• Journal of Integrative Natural Science
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• v.10 no.4
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• pp.175-191
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• 2017

In organic chemistry amide synthesis is performed through condensation of a carboxylic acid and an amine with releasing one equivalent of water via the corresponding ammonium carboxylate salt. This method is suffering from tedious processes and poor atom-economy due to the adverse thermodynamics of the equilibrium and the high activation barrier for direct coupling of a carboxylic acid and an amine. Most of the chemical approaches to amides formations have been therefore being developed, they are mainly focused on secondary amides. Direct carbonylations of tertiary amines to amides have been an exotic field unresolved, in particular direct carbonylation of trimethylamine in lack of commercial need has been attracted much interests due to the versatile product of N,N-dimethylacetamide in chemical industries and the activation of robust N-C($sp^3$) bond in tertiary amine academically. This review is focused mainly on carbonylation of trimethylamine as one of the typical tertiary amines by transition metals of cobalt, rhodium, platinum, and palladium including the role of methyl iodide as a promoter, the intermediate formation of acyl iodide, the coordination ability of trimethylamine to transition metal catalysts, and any possibility of CO insertion into the bond of Me-N in trimethylamine. In addition reactions of acyl halides as an activated form of acetic acid with amines are reviewed in brief since acyl iodide is suggested as a critical intermediate in those carbonylations of trimethylamine.

• Korean Journal of Crystallography
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• v.10 no.1
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• pp.88-93
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• 1999

The complex [Ni(L)](ClO4)2 (1) (L=2,13-bis(2-pyridylmethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.1807.12]docosane) has been synthesized and characterized by X-ray crystallography. (1) crystallizes in the triclinic, space group P, with a=10.948(2), b=10.948(2), c=14.911(4) , α=93.73(2), β=93.77(2), γ=99.29(2)o, V=1754.8(7) 3, Z=2, R1(wR2) for 5217 observed reflections of [I>2σ(I)] was 0.048(0.099). The coordination environment around nickel(II) ion shows a distorted octahedron with four secondary and tertially amines of the macrocycle and two nitrogen atoms of pyridylmethyl groups.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.883-890
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• 1990

Although various theories have been presented on the mechanism of setting retardation of 3CaO·Al2O3, this phenomenon has not yet been defined. The present investigation was initiated in order to solve the mechanism from the view point of coordination chemistry. The solubility of Ca(OH)2 in aquous solution of soldium gluconate was abnormally high, and was proportional to the concentration of sodium gluconate. These phenomena were attributed to the soluble complex formation, that is, (1 : 1)Ca complex formation between calcium ion and gluconate ion. The author's proposal was further confirmed by the results of electrical conductivity measurement. The formation of calcium complex was also supported by IR spectra and DTA. When sodium gluconate was dissolved in 3CaO·Al2O3 suspension, calcium complex and aluminum complex were formed. As an experimental evidence, the asymmetric stretching vibration of carboxyl group in sodium gluconate was observed to be shifted to lower frequency from 1625cm-1 to 1585cm-1 characteristically. The characteristic exothermic peaks of the complexs at 430℃ and 700℃ observed in DTA curve also suggest the formation of the complexs between sodium gluconate and 3CaO·Al2O3.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1965-1969
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• 2014

A new tetranuclear Mn(III) complex $[Mn^{III}{_4}(sae)_4({\mu}_3-O)({\mu}_{1,1}-N_3)(OH)(H_2O)_2]{\cdot}H_2O$ (1) ($H_2sae$ = 2-salicylideneamino-1-ethanol) has been synthesized by the reaction of $MnCl_2{\cdot}4H_2O$, $H_2sae$ and sodium azide in the mixed solvent of methanol, acetonitrile and water. The X-ray diffraction analysis shows that the four Mn(III) ions in complex 1 have a unique adamantine arrangement, whereas the coordination environment of each Mn(III) ions is different. Magnetic studies indicate that complex 1 manifests antiferromagnetic behaviors. The magnetic susceptibilities of complex 1 have been fitted by two magnetic models based on the suitable analysis of its magnetic structural topology.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.364.2-364.2
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• 2014

Magnesium oxide (MgO) thin films have attracted great scientific and technological interest in recent decades. Because of its distinguished properties such as a wide band gap (7.2 eV), a low dielectric constant (9.8), a low refractive index, an excellent chemical, and thermal stability (melting point=$2900^{\circ}C$), it is widely used as inorganic material in diverse areas such as fire resistant construction materials, optical materials, protective layers in plasma display panels, buffer layers of multilayer electronic/photonic devices, and perovskite ferroelectric thin films. Precursor used in the ALD requires volatility, stability, and low deposition temperature. Precursors using a heteroleptic ligands with different reactivity have advantage of selective reaction of the heteroleptic ligands on substrate during ALD process. In this study, we have synethesized new heteroleptic magnesium precursors ${\beta}$-diketonate and aminoalkoxide which have been widely used for the development of precursor because of the excellent volatility, chelating effects by increasing the coordination number of the metal, and advantages to synthesize a single precursor. A newly-synthesized Mg(II) precursor was adopted for growing MgO thin films using ALD.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3233-3238
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• 2013

