Lewis versus Bronsted Acid Activation of a Mn(IV) Catalyst for Alkene Oxidation

Jorn D. Steen, Stepan Stepanovic, Mahsa Parvizian, Johannes W. de Boer, Ronald Hage, Juan Chen, Marcel Swart, Maja Gruden, Wesley R. Browne*

*Bijbehorende auteur voor dit werk

OnderzoeksoutputAcademicpeer review

11 Citaten (Scopus)
125 Downloads (Pure)

Samenvatting

Lewis acid (LA) activation by coordination to metal oxido species has emerged as a new strategy in catalytic oxidations. Despite the many reports of enhancement of performance in oxidation catalysis, direct evidence for LA-catalyst interactions under catalytically relevant conditions is lacking. Here, we show, using the oxidation of alkenes with H2O2 and the catalyst [Mn-2(mu-O)(3)(tmtacn)(2)](PF6)(2) (1), that Lewis acids commonly used to enhance catalytic activity, e.g., Sc(OTf)(3), in fact undergo hydrolysis with adventitious water to release a strong Bronsted acid. The formation of Bronsted acids in situ is demonstrated using a combination of resonance Raman, UV/vis absorption spectroscopy, cyclic voltammetry, isotope labeling, and DFT calculations. The involvement of Bronsted acids in LA enhanced systems shown here holds implications for the conclusions reached in regard to the relevance of direct LA-metal oxido interactions under catalytic conditions.

Originele taal-2English
Pagina's (van-tot)14924-14930
Aantal pagina's7
TijdschriftInorganic Chemistry
Volume58
Nummer van het tijdschrift21
DOI's
StatusPublished - 4-nov-2019

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