• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1809-1814
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• 2006

The L-Valinate anion coordinating zinc complex, [$Zn(val)_2(H-2O)$], was isolated and structurally characterized by single crystal X-ray crystallography. The crystal possess orthorhombic symmetry with a space group $P2_12_12_1$, Z = 4, and a = 7.4279(2)$\AA$, b = 9.4342(2)$\AA$, c =20.5862(7)$\AA$ respectively. The compound features a penta-coordinate zinc ion in which the two valine anion molecules are directly coordinating the central zinc metal ion via their N (amine) and O (carboxylate) atoms, and an additional coordination to zinc is made by water molecule (solvent) to form a distorted square pyramidal structure. In addition, further synthesis of the valine capped ZnS:Mn nanocrystal from the reaction of [$Zn(val)_2(H-2O)$] precursor with $Na_2S$ and 1.95 weight % of $Mn^{2+}$ dopant is described. Obtained valine capped nanocrystal was water dispersible and was optically characterized by UV-vis and solution PL spectroscopy. The solution PL spectrum for the valine capped ZnS:Mn nanocrystal showed an excitation peak at 280 nm and a very narrow emission peak at 558 nm respectively. The measured and calculated PL efficiency of the nanocrystal in water was 15.8%. The obtained powders were characterized by XRD, HR-TEM, and EDXS analyses. The particle size of the nanocrystal was also measured via a TEM image. The measured average particle size was 3.3 nm.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.5
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• pp.389-399
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• 2015

Zinc has been considered as a vital constituent of proteins, including enzymes. Mobile reactive zinc ($Zn^{2+}$) is the key form of zinc involved in signal transductions, which are mainly driven by its binding to proteins or the release of zinc from proteins, possibly via a redox switch. There has been growing evidence of zinc's critical role in cell signaling, due to its flexible coordination geometry and rapid shifts in protein conformation to perform biological reactions. The importance and complexity of $Zn^{2+}$ activity has been presumed to parallel the degree of calcium's participation in cellular processes. Whole body and cellular $Zn^{2+}$ levels are largely regulated by metallothioneins (MTs), $Zn^{2+}$ importers (ZIPs), and $Zn^{2+}$ transporters (ZnTs). Numerous proteins involved in signaling pathways, mitochondrial metabolism, and ion channels that play a pivotal role in controlling cardiac contractility are common targets of $Zn^{2+}$. However, these regulatory actions of $Zn^{2+}$ are not limited to the function of the heart, but also extend to numerous other organ systems, such as the central nervous system, immune system, cardiovascular tissue, and secretory glands, such as the pancreas, prostate, and mammary glands. In this review, the regulation of cellular $Zn^{2+}$ levels, $Zn^{2+}$-mediated signal transduction, impacts of $Zn^{2+}$ on ion channels and mitochondrial metabolism, and finally, the implications of $Zn^{2+}$ in health and disease development were outlined to help widen the current understanding of the versatile and complex roles of $Zn^{2+}$.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.892-898
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• 2005

A long, bis(monodentate), linking Schiff-base ligand L (py-CH=N-$C_6H_4$-N=CH-py) was prepared from 1,4-phenylenediamine and 3-pyridinecarboxaldehyde by the Schiff-base condensation. Ligand L has two terminal pyridyl groups capable of coordinating to metals through their nitrogen atoms. In contrast, the same reaction between 1,2-phenylenediamine and 3-pyridinecarboxaldehyde produced a mixture of imidazol isomers (2-pyridin-3-yl-1H-benzoimidazole), which are connected to one another by the N-H…N hydrogen bonding to form a tetramer. From Zn($NO_3)_2{\cdot}6H_2O$ and ligand L under various conditions, one discrete molecule, trans- [Zn($H_2O)_4L_2]{\cdot}(NO_3)_2{\cdot}(MeOH)_2$, and two 1-D zinc polymers, [Zn$(NO_3)(H_2O)_2(L)]{\cdot}(NO_3){\cdot}(H_2O)_2$ and [Zn(L) (OBC)($H_2O$)], were prepared. In ligand L, the N$\ldots$N separation between the terminal pyridyl groups is 13.994 $\AA$, with their nitrogen atoms at the meta positions (3,3’) in a trans manner. The corresponding N$\ldots$N separations in its compounds range from 13.853 to 14.754 $\AA$.

