| Autor: |
Lueckheide MJ; Department of Chemistry, Brown University, Providence, Rhode Island02912, United States., Ertem MZ; Chemistry Division, Energy & Photon Sciences, Brookhaven National Laboratory, Upton, New York11973, United States., Michon MA; Department of Chemistry, Brown University, Providence, Rhode Island02912, United States., Chmielniak P; Department of Chemistry, Brown University, Providence, Rhode Island02912, United States., Robinson JR; Department of Chemistry, Brown University, Providence, Rhode Island02912, United States. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2022 Sep 21; Vol. 144 (37), pp. 17295-17306. Date of Electronic Publication: 2022 Sep 09. |
| DOI: |
10.1021/jacs.2c08140 |
| Abstrakt: |
Metal peroxides are key species involved in a range of critical biological and synthetic processes. Rare-earth (group III and the lanthanides; Sc, Y, La-Lu) peroxides have been implicated as reactive intermediates in catalysis; however, reactivity studies of isolated, structurally characterized rare-earth peroxides have been limited. Herein, we report the peroxide-selective (93-99% O 2 2- ) reduction of dioxygen (O 2 ) at redox-inactive rare-earth triflates in methanol using a mild metallocene reductant, decamethylferrocene (Fc*). The first molecular praseodymium peroxide ([Pr III 2 (O 2 2- )(18C6) 2 (EG) 2 ][OTf] 4 ; 18C6 = 18-crown-6, EG = ethylene glycol, - OTf = - O 3 SCF 3 ; 2-Pr ) was isolated and characterized by single-crystal X-ray diffraction, Raman spectroscopy, and NMR spectroscopy. 2-Pr displays high thermal stability (120 °C, 50 mTorr), is protonated by mild organic acids [p K a1 (MeOH) = 5.09 ± 0.23], and engages in electrophilic (e.g., oxygen atom transfer) and nucleophilic (e.g., phosphate-ester cleavage) reactivity. Our mechanistic studies reveal that the rate of oxygen reduction is dictated by metal-ion accessibility, rather than Lewis acidity, and suggest new opportunities for differentiated reactivity of redox-inactive metal ions by leveraging weak metal-ligand binding events preceding electron transfer. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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