• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2617-2622
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• 2011

Two new Zn(II) complexes, $[Zn_2(dpa)_2(phen)_2(H_2O)_2]{\cdot}H_2O$ (1) (dpa = dephenate, phen = 1,10-phenanthroline) and [$Zn_2(dpa)_2(bpy)_2(H_2O)_2$] (2) (bpy = 2,2'-bipyridine) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The X-ray analysis reveals that the structures of 1 and 2 are dinuclear zinc(II) complexes bridged by dpa dianions, respectively. The zinc ions in 1 exhibit a distorted square pyramidal environments, while the zinc ions in 2 exhibit a trigonal bipyramid geometry. In each complex, the dpa ligand is coordinated to zinc ions as a bis-monodentate.

• Mass Spectrometry Letters
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• v.3 no.3
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• pp.82-85
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• 2012

The formation of zinc finger peptide-$Zn^{2+}$ complexes in electrospray ionization mass spectrometry (ESI-MS) was examined using three different metal ion sources: $ZnCl_2$, $Zn(CH_3COO)_2$, and $Zn(OOC(CHOH)_2COO)$. For the four zinc finger peptides (Sp1-1, Sp1-3, CF2II-4, and CF2II-6) that bind only a single $Zn^{2+}$ in the native condition, electrospray of apo-zinc finger in solution containing $ZnCl_2$ or $Zn(CH_3COO)_2$ resulted in the formation of zinc finger-$Zn^{2+}$ complexes with multiple zinc ions. This result suggests the formation of nonspecific zinc finger-$Zn^{2+}$ complexes. Zn(tartrate), $Zn(OOC(CHOH)_2COO)$, mainly produced specific zinc finger-$Zn^{2+}$ complexes with a single zinc ion. This study clearly indicates that tartrate is an excellent counter ion in ESI-MS studies of zinc finger-$Zn^{2+}$ complexes, which prevents the formation of nonspecific zinc finger-$Zn^{2+}$ complexes.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2929-2934
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• 2014

The reaction between $[CdBr_2{\cdot}4H_2O]$ and anhydrous $[ZnCl_2]$ with N,N'-bidentate N-(pyridin-2-ylmethylene)-cyclopentanamine (impy) in ethanol yields dimeric $[(impy)Cd({\mu}-Br)Br]_2$ and monomeric $[(impy)ZnCl_2]$ complexes, respectively. The X-ray crystal structure of Cd(II) and Zn(II) complexes revealed that the cadmium atom in $[(impy)Cd({\mu}-Br)Br]_2$ and zinc in $[(impy)ZnCl_2]$ formed a distorted trigonal-bipyramidal and tetrahedral geometry, respectively. Both complexes showed moderate catalytic activity for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO), with polymethylmethacrylate (PMMA) syndiotacticity of about 0.70.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.555-562
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• 2002

Isomers based on the RS and EZ geometrical isomerism of the neutral, deprotonated species of HMPAO and their complexes with zinc(Ⅱ) ion have been investigated by semiempirical AM1 optimization method. The Hartree-Fock energies on AM1 geometries o f HMPAO species were calculated with HF/6-31G* methods. Twenty-two isomers of the neutral and twenty isomers of the deprotonated species of HMPAO have been found. The presence of four EE-series isomers of both zinc(Ⅱ) complexes with the neutral and deprotonated HMPAO have been expected and the SREE typical isomer of both types of complexes is the most stable isomer. Energies of complexation of zinc(Ⅱ)/HMPAO isomers with AM1 geometries were calculated by HF/ 6-31G*method. Due to the complexations with zinc(Ⅱ), the structural reorganizations of some isomers of the neutral HMPAO have been occurred. The optimized geometrical parameters of the related conformations have been discussed in terms of their stabilities and existences.

