• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.50-55
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• 1996

Reaction of carbonyl compounds with diisopinocampheylhaloboranes (Ipc2BX,X=Cl, Br, I) was investigated in detail in order to establish their usefulness as selective reducing agents. The reagents reduced aldehydes and ketones to the corresponding alcohols. The reactivities are in the order of Ipc2BCl Ipc2BBr>Ipc2BI.The reagents also reduced ${\alpha}{\beta}-unsaturated$, aldehydes and ketones to the corresponding allylic alcohols without any detectable 1,4-reduction. Especially, the chloro derivative nicely achieved the selective reduction of aldehyde or ketone groups in the presence of many other functional groups. The most remarkable result of this investigation is that aldehydes and ketones can be selectively reduced in the presence of acid chlorides.

• Bulletin of the Korean Chemical Society
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• v.8 no.2
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• pp.63-68
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• 1987

The photolysis and thermal reaction of hexafluorobenzene solution of icosahedral dicarba-closo-dodecaborane and various carbenes have been shown to lead to the formation of four isomeric insertion products to icosahedral molecules. The results showed the carbene insertion reaction to 1, 2-dicarba-closo-dodecaborane to occur at the positions of 4-, 5-, 7-, and 11-borons, 9-, and 12-borons 3-, and 6-borons and 8-, and 10-borons. The samples of 1, 7-, and 1, 12-dicarba-closo-dodecaborane with carbenes in hexafluorobenzene by photolysis showed no reaction. To find out the reactivities of carbenes to dicarba-closo-dodecaboranes, the total energies have been calculated and have been discussed the tendency for carbene insertion reactions to icosahedral carboranes.

• Bulletin of the Korean Chemical Society
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• v.17 no.6
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• pp.506-510
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• 1996

The syntheses and photoreactions of haloarenes, in which the aryl and haloaryl moieties are tethered by a simple alkyl group, were studied. For 2-benzyl-1-halobenzene, in which two aryl moieties were connected by methylene group, photoreduced product, diphenylmethane, was obtained along with the minor formation of the photocyclized product, fluorene, in acetonitrile solvent. For 1-halo-2-phenethylbenzene, in which two aryl moieties were connected by ethylene group, photocyclized products, 9,10-dihydrophenanthrene and phenanthrene, were obtained along with the minor formation of photoreduced product, bibenzyl, in acetonitrile solvent. The photoreaction selectivities in several solvent systems were studied: In cyclohexane, 2-benzyl-1-chlorobenzene was photoreduced more effective than 2-benzyl-1-bromobenzene; In the presence of NaOH, 1-halo-2-phenethylbenzenes gave 9,10-dihydrophenanthrene and, in the presence of toluene, they gave phenanthrene. A radical reaction mechanism is proposed for the explanation of the reactions. This study shows that the photoreaction of haloarene, in which haloaryl and aryl moieties are tethered by ethylene group, can be used for ring formation of 9,10-dihydrophenanthrene otherwise difficultly accessible.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1112-1118
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• 1994

Epoxidation of olefins has been studied using iodosylbenzene (PhIO) as the terminal oxidant and binuclear and mononuclear complexes of $Mn^{2+}$, $Co^{2+}$, and $Cu^{2+}$ as catalysts. Epoxides were the predominant products with trace amounts of allylic oxidation products, and the metal complexes were found to be effective catalysts in the epoxidation reactions. The reactivity of binuclear copper complexes was greater than that of the mononuclear copper complexes, whereas the binuclear and mononuclear complexes of $Mn^{2+}$ and $Co^{2+}$ showed similar reactivities. The nature of the ligands bound to copper did not influence the reactivity of the binuclear copper complexes so long as copper ions were held in close proximity. A metal-iodosylbenzene complex, such as suggested previously for Lewis acidic metal complex-catalyzed epoxidation by iodosylbenzene, is proposed as the active epoxidizing species. Some mechanistic aspects are discussed as well.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1118-1121
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• 1994

Reactions of alkaline metal carbonates with sulfur are investigated in detail. The evolution of CO and a trace of $SO_2$ were observed in the course of reaction with major component of polysulfides. Some evidences that the reaction proceeds with breaking of terminal sulfur-sulfur bond in the sulfur polymer, and forming CO, $SO_2$ and polysulfide are presented. Polysulfides have the role of keeping free sulfur and allow it to react with other chemicals to rather high temperatures.plexes, whereas the binuclear and mononuclear complexes of Mn$^{2+}$ and Co$^{2+}$

