Effect of the Polyanion Structure on the Mechanism of Alcohol Oxidation with H2O2 Catalyzed by Zr-Substituted Polyoxotungstates Full article
| Journal |
Inorganic Chemistry
ISSN: 0020-1669 , E-ISSN: 1520-510X |
||||
|---|---|---|---|---|---|
| Output data | Year: 2024, Volume: 63, Number: 39, Pages: 18043–18057 Pages count : 15 DOI: 10.1021/acs.inorgchem.4c02641 | ||||
| Tags | Ethanol; Fourier transform infrared spectroscopy; Fourier transforms; Free radical reactions; Ketones; Nuclear magnetic resonance spectroscopy; Peroxides; Photodissociation; Rate constants; Zircon | ||||
| Authors |
|
||||
| Affiliations |
|
Funding (1)
| 1 | Russian Science Foundation | 23-13-00156 |
Abstract:
Zr-monosubstituted polyoxometalates (Zr-POMs) of the Lindqvist (Bu4N)6[{W5O18Zr(μ-OH)}2] (1), Keggin (Bu4N)8[{PW11O39Zr(μ-OH)}2] (2), and Wells–Dawson (Bu4N)11.3K2.5H0.2[{P2W17O61Zr}2(μ-OH)2] (3) structures catalyze oxidation of alcohols using aqueous hydrogen peroxide as an oxidant. With 1 equiv of H2O2 and 1 mol % of Zr-POM, selectivity toward aldehydes and ketones varied from good to excellent, depending on the alcohol nature. Catalytic activity and attainable substrate conversions strongly depended on the Zr-POM structure and most often decreased in the order 1 > 2 ≫ 3. The reaction mechanism was probed using a test substrate, cyclobutanol, radical and 1O2 scavengers, and kinetic and spectroscopic (attenuated total reflectance-Fourier transform infrared (ATR-FT-IR), 31P NMR and electrospray ionization-mass spectrometry (ESI-MS)) tools. The results point to heterolytic alcohol oxidation in the presence of 1 and 2 and homolytic alcohol oxidation in the presence of 3. Kinetic and spectroscopic studies implicated an oxidation mechanism that involves both alcohol and peroxide binding to 2 followed by an inner-sphere heterolytic H-abstraction from the α–C-H bond by the Zr-hydroperoxo group, leading to a carbonyl compound. The unique capability of 1 to generate 1O2 upon interaction with H2O2 complicates the reaction kinetics and improves the product yield. Spectroscopic studies coupled with stoichiometric experiments unveiled that dimeric monoperoxo {Zr2(μ-η2:η2-O2)} and monomeric hydroperoxo {Zr(η2-OOH)} species accomplish the transformation of alcohols to carbonyl compounds.
Cite:
Maksimchuk N.V.
, Marikovskaya S.M.
, Larionov K.P.
, Evtushok V.Y.
, Yanshole V.V.
, Antonov A.A.
, Kholdeeva O.A.
Effect of the Polyanion Structure on the Mechanism of Alcohol Oxidation with H2O2 Catalyzed by Zr-Substituted Polyoxotungstates
Inorganic Chemistry. 2024. V.63. N39. P.18043–18057. DOI: 10.1021/acs.inorgchem.4c02641 WOS Scopus РИНЦ ANCAN OpenAlex
Effect of the Polyanion Structure on the Mechanism of Alcohol Oxidation with H2O2 Catalyzed by Zr-Substituted Polyoxotungstates
Inorganic Chemistry. 2024. V.63. N39. P.18043–18057. DOI: 10.1021/acs.inorgchem.4c02641 WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
| Submitted: | Jun 26, 2024 |
| Accepted: | Sep 9, 2024 |
| Published online: | Sep 20, 2024 |
| Published print: | Sep 30, 2024 |
Identifiers:
| Web of science: | WOS:001318664800001 |
| Scopus: | 2-s2.0-85205407329 |
| Elibrary: | 74116921 |
| Chemical Abstracts: | 2024:2001408 |
| Chemical Abstracts (print): | 188:193005 |
| OpenAlex: | W4402687890 |