1,721,359 research outputs found
Enantioselective isotactic alternating copolymerization of styrene and 4-metylstyrene with carbon monoxide catalyzed by a cationic bioxazoline Pd(II) complex.
No full textalfa-diimine and bioxazoline Pd(II) complexes as catalysts in the CO-styrene copolymerization
No full textTransmission of substituent effects through the methyleneamino group N=CH : Aldehyde phenylhydrazones and conjugate anions
No full textMgH2 as a reducing agent. Part II. Reduction of organic halides in presence of Ni (0) and Pd (0) complexes
No full textSynthesis of a Novel alpha-Diimine Palladium(II) Complex Bearing an eta3-Allyl gamma-Lactone Ligand, a Key Intermediate in Alkyne Cyclocarbonylation Processes
No full textPlatinacyclobutane complexes from nucleophilic attack at a coordinated allyl group and catalytic formation of cyclopropanes in the presence of platinum complexes
No full textReaction of allyl acetates and ketene silyl acetals catalyzed by Palladium (0) complexes part II. Cyclopropanation vs. allylic alkylation
No full textIntermediates in the Copolymerization of p-Methylstyrene and Carbon Monoxide Catalyzed By Pd(II) Complexes.
No full textComputational Overview of a Pd-Catalyzed Olefin Bis-alkoxycarbonylation Process
No full textA comprehensive density functional theory analysis is reported for the one-pot bis-alkoxycarbonylation reaction of olefins to form succinic acid esters by action of the catalyst (N-N)Pd(TFA)2 (N-N = bis(2,6-dimethylphenyl)-2,3-dimethyl-1,4-diazabutadiene, TFA- = CF3CO2-). The selective and efficient process involves alkene (H2C=CHR), CO, methanol, and p-benzoquinone (BQ) molecules as reactants. The catalytic mechanism, previously proposed on the basis of available experimental and literature data, is critically revised here. A plethora of optimized intermediates and transition states and their correlating energy profiles allow a step by step reconstruction of the entire cycle, highlighting key mechanistic aspects, such as the role of the R substituent in the olefin. One of its effects is determined by the presence of a 2e- donor group, which, depending on its power, may affect the catalysis up to its total inhibition. As another aspect, the key diester product forms through a reductive elimination step (Pd(II) → Pd(0) transformation) that excludes the previously proposed attainment of a Pd(II)-hydride complex. Finally, the paper illustrates the action of the sacrificial BQ oxidant in the restoration of the original Pd(II) catalyst, as found for other strictly related cases. The energy profile indicates that the rate-determining step occurs in the initial part of the reaction, given a +29.6 kcal mol-1 energy barrier, associated with a methoxo migration into an adjacent CO ligand. The result foreshadows a rather slow activation of the catalyst and a long duration of the cycle
Procedimento perfezionato per la riduzione di composti organici mediante l'impiego di idruro di magnesio
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