• Journal of Integrative Natural Science
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• v.7 no.4
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• pp.241-252
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• 2014

A series of N-benzoylated ligands incorporating three different benzoyl groups 2,2'-(benzoyliminodiethylene)-4-substituted phenols ($L^{1,4,7}$), 2,2'-(4-nitrobenzoyliminodiethylene)-4-substituted phenols ($L^{2,5,8}$) and 2,2'-(3,5-dinitrobenzoyliminodiethylene)-4-substituted phenols ($L^{3,6,9}$) were synthesized and characterized by IR, $^1H$ NMR, $^{13}C$ NMR and mass spectroscopy. The In vitro antibacterial activity of investigated ligands were tested against human pathogenic bacteria such as four Gram (-) Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus, Vibrio cholera, Vibrio harveyi and two Gram (+) Staphylococcus aureus, Streptococcus mutans. Furthermore, docking studies were undertaken to gain insight into the possible binding mode of these compounds with the binding site of the topoisomerase II (PDB: 4FM9) enzyme which is involved in DNA superhelicity and chromosome seggregation. The N-benzoylated derivatives $L^{5,7,8}$ have significant anticancer activity as Topoisomerase inhibitors. The ligands $L^5$ and $L^8$ were tested for their anticancer activity against human liver adenocarcinoma (HepG2) cell line with the MTT assay.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.166-170
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• 2016

Collagen plays a vital role in the maintenance of structure and function of a human body. It has been widely applied in various fields including biomedical, cosmeceutical, food, pharmaceutical and tissue engineering. In the present study, the docking behaviour of type I collagen with 15 different ligands namely hydroxymethylfurfural, methylglyoxal, methylsyringate, O-methoxyacetophenone, 3-phenyllactic acid, 4-hydroxybenzoic acid, kojic acid, lumichrome, galangin, artoindonesianin F, caffeic acid, 4-coumaric acid, origanol A, thymoquinone and quercetin was evaluated along with their putative binding sites using Discovery Studio Version 3.1. Docking studies and binding free energy calculations revealed that origanol A has maximum interaction energy (-40.48 kcal/mol) and quercetin with the least interaction energy (-15.44 kcal/mol) as compared to the other investigated ligands. Three ligands which are galangin, methylsyringate and origanol A were shown to interact with Asp21 amino acid residue of chain B (type I collagen). Therefore, it is strongly suggested that the outcomes from the present study might provide new insight in understanding these 15 ligands as potential type I collagen modulators for the prevention of collagen associate disorders.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3600-3604
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• 2010

Rhodium(III)-$Cp^*$ complexes containing labile ligands, $[Cp^*RhCl_2]_2$, [$Cp^*Rh({\eta}^2-NO_3)$(OTf)], and $[Cp^*Rh(OH_2)_3](OTf)_2$, reacted with potential linking ligands [$L^1$ = (2-thiophene)-CH=N-N=CH-(2-thiophene); $L^2$ = (2-furan)-CH=N-N=CH-(2-furan)] to give two molecular compounds, [$Cp^*Rh(L^1)Cl_2$] (1) and [$Cp^*Rh({\eta}^2-NO_3)(L^1)$]$(OTf){\cdot}CH_2Cl_2$ ($2{\cdot}CH_2Cl_2$), and one 1-dimensioanl coordination polymer, $\{[Rh(L^2)]{\cdot}(OTf)}_{\infty}$ (3). Whereas one imine nitrogen atom within the ligand is coordinated to the Rh metal in compounds 1 and 2, both nitrogen atoms are bound to two neighboring Rh metals in compound 3 to lead to a 1-D chain polymer.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.636-646
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• 2009

A series of the noble palladium complexes containing $\beta$-ketoiminate ligands with internal bases, [Pd(${\eta}^3$-allyl)($\beta$- ketoiminate)], [Pd(Me)($PPh_3$)($\beta$-ketoiminate)] and [Pd(Me)($\beta$-ketoiminate)], have been successfully prepared. Crystallographically determined structures showed that these complexes are distorted square planar and pendant bases of the $\beta$-ketoiminate ligands fail to coordinate to the metal in the first two classes of complexes while bases do coordinate in the 3rd class complexes. These complexes are active towards norbornene polymerization on activation with $H(OEt_2)_2BAr^'_4$ (Ar' = 3,5-bistrifluoromethylphenyl) and modified methylalumioxane (MMAO). MMAO is more efficient for the activation for polymerization. Generally, the polymerization activity increases with the following order; [Pd(allyl)($\beta$-ketoiminate)] < [Pd(Me)($PPh_3$)($\beta$-ketoiminate)] < [Pd(Me)($\beta$-ketoiminate)].

