• Environmental Engineering Research
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• v.20 no.3
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• pp.205-211
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• 2015

Reduced forms of iron, such as zero-valent ion (ZVI) and ferrous ion (Fe[II]), can activate dissolved oxygen in water into reactive oxidants capable of oxidative water treatment. The corrosion of ZVI (or the oxidation of (Fe[II]) forms a hydrogen peroxide ($H_2O_2$) intermediate and the subsequent Fenton reaction generates reactive oxidants such as hydroxyl radical ($^{\bullet}OH$) and ferryl ion (Fe[IV]). However, the production of reactive oxidants is limited by multiple factors that restrict the electron transfer from iron to oxygen or that lead the reaction of $H_2O_2$ to undesired pathways. Several efforts have been made to enhance the production of reactive oxidants by iron-induced oxygen activation, such as the use of iron-chelating agents, electron-shuttles, and surface modification on ZVI. This article reviews the chemistry of oxygen activation by ZVI and Fe(II) and its application in oxidative degradation of organic contaminants. Also discussed are the issues which require further investigation to better understand the chemistry and develop practical environmental technologies.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.500-505
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• 1991

The stereoselectivity on the electron-transfer reaction between optical active ${\bigwedge}$-[CO(EDDS)]- and conformationally restricted complex $[Co({\pm}chxn)_3]^{2+}$ has been examined in aqueous solution. The products are four conformational isomers $(lel_3,\;lel_2ob,\;lelob_2,\;and\;ob_3)$ of ${\bigwedge}$-[Co(chxn)$_3]^{3+}$ with optical purities of 22% e.e, 25% e.e, 11% e.e, and 10% e.e, respectively. The reaction between ${\bigwedge}$-[CO(EDDS)]- and $[Co({\pm}chxn)_3]^{2+}$ in DMSO produced lel3-${\Delta}$ and lel2ob-${\Delta}$-[Co(chxn)$_3]^{3+}$ whose optical purities are 100% e.e, and 75% e.e, respectively.

• Journal of the Korean Chemical Society
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• v.33 no.5
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• pp.496-503
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• 1989

The chemical behavior of trivalent lanthanide (Pr(III) and Yb(III)) and 2, 2, 6, 6-tetramethyl-3, 5-heptanedione(dipivaloylmethane) complexes was investigated by the use of direct current, differential pulse polarography and cyclic voltammetry. In this study, it was founded that the reduction of trivalent lanthanide complexes was observed by one electron transfer process at Epc = -0. 13 V and -0.80 V of Pr(III), and -0.02 V of Yb(III) vs. Ag-AgCl electrode. Also, it was founded that the treatment of DP and CV to the case of a first-order chemical equilibrium reaction preceding a reversible and irreversible one electron transfer reaction, (a >0. 5) the socalled ErCr electrode process. The equilibrium constant (lnK) obtained, of various solvents, these constant were founded to be increases with decreasing dielectric constant of the solvents. Plots of lnK for these reaction against ln(l/D) for the solvents was fairly straight lines, and the behavior of the heavier lanthanides was decreased equilibrium constant with increasing atomic number.

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.135-142
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• 1984

New type dioxygen bridged complexes of palladium were prepared by using $KO_2$ as a source of superoxide ion $(O_2^-)$. The method is completely different from the traditional one which has adopted the oxidative addition of molecular oxygen to transition metal complexes in low valency. It was suggested that the reaction to prepare the dioxygen complexes proceeded via nucleophilic displacement followed by electron transfer reaction. Five new type dioxygen complexes having ${\pi}$-allyl ligand were prepared and characterized by the application of the reaction of $O_2^-$.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.64-71
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• 1992

New type dioxygen bridged complexes of palladium were prepared by using $KO_2$ as a source of superoxide ion($O_2{^-}$). The method is completely different from the traditional one which has adopted the oxidative addition of molecular oxygen to prepare the dioxygen complexes. This reaction proceeds via nucleophilic displacement followed by electron transfer reaction. Three new type dioxygen complexes of palladium having amine ligands were prepared and characterized by the application of the reaction of $O_2{^-}$.

• Journal of the Korean Chemical Society
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• v.41 no.3
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• pp.117-122
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• 1997

On the basis of our previous paper[Bull. Korean Chem. Soc. 1995, 16, 1015], the relative stability, ionization potential, and chemical reaction of the neutral and multiply charged $C_{60}$n ions(n=3+ to 6-) have been investigated by the semi-empirical MNDO method. $C_{60}^{1-}$ has the highest stability. The ionization potential values of the $C_{60}$ ions range from 15.31 eV of $C_{60}^{2+}$ to -13.01 eV of $C_{60}^{6-}$. These values show a linear relationship according to charges. The average IP per charge is 3.15 eV from our calculations and 3.22 eV from the linear function of IP. A charge- or electron-transfer reaction of $C_{60}^{n+}$ will only occur if the ionization potential of any guest molecule is lower than the electron affinity of the host $C_{60}^{n+}$. If the energy gap between ionization potential and electron affinity, ${\Delta}_{IP-EA}$, is high, charge-transfer reactions arise by the charge-controlled effect. However, if ${\Delta}_{IP-EA}$ is low, electron-transfer reactions arise by the frontier-controlled effect.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.249-252
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• 2004

Cytochrome P450 (P450)/$O_2$/NADPH engender electron transfer reaction of N-benzyl-N-substituted benzylamines to yield corresponding radical cation 1 that is simultaneously converted into 2 and 3. Subsequently, expulsion of proton and hydroxylation yielding a-hydroxylamines are followed by formation of benzaldehydes and benzylamines.

• Bulletin of the Korean Chemical Society
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• v.16 no.1
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• pp.21-26
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• 1995

Electrochemical reduction of oxygen has been carried out at glassy carbon electrode and carbon ultramicroelectrode, the surface of which is modified with a new Co(Ⅱ)-Schiff base complex, Co(Ⅱ)-3,4-bis(salicylidene diimine)toluene in 1 M KOH solution. The results obtained from cyclic voltammetric and chronoamperometric experiments are consistent with the formation of the reasonably stable superoxide ions as a primary electron transfer reaction product. The exchange rate constant obtained for oxygen reduction is about 0.02 cm/s.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.380-384
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• 1987

Reactions of methylenethioxanthene (3) with n-propanethiol in the presence of di-t-butyl peroxide(DTBP) afforded preferentially propyl 9-thioxanthenylidenemethyl sulfide(8) rather than propyl 9-thioxanthenylmethyl sulfide(9) regardless of the concentration of n-propanethiol. On the other hand reactions of 3 with a low concentration of n-propanethiol in the presence of dibenzoyl peroxide(DBPO) gave 8, 1,2-bisthioxanthenylidene ethane(11), and thioxanthenylidenemethyl benzoate(12) but only 8 was formed at high concentration of the thiol. The formations of these products were rationallized by an electron transfer mechanism.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.165-167
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• 1987

Reaction of 5-(2-thianthreniumyl)thianthrene perchlorate with sodium naphthalenide in the presence of benzenethiol in tetrahydrofuran at -$78^{\circ}C$ proceeded via a formation of a sulfuranyl radical to give thianthrene (66%), 2-phenylthiothianthrene (33%), phenyl 2-(2-thianthrenylthio)phenyl sulfide (traceable amount), and some unknowns, along with naphthalene and very small amount of 1,4-dihydronaphthalene.