Reduction of RuVI≡N to RuIII—NH3 by Cysteine in Aqueous Solution

Wang, Qian; Man, Wai‐Lun; Lam, William W. Y.; Yiu, Shek Man; Tse, Man Kit; Lau, Tai‐Chu

doi:10.1021/acs.inorgchem.8b00238

Cited by 2 publications

(3 citation statements)

References 52 publications

(65 reference statements)

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“…Our group and those of Matveev, Kozhevnikov, ,, and Neumann − reviewed organic substrate oxidations, including ones based on O 2 as the terminal oxidant, catalyzed by POMs, including PV n Mo 12– n O 40 /Pd systems, while Misono and Mizuno − reviewed industrial POM-catalyzed oxidations some time ago. Thiol oxidations are also important in organic chemistry, physiological processes, and environmental science. − Numerous catalytic and stoichiometric systems are known to selectively oxidize thiols in context with either deodorization or synthesis, including nanoparticle systems, , POMs, ,,− metal–organic frameworks (MOFs), ,, strong stoichiometric oxidants, − and noble metals. − Most of these systems do not use O 2 as the terminal oxidant. In addition, most are slow, require elevated temperatures, and form side products.…”

Section: Introductionmentioning

confidence: 99%

Catalytic System for Aerobic Oxidation That Simultaneously Functions as Its Own Redox Buffer

Tang

Geletii

et al. 2023

Inorg. Chem.

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The control of the solution electrochemical potential as well as pH impacts products in redox reactions, but the former gets far less attention. Redox buffers facilitate the maintenance of potentials and have been noted in diverse cases, but they have not been a component of catalytic systems. We report a catalytic system that contains its own built-in redox buffer. Two highly synergistic components (a) the tetrabutylammonium salt of hexavanadopolymolybdate TBA 4 H 5 [PMo 6 V 6 O 40 ] (PV 6 Mo 6 ) and (b) Cu(ClO 4 ) 2 in acetonitrile catalyze the aerobic oxidative deodorization of thiols by conversion to the corresponding nonodorous disulfides at 23 °C (each catalyst alone is far less active). For example, the reaction of 2-mercaptoethanol with ambient air gives a turnover number (TON) = 3 × 10 2 in less than one hour with a turnover frequency (TOF) of 6 × 10 −2 s −1 with respect to PV 6 Mo 6 . Multiple electrochemical, spectroscopic, and other methods establish that (1) PV 6 Mo 6 , a multistep and multielectron redox buffering catalyst, controls the speciation and the ratio of Cu(II)/Cu(I) complexes and thus keeps the solution potential in different narrow ranges by involving multiple POM redox couples and simultaneously functions as an oxidation catalyst that receives electrons from the substrate; (2) Cu catalyzes two processes simultaneously, oxidation of the RSH by PV 6 Mo 6 and reoxidation of reduced PV 6 Mo 6 by O 2 ; and (3) the analogous polytungstate-based system, TBA 4 H 5 [PW 6 V 6 O 40 ] (PV 6 W 6 ), has nearly identical cyclic voltammograms (CV) as PV 6 Mo 6 but has almost no catalytic activity: it does not exhibit self-redox buffering.

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Section: Introductionmentioning

confidence: 99%

Catalytic System for Aerobic Oxidation That Simultaneously Functions as Its Own Redox Buffer

Tang

Geletii

et al. 2023

Inorg. Chem.

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“…The UV/vis spectrum in 0.01 M CF 3 CO 2 H is almost identical with the final spectrum of the reaction of Ru VI N with H 3 PO 2 shown in Figure S8; the peak at ca. 640 nm is characteristic of (L)Ru III complexes. − The complex is paramagnetic with a magnetic moment of 1.69 μ B at room temperature, as determined by the Evans method, consistent with a low-spin ( S = 1/2) ruthenium(III) complex.…”

Section: Resultsmentioning

confidence: 86%

“…Our group has also reported novel reactivities of a highly electrophilic/oxidizing (salen)ruthenium(VI) nitrido complex, [(L)Ru VI (N)(OH 2 )] + ( Ru VI N ; where L = N,N ′-bis(salicylidene)- o -cyclohexyldiamine dianion). In particular, we have demonstrated C–N cleavage of aniline, C–H activation of alkanes, aziridination of alkenes, nitrogenation of alkynes and oxidation of phenols by Ru VI N in organic solvents. − Recently, we have also been interested in the reactivity of Ru VI N in aqueous solutions, since in comparison to metal oxo species, the aqueous redox chemistry of metal nitrido species has received much less attention. − …”

Section: Introductionmentioning

confidence: 99%

Oxidation of Hypophosphorous Acid by a Ruthenium(VI) Nitrido Complex in Aqueous Acidic Solution. Evidence for a Proton-Coupled N-Atom Transfer Mechanism

Jiang

et al. 2022

Inorg. Chem.

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The oxidation of hypophosphorous acid (H3PO2) by a ruthenium(VI) nitrido complex, [(L)RuVI(N)(OH2)]+ (Ru VI N; L = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion), has been studied in aqueous acidic solutions at pH 0–2.50. The reaction has the following stoichiometry: 2[(L)RuVI(N)(OH2)]+ + 3H3PO2 + H2O → 2[(L)RuIII(NH2P(OH)2)(OH2)]+ + H3PO3. The pseudo-first-order rate constant, k obs, depends linearly on [H3PO2], and the second-order rate constant k 2 depends on [H+] according to the relationship k 2 = k[H+]/([H+] + K a), where k is the rate constant for the oxidation of H3PO2 molecule and K a is the dissociation constant of H3PO2. At 298.0 K and I = 1.0 M, k = (2.04 ± 0.19) × 10–2 M–1 s–1 and K a = (6.38 ± 0.63) × 10–2 M. A kinetic isotope effect (KIE) of 2.9 ± 0.1 was obtained when kinetic studies were carried out with D3PO2 at pH 1.16, suggesting P–H bond cleavage in the rate-determining step. On the other hand, when the kinetics were determined in D2O, an inverse KIE of 0.21 ± 0.03 (H3PO2 in H2O vs H3PO2 in D2O) was found. On the basis of experimental results and DFT calculations, the proposed mechanism involves an acid-catalyzed tautomerization of H2P(O)(OH) to HP(OH)2; the latter molecule is the reacting species which reacts with Ru VI N via a proton-coupled N-atom transfer pathway.

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Reduction of Ru^VI≡N to Ru^III—NH₃ by Cysteine in Aqueous Solution

Cited by 2 publications

References 52 publications

Catalytic System for Aerobic Oxidation That Simultaneously Functions as Its Own Redox Buffer

Catalytic System for Aerobic Oxidation That Simultaneously Functions as Its Own Redox Buffer

Oxidation of Hypophosphorous Acid by a Ruthenium(VI) Nitrido Complex in Aqueous Acidic Solution. Evidence for a Proton-Coupled N-Atom Transfer Mechanism

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