• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2446-2450
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• 2013

Oxindole dimers have been used as intermediates in the synthesis of various cyclotryptamine alkaloids. An efficient direct synthesis of oxindole dimers has been carried out from 3-substituted oxindoles via an oxidative dimerization using manganese(III) acetate or copper acetate/silver acetate system.

• Proceedings of the Petrological Society of Korea Conference
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• 1999.06a
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• pp.25-29
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• 1999

Manganese (Mn) oxides in soils and sediments differ in structure and composition. The influence of that diversity on the chromium (Cr) oxidation is the subject of this report. Oxidation of Cr(III) to Cr(VI) by coarse clay size Mn oxides (synthetic pyrolusite and natural lithiophorite, todorokite, and bimessite) was studied. Chromium oxidation by Mn oxides was initially fast and followed by a slow reaction. More Cr was oxidized by the Mn oxides at lower pH and higher initial Cr(III) concentration in solution. Birnessite had the highest chromium oxidation capacity per unit external surface area (COCUESA) and lithiophorite had the lowest COCUESA. The kinetics of Cr oxidation and COCUESA of Mn oixdes were apparently controlled by reactivity of surface Mn, mineralogy, and solution properties (pH and Cr(III) concentration).

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4015-4022
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• 2012

Manganese(III) 5-(4-carboxyphenyl)-10,15,20-triphenyl porphyrin chloride (Mn(TCPP)Cl) was grafted through amide bond on silica zeolite Y (HY), zeolite beta ($H{\beta}$) and hexagonal mesoporous silica (HMS). XRD, ICP-AES, $N_2$ physisorption, SEM, TEM, FTIR and thermal analysis were employed to analyse these novel heterogeneous materials. These silica supported catalysts were shown to be used for epoxidation and good shape selectivity was observed. The effect of support structure on catalytic performance was also discussed. The catalytic activity remained when the catalysts were recycled five times. The energy changes about epoxidation of alkenes by $NaIO_4$ and $H_2O_2$ were also computationally calculated to explain the different catalytic efficiency.

• Environmental Engineering Research
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• v.14 no.2
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• pp.134-139
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• 2009

In this study, oxidation of As (III) as well as removal of total arsenic by adsorbents coated with single oxides or multi-oxides (Fe (III), Mn (IV), Al (III)) was investigated. In addition, multi-functional properties of adsorbents coated with multi-oxides were evaluated. Finally, application of activated carbon impregnated with Fe or Mn-oxides on the treatment of As (III) or As (V) was studied. As (V) adsorption results with adsorbents containing Fe and Al shows that adsorbents containing Fe show a greater removal of As (V) at pH 4 than at pH 7. In contrast adsorbents containing Al shows a favorable removal of As (V) at pH 7 than at pH 4. In case of iron sand, it has a negligible adsorption capacity for As (V) although it contains 217.9 g-Fe/kg-adsorbent, Oxidation result shows that manganese coated sand (MCS) has the greatest As (III) oxidation capacity among all metal oxides at pH 4. Oxidation efficiency of As (III) by IMCS (iron and manganese coated sand) was less than that by MCS. However the total removed amount of arsenic by IMCS was greater than that by MCS.

• Bulletin of the Korean Chemical Society
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• v.17 no.10
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• pp.929-934
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• 1996

The electrochemistry and the reaction of non-μ-oxo dimer-forming [5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrinato] manganese(Ⅲ) chloride [(Cl8TPP)MnⅢCl] with tetraethylammonium hydroxide in water [-OH(H2O)] have been investigated by electrochemical and spectroscopic methods under anaerobic conditions. The stronger autoreduction of (C18TPP)MnⅢCl by -OH(H2O) in comparison with (Me12TPP)MnⅢCl by -OH(CH3OH) in MeCN is explained as the influence of electronic effects on substituted phenyl groups bonded to meso-position of porphyrin ring and the positive shift of reduction potential (-0.11 V) for (C18TPP)MnⅢCl. The autoreduction of manganese(Ⅲ) porphyrin to manganese (Ⅱ) by this process is only observed when one axial position is occupied by a ligating solvent and OH- coordinates the other axial site. The results are discussed in relation to the mechanisms for the reduction of manganese(Ⅲ) porphyrin.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2684-2688
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• 2014

