• Journal of the Korean Chemical Society
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• v.53 no.4
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• pp.407-414
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• 2009

The solid complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with 4-hydroxy-3-(1-{2-(2-hydroxybenzylidene)- amino phenylimino}-ethyl)-6-methy-pyran-2-one (H2L) derived from o-phenylenediamine, 3-acetyl- 6-methyl-(2H) pyran, 2,4 (3H)-dione (dehydroacetic acid or DHA) and salicylic aldehyde have been synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-visible, IR, $^1H$-NMR spectra, X-ray diffraction, thermal analysis, and screened for antimicrobial activity. The IR spectral data suggest that the ligand behaves as a dibasic tetradentate ligand with ONNO donor atoms sequence towards central metal ion. From the microanalytical data, the stoichiometry of the complexes has been found to be 1:1 (metal: ligand). The physico-chemical data suggests square planar geometry for Cu(II) and Ni(II) complexes and octahedral geometry for Co(II), Mn(II) and Fe(III) complexes. The x-ray differaction data suggests orthorhombic crystal system for Cu(II) complex, monoclinic crystal system for Ni(II), Co(II) and Fe(III) and tetragonal crystal system for Mn(II) complex. Thermal behaviour (TG/DTA) of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. The ligand and their metal complexes were screened for antibacterial activity against Staphylococcus aureus and Escherichia coli and fungicidal activity against Aspergillus Niger and Trichoderma.

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.2927-2929
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• 2009

The hydricities of d$^6$ metal hydride complexes in aqueous solution were calculated by using density functional theoretical (DFT) calculations coupled with a Poisson-Boltzmann (PB) solvent model. Hydricity describes the hydride donor ability of the metal-hydrogen bond, which assists in the study of the mechanism of many catalytic processes and chemical reactions that involve transition metal hydrides. The calculation scheme produced hydricity values that were in good agreement with experimental estimation. The inclusion of a water molecule as a weakly bound ligand to five-coordinate metal complexes gave an improved correlation result.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.177-184
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• 2016

CXC chemokine receptor 2 (CXCR2) is a prominent chemokine receptor on neutrophils and it regulates the neutrophilic inflammation in the lung diseases. CXCR2 antagonist may reduce the neutrophil chemotaxis and alter the inflammatory response. Hence, in the present study, ligand based Comparative Molecular Similar Indices Analysis (CoMSIA) was performed on a series of CXCR2 antagonist named pyrimidine-5-carbonitrile-6-alkyl derivatives. The optimum CoMSIA model was obtained with statistically significant cross-validated coefficients ($q^2$) of 0.582 and conventional coefficients ($r^2$) of 0.987 with steric, electrostatic, hydrophobic, donor and acceptor fields. The contour maps suggest the important structural modifications and this study can be used to guide the development of potent CXCR2 antagonist.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.766-771
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• 1994

A number of molybdenum(VI), -(V), and -(IV) oxo complexes with S-methyl 3-(2-hydroxyphenyl)methylenedithiocarbazate and its derivatives as the ONS-donor metal-binding substrate are synthesized. The Mo(VI)-dioxo complexes are cis-dioxo Mo$O_2$L(D), where D is solvent molecules such as MeOH, DMF, Py(pyridine), DMSO, and ${\gamma}$-Pic(${\gamma}$-picoline). The Mo(V)-oxo complexes are of the type (PyH)[MoO(NCS$)_2$L] with an octahedral geometry. The Mo(IV)-oxo complexes, MoOL are derived from corresponding Mo(VI)-dioxo complexes by oxo abstraction with PP$h_3$. The complexes are characterized by IR, $^1$H-NMR, UV-Vis spectroscopy and cyclic voltammetry. On the basis of ligand displacement reaction, the qualitative order of D binding for Mo$O_2$L(D) complexes is also discussed.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.507-511
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• 1992

Six-coordinate molybdenum(V) complexes X[MoO$(NCS)_2$(L)], where X=$PyH^+$, $Me_4N^+$, $Et_4N^+$, n-$Bu_4N^+$, and L= the tridentate schiff base dianions derived from the condensation reaction between various salicylaldehydes and 2-aminophenol have been synthesized. The complexes have been characterized by elemental analysis, conductivity, UV-visible, IR, $^1H$-NMR, and mass spectroscopy. The coordination around the molybdenum appears to be distorted octahedral. A tridentate ligand containing the ONO donor atoms occupies meridional positions with the N atom trans to the terminal oxo group. Two NCS ligands bond to the molybdenum through the N atom and are cis to the Mo = $O_t$ group. The electrochemical behaviors of the complexes have also been investigated by cyclic voltammetry in dimethylsulfoxide.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.231-235
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• 1998