Two new Cu(II) complexes, $[Cu_2(acpy-mdtc)_2(HBA)(ClO_4)]{\cdot}H_2O$ (1) (acpy-mdtc- = 2-acetylpyridine S-methyldithiocarbamate and $HBA^-$ = benzilic acid anion) and $[Cu_2(acpy-phtsc)_2(HBA)]{\cdot}ClO_4$ (2) (acpy-$phtsc^-$ = 2-acetylpyridine 4-phenyl-3-thiosemicarbazate) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The X-ray analysis reveals that the structures of 1 and 2 are dinuclear copper(II) complexes bridged by two thiolate sulfur atoms of Schiff base ligand and bidentate bridging $HBA^-$ anion. For 1, each of the two copper atoms has different coordination environments. Cu1 adopts a five-coordinate square-pyramidal with a $N_2OS_2$ donor, while Cu2 exhibits a distorted octahedral geometry in a $N_2O_2S_2$ manner. For 2, two Cu(II) ions all have a five-coordinate square-pyramidal with a $N_2OS_2$ donor. In each complex, the Schiff base ligand is coordinated to copper ions as a tridentate thiol mode.

• Korean Journal of Materials Research
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• v.27 no.4
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• pp.229-235
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• 2017

Through density functional theory calculations, to provide insight into the origins of the catalytic activity of Au nanoparticles (NPs) toward oxidation reactions, we have scrutinized the oxygen adsorption chemistry of 9 types of small unsupported Au NPs of around 1 nm in size (Au13, Au19, Au20, Au25, Au38, and Au55) looking at several factors (size, shape, and coordination number). We found that these NPs, except for the icosahedral Au13, do not strongly bind to $O_2$ molecules. Energetically most feasible $O_2$ adsorption that potentially provides high CO oxidation activity is observed in the icosahedral Au13, our smallest Au NP. In spite of the chemical inertness of bulk Au, the structural fluxionality of such very small Au NP enables strong $O_2$ adsorption. Our results can support recent experimental findings that the exceptional catalytic activity of Au NPs comes from very small Au species consisting of around 10 atoms each.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1489-1495
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• 2010

A porous coordination solid of nickel(II) dihydroxyterephthalate has been synthesized by the microwave-assisted (MW) method. The synthesized nickel(II) dihyroxylterephthalate was designated by the general formula of [$Ni_2$(dhtp) $(H_2O)_2]{\cdot}8H_2O$ (where, dhtp = 2,5-dihydroxyterephthalate, denoted by Ni-DHTP). The effect of microwave-irradiation temperature and time of irradiation on the porosity and morphological changes in the solids have also been investigated. The catalytic performance of Ni-DHTP synthesized by MW method has been studied in the oxidation of cyclohexene with aqueous $H_2O_2$, which gave cyclohexene oxide as the primary product and 2-cyclohexene-1-ol as a major product.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3707-3710
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• 2010

A chromo/fluorogenic $NO_2S_2$-macrocycle L functionalized with nitrobenzofurazan unit as a dual-signaling probe was synthesized and structurally characterized by single crystal X-ray analysis. In a cation-induced color change experiment, L exhibited excellent $Hg^{2+}$ ion selectivity by showing the color change from orange-red to yellow. However, this hypochromic shift by $Hg^{2+}$ was observed for the weaker coordinating anion system such as ${NO_3}^-$ and ${ClO_4}^-$ ions. The observed anion effect is due to the strong coordination of anions inhibits the bond formation between $Hg^{2+}$ and the macrocyclic tert-N atom, which is sensitive to induce the color change. In the fluorometric experiment, L showed chelate-enhanced fluorescence change effect only with $Hg^{2+}$ ion, together with a change from yellow to green emission. The sensing ability for $Hg^{2+}$ with the proposed chemosensor L is due to the stable complexation with 1:1 stoichiometry (metal-to-ligand).

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.1
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• pp.22-36
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• 2016

$^{68}Ga$ is a promising radionuclide for positron emission tomography (PET). It is a generator-produced ($^{68}Ge/^{68}Ga$-generator) radionuclide with a half-life of 68 min. The employment of $^{68}Ga$ for basic research and clinical applications is growing exponentially. Bifunctional chelators (BFCs) that can be efficiently radiolabeled with $^{68}Ga$ to yield complexes with good in vivo stability are needed. Given the practical advantages of $^{68}Ga$ in PET applications, gallium complexes are gaining increasing attention in biomedical imaging. However, new $^{68}Ga$-labeled radiopharmaceuticals that can replace $^{18}F$-labeled agents like [$^{18}F$]fluorodeoxyglucose (FDG) are needed. The majority of $^{68}Ga$-labeled derivatives currently in use consist of peptide agents, but the development of other agents, such as amino acid or nitroimidazole derivatives and glycosylated human serum albumin, is being actively pursued in many laboratories. Thus, the availability of new $^{68}Ga$-labeled radiopharmaceuticals with high impact is expected in the near future. Here, we present an overview of the different new classes of chelators for application in molecular imaging using $^{68}Ga$ PET.