• Toxicological Research
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• v.35 no.2
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• pp.155-160
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• 2019

Zinc pyrithione (ZnPT) is a coordination complex of zinc and has been used widely as an anti-dandruff agent in shampoos. Many shampoos contain both ZnPT and EDTA, a chelating agent speculated to increase ZnPT absorption, thereby raising concerns about neurotoxicity. Here, we investigated the effect of EDTA on ZnPT absorption by direct comparison of ZnPT and pyrithione (PT) concentrations in shampoo formulations, and by pharmacokinetic analysis of ZnPT, PT, and 2-methanesulfonylpyridine (MSP), the main ZnPT metabolite, in rat plasma or urine following exposure to shampoo containing ZnPT alone or a combination of ZnPT and EDTA. Approximately 17.3% of ZnPT was converted to PT by the addition of EDTA in the shampoo formulation. Plasma ZnPT and PT concentrations were not measured up to 24 hr after treatment with shampoo containing 1% ZnPT or 1% ZnPT + 2% EDTA in all rats. However, PT amount in 24-hr urine sample, MSP concentration in plasma, and MSP amount in 24-hr urine sample were approximately 4-, 2.6-, and 2.7-fold higher, respectively, in the 1% ZnPT + 2% EDTA shampoo group than in the 1% ZnPT shampoo group. As confirmed by the formulation analysis and in vivo pharmacokinetic analysis, the exposure of ZnPT could be increased by the absorption of PT due to partial dissociation of ZnPT into PT.

• Journal of the Korean Chemical Society
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• v.68 no.1
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• pp.32-39
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• 2024

Glycerol dehydrogenase (GlyDH) plays a crucial role in the glycerol metabolism pathway by catalyzing the oxidation of glycerol to dihydroxyacetone (DHA). Previous studies of GlyDH have predominantly focused on unraveling the structural features of the active site and its binding interactions with ligand. However, the structural details of GlyDH in complex with both NAD⁺ and the substrate bound have remained elusive. In this study, we present the crystal structures of Klebsiella pneumoniae GlyDH (KpGlyDH) in the absence and presence of NAD⁺ at a resolution of 2.1 Å. Notably, both structures reveal the binding of the substrate, ethylene glycol, to the zinc ion. Interestingly, a significant change in the coordination number of the zinc ion is observed, with three in the absence of NAD⁺ and four in its presence. These findings shed light on the structural aspects of GlyDH and its interactions with NAD⁺ and the substrate.

• 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.31 no.10
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• pp.2923-2928
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• 2010

This study examined the synthesis of the crystal structure of bis(2,2'-bipyridine)nitrato zinc (II) nitrate, $[Zn(bipy)_2(NO_3)]^+NO_3^-$ using a microwave treatment at 300 W and 60 Hz for the application to dye-sensitized solar cells. The simulated complex structure of the complex was optimized with the density functional theory calculations for the UV-vis spectrum of the ground state using Gaussian 03 at the B3LYP/LANL2DZ level. The structure of the acquired complex was expected a penta-coordination with four nitrogen atoms of bipyridine and the oxygen bond of the $NO_3^-$ ion. The reflectance UV-vis absorption spectra exhibited two absorptions (L-L transfers) that were assigned to the transfers from the ligand ($\sigma$, $\pi$) of $NO_3$ to the ligand ($\sigma^*$, $\pi^*$) of pyridine at around 200 - 350 nm, and from the non-bonding orbital (n) of O in $NO_3$ to the p-orbital of pyridine at around 450 - 550 nm, respectively. The photoelectric efficiency was approximately 0.397% in the dye-sensitized solar cells with the nanometer-sized $TiO_2$ at an open-circuit voltage (Voc) of 0.39 V, a short-circuit current density (Jsc) of $1.79\;mA/cm^2$, and an incident light intensity of $100\;mW/cm^2$.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.567-573
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• 2007