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2523-2531
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• 2009

Effects of some diacid, diamine and dinitro aromatic compounds on the structure and activity of adenosine deaminase (ADA) were investigated by UV-Vis spectrophotometry in 50 mM phosphate buffer at pH = 7.5 and 27 ${^{\circ}C}$ and molecular docking studies. The results showed that all tested ligands are showing inhibition; five ligands are uncompetitive and other two ligands are mixed of competitive and noncompetetive inhibitors with majority of competitive behavior. For the later case analysis was done based on competitive inhibition. Diacids have larger size and higher inhibition constant ($K_I$) relative to others. A logical correlation between calculated free energy of binding and experimental values was obtained for un-competitive. Experimental and calculated data showed that competitive inhibitors are distributed near the active site of enzyme and form several cluster of ranks, whereas uncompetitive inhibitors bind to the enzyme-substrate complex and distributed far from the active site. Results of structure-activity relationship showed that, larger, more hydrophobe, less spherical and more aromatic ligands have higher inhibition constants.

• Preventive Nutrition and Food Science
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• v.2 no.3
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• pp.219-224
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• 1997

The pancreas is an important organ in the maintenance of zine homeostasis. The pancreatic tissue used in this study was obtained from rats fed varying levels of dietary Ca nd phytate followed by intraperitoneal {TEX}${65}^Zn${/TEX} injection. THe objective of this study was to determine the molecular size and distribution of compounds that may represent zinc-binding complexes in pancreatic tissue homogenates. The supernatant of the homogenized pancreatic tissue was separated using a Sephadex G-75 column with Tris buffer at pH 8.1. All subfractions were assayed for zinc, protein and {TEX}${65}^Zn${/TEX} activity. The elution of subfractions from pancreatic tissue homogenates showed a prominent peak corresponding to the high molecular weight protein standard (>66kd). A sall molecular weigth protein (<6.5kd), that was absorbed at 280nm, was also present: prominently in low Ca group, however not much as in high Ca group. These small compounds may combine weakly with zinc in pancreatic tissue an serve as zinc-binding ligands in pancreatic/biliary fluid. In the duodenum, these ligands dissociate zinc into an ionic form which becomes vulnerable to phytate complexation.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.355-355
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• 2016

There has been an explosive development of nanocrystal (NC) synthesis and application due to their composition-dependent specific properties. Despite the composition, shape, and size of NCs foremost determine their physicochemical properties, the surface state and molecule conjugation also drastically change their characteristics. To make practical use of NCs, it is a prerequisite to understand the NC surface state and the degree to which they have been modified because the reaction occurs on the interface between the NCs and the surrounding medium. We report in here an analysis method to identify conjugated ligands and their binding states on semiconductor nanocrystals based on their molecular information. Surface science techniques, such as time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and FT-IR spectroscopy, are adopted based on the micro-aggregated sampling method. Typical trioctylphosphine oxide-based synthesis methods of CdSe/ZnS quantum dots (QDs) have been criticized because of the peculiar effects of impurities on the synthesis processes. Since the ToF-SIMS technique provides molecular composition evidence on the existence of certain ligands, we were able to clearly identify the n-octylphosphonic acid (OPA) as a surface ligand on CdSe/ZnS QDs. Furthermore, the complementary use of the ToF-SIMS technique with the FT-IR technique could reveals the OPA ligands' binding state as bidentate complexes.

