Aerobic Carbon–Carbon Bond Cleavage of Alkenes to Aldehydes Catalyzed by First-Row Transition-Metal-Substituted Polyoxometalates in the Presence of Nitrogen Dioxide

Abstract

A new aerobic carbon-carbon bond cleavage reaction of linear di-substituted alkenes, to yield the corresponding aldehydes/ketones in high selectivity under mild reaction conditions, is described using copper(II)-substituted polyoxometalates, such as {α2-Cu(L)P2W17O61}(8-) or {[(Cu(L)]2WZn(ZnW9O34)2}(12-), as catalysts, where L = NO2. A biorenewable-based substrate, methyl oleate, gave methyl 8-formyloctanoate and nonanal in >90% yield. Interestingly, cylcoalkenes yield the corresponding epoxides as products. These catalysts either can be prepared by pretreatment of the aqua-coordinated polyoxometalates (L = H2O) with NO2 or are formed in situ when the reactions are carried with nitroalkanes (for example, nitroethane) as solvents or cosolvents. Nitroethane was shown to release NO2 under reaction conditions. (31)P NMR shows that the Cu-NO2-substituted polyoxometalates act as oxygen donors to the C-C double bond, yielding a Cu-NO product that is reoxidized to Cu-NO2 under reaction conditions to complete a catalytic cycle. Stoichiometric reactions and kinetic measurements using {α2-Co(NO2)P2W17O61}(8-) as oxidant and trans-stilbene derivatives as substrates point toward a reaction mechanism for C-C bond cleavage involving two molecules of {α2-Co(NO2)P2W17O61}(8-) and one molecule of trans-stilbene that is sufficiently stable at room temperature to be observed by (31)P NMR.

Two New Preyssler‐Type Polyoxometalate‐Based Coordination Polymers and Their Application in Horseradish Peroxidase Immobilization

“…Hence, it can be inferred that CuCl 2 and {ZP 5 W 30 } must promote breakage of the C−C bond and C−Cl bond formation. The C−C bond breakage may be also caused by the redox activity of the Preyssler‐type POMs . To investigate the influence of the Na I /Ag I center on the structure of the {ZP 5 W 30 }‐based product, in the synthetic process, we used K 14 [AgP 5 W 30 O 110 ] ⋅ 18 H 2 O (abbreviated as parent‐ 2 ) in place of parent‐ 1 ; all above experiments were repeated under the same conditions.…”

Potassium Permanganate-Catalyzed Alpha-Pinene Oxidation: Formation of Coordination Compound with Zinc(II) and Copper(II), and Growth Inhibition Activity on <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>

“…Some report has been devoted using different catalyst such as ozone [10][11][12], complex [Mn(TPP-PEO)Cl] catalyst [13], ruthenium [14][15][16][17], rhodium [18], palladium [19], complex of metal-oxalate [20], and silica-supported permanganate [21]. The oxidized of alpha-pinene, then, can coordinate with some metal ions such as Zn, Cu, Pt, and Mo.…”

A polyoxometalate-based inorganic–organic hybrid polymer constructed from silver-Schiff base building block and Keggin-type cluster: Synthesis, crystal structure and photocatalytic performance for the degradation of rhodamine B

“…Polyoxometalates (POMs), a large family of soluble anionic early transition-metal oxide clusters, have attracted much interest due to their enormous structural varieties and an unmatched range of physical and chemical properties applicable to diverse areas of research such as catalysis, magnetism, sensing, medicine and materials science [1][2][3]. Currently, the design and synthesis of POM-based inorganic-organic hybrid materials is not only an emerging multidisciplinary research area but also one of the biggest areas in POM chemistry.…”