• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.80-83
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• 1992

The secondary nitrogen donors of the Ni(II) complexes of macrotricyclic ligands 8-methyl-1,3,6,8,10,13,15-heptaazatricyclo $[13.1.1.1^{13,15}]$octadecane (A) and 1,3,6,9,11,14-hexaazatricyclo $[12.2.1.1^{6,9}]$octadecane (B) are N-alkylated and the Ni(II) complexes of $N-Me_2A,\;N-Et_2A,\;and\;N-Me_2B$ are obtained. The Ni(II) complexes of $N-Me_2A\;and\;N-Et_2A$ are stable in acidic aqueous solutions while that of $N-Me_2B$ decomposes relatively rapidly. The N-alkylation leads to the decrease in the ligand field strength as well as an anodic shift in both of the oxidation and the reduction potentials of the Ni(II) complexes.

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.500-506
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• 1993

$^1H$ and $^{13}C$ NMR spectra for pyridine, ${\beta}$-and ${\gamma}$-picoline, pyrazine, and 4,4'-bipyridyl complexed with paramagnetic undecatungstocobalto(II)silicate and undecatungstonickelo(II)silicate anions are reported. For these complexes the ligand exchange is slow on the NMR time scale and the pure resonance lines have been observed at room temperature. The isotropic shifts in nickel complexes can be interpreted in terms of contact shifts by ${\sigma}$-electron delocalization. Both contact and pseudocontact shifts contribute to the isotropic shifts in cobalt complexes. The contact shifts, which are obtained by subtracting the pseudocontact shifts from the isotropic shifts, require both ${\sigma}$-and ${\pi}$-electron delocalization from the cobalt ion. Slow ligand exchange has also allowed us to identify the species formed when bidentate ligands react with the heteropolyanions. Pyrazine forms a 1 : 1 complex, while 4,4'-bipyridyl forms both 1 : 1 and dumbbell-shaped 1 : 2 complexes.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.219-224
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• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.

• Bulletin of the Korean Chemical Society
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• v.20 no.8
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• pp.961-964
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• 1999

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.430-431
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• 1993

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1382-1385
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• 1998

• Journal of the Korean Chemical Society
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• v.32 no.5
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• pp.428-435
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• 1988

Some nickel(Ⅱ) and palladium(Ⅱ) complexes of the ambidentate ligands derived from condensation of the isonitrosoacetylacetone and various diamines, $Ni(IAA)_2-en$, $Ni(IAA)_2-pn$, $Ni(IAA)_2-tn$, $Pd(IAA)_2-en$, PdCl(IAA)-pn, and $Pd(IAA)_2$-tn, where (IAA)$_2$-en, $(IAA)_2$-tn, and (IAA)-pn represent N,N'-enthylenbis(isonitrosoacetylacetone imine), N,N'-propylenebis(isonitrosoacetylacetone imine), N,N'-trimethylenebis(isonitrosoacetylacetone imine) and N-(2-aminopropyl)isonitrosoacetylacetone imine, respectively, have been prepared. The nickel(Ⅱ) and palladium(Ⅱ) complexes were characterized on the bases of the elemental analysis, IR, NMR, and electronic spectra. It is suggested that a isonitroso group of (IAA)$_2$-en or (IAA)$_2$-tn coordinates to the metal ion through the nitrogen atom to form five-membered ring, while the other isonitroso group of (IAA)$_2$-en or (IAA)$_2$-tn coordinates to the metal ion through the oxygen atom to form six membered ring in square-planar complexes of Ni(IAA)$_2$-tn and Pd(IAA)$_2$-en. And two isonitroso groups of (IAA)$_2$-en, (IAA)$_2$-pn, or (IAA)$_2$-tn coordinate to the metal ion through the nitrogen atom to form five-membered rings in square-planar complexes of Ni(IAA)$_2$-en, Ni(IAA)$_2$-pn, and Pd(IAA)$_2$-tn. On the other hand, square-planar PdCl(IAA)-pn is formed by the reaction of propylenediamine with a isonitrosoacetylacetone in the presence of palladium(Ⅱ)ion.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.629-632
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• 1991

The rate constants for the formation and dissociation of nickel(II) and cobalt(II) complexes with mandelate have been determined by the pressure-jump relaxation study. The forward and reverse rate constants for the mandelate complex formation reactions were obtained to be $k_f=3.60{\times}10^4\;M^{-1}s^{-1}$ and $k_r=1.73{\times}10^2\;s^{-1}$ for the nickel(II), and $k_f=1.75{\times}10^5\;M^{-1}s{-1}$ and $2.33{\times}10^3\;s^{-1}$ for the cobalt(II) in aqueous solution of zero ionic strength ($(\mu{\to}0)\;at\;25^{\circ}C$. The results were interpreted by the use of the multistep complex formation mechanism. The rate constants evaluated for each individual steps in the multistep mechanism draw a conclusion that the rate of the reaction would be controlled by the chelate ring closure step in concert with the solvent exchange step in the nickel(II) complexation, while solely by the chelate ring closure step for the cobalt(II) complex.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2546-2548
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• 2007

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.726-730
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• 2013

Complexes synthesized by reacting alkyl and aryl phosphines with different transition metals are of great interest due to their catalytic properties. Many of the phosphine complexes are soluble in polar solvents as a result they find applications in homogeneous catalysis. In our present work we report, four transition metal complexes of Ni(II), Pd(II), Pt(II) and Ru(II) with an asymmetrical ditertiaryphosphine ligand. The synthesized ligand bears a less electronegative substituent such as methyl group on the aromatic nucleus hence makes it a strong ${\sigma}$-donor to form stable complexes and thus could effectively used in catalytic reactions. The complexes have been completely characterized by elemental analyses, FTIR, $^1HNMR$, $^{31}PNMR$ and FAB Mass Spectrometry methods. Based on the spectroscopic evidences it has been confirmed that Ni(II), Pd(II) and Pt(II) complexes with the ditertiaryphosphine ligand showed cis whereas the Ru(II) complex showed trans geometry in their molecular structure.