• Mycobiology
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• v.36 no.2
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• pp.93-98
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• 2008

Two Schiff base ligands $L_1\;and\;L_2$ were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1:1 electrolytes. The IR data demonstrate the tetradentate binding of $L_1$ and tridentate binding of $L_2$. The XRD data show that Zn(II) complexes with $L_1\;and\;L_2$ have the crystallite sizes of 53 and 61 nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.2069-2072
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• 2010

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.61-65
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• 2003

Zinc occurs in the nature as sulfide, carbonate, silicate, and oxide. In natural water, zinc is generally in the form of the divalent cation $Zn^{2+}$ as well as in the form of fairly weakly bound complexes. Human activities introduce zinc ion to the hydrosphere in many ways. The zinc complexes in the aqueous environment are accumulated not only in aquatic organisms but also in human body ultimately through physico-chemical and/or biological processes. (omitted)

• Journal of the Korean Chemical Society
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• v.62 no.1
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• pp.14-18
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• 2018

The complexes $[Zn(L)(H_2O)_2]{\cdot}2NO_2$ (1) and $[Zn(L)(NO_3)_2]$ (2) (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo $[14,4,0^{1.18},0^{7.12}]$docosane) have been synthesized and structurally characterized. The compound 1 crystallizes in the monoclinic system $P2_1/c$ with a = 8.74650(10), b = 18.6880(3), c = $7.96680(10){\AA}$, ${\beta}=109.1920(10)^{\circ}$, $V=1229.84(3){\AA}^3$, Z = 2. The compound 2 crystallizes in the monoclinic system P1 with a = 8.1292(5), b = 8.9244(5), c = $9.1398(5){\AA}$, ${\alpha}=68.035(2)$, ${\beta}=70.109(2)$, ${\gamma}=75.649(3)^{\circ}$, $V=572.70(6){\AA}^3$, Z = 1. The crystal structures of the compounds 1 and 2 show a distorted octahedral coordination geometry around the zinc(II) ion, with four secondary amines and two oxygen atoms of the two water and two nitrate ligands at the axial position. The TGA behaviors of the complexes are significantly affected by the nature of the tetraaza macrocycle and the axial ligands.

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1477-1483
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• 2004

We present the tandem mass spectrometry applications carried out to elucidate the coordination structure of Zn(II) bound lysine ternary complexes, $(Zn+Lys+Lys-H)^+$, which is a good model system to represent a simple (metallo)enzyme-substrate complex (ES). In particular, experimental efforts were focused on revealing the involvement of a lysine side chain ${\varepsilon}$-amino group in the coordination of $Zn^{2+}$ divalent ions. MS/MS fragmentation pattern showed that all the oxygen species within a complex fell off in the form of $H_2O$ in contrast to those of other ternary complexes containing amino acids with simple side chains (4-coordinate geometries, Figure 1a), suggesting that the lysine complexes have different coordination structures from the others. The participation of a lysine basic side chain in the coordination of Zn(II) was experimentally evidenced in MS/MS for $N{\varepsilon}$-Acetyl-L-Lys Zn(II) complexes with acetyl protection groups as well as in MS/MS for the ternary complexes with one $NH_3$ loss, $(Zn+Lys+Lys-NH_3-H)^+$. Detailed structures were predicted using ab initio calculations on $(Zn+Lys+Lys-H)^+$ isomers with 4-, 5-, and 6-coordinate structures. A zwitterionic 4-coordinate complex (Figure 7d) and a 5-coordinate structure with distorted bipyramidal geometry (Figure 7b) are found to be most plausible in terms of energy stability and compatibility with the experimental observations, respectively.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3743-3748
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• 2013

A tetradentate ligand of 2-phenyl-4,6-di(pyridin-2-yl)pyrimidine (L) has been synthesized and its complexes with $ZnI_2$ and CuI have been obtained by hydrothermal method. single crystal X-ray diffraction analysis indicates that ligand L coordinates with Zn(II) ions to form a simple four-coordinate di-nuclear complex, while the complexation of L with Cu(I) constructs a one-dimensional chain polymer. The existence of $I^-$ ion hampers the L to assemble grid-type complexes with Zn(II) and Cu(I). Fluorescence spectra show that the L emits blue fluorescence while its Cu(I) polymer decrease the fluorescence intensity and Zn(II) complex quenches the fluorescence.