Two two-dimensional cyanide- and phenoxo-bridged heterometallic M(II)-Mn(III) (M = Ni, Pd) coordination polymers $\{[Mn(saltmen)]_4[Ni(CN)_4]\}(ClO_4)_2{\cdot}CH_3OH{\cdot}H_2O$ (1) and $\{[Mn(saltmen)]_4[Pd(CN)_4]\}(ClO_4)_2{\cdot}CH_3CN{\cdot}H_2O$ (2) ($saltmen^{2-}$ = N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneaminato)dianion) have been obtained by using $K_2[M(CN)_4]$ as building blocks and a salen-tpye Schiff-base manganese(III) compound as assembling segment. Single X-ray analysis reveals their isostrutural cyanide-bridged $MMn_4$ pentanuclear cationic structure. The four Schiff base manganese units of the pentanuclear entity are self-complementary through the phenoxo oxygen atoms from the neighboring complex, therefore forming cyanide- and phenoxo-bridged 2D sheet-like structure. Investigation over magnetic susceptibilities reveals the overall ferromagnetic coupling between the adjacent Mn(III) ions bridged by the phenoxo oxygen atoms with J = 2.13 and $2.21cm^{-1}$ for complexes 1 and 2, respectively.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.431-439
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• 2014

The purposes of this research were to investigate the enrichment of metal-reducing bacteria from KURT groundwater and the identification of the microbial diversity by 16S rRNA as well as to examine microbial Fe(III)/Mn(IV) reduction and to analyze morphological features of interactions between microbes and precipitates and their mineralogical composition. To cultivate metal-reducing bacteria from groundwater sampled at the KURT in S. Korea, different electron donors such as glucose, acetate, lactate, formate, pyruvate and Fe(III)-citrate as an electron accepter were added into growth media. The enriched culture was identified by 16S rRNA gene sequence analysis for the diversity of microbial species. The effect of electron donors (i.e., glucose, acetate, lactate, formate, pyruvate) and electron acceptors (i.e., akaganeite, manganese oxide) on microbial iron/manganese reduction and biomineralization were examined using the 1st enriched culture, respectively. SEM, EDX, and XRD analyses were used to determine morphological features, chemical composition of microbes and mineralogical characteristics of the iron and manganese minerals. Based on 16S rRNA gene analysis, the four species, Fusibacter, Desulfuromonas, Actinobacteria, Pseudomonas sp., from KURT groundwater were identified as anaerobic metal reducers and these microbes precipitated metals outside of cells in common. XRD and EDX analyses showed that Fe(III)-containing mineral, akaganeite (${\beta}$-FeOOH), reduced into Fe(II)/Fe(III)-containing magnetite ($Fe_3O_4$) and Mn(IV)-containing manganese oxide (${\lambda}-MnO_2$) into Mn(II)-containing rhodochrosite ($MnCO_3$) by the microbes. These results implicate that microbial metabolism and respiratory activities under anaerobic condition result in reduction and biomineralization of iron and manganese minerals. Therefore, the microbes cultivated from groundwater in KURT might play a major role to reduce various metals from highly toxic, mobile to less toxic, immobile.

• Analytical Science and Technology
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• v.8 no.4
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• pp.569-574
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• 1995

In-situ spectroelectrochemical studies have been carried out on the oxidation of Mn(II) at platinum, gold, lead dioxide, and bismuth doped lead dioxide electrodes. The Mn(III), $MnO_2$, and/or ${MnO_4}^-$ species are produced depending on experimental conditions employed during electrolysis. Mn(III) is shown to be produced from a very early stage during the anodic potential scan and undergo disproportionation-conproportionation reactions depending on the relative concentration of each species near the electrode surface. An oxidation mechanism consistent with these observations is proposed.

• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.917-920
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• 2004

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1455-1456
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• 2004