Catalytic sulfoxidation and epoxidation using oxomolybdenum compounds generated from tricarbonyl(1-methylimidazole)molybdenum(0)

resumo

The scope of molybdenum carbonyl precatalysts has been expanded to include [Mo(CO)3(1-mim)3] (1) (1-mim = 1-methylimidazole) for application in epoxidation and sulfoxidation processes, using relatively ecofriendly and industrially used oxidants. The mechanisms of conversion of 1 to active species were investigated by systematically combining catalytic and characterization studies. With tert-butylhydroperoxide (TBHP), 1 gives the functionalized polyoxomolybdate (1-Hmim)4[Mo8O26(1-mim)2]& sdot;2H2O (2), which then leads to the stable salt (1Hmim)4[Mo8O26]& sdot;2H2O (3) containing beta-octamolybdate molecular anions. With H2O2, 1 gives a structurally distinct octamolybdate, (1-Hmim)4[Mo8O26] (4), with characterization data that point to the presence of [Mo8O26]n4n- chains. In the reactions of cis-cyclooctene or dl-limonene with H2O2, 4 is a reaction-induced selfseparating catalyst, i.e., in the initial stages it dissolves to give a homogeneous solution, but then self-precipitates once the oxidant is consumed. In the sulfoxidation of methyl phenyl sulfide, 4 was effective in producing the sulfoxide selectively with TBHP, and the sulfone with H2O2.

palavras-chave

OLEFIN EPOXIDATION; DIOXOMOLYBDENUM(VI) COMPLEXES; MONOTERPENES OXIDATION; LIMONENE EPOXIDATION; HYDROGEN-PEROXIDE; PRECURSORS; OCTAMOLYBDATE; CYCLOHEXENE; MECHANISM; POLYMERS

categoria

Chemistry; Environmental Sciences & Ecology

autores

Antunes, MM; Gomes, AC; Goncalves, IS; Pillinger, M; Valente, AA

Grupos

G1 - Materiais Porosos e Nanossistemas
G4 - Materiais Renováveis e Economia Circular

Projectos

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Rede Nacional de Ressonância Magnética Nuclear (PTNMR)

agradecimentos

The work in this paper was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT (Fundacao para a Ciencia e a Tecnologia) / MCTES (Ministerio da Ciencia, Tecnologia e Ensino Superior) (PIDDAC). The authors acknowledge the support of the project with ref. 2023.14213.PEX financed by national funds through the FCT/MCTES (PIDDAC). The position held by M.M.A. was funded by national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of article 23 of the Decree-Law 57/2016 of 29 August, changed by Law 57/2017 of 19 July (https://doi.org/10.54499/DL57/2016/CP1482/CT0062). A.C.G. acknowledges the FCT/MCTES for an Assistant Researcher Position funded through the Individual Call to Scientific Employment Stimulus (ref. CEECIND/02128/2017; https://doi.org/10.54499/CEECIND/02128/2017/CP1459/CT0039). The NMR spectrometers used in this work are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL, and FCT through PIDDAC).