• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1839-1843
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• 2006

Hydrothermal reactions of $Ln(NO_3)_3{\cdot}5H_2O $ (Ln = Eu (1), Sm (2), Ho (3), Dy (4)) with 3,5-pyridinedicarboxylic acid (3,5-pdcH2) in the presence of 4,4'-bipyridine led to the formation of the 3-D Ln(III)-coordination polymers with a formula unit of $[Ln_2(3,5-pdc)_2(C_2O_4)(H_2O)_4]{\cdot}2H_2O$. These polymers contain a bridging oxalate ligand ($C_2O_4\;^2$). On the basis of GCMS study of the mother liquor remaining after the reaction, we proposed that the $C_2O_4\;^2$ formation proceeds in three steps: (1) Ln(III)-mediated decarboxylation of $3,5-pdcH_2$ to give $CO_2$, (2) the reduction of $CO_2$ to $CO_2\;^{\cdot}$ by the Ln(II) species, and (3) the reductive coupling of the two $CO_2\;^{\cdot}$ radicals to the oxalate ($C_2O_4\;^2$) ion. All polymers were structurally characterized by X-ray diffraction.

• Journal of the Korean Chemical Society
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• v.36 no.4
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• pp.536-539
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• 1992

Eight-membered ring spiro orthocarbonate (C$_{25}H_{20}O_4$, M$_r$ = 384) is monoclinic, space group C2/c, with a = 15.319(4), b = 9.057(3), c = 13.168(3)${\AA}$, ${\beta}$ = 98.53(3)$^{\circ}$, Z = 4, F(000) = 808, T = 290 K, ${\mu}$(Mo-K${\alpha}$) = 0.55 cm$_1$, D$_c$ = 1.36 g/cm$^3$ and D$_m$ = 1.40 g/cm$^3$. The intensity data were collected with Mo-K${\alpha}$ radiation (${\lambda}$ = 0.7107 ${\AA}$) on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by direct methods and refined by full matrix least-squares methods. The final R value was 0.052 for 1412 observed reflections. The molecule has C$_2$point symmetry. The eight-membered ring has a chair conformation with pseudo-C$_s$ symmetry. The naphthyl ring is planar with the C-C bond lengths being in the range of 1.352∼1.444${\AA}$ and bond angles of 117.2∼123.5$^{\circ}$. The bond lengths of C(1)-C(9), C(8)-C(9) and C(9)-C(10) are somewhat longer than those of the other C-C bonds.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.189-193
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• 1974

The tridentate schiff base, salicylidene imino-o-thiolbenzene, has been synthetized from salicylaldehyde and o-amino thiolbenzene by Duff reaction. The schiff base has been reacted with Cu(II), Ni(II), and Zn(II), to form new complexes; Cu(II)$[C_{13}H_9ONS]{\cdot}3H_2O$, Ni(II)$[C_{13}H_9ONS]{\cdot}3H_2O,\;Zn(II)[C_{13}H_9ONS]{\cdot}3H_2O$ It appears that the Cu(II)-complex has tetra-coordinated configuration with the schiff base and one molecule of water, while the Ni(II) and Zn(II)-complexes have hexacoordinated configuration with the schiff base and three molecules of water. The mole ratio of tridentate schiff base ligand to metals was 1:1. These complexes have been identified by infrared spectra, visible spectra, TGA, DTA and elemental analysis.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.202.3-202.3
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• 2003

Two Known compounds, syringaresinol monoglucoside(8), chimaphilin(14), together with three new compounds, (9)[mp. $106{\sim} 111^{\circ}C$, C_{29}H_{44}O_{13}$], (10)[mp. $180{\sim}182^{\circ}C$, $C_{15}H_{20}O_{9}$] and (11)[mp. $100{\sim}105^{\circ}C$, $C_{18}H_{28}O_{8}$] were isolated from the BuOH fractionof Pyrola japonics(Pyrolaceae). The structures of the known compounds were determined by chemical and spectorscopic methods. The assignments of the $^{1}H-$ and $^{13}C-NMP$ spectra of these compounds were carried out by two-dimensional $^1H-^1H-COSY$, NOESY and $^1H-^{13}C$ multiple-bond, multiplequantum spectroscopic correlation techniques. The characterization of the three new compounds is now in progress.

• Journal of the Korean Chemical Society
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• v.63 no.3
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• pp.216-219
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• 2019

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.605-609
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• 2003

The lower-order lithium organocyanocuprate compound, (THF)₃Li(NC)Cu($C_6$H₃-2,6-Mes₂) (1), and the bulky terphenyl Grignard reagent, Br(THF)₂Mg($C_6$H₃-2,6-Trip₂) (2), have been synthesized and structurally characterized both in the solid state by single crystal x-ray crystallography and in solution by multi-nuclear NMR and IR spectroscopy. The compound (1) was isolated as a monomeric contact ion-pair in which the C (organic ipso)-Cu-CN-Li atoms are coordinated linearly. The lithium has a tetrahedral geometry as a result of solvation by three THF molecules. The compound (1) is the first example of fully characterized monomeric lower order lithium organocyanocuprate. The bulky Grignard reagent (2) was also isolated as a monomer in which the magnesium, solvated by two THF molecules, has a distorted tetrahedral geometry. The crystals of (1) possess triclinic symmetry with the space group $P{\={1}}$, Z = 2, with a = 12.456(3) Å, b = 12.508(3) Å, c = 13.904(3) Å, α = 99.81°, β = 103.72(3)°, and γ = 119.44(3)°. The crystals (2) have a monoclinic symmetry of space group $P2_{1/C}$, Z = 4, with a = 13.071(3) Å, b = 14.967(3) Å, c = 22.070(4) Å, and β = 98.95(3)°.

