• Journal of the Korean Chemical Society
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• v.54 no.5
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• pp.515-522
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• 2010

A relation between antimicrobial activities and the formation constants of solid complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with tridentate Schiff base ligand, 4-hydroxy-3(1-{2-(benzylideneamino)-phenylimino}-ethyl)-6-methyl-2Hpyran-2-one (HL) derived from o-phenylene diamines, dehydroacetic acid (DHA) and p-chloro benzaldehyde have been studied. The ligand and metal complexes were characterized by elemental analysis, conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, $^1H$-NMR, UV-vis and mass spectra. From the analytical data, the stiochiometry of the complexes was found to be 1:2 (metal:ligand) with octahedral geometry. The molar conductance values suggest the nonelectrolytic nature of metal complexes. The X-ray diffraction data suggests monoclinic crystal system for Ni(II) and orthorhombic crystal system for Cu(II) and Co(II) complexes. The IR spectral data suggest that the ligand behaves as tridentate ligand with ONN donor atoms sequence towards central metal ion. Thermal behavior (TG/DTA) and kinetic parameters calculated by Coats-Redfern method suggests more ordered activated state in complex formation. The protonation constants of the complexes were determined potentiometrically in THF:water (60:40) medium at $25^{\circ}C$ and ionic strength ${\mu}=0.1\;M$ ($NaClO_4$). Antibacterial activities in vitro were performed against Staphylococcus aureu and Escherichia coli. Antifungal activities were studied against Aspergillus Niger and Trichoderma. The effect of the metal ions and stabilities of complexes on antimicrobial activities are discussed.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2881-2882
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• 2011

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.511-516
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• 1999

Shiff Base ligand such as [NOIPH] have been synthesized from 2-hydroxy-1-naphthaldehyde and arometic amine. Co(II), Ni(II), and Cu(II) complexes from the reaction metal salts with Tridentate Schiff Base [NOIPH] were sythesized. The ligand and metal(II) complexes were characterized by the elementary analysis, IR, UV-Vis, NMR spectra, and thermogravimetric analysis. Metal(II) complexes in solid state have been shown that the mole raio of Schiff base [NOIPH] as $N_2O$ type to Metal(II) is 2:1 and the metal(II) complexes of $N_2O$ ligand type were four-coordinated configuration.

• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.72-76
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• 2005

Some mononuclear oxovanadium(IV) complexes having the general formula [VOL(bidentate)] (1-4) of which L is tridentate ONS-donor salicylaldehyde S-methyldithiocarbazate (sal-mdtc$^{2-}$) or salicylaldehyde 4- phenylthiosemicarbazate (sal-phtsc$^{2-}$) and bidentate stands for 2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen) have been synthesized. The complexes were characterized by elemental analyses, FAB mass, UV, IR spectroscopy, and cyclic voltammetry. Two of the complexes [VO(sal-mdtc)(bpy)] (1) and [VO(sal-mdtc) (phen)] (2) were crystallographically characterized. The structures revealed that vanadium atom is octahedrally coordinated by the O, N, and S donor atoms of the tridentate ligand, the two N atoms of bidentate ligand, and the oxo atom. The oxygen donor, occupying an apical position has a trans-labilizing effect, resulting in elongation of the V-N bond. The cyclic voltammograms of the complexes exhibited one cathodic response in the range −d1.45 $\sim$ −f1.52 V due to the reduction of V(IV) to V(III).

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.569-577
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• 2003

Ligands, Br-PEMP, Cl-PEMP and $CH_3O-PEMP$ having Br, Cl and $CH_3O$ substituents at 5-position of the $N_2O$ tridentate ligand, 2-[(2-pyridine-2-ethylamio)-methyl]-phenol (H-PEMP) containing pyridine and phenol were synthesized. Another ligand, Naph-PEMP having pyridine and 2-hydroxy-1-naphthalene was also synthesized. The ligands were characterized using elemental analysis, UV-visible, IR, $^1H\;NMR\;and\;^{13}C$ NMR spectroscopy and mass analysis. The potentiometric titration study in aqueous solution revealed that the proton dissociation of the ligands occurred in three steps and the order of overall proton dissociation constants (log${\beta}$) was $CH_3O-PEMP$ > Naph-PEMP > H-PEMP > Cl-PEMP > Br-PEMP. The order of stability constants (logML and log$ML_2$) of their transition metal complexes was Co(II) < Ni(II) < Cu(II) > Zn(II). The order in their stability constants values of each transition metal complex agreed well with that in overall proton dissociation constant value of the ligands.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.422-431
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• 1998

Tridentate Schiff base ligands such as $SIPH_2,\;SIPCH_2,\;HNIPH_2,\;and\; HNIPCH_2$ were prepared by the reaction of salicylaldehyde and 2-hydroxy-l-naphthaldehyde with 2-aminophenol and 2-amino-p-cresol. The structures and properties of ligands and their Co(II) complexes were investigated by elemental analysis, $^1H$NMR, IR, UV-visible spectra, and thermogravimetric analysis. The molar ratio of Schiff base to the metal of complexes was found to be 1:1. Co(II) complexes were contemplated to be hexa-coordinated octahedral configuration containing three water molecules. The redox process of ligands and complexes in DMSO solution containing 0.1 M TBAP as a supporting electrolyte were investigated by cyclic voltammetry with glassy carbon electrode. The redox process of the tridentate Schiff base ligands was totally irreversible. The redox process of Co(II) complexes were irreversible and one electron processes by two steps in diffusion controlled reaction. The reduction potential of the Co(II) complexes was shifted to the positive direction in the order [Co(Ⅱ)$(HNIPC)(H_2O)_3$]>[Co(Ⅱ)$(HNIP)(H_2O)_3$]>[Co(II)$(SIPC)(H_2O)_3$]>[Co(Ⅱ)$(SIP)(H_2O)_3], and their dependence on ligands were not so high.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.1081-1084
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• 2012

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.345.3-346
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• 2002

In connection with the asymmetric synthesis of chiral l.2-diol. we report here the total synthesis of (＋)-frontalin using diastereoselective alkylation featuring tridentate chelation-controlled asymmetric alkylation of a-hydroxyketone, in which the chiral auxiliary is attached to the hydroxyl group as ether linkage. The starting D-glyceraldehyde acetonide was converted (S)- ［(4R)-2.2-dimethyH,3-dioxolan-4-yl］ (4-methoxyphenyl) methanol. (omitted)

• Journal of the Korean Chemical Society
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• v.52 no.4
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• pp.439-444
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• 2008

• Bulletin of the Korean Chemical Society
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• v.19 no.1
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• pp.83-86
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• 1998

The luminescence spectra of Eu(Ⅲ) complexes have been measured as a function of molar metal-to-ligand ratio and pH. The ligands used in this study are tridentate iminodiacetate (IDA) and methyliminodiacetate (MIDA). The 620 nm emission band, attributed to the $^5D_0{\to}^7F_2$ transition, is monitored to investigate the optimum condition for $EuL_3^{3-}$ complex formation in aqueous state. In addition, the sensitivity of the 465 nm absorption band, attributed to the $^7F_0{\to}^5D_2$ transition, to the ligand environment has been also investigated.