• Journal of the Korean Mathematical Society
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• v.50 no.5
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• pp.959-972
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• 2013

Rege-Chhawchharia, and Nielsen introduced the concept of right McCoy ring, based on the McCoy's theorem in 1942 for the annihilators in polynomial rings over commutative rings. In the present note we concentrate on a natural generalization of a right McCoy ring that is called a right nilpotent coefficient McCoy ring (simply, a right NC-McCoy ring). The structure and several kinds of extensions of right NC-McCoy rings are investigated, and the structure of minimal right NC-McCoy rings is also examined.

• Bulletin of the Korean Mathematical Society
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• v.56 no.4
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• pp.993-1006
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• 2019

This article concerns a ring property which preserves the reversibility of elements at nonzero idempotents. A ring R shall be said to be quasi-reversible if $0{\neq}ab{\in}I(R)$ for a, $b{\in}R$ implies $ba{\in}I(R)$, where I(R) is the set of all idempotents in R. We investigate the quasi-reversibility of 2 by 2 full and upper triangular matrix rings over various kinds of reversible rings, concluding that the quasi-reversibility is a proper generalization of the reversibility. It is shown that the quasi-reversibility does not pass to polynomial rings. The structure of Abelian rings is also observed in relation with reversibility and quasi-reversibility.

• Journal of the Korean Mathematical Society
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• v.51 no.6
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• pp.1251-1267
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• 2014

The semicommutative property of rings was introduced initially by Bell, and has done important roles in noncommutative ring theory. This concept was generalized to one of nil-semicommutative by Chen. We first study some basic properties of nil-semicommutative rings. We next investigate the structure of Ore extensions when upper nilradicals are ${\sigma}$-rigid ${\delta}$-ideals, examining the nil-semicommutative ring property of Ore extensions and skew power series rings, where ${\sigma}$ is a ring endomorphism and ${\delta}$ is a ${\sigma}$-derivation.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.183-188
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• 2011

The electronic structure and properties of Ni$(C_6H_{4-n}F_n)(CO)_2$ ($C_6H_4$=benzyne, n=1-4) complexes have been investigated using hybrid density functional B3LYP theory. Both aromatic natures and nucleus independent chemical shift (NICS) of the benzyne rings have been analyzed. Among mono-, di-, and tri-fluorinated complexes, 3-F, 3,6-F, and 4-H are the most stable isomers, respectively. NICS values calculated at the several points above the ring centers are consistent with those based on the relative energies of the complexes. The atoms in molecules (AIM) analysis indicates that Ni-C bond distance is well correlated with the electron density of a ring critical point (${\rho}_{rcp}$) in all species.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.431-434
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• 1990

Template condensation reaction of diethylenetriamine, ethylenediamine, methylamine, and formaldehyde in the presence of Ni(II) or Cu(II) ion yields new saturated hexaaza macrobicyclic complexes $[Ni(C)]^{2+}\;and\;[Cu(C)]^{2+}$, where C is 8-methyl-1,3,6,8,10,13-hexaazabicyclo[11,2,1]hexad ecane. The macrobicyclic complexes contain one 1,3-diazacyclopentane ring and one methyl pendant arm in the ligand C and have square planar geometry with 5-6-5-6 chelate ring sequence. Synthesis, characterization, and the properties of the macrobicyclic complexes are described.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.846-848
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• 2009

Two modifications of the ${\alpha}\;and\;{\beta}$ forms of propyl mercaptan nickel(II) cluster, [$Ni_6(SCH_2CH_2CH_3)_{12}$], have been synthesized and their crystal structures have been determined by single-crystal X-ray diffraction. The alkyl groups are away from $Ni_6$ ring in $\alpha$ form whereas they are near to the Ni atom in $\beta$ form. The distance of Ni-H in $\beta$ form [2.576(5) $\AA$] is much shorter than that in $\alpha$ form [3.101(2) $\AA$]. In the crystal lattice of $\beta$ form, the whole structure forms a flower shape.

• 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.

• Journal of the Korean Magnetic Resonance Society
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• v.18 no.2
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• pp.74-81
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• 2014

The $N_2O_2$ tetradentate Schiff base ligand, N,N'-bis(salicylidene)pentane-1,3-diamine (Salpn), coupled with 1:2 concentration ratio of 1,3-diaminopentane and salicylaldehyde was used to produce a series of macrocyclic Nikel(II) complexes. In the metal complexation, it was observed that Salpn macrocyclic ligand can adopt more than a metal ion giving an unique multinuclear metal complexes including Ni(II)Salpn and $Ni(II)_3(Salpn)_2$. Characteristic IR ${\upsilon}(M-O)$ peaks for Ni(II)Salpn and $Ni(II)_3(Salpn)_2$ were observed to be $1028cm^{-1}$ and $1024cm^{-1}$, respectively. Characteristic UV-Vis absorption ${\lambda}_{max}$ peaks for $Ni(II)_3(Salpn)_2$ were observed to be 241nm and 401 nm. Structural characterization of $Ni(II)_3(Salpn)_2$ by NMR exhibits that the salicylidene ring moiety has two different resonance signals originated from the magnetically asymmetric diligand and trinuclear bis complex. Complete NMR signal assignments and characterizations elucidating structural features of $Ni(II)_3(Salpn)_2$ were described in detail.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.92-98
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• 2000

A ring comprising a coated conductor was fabricated. A ring was made first using a biaxially textured Ni tape whose two ends were connected by means of the atomic diffusion bonding technique. Then buffer layers and a YBCO film were deposited on it. All the films were well textured as confirmed by XRD pole figures. The B-H loops, where B and H are the magnetic field at the center of the ring and the applied field respectively, were measured as a function of temperature. The persistent current density (J$_c$) flowing circularly was estimated from the remanent field of B. In the range of temperature from 72K to 20K, J$_c$ changed from zero to 2${\times}$1 0$^5$A/cm$^2$.

• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.527-533
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• 1991

Template condensation reactions of formaldehyde with appropriate tetramines and diamines in the presence of N(II) or Cu(II) ion produce square planar complexes of hexaaza macrotricyclic and macrotetracyclic ligands $[M(L)]^{2+}$(M = Ni(II) or Cu(II); L = 4-methyl-1,3,6,8,11,14-hexaazatricyclo[12,2,1,$1^{8,11}$]octadecane(C), 1,3,10,12,15,18-hexaazatetracyclo[16,2,1,$1^{12,15},0^{4,9}]$docosane(D) 4-methyl-1,3,6,8,12,15-hexaazatricyclo[13,3,1,$1^{8,12}$]eicosane(F), or 1,3,10,12,16,19-hexaazatetracyclo[l7,3,1,$1^{12,16},0^{4,9}]$tetracosane(G). These complexes contain two 1,3-diazacyclopentane or 1,3-diazacyclohexane rings in the six-membered chelate rings. The complexes of C and F contain one methyl group and those of D and G one cyclohexane ring in the five-membered chelate ring. Synthesis and characterization of the Ni(II) and Cu(II) complexes are presented. The effects of the ligand structure on the equilibrium $[Ni(L)]^{2+}2H_2O{\rightleftharpoons}[Ni(L)(H_2O)_2]^{2+}$ in aqueous solutions are described.