• Elastomers and Composites
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• v.50 no.2
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• pp.126-131
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• 2015

$C_{60}$ nanowhiskers were synthesized from $C_{60}$ by liquid-liquid interfacial precipitation (LLIP) using $C_{60}$-saturated toluene and isopropyl alcohol. The $WO_3$ nanoparticles were synthesized by adding $3.8{\times}10^{-4}$ mole amount of ammonium metatungstate hydrate ($H_{26}N_6O_{40}W_{12}{\cdot}H_2O$) to 500 ml of distilled water, and the resulting solution was heated on a hot plate for 4 h. The $C_{60}$ nanowhiskers/$WO_3$ nanocomposites were prepared with $C_{60}$ nanowhiskers and $WO_3$ nanoparticles in an electric furnace at $700^{\circ}C$ in an argon gas atmosphere for 2 h. The $C_{60}$ nanowhiskers/$WO_3$ nanocomposites were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. UV-vis spectroscopy was used to evaluate the performance of the $C_{60}$ nanowhiskers/$WO_3$ nanocomposites as a photocatalyst in the degradation of organic dyes, such as methylene blue (MB) and brilliant green (BG) under ultraviolet light (254 nm).

• The Korean Journal of Ceramics
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• v.2 no.3
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• pp.152-156
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• 1996

Fine (~0.09 $\mu$m) $\beta$-SiC Powders with 3.3wt% of large (~0.44$\mu$m) $\alpha$-SiC of $\beta$-SiC particles (seeds) added were hotpressed at 175$0^{\circ}C$ using $Y_2O_3$, $Al_2O_3$ and CaO as sintering aids and then annealed at 185$0^{\circ}C$ for 4 h to enhance grain growth. The resultant microstructure and polytypes were analyzed by high resolution electron microscopy (HREM).Growth of $\beta$-SiC with high density of microtwins and formation of ${\alpha}/{\beta}$ composite grains consisting of $\alpha$-SiC domain sandwiched between $\beta$-SiC domains were found in both specimens. When large $\alpha$-SiC (mostly 6H) seeds were added, the $\beta$-SiC transformend preferentially to the 6H polytype. In contrast, when large $\beta$-SiC (3C) seeds were added, the fine $\beta$-SiC transformed preferentially to the 4H polytype. Such results suggested that the polytype formation in SiC was influenced by crystalline form of seeds added as well as the chemistry of sintering aids. The ${\alpha}/{\beta}$ interface played and important role in the formation of elongated grains as evidenced by presence of ${\alpha}/{\beta}$ composite grains with high aspect ratio.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.318-323
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• 1990

The bis(malonato)diaquochromate(III) ion, $Cr(C_3H_2O_4)_2^-$ in acidic solution hydrolyzes to give $Cr(C_3H_2O_4)^{+}.$ This reaction is catalyzed by ferric ion and the rate law for this cation catalyzed-aquation in a $HClO_4/NaClO_4$ medium, $I = 1.00 M, is-d[Cr(C_3H_2O_4)_2^-]/dt = ({\kappa}_1[Fe^{3+}] + {\kappa}_2[H^+])[Cr(C_3H_2O_4)_2^-]$ where ${\kappa}_1(25^{\circ}C) = 4.72×10^{-5} M^{-1}sec^{-1} ({\Delta}H^{\neq} = 22.5 Kcal/mol, {\Delta}S^{\neq} = - 2.58 eu) and {\kappa}_2(25^{\circ}C) = 4.75{\times}10^{-5} M^{-1}sec^{-1} ({\Delta}H^{\neq} = 21.2 Kcal/mol, {\Delta}S^{\neq} = - 7.13 eu).$ Rapid preequilibrium association of basic Cr-bound oxygen with $Fe^{3+},$ followed by rate-determining ring opening, is proposed to account for the ${\kappa}_1,$ hydrolysis pathway.

• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.208-213
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• 1994

The solubility of i-butyl bromide in nitrobenzene have been measured at 19, 25 and $40^{\circ}C$ in the presence and absence of gallium bromide. In the presence of gallium bromide, 1 : 1 complex, $i-C_4H_9Br{\cdot}GaBr_3$ is formed in the solution. The instability constant K of the complex formation was evaluated from the following equilibrium equation. $i-C_4H_9Br{\cdot}GaBr_3{\rightleftharpoons}C_4H_9Br + 1/2Ga_2Br_6.$ From these result, it seems that the stabilities of the complex formation, gallium bromide with alkyl bromide, are directly related with those of the carbonium ions of alkyl bromide.