The crystal structure of ZnI2 molecule synthesized in zeolite A (LTA) has been studied by single-crystal X-ray diffraction techniques. A single crystal of |Zn6|[Si12Al12O48]-LTA, synthesized by the dynamic ion-exchange of |Na12|[Si12Al12O48]-LTA with aqueous 0.05 M Zn(NO3)2 and washed with deionized water, was placed in a stream of flowing 0.05 M KI in CH3OH at 294 K for four days. The resulting crystal structure of the product (|K6Zn3(KI)3(ZnI2)0.5|[Si12Al12O48]-LTA, a = 12.1690(10) A) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm3m. It was refined with all measured reflections to the final error index R1 = 0.078 for 431 reflections which Fo > 4σ (Fo). At four crystallographically distinct positions, 3.5 Zn2+ and nine K+ ions per unit cell are found: three Zn2+ and five K+ ions lie on the 3-fold axes opposite 6-rings in the large cavity, two K+ ions are off the plane of the 8-rings, two K+ ions are recessed deeply off the plane of the 8-rings, and the remaining a half Zn2+ ion lie on the 3-fold axes opposite 6-rings in the sodalite cavity. A half Zn2+ ion and an I- ion per unit cell are found in the sodalite units, indicating the formation of a ZnI2 molecule in 50% of the sodalite cavities. Each ZnI2 (Zn-I = 3.35(5) A) is held in place by the coordination of its one Zn2+ ion to the zeolite framework oxygens and by the coordination of its two I- ions to K+ ions through 6-rings (I-K = 3.33(8) A). Three additional I- ions per unit cell are found opposite a 4-ring in the large cavity and form a K3I2+ and two K2ZnI3+ ionic clusters, respectively.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.107-127
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• 2005

Five Cu(II) compounds were obtained from different copper salts with btp ligands, and their structures were determined by X-ray crystallography. The structure of coordination polymer 2 contains btp-bridged tetranuclear Cu(II) units weakly connected by nitrate ions, and the structure of a discrete Cu(II) molecule 1 contains acetates and btp ligands. With perchlorate anions, two btp ligands bridge Cu(II) ions to form a double zigzag chain 3, while a single zigzag chain 4 is created with sulfate anions. The reaction of $Cu(NO_{3})_{2}$ containing $NH_{4}PF_{6}$ with btp ligands also produced a polymeric compound 5 containing $Cu(H_{2}O)_{2}^{2+}$ and $Cu(NO_{3})_{2}$ units alternatively bridged by btp ligands with H-bonds between copper bonded water and nitrate oxygen atoms. Five Zn(II) compounds were obtained from different zinc salts with btp ligands, and the structures of polymeric compounds (6, 7 and 8) and monomeric compounds (9 and 10) were determined by X-ray crystallography. With nitrate, chloride and bromide anions, btp ligands bridge Zn(II) ions to form polymeric compounds (6, 7 and 8), but btp ligands coordinate to a Zn(II) ion to form monomeric complexes (9 and 10) with $PF_{6}^{-}$ and perchlorate anions. Four silver salts and btp ligands produced two kinds of structures, dinuclear 20-membered rings and one-dimensional zigzag chain depending on different anions. For $ClO_{4}^{-}$ and OTf anions, weak interactions between Ag(I) and anions make dinuclear 20-membered rings construct polymeric compounds (11 and 13). For $PF_{6}^{-}$ anion, there are also weak interactions between Ag(I) and $F(PF_{6}^{-})(12)$, but they do not construct a polymeric compound. For $O_{2}CCF_{3}^{-}$ anion, btp ligands bridge Ag(I) atoms to make one-dimensional zigzag chain (14), and there are also interactions between Ag(I) and anions.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1692-1696
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• 2011

The reactions of 1H-1,2,4-triazole (Htr) with $MX_2$ ($ZnCl_2$ for 1; $CdBr_2$ for 2) resulted in two coordination polymers, [Zn(tr)Cl]$_n$ (1) and $[Cd(Htr)_2Br_2]_n$ (2). The structural analyses indicate that 1 and 2 feature a 2D layer and 1D triple chain, respectively. In 1, neighouring Zn atoms are connected by ${\mu}_3-1$ ${\kappa}N$: 2 ${\kappa}N$: $4{\kappa}N-tr^-$ anionic ligand into 6- and 16-membered rings, further grow into a 2D sheet. Cd atoms in 2 are bonded by two ${\mu}_2-Br^-$ bridges and neutral ${\mu}_2$-1 ${\kappa}N$: 2 ${\kappa}N$-Htr to form a 1D triple chain. The fluorescent characterizations of 1, 2 and the free Htr ligand feature simlilar emission peakes at 444, 446 and 423 nm respectively, which can be assigned to intra-ligand ${\pi}-{\pi}^*$ transition of (H)tr. The energy gaps of 5.90 eV for 1, 5.16 eV for 2, and 5.93 eV for Htr suggest that the compounds behave as insulators.