Selective abatement of electron-rich organic contaminants by trace complexed Mn(II)-catalyzed periodate via high-valent manganese-oxo species.

Mn(II) is among the most efficient catalysts for the periodate (PI)-based oxidation process. In-situ formed colloidal MnO2 simultaneously serves as the catalyst and oxidant during the degradation of organic contaminants by PI. Here, it is revealed that the complexation of Mn(II) by ethylene diamine tetraacetic acid (EDTA) further enhances the performance of PI-based oxidation in the selective degradation of organic contaminants. As evidenced by methyl phenyl sulfoxide probing, 18O-isotope labeling, and mass spectroscopy, EDTA complexation modulates the reaction pathway between Mn(II) and PI, triggering the generation of high-valent manganese-oxo (MnV-oxo) as the dominant reactive species. PI mediates the single-electron oxidation of Mn(II) to Mn(III), which is stabilized by EDTA complexation and then further oxidized by PI via the oxygen-atom transfer step, ultimately producing the MnV-oxo species. Ligands analogous to EDTA, namely, [S,S]-ethylenediaminedisuccinic acid and L-glutamic acid N,N-diacetic acid, also enhances the Mn(II)/PI process and favors MnV-oxo as the dominant species. This study demonstrates that functional ligands can tune the efficiency and reaction pathways of Mn(II)-catalyzed peroxide and peroxyacid-based oxidation processes.

Materials for the Simultaneous Entrapment and Catalytic Aerobic Oxidative Removal of Sulfur Mustard Simulants.

Materials that both sequester chemical warfare agents (CWAs) and then catalytically decontaminate the entrapped CWAs are highly sought. This article reports such a system for air-based catalytic removal of the sulfur mustard (HD) simulant, 2-chloroethyl ethyl sulfide (CEES). Hypercrosslinked polymers (HCPs) sequester CEES, and an HCP-embedded oxidation system comprising tribromide, nitrate, and acid (NOxBrxH+) simultaneously catalyzes the aerobic and selective, oxidative conversion of the entrapped CEES to the desired far less-toxic sulfoxide under ambient conditions (air and temperature). (NOxBrxH+) has been incorporated into three HCPs, a fluorobenzene HCP (HCP-F), a methylated HCP (HCP-M), and an HCP with acidic moieties (HCP-A). HCP-A acts as both an absorbing material and a catalytic component due to its acidic side chains. All three HCP/NOxBrxH+ systems work rapidly under these optimally mild conditions. No light or added oxidants are required. The HCP/NOxBrxH+ systems are recyclable.