• Journal of Animal Science and Technology
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• v.57 no.11
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• pp.40.1-40.7
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• 2015

Background: Activation of peroxisome proliferator activated receptor gamma ($PPAR{\gamma}$) in the alveolar macrophages (AM) by selective synthetic $PPAR{\gamma}$ ligands, improves the ability of the cells to resolve inflammation. In birds, respiratory macrophages are known as free avian respiratory macrophages (FARM) and show distinct functional differences from AM. The effects of treating FARM with $PPAR{\gamma}$ ligands are unclear. Methods: FARM were harvested by lavage of chicken respiratory tract and their morphology assessed at microscopic level. The effects of $PPAR{\gamma}$ agonists on the FARM in vitro viability, phagocytic capacity and proinflammatory cytokine (TNF-${\alpha}$) production were assessed. Results: FARM had eccentric nucleus and plasma membrane ruffled with filopodial extensions. Ultrastructurally, numerous vesicular bodies presumed to be lysosomes were present. FARM treated with troglitazone, a selective $PPAR{\gamma}$ agonist, had similar in vitro viability with untreated FARM. However, treated FARM co-cultured with polystyrene particles, internalized more particles with a mean volume density of 41 % compared to that of untreated FARM of 21 %. Further, treated FARM significantly decreased LPS-induced TNF-${\alpha}$ production in a dose dependent manner. Conclusion: Results from this study show that $PPAR{\gamma}$ synthetic ligands enhance phagocytic ability of FARM. Further the ligands attenuate production of proinflammatory cytokines in the FARM, suggesting potential therapeutic application of $PPAR{\gamma}$ ligands in the management of respiratory inflammatory disorders in the poultry industry.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.201-214
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• 2005

We have designed and developed novel luminescent lanthanide complexes for advanced photonics applications. Lanthanide(III) ions (Ln$^{3+}$) were encapsulated by the luminescent ligands such as metalloporphyrins and naphthalenes. The energy levels of the luminescent ligands were tailored to maintain the effective energy transfer process from luminescent ligands to Ln$^{3+}$ ions for getting a higher optical amplification gain. Also, key parameters for emission enhancement and efficient energy transfer pathways for the sensitization of Ln$^{3+}$ ions by luminescent ligands were investigated. Furthermore, to enhance the optophysical properties of novel luminescent Ln$^{3+}$ complexes, aryl ether-functionalized dendrons as photon antennas have been incorporated into luminescent Ln$^{3+}$ complexes, yielding novel Ln(III)-cored dendrimer complex. The novel Ln(III)-cored dendrimer complex has much higher PL intensity than the corresponding simple complex, due to the efficient site-isolation effect. In this article, we will deal with recent progress in the synthesis and photophysical studies of inert and stable luminescent Ln$^{3+}$ complexes for advanced photonics applications. Also, our review will include the exploratory investigation of the key parameters for emission enhancement and the effective energy transfer pathways from luminescent ligands to Ln$^{3+}$ ions with Ln(III)-chelated prototype complexes.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3459-3464
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• 2014

Synthesis and structural characterization of mercury(II) halides and perchlorate complexes (1-4) of bis-$OS_2$-macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type $[Hg(L)X_2]_n$ (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies outside the cavity is six-coordinate with a distorted octahedral geometry, being bound to four adjacent ligands via monodentate Hg-S bonds and two remaining sites are occupied by two terminal chlorido ligands to form a fishnet-like 2D structure. When reacting with mercury(II) iodide, L afforded a 1D coordination polymer $\{[Hg_2(L)I_4]{\cdot}CHCl_3\}_n$ (3) in which each exocyclic Hg atom is four-coordinate, being bound to two sulfur donors from different ligands doubly bridging the ligand molecules in a head-to-tail mode. The coordination sphere in 3 is completed by two iodo terminal ligands, adopting a distorted tetrahedral geometry. On reacting with mercury(II) perchlorate, L forms solvent-coordinated 1D coordination polymer $\{[Hg_2(L)(DMF)_6](ClO_4)_4{\cdot}2DMF\}_n$ (4) instead of the anion-coordination. In 4, the Hg atom is five-coordinate, being bound to two sulfur donors from two different ligands doubly bridging the ligand molecules in a side-by-side mode to form a ribbon-like 1D structure. The three remaining coordination sites in 4 are completed by three DMF molecules in a monodentate manner. Consequently, the different structures and connectivity patterns for the observed exocyclic coordination polymers depending on the anions used are influenced not only by the coordination ability of the anions but also by anion sizes.