• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.679-682
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• 2009

Utilizing a planar five coordinating N3S2 ligand, 2,6-bis(2-methylthiophenyliminomethyl)pyridine, a pseudo 7-coordinated manganese(II) complex with two labile triflate anions in the axial positions was synthesized. The reaction of the manganese(II) complex with an oxidant, iodosylbenzene, produced a metastable high-valent manganese(IV)-oxo species at 0 ${^{\circ}C}$. The high-valent Mn(IV)-oxo intermediate was characterized with a UV-vis spectrophotometer and an electrospray ionization mass spectroscopy. Reactivity studies of the Mn(IV)=O species revealed that the intermediate is capable of oxygenating $PPh_3$ and N-dealkylating N,N-dimethyl-toludine.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.417-420
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• 2007

Mononuclear mixed-anions Mn complex of TPAMn(η2-NO3)(η-ClO4), where TPA is tris(2-pyridylmethyl)-amine, has been synthesized and characterized. The neutral TPAMn(η2-NO3)(η-ClO4) was obtained from the reaction between Mn(NO3)2·4H2O and [H3TPA](ClO4)3 in MeOH. X-ray crystallographic structure of mononuclear TPAMn(η2-NO3)(η-ClO4) complex showed a seven-coordinated geometry with a tripodal tetradentate TPA, a terminal perchlorate and an η2-bound nitrate.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3173-3179
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• 2010

New complex $[Mn(II)H_{1.5}L]_2[Mn(II)H_3L]_2(ClO_4)_5{\cdot}3H_2O$ (1), where $H_3L$ is tris {2-(4-imidazolyl)methyliminoethyl} amine (imtren), has been prepared by reacting manganese(II) perchlorate hexahydrate with the imtren ligand in methanol. X-ray crystallographic study revealed that the imtren ligand hexadentately binds to Mn(II) ion through the three Schiff-base imine N atoms and three imidazole N atoms with a distorted octahedral geometry, and the apical tertiary amine N atom of the ligand pseudo-coordinates to Mn(II), forming overall a pseudo-seven coordination environment. The hydrogen-bonds between imidazole and imidazolate of $[Mn(II)H_{1.5}L]^{0.5+}$ complex ions are extended to build a 2D puckered network with trigonal voids. $[Mn(II)H_3L]^{2+}$ complex ions constitutes another extended 2D puckered layer without hydrogen bonds. Two layers are wedged each other to constitute overall stack of the crystal. Peroxidase activity of complex 1 was examined by observing the oxidation of 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) with hydrogen peroxide in the presence of complex 1. Generation of $ABTS^{+{\cdot}}$ was observed by UV-vis and EPR spectroscopies, indicating that the complex 1, a fully-coordinated mononuclear Mn(II) complex with nitrogen-only ligand, has a heme-independent peroxidase activity.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1581-1585
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• 2012

Two pyridinecarboxamide dicyanidecobalt(III) building blocks and two mononuclear seven-coordinated macrocycle manganese(II) compounds have been rationally selected to assemble cyanide-bridged heterobimetallic complexes, resulting in three cyanide-bridged $Co^{III}-Mn^{II}$ complexes. Single X-ray diffraction analysis show that these complexes $\{[Mn(L^1)][Co(bpb)]\}ClO_4{\cdot}CH_3OH{\cdot}0.5H_2O$ ($\mathbf{1}$), $\{[Mn(L^2)][Co(bpb)]\}ClO_4{\cdot}0.5CH_3OH$ ($\mathbf{2}$) and ${[Mn(L^1)][Co(bpb)]\}ClO_4{\cdot}H_2O$ ($\mathbf{3}$) ($L^1$ = 3,6-diazaoctane-1,8-diamine, $L^2$ = 3,6-dioxaoctano-1,8-diamine; $bpb2^{2-}$ = 1,2-bis(pyridine-2-carboxamido)benzenate, $bpmb2^{2-}$ = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate) all present predictable one-dimensional single chain structures. The molecular structures of these one-dimensional complexes consists of alternating units of $[Mn(L)]^{2+}$ ($L=L^1$ or $L^2$) and $[Co(L^{\prime})(CN)2]^-$ ($L^{\prime}=bpb2^{2-}$, or $bpmb2^{2-}$), forming a cyanide-bridged cationic polymeric chain with free $ClO_4{^-}$ as the balance anion. The coordination geometry of manganese(II) ion in the three one-dimensional complexes is a slightly distorted pentagonal-bipyrimidal with two cyanide nitrogen atoms at the trans positions and $N_5$ or $N_3O_2$ coordinating mode at the equatorial plane from ligand $L^1$ or $L^2$. Investigation over magnetic properties of these complexes reveals that the very weak magnetic coupling between neighboring Mn(II) ions connected by the diamagnetic dicyanidecobalt(III) building block. A best-fit to the magnetic susceptibility of complex ${\mathbf}{1}$ leads to the magnetic coupling constants $J=-0.084(3)cm^{-1}$.