - 1431

Published: Feb. 9, 2024

A direct asymmetric reductive amination of α-keto acids catalyzed by Cp*Ir complexes bearing a chiral N-(2-picolyl)sulfonamidato ligand is described. The combined use optically active 2-phenyglycinol as an aminating agent effective for the chemo- and stereoselective transfer hydrogenation using formic acid. subsequent elimination hydroxyethyl moiety orthoperiodic acid can afford various unprotected α-amino in satisfactory isolated yields (20 examples) with excellent optical purities (up to >99% ee).

Language: Английский

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NADH-Type Hydride Storage and Release on a Functional Ligand for Efficient and Selective Hydrogenation Catalysis

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(14), P. 9839 - 9844

Published: July 12, 2023

Reminiscent to nature's NAD+/NADH hydride storage and transfer system, we demonstrate here that an iridium complex containing a pyridinium ligand, IrPYE+, is capable of reversibly storing upon reaction with formate. The in IrPYEH stable toward air water, yet it released the presence electrophiles such as acids or carbonyl compounds. full reversibility provides access hydrogenation procedure catalytic IrPYEH, reaching up 100,000 turnover numbers surpassing other related catalysts by several orders magnitude. With deuterated formate, IrPYED allows for selective deuterium isotope labeling without notable scrambling even acids, air, moisture.

Language: Английский

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Acceptorless dehydrogenation of glycerol catalysed by Ir(III) complexes with carbohydrate‐functionalised ligands: a sweet pathway to produce hydrogen and lactic acid

European Journal of Inorganic Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 9, 2024

Abstract Glycerol, a by‐product of biodiesel production, has gained prominence as precious platform chemical. To enhance the economic viability production process and address surplus glycerol it is essential to transform into value‐added products. In this context, homogeneous catalysis offers promising avenue for valorisation. study, we introduce family iridium complexes bearing picolineamidate ligands with glucose‐functionalised substituents novel catalysts hydrogen lactic acid conversion. These exhibit high activity (conversion up 53.3 %) 99 % selectivity after 24 hours reaction (TOF MAX =159 h −1 , TON 24h =2498). Notably, occurs under ambient air at milder temperature conditions (120 °C) compared other catalysts. efforts in valorisation contribute reducing costs, increasing competitiveness biofuels against petroleum‐based liquid fuels, giving rise H 2 through global negative carbon dioxide emission, utilizable, among other, monomer synthesis biodegradable plastics.

Language: Английский

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