• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1079-1085
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• 1999

An investigation was made of the effect of various transition metal catalysts, ligands, and a promoter on the synthesis of N,N'-diphenylurea(DPU) from nitrobenzene, aniline, and carbon monoxide. Homogeneous Pd and Ni catalysts were found to be highly efficient, giving almost quantitative isolated DPU yields at 100% nitrobenzene conversion. Bidentate ligand, 1,3-bis(diphenylphosphino)proane(dppp) showed much improved activity and significantly different reactivity relative to the usual monodentate $PPh_3$ ligand in the presence of Ni and Pd catalysts. These results were inferred to the effect of the cis coordination of bidentate dppp ligand on the metal. The use of a promoter $Et_4NCl$ was indispensable in the case of $PPh_3$, yet inhibited the reaction if used with dppp. It was possible to reuse the Pd-dppp catalyst system, although the catalytic activity was reduced slowly.

• Bulletin of the Korean Chemical Society
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• v.24 no.3
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• pp.269-273
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• 2003

The synthesis and properties of 2,13-bis(3'-pyridylmethyl) $(L^3)$, 2,13-bis(4'-pyridylmethyl) $(L^4)$, and 2,13-bis(phenylmethyl) $(L^5)$ derivatives of 5,16-dimethyl-2,6,13,17-tetraazatrcyclo$[16.4.0.^{1.18}0^{7.12}]$docosane are reported. The 3- or 4-pyridylmethyl groups of $[ML^3](ClO_4)_2\;or\;[ML^4](ClO_4)_2$ (M = Ni(Ⅱ) or Cu(Ⅱ)) are not involved in coordination, and the coordination geometry (square-planar) and ligand field strength of the complexes are quite similar to those of $[ML^5](ClO_4)_2$, bearing two phenylmethyl pendant arms. However, the complex formation reactions of $L^3\;and\;L^4$ are strongly influenced by the pyridyl groups, which can interact with a proton or metal ion outside the macrocyclic ring. The macrocycle $L^5$ exhibits a high copper(Ⅱ) ion selectivity against nickel(Ⅱ) ion; the ligand readily reacts with copper(Ⅱ) ion to form $[CuL^5]^{2+}$ but does not react with hydrated nickel(Ⅱ) ion in methanol solutions. On the other hand, $L^3\;and\;L^4$ form their copper(Ⅱ) and nickel(Ⅱ) complexes under a similar condition, without showing any considerable metal ion selectivity. The ligands $L^3\;and\;L^4$ react with copper(Ⅱ) ion more rapidly than does $L^5$ at pH 6.4. At pH 5.0, however, the reaction rate of the former macrocycles is slower than that of the latter. The effects of the 3- or 4-pyridylmethyl pendant arms on the complex formation reaction of $L^3\;and\;L^4$ are discussed.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3777-3787
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• 2012

Three kinds of 3D isomorphous and isostructural coordination polymers, namely, $\{[Ln_2(PDA)_3(H_2O)_3]{\cdot}0.25H_2O\}_{\infty}$ (Ln = La(1), Sm(2), and Gd(3)) ($PDA^{2-}$ = pyridine-2,6-dicarboxylate anion) have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, thermal analyses and single crystal X-ray diffraction. In these MOFs, Ln(III) centers adopt eight-coordinated and nine-coordinated with the $N_1O_7$ and $N_2O_7$ donor sets to construct distorted trianglar dodecahedron geometry and tricapped trigonal prism configurations, respectively. Based on the building block of tetranuclear homometallic $Ln_4C_4O_8$ unit (16-membered ring), 1-3 are connected into highly ordered 2D sheets via O-C-O linkers and further constructed into 3D architectures through hydrogen bonds. Crystallographic parameters suggest that the lanthanide contraction effect exist in these coordination polymers. Luminescent properties of the lanthanide-based MOFs (metal-organic frameworks) have been measured at room temperature, which reveal that they presenting ionselective characters toward certain metals, such as $Mg^{2+}$, $Cd^{2+}$ and $Pb^{2+}$ ions.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.636-640
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• 2012

We modify ZnO nanorods with Zn-porphyrin to obtain the improved characteristics of energy transfer, which is further investigated for the applicability to photovoltaic devices. A nitrogen heterocyclic ligand containing a thiol group is covalently grafted onto the surface of finely structured ZnO nanorods with a length of 50-250 nm and a diameter of 15-20 nm. Zn-porphyrin is then attached to the ligand molecules by the mechanism of metalligand axial coordination. The resulting energy band diagram suggests that the porphyrin-modified ZnO nanorods might provide an efficient pathway for energy transfer upon being applied to photovoltaic devices.