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.571-576
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• 1994

The photoreactions of $ReH_5(Cyttp)\;(1)\;(Cyttp=PhP(CH_2CH_2CH_2PCy_2)_2)\;with\;CO,\;CO_2\;and\;PMe_3 has been investigated to find the differences in reactivities from those of trismonophosphine analog. Irradiation of 1 under CO, $CO_2$ and excess $PMe_3$ in benzene results in the formation of the complexes, $ReH(CO)_2(Cyttp)\;(2),\;ReH_2({\eta}^2-HCO_2)(Cyttp)\;(3)\;and\;$ReH_3(PMe_3)(Cyttp)$ (4), respectively. The resulting products suggest that photoreactions of $ReH_5(Cyttp)$ proceed by photoextrusion of $H_2$ giving a phototransient species "$ReH_3$(Cyttp)" which can be trapped by CO, $CO_2\;and\;PMe_3$. The structures of 2, 3 and 4 are inferred based on $^1H,\;^{31}P$ NMR and I. R spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.682-686
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• 1993

The syntheses and reactivities with olefins of $[Ru^{II}(L_3)(L_2)OH_2]^{2+}$ $[L_3$= 2,6-bis(N-pyrazolyl)pyridine(bpp), 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine $(Me_4bpp);\;L_2$= 2,2'-bipyridine(bpy), 4,4'-dimethyl-2,2'-bipyridine $(Me_2bpy)$] are described. Their spectral and redox properties in aqueous solution were investigated. Evidence for each one electron redox process for the $Ru^{IV}-Ru^{III}$ and $Ru^{III}-Ru^{II}$ couples has been obtained. Oxidation of $[Ru^{II}(bpp)(bpy)OH_2]^{2+}$ with $Ce^{IV}$ gave $[Ru^{IV}(bpp)(bpy)O]^{2+}$. The $[Ru^{IV}$= 0 complex is paramagnetic $({\mu}_{eff}=2.82)$ and the complexes $[Ru(L_3)(L_2)OH_2]^{2+}$ are robust catalysts for the oxidation of styrene, cyclohexene, and cyclooctene with cooxidant such as NaOCl. Product distributions and selectivities are discussed by varying the number of the substituted-methyl group in the ring.

• Bulletin of the Korean Chemical Society
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• v.16 no.4
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• pp.299-304
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• 1995

In order to find out the relationship between electronic structures of metal oxychlorides (MOCl) and their physicochemical properties, we have carried out the tight-binding band electronic structure calculations with Extended Huckel (EH) method for TiOCl, VOCl and FeOCl. The relative contribution of metal atom to DOS at Fermi level increases in the order of Ti, V and Fe, which is parallel to the reactivities of MOCl toward guest species. The M2+ ion plays a crucial role in the electric conductivity of MOCl and its intercalation compounds. Hopping conduction theory is applied to explain the increase of conductivity after intercalation.

• ETRI Journal
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• v.26 no.1
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• pp.38-44
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• 2004

Searching for systems of self-assembled monolayers (SAMs) that can be used as templates for chemical lithography, we found that nitro groups on aromatic SAMs are selectively converted on Ag to amino groups by irradiation with a visible laser. 4-nitrobenzenethiol on Ag was thus converted to 4-aminobenzenethiol by irradiating it with an $Ar^+$ laser. This was evident from surface-enhanced Raman scattering (SERS) as well as from a coupling reaction forming amide bonds. The surface-induced photoreaction allowed us to prepare patterned binary monolayers on Ag that showed different chemical reactivities. Using the binary monolayers as a lithographic template, we induced site-specific chemical reactions, such as the selective growth of biominerals on either the nitro- or amine-terminated regions by adjusting the crystal-growth conditions. We also demonstrated that patterned, amine-terminated monolayers can be fabricated even on gold by using silver nanoparticles as photoreducing catalysts.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.105-113
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• 2003

The pyrolysis for production of hydrogen and high quality carbon black from natural gas were studied. The reactivities in tubular reactor and FVR(free volume reactor) for the methane pyrolysis were compared, in order to prevent the formation of undesirable carbon product such as pyrocarbon, the FVR was designed. The hydrogen yield and the formation of carbon black from methane pyrolysis in this reactor were investigated at temperature range between 1443 and 1576K. From the result of TEM (transmission electron microscopy) analysis, it was confirmed that the CFC(catalytic filamentous carbon) was formed without pyrocarbon.