101032-23-9

Upstream product

• 103-04-8 (phenylthio)acetic acid 
• 101032-17-1 Mn(C₆H₄OCNCH₂)2(C₆H₅)2 

Relevant academic research and scientific papers

Epoxidation of Olefins with Cationic (salen)MnIII Complexes. The Modulation of Catalytic Activity by Substituents

Cationic manganese(III) complexes of the salen ligand are effective catalysts for the epoxidation of various olefins with iodosylbenzene as the terminal oxidant.The presence of electron-withdrawing groups, such as 5,5'-dichloro or -dinitro substituents, enhances the catalytic activity of the (salen)MnIII catalyst in measure with the electron-deficient character of the cationic complex as evaluated by the standard reduction potential E0.Various types of olefins, including substituted styrenes, stilbenes, and cyclic and acyclic alkenes, are epoxidized in 50-75percent yields within 15 min at ambient temperatures in acetonitrile.Stereospecific epoxidation in achieved with trans-olefins such as (E)-2-hexene and (E)-β-methylstyrene. cis-Olefins produce high yields of cis-epoxides which contain minor amounts of the corresponding trans isomer.Competition from allylic oxidation is minor with this catalyst system-cyclohexene being converted selectively to its epoxide accompanied by only traces of cyclohexenol.Competition studies indicate that the relative reactivity of olefins toward catalytic epoxidation with the cationic (salen)MnIII complexes falls into an unusually narrow range, the difference between the most reactive, p-methoxystyrene, and the least reactive, 1-octene, being only a factor of 10.The effect of donor ligands such as pyridine and imidazole is discussed in the context of a radical-like behavior of an oxomanganese species as the reactive intermediate.The latter is supported by some preliminary studies of alkane oxdation using cyclohexane as a model.

Mechanistic study on the oxidation of (phenylthio)acetic acids by oxo(salen)manganese(V) complexes and the reactivity-selectivity principle

A systematic study on the kinetics and mechanism of oxidation of several (para-substituted phenylthio)acetic acids with various substituted oxo(salen)manganese(V) complexes in acetonitrile at 20 °C is presented. The kinetic data indicate that the reaction is second-order overall, first-order each in (phenylthio)acetic acid and oxo(salen)manganese(V) complex. Rate studies with substituted (phenylthio)acetic acids give an excellent Hammett correlation with σ+/σ- constants and the ρ-values are in the range of -0.82 to -1.17 for different oxo(salen)manganese(V) complexes. The log k2 values observed in the oxidation of each (phenylthio)acetic acid by substituted oxo(salen)manganese(V) complexes correlate with 2σ, giving ρ-values from 0.26 to 0.56. A mechanism involving single electron transfer from the sulfur center of the substrate to the oxo complex in the rate-controlling step is envisaged. Kinetic data were obtained over a temperature range of 15-35 °C and the activation parameters evaluated. Correlation analyses show the presence of an inverse relationship between reactivity and selectivity in the reactions of various (phenylthio)acetic acids with a given oxo(salen)manganese(V) complex and also in various oxo(salen)manganese(V) complexes with a given (phenylthio)acetic acid. Mathematical treatment of the results shows the operation of a valid reactivity-selectivity principle in this redox system.

Kinetics and mechanism of oxidation of diphenyl sulphides by oxo(salen) manganese(V) complexes and a study of reactivity-selectivity principle

The kinetics of oxidation of a few 4-substituted diphenyl sulphides with six oxo(salen)manganese(V) complexes has been studied in acetonitrile spectrophotometrically at 25°C. The reaction is second order overall, first order each in the complex and the su