• Journal of the Korean Ceramic Society
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• v.55 no.6
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• pp.625-634
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• 2018

In this work, we describe a novel and simple technique to produce non-hydrate surfactant complexes for the formation of highly crystalline fatty acid modified SPIONs by thermolysis of iron oleate (FeOl) complexes in a non-coordinating solvent. FeOl complexes were prepared by direct coordination of iron ions and carboxylic acid; thus, we could control the stoichiometric composition of the precursor by changing the molar ratio of fatty acid and metal ions. The discrete thermal behaviors and chemical coordination of the intermediate non-hydrated FeOl were studied by thermo-analytic techniques including differential scanning calorimetry, thermal gravimetric analysis, and Fourier transform infrared spectroscopy.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2701-2704
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• 2010

This work shows that both L2 and L3 bearing two and four N-$(CH_2)_2OCH_3$ groups, respectively, can be prepared selectively by the reaction of $L^1$ with 1-bromo-2-methoxyethane. The di-N-substituted macrocycle $L^2$ readily forms its copper(II) and nickel(II) complexes. The N-$(CH_2)_2OCH_3$ groups in $[CuL^2]^{2+}$ are coordinated to the metal ion, whereas those in $[NiL^2]^{2+}$ are not involved in coordination. Interestingly, $L^3$ reacts with $Cu^{2+}$ ion to form $[Cu(HL^3)]^{3+}$, in which one tertiary amino group is not involved in coordination.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.311-316
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• 1997

The synthesis and characterization of the mononuclear group 13 heterocyclic carboxaldehyde methyldithiocarbazate complexes Me2M[NC5H4CRNNC(S)SCH3] (M=Al, R=H(1); M=Ga, R=H(2); M=Al, R=CH3(3); M-Ga, R=CH3(4); M=In, R=CH3(5)) are described. Compounds 1-5 were prepared by the reaction of MMe3 (M=Al, Ga, In) with 2-formy or 2-acetylpyridine-S-methyldithiocarbazate in toluene. These compounds 1-5 have been characterized by microanalysis, NMR (1H, 13C) spectroscopy, mass spectra, and single-crystal X-ray diffraction. X-ray single-crystal diffraction analyses reveal that 4-5 are mononuclear metal compounds with coordination number of 5 and N,N,S coordination mode.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.368-376
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• 1988

Transition metal PSSA ionomers containing Co(II), Ni(II), Cr(III), Ru(III), and Rh(III) are investigated by IR, Far-IR, UV-Vis and DSC. Reliable IR Spectroscopic criteria are established for assessing the degree of ion-exchange of PSSA ionomers and the local structures around metal cations in them. In the hydrated transition metal PSSA ionomers, the ionic groups are solvated by water molecules and there is no significant interactions between sulfonate group and metal cations. The visible spectra indicated that metal cations are present as [M$(H_2O)_6$]$^{n+}$ with Oh symmetry. Their $T_g$ values increase as the extent of ionic site concentration increases, but there is no direct dependence of $T_g$ on the nature of metal cations or their oxidation states. Thus, the water content in PSSA ionomer is found to have dominant influence on $T_g$ of hydrated transition metal PSSA ionomers. Dehydration of the hydrated transition metal PSSA ionomers results in direct interaction between ionic groups and significant color changes of the ionomers due to the changes of the local structures around metal cations. On the base of spectral data, their local structures are discussed. In case of dehydrated 12.8 and 15.8 mol % transition metal PSSA ionomers, no glass transition is observed in 25-$250^{\circ}C$ region and this is believed to arise from the formation of highly crosslinked structures caused by direct coordination of sulfonate groups of metal cations. In the 6.9 mol % transition metal PSSA ionomers, the glass transition is always observed whether they are hydrated or dehydrated and this is though to be caused by the sufficient segmental mobility of the polymer backbone.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.26-30
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• 2003

The dinuclear $Ag_2[Phen]_2[S_2P(OPr)_2]_2$(phen=1,10-phenanthroline; Pr=propyl), was prepared by the reaction of bis(dipropyldithiophosphato) silver(I) complex with 1,10-phenanthroline ligand, and its structure was determined by X-ray crystallography. The two dipropyldithiophosphato ligands each bridge two silver atoms to form an eight-membered $Ag_2S_4P_2$ ring, while the 1,10-phenanthroline molecule coordinates to a silver atom to complete the local tetrahedral geometry for the metal ion. The Ag-S bond distances are 2.559(1) and 2.567(1)${\AA}$, and the Ag-N bond distances are 2.366(3) and 2.471(3)${\AA}$.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3111-3114
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• 2012