Two holmium β-diketonate complexes, Ho(hfa)3(H2O)2 (1) and [Ho(hfa)3(H2O)2](triglyme) (2), have been prepared and characterized by IR, TGA, and single-crystal X-ray analyses. These complexes show polymeric chains by the intermolecular hydrogen bondings. The donor atoms of the intermolecular hydrogen bonding in both complexes are hydrogen atoms of the coordinated water molecules. The acceptor atoms in 1 are the carbonyl oxygen atoms of β-diketonate ligands whereas those in 2 are oxygen atoms of the triglyme ligand. While compound 1 decomposes cleanly to Ho2O3, compound 2 sublimes intact. Crystal data for 1 and 2 are as follows: Ho(hfa)3(H2O)2 triclinic P1, a=10.158(4), b=11.628(2), c=12.579(6) Å, α=67.02(3)°, β=73.95(4)°, γ=76.12(2)°, V=1299.8(8) Å3. [Ho(hfa)3(H2O)2](triglyme), monoclinic P21/c, a=12.559(3), b=19.111(2), c=16.789(6) Å, β=110.59(4)°, V=3772(2) Å3.

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.251-253
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• 1990

L-Alanine(L-ala) and S-methyl-L-cysteine(L-mcy) cobalt(III) complexes of a flexible $N_2O_2$-type tetradentate ligand ethylenediamine-N,N'-di- -butyric acid(eddb), s-cis-[Co(eddb)(L-ala)] and s-cis-[Co(eddb)(L-mcy), have been prepared via the substitution reactions of the s-cis-$[Co(eddb)Cl_2]$-complex with, respectively, L-alanine and S-methyl-L-cysteine. Both L-alanine and S-methyl-L-cysteine are found to coordinate to the cobalt(III) ion via the nitrogen and oxygen donor atoms to give the meridional s-cis isomer. Electronic absorption, ir and pmr spectra are used to characterize the complexes obtained in this work along with elemental analysis data.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.256-259
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• 1992

The 14-membered tetraaza macrocyclic ligand 1,8-diethyl-5,12-dimethyl-1,4,8,11-tetraazacyclote tradeca-4,11-diene(B) can be synthesized as its dihydroperchlorate salt by the one-pot reaction of 2-ethylaminoethylamine, methylvinyl ketone, and perchloric acid in absolute ethanol. The reaction of Ni(II) or Cu(II) ion and the salt yields $[M(B)]^{2+}$ (M = Ni(II) or Cu(II)), which reacts with $NaBH_4$ to produce $[M(D)]^{2+}$ (D = 1,8-diethyl-5,12-dimethyl-1,4,8,11-tetraazacyclote tradecane). The complexes $[M(L)]^{2+}$ (L = B or D) have planar geometry and contain two ethyl groups at the donor nitrogen atoms of the ligands. The red solids $[Cu(B)](X)_2(X)$ = $ClO_4-$ or $PF_6^-$) react with water molecules of atmospheric moisture to produce the purple solids in which water molecules are coordinated to the metal ion. Synthesis, characterization, and the properties of the new N-ethylated macrocyclic ligands and their Ni(II) and Cu(II) complexes are reported.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.354-357
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• 1990

Synthesis of dichloro cobalt (Ⅲ) complexes of a flexible $N_2O_2-type$ tetradentate ligand, ethylenediamene-N,N'-di-${\alpha}$-isobutyric acid (eddib), has yielded two geometrical isomers, s-cis-$(Co(eddib)Cl_2)- and uns-cis-(Co(eddib)Cl_2)-.$ A series of substitution reactions, $(Co(eddib)Cl_2)^- {\to} (CO(eddib)Cl H_2O) {\to} (Co(eddib)CO_3)^- {\to} (Co(eddib(H_2O)_2)^+$ have been run for each of the two geometrical isomers. The reaction between the s-cis-(Co(eddib)Cl_2)^-$ complex and L-alanine (L-als) or S-methyl-L-cysteine (L-mcy) gave the meridional s-cis-[Co(eddib)(aa)) (aa = L-ala or L-mcy) complex. The S-methyl-L-cysteine was found to coordinate to cobalt (Ⅲ) ion via the nitrogen and oxygen donor atoms.

• Analytical Science and Technology
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• v.35 no.4
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• pp.143-152
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• 2022

In this review, previous studies on the synthesis and characterization of the metal Complexes with paracetamol by elemental analysis, thermal analysis, (IR, NMR and UV-Vis (spectroscopy and conductivity. In reviewing these studies, the authors found that paracetamol can be coordinated through the pair of electrons on the hydroxyl O-atom, carbonyl O-atom, and N-atom of the amide group. If the paracetamol was a monodentate ligand, it will be coordinated by one of the following atoms O-hydroxyl, O-carbonyl or N-amide. But if the paracetamol was bidentate, it is coordinated by atoms (O-carbonyl and N-amide), (O-hydroxyl and N-amide) or (O-carbonyl and O-hydroxyl). The authors also found that free paracetamol and its complexes have antimicrobial activity.