کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1336232 | 1500223 | 2016 | 8 صفحه PDF | دانلود رایگان |
A systematic study on the oxidative decarboxylation of a series of phenylsulfinylacetic acids (PSAA) by hydrogen peroxide with four oxovanadium(IV)-salophen catalysts in 100% acetonitrile medium is presented. The hydroperoxovanadium(V)-salophen generated from the reaction mixture is identified as the bonafide active oxidizing species. Introduction of electron donating groups (EDG) in the oxovanadium(IV)-salophen catalyst and electron withdrawing groups (EWG) in PSAA enhances the reactivity, whereas EWG in the catalyst and EDG in PSAA have a retarding effect on the reaction. A Hammett correlation displays a non-linear downward curvature, which consists of two intersecting straight lines and the ρ value shifts from small positive to moderately high as the substituents change from EWG to EDG. The importance of the ground state stabilization of PSAA is inferred from a linear Yukawa–Tsuno plot. Based on the observed substituent effects and the spectral changes, a mechanism involving electrophilic attack of PSAA on the nucleophilic peroxo oxygen atom of the vanadium complex in the rate determining step followed by oxygen atom transfer is proposed.
Hydroperoxovanadium(V)-salophen is identified as the oxidizing species. Electron donating groups in the complex and withdrawing groups in phenylsulfinylacetic acid enhance the reaction. Ground state stabilization is inferred from a non-linear Hammett correlation and linear Yukawa–Tsuno plot. The mechanism proposed involves electrophilic attack of phenylsulfinylacetic acid on the nucleophilic peroxo oxygen atom of the vanadium complex.Figure optionsDownload as PowerPoint slide
Journal: Polyhedron - Volume 117, 15 October 2016, Pages 496–503