• BMB Reports
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• v.34 no.6
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• pp.551-558
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• 2001

We extended the measurable time scale of DNA dynamics to submicrosecond using a long-lifetime metal-ligand complex, $[Ru(phen)_2(dppz)]^{2+}$ (phen=1,10-phenanthroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) (RuPD), which displays a mean lifetime near 350 ns. We partially characterized the fluorescence resonance energy transfer (FRET) in calf thymus DNA from RuPD to nile blue (NB) using frequency-domain fluorometry with a high-intensity, blue light-emitting diode (LED) as the modulated light source. There was a significant overlap of the emission spectrum of the donor RuPD with the absorption spectrum of the acceptor NB. The F$\ddot{o}$rster distance ($R_0$) that was calculated from the spectral overlap was $33.4\;{\AA}$. We observed dramatic decreases in the steady-state fluorescence intensities of RuPD when the NB concentration was increased. The intensity decays of RuPD were matched the closest by a triple exponential decay. The mean decay time of RuPD in the absence of the acceptor NB was 350.7 ns. In a concentration-dependent manner, RuPD showed rapid intensity decay times upon adding NB. The mean decay time decreased to 184.6 ns at $100\;{\mu}M$ NB. The FRET efficiency values that are calculated from the mean decay times increased from 0.107 at $20\;{\mu}M$ NB to 0.474 at $100\;{\mu}M$ NB concentration. The use of FRET with a long-lifetime metal-ligand complex donor is expected to offer the opportunity to increase the information about the structure and dynamics of nucleic acids.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1648-1650
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• 2006

The synthesis of a new C,N-bipyrazolic ligand with a functionalized donor-group is reported. The binding properties of the ligand and two other ligand of similar structures towards heavy metal ions ($Hg^{2+}$, $Cd^{2+}$, $Pb^{2+}$, $Zn^{2+}$, $Cu^{2+}$) and alkaline metal ions ($K^+$, $Na^{+}$, $Li^+$) were studied by a liquid-liquid extraction process and the extracted cation percentage was determined by atomic absorption measurements. The selectivity of the ligand to Hg(II) has been mentioned in the abstract.

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1311-1316
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• 2007

To develop photo-sensitizers for dye-sensitized solar cells (DSCs) used in harvesting sunlight and transferring solar energy into electricity, we synthesize novel Ru(II) polypyridyl dyes and describe their characterization. We also investigate the photo-electrochemical properties of DSCs using these sensitizers. New dyes contain chromophore unit of dafo (4,5-diazafluoren-9-one) or phen-dione (1,10-phenanthroline-5,6-dione) instead of the nonchromophoric donor unit of thiocyanato ligand in cis-[RuII(dcbpy)2(NCS)2] (dcbpy = 4,4'-dicarboxy- 2,2'-bipyridine) coded as N3 dye. For example, the photovoltaic data of DSCs using [RuII(dcbpy)2(dafo)](CN)2 as a sensitizer show 6.85 mA/cm2, 0.70 V, 0.58 and 2.82% in short-circuit current (Jsc ), open-circuit voltage (Voc), fill factor (FF) and power conversion efficiency (Eff), which can be compared with those of 7.90 mA/ cm2, 0.70 V, 0.53 and 3.03% for N3 dye. With the same chelating ligand directly bonded to the Ru metal in the complex, the CN ligand increases the Jsc value by double, compared to the SCN ligand. The extra binding ability in these new dyes makes them more resistant against ligand loss and photo-induced isomerization within octahedral geometry.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.145-150
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• 1994

The low temperature luminescence and excitation, room-temperature UV-visible and infrared spectra of [Cr(${\pm})chxn_3]Cl_3$ (chxn=trans-1,2-cyclohexanediamine) have been measured. It is found that the zero-phonon line in the excitation spectrum splits into two components by $47\;cm^{-1}$. The eight electronic transitions due to spin-allowed and spin-forbidden are assigned. As expected, nitrogen atoms of chxn ligand have strong ${\sigma}-donor $properties toward chromium(Ⅲ). The positions and splittings of sharp-line transitions are analyzed as a function of the Cartesian bite (${\alpha}$) and twist (${\beta}$) angles to predict the metal-ligand geometry.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1475-1478
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• 1999

Ligand field calculations have been performed based on the data from the absorption and low temperature sharp-line excitation spectra of fac-Cr(gly)₃, fac-Cr(L-serine)₃ · 2H₂O and fac-Cr(L-leucine)₃·2H₂O. The optimized ligand field parameters for all complexes show that the carboxylate and the amino groups are moderate σ-donor. The values of $e_{{\pi}O}$ are typical of other complexes with carboxylate ligands. However, the π-interaction of carboxylic oxygen to the chromium in serinato complex is much weaker than that of other complexes. The inclusion of π-anisotropy is necessary to adequately explain the large doublet splittings.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.436-441
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• 2001

The emission and excitation spectra of mer-[Cr(dien)(glygly)]ClO$_4$(glygly=glycylglycinate;dien=N-(2-aminoethyl)-1,2-ethanediamine) taken at 77 K are reported. The infrared and visible spectra at 298 K are also measured. The twelve electronic bands due to spin-allowed and spin-forbidden transitions are assigned. Using the observed transitions, a ligand field analysis has been performed to determine the bonding property of coordinated atoms in the chromium(III) complex. It is confirmed that the amine nitrogen atoms of the dien and glygly have strong $\sigma$-donor characters, but the peptide nitrogen of glygly has weak $\pi$-donor property toward chromium(III) ion.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3233-3238
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• 2013

Two new Cu(II) complexes, $[Cu_2(acpy-mdtc)_2(HBA)(ClO_4)]{\cdot}H_2O$ (1) (acpy-mdtc- = 2-acetylpyridine S-methyldithiocarbamate and $HBA^-$ = benzilic acid anion) and $[Cu_2(acpy-phtsc)_2(HBA)]{\cdot}ClO_4$ (2) (acpy-$phtsc^-$ = 2-acetylpyridine 4-phenyl-3-thiosemicarbazate) 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 copper(II) complexes bridged by two thiolate sulfur atoms of Schiff base ligand and bidentate bridging $HBA^-$ anion. For 1, each of the two copper atoms has different coordination environments. Cu1 adopts a five-coordinate square-pyramidal with a $N_2OS_2$ donor, while Cu2 exhibits a distorted octahedral geometry in a $N_2O_2S_2$ manner. For 2, two Cu(II) ions all have a five-coordinate square-pyramidal with a $N_2OS_2$ donor. In each complex, the Schiff base ligand is coordinated to copper ions as a tridentate thiol mode.

• Bulletin of the Korean Chemical Society
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• v.26 no.8
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• pp.1293-1296
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• 2005

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.23-26
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• 2010

A Schiff base ligand (Z)-N-((Z)-2-(sec-butylimino)-1,2-diphenylethylidene)butan-2-amine was synthesized by condensation of benzil with sec-butyl amine. Complexation of the ligand was carried out with first row transition elements, manganese(II) and nickel(II). Ligand and complexes were characterized by FTIR, elemental analysis and thermogravimetric analysis in solid state and by NMR ($^1H,\;^{13}C$) in solution form. Both the complexes demonstrate good catalytic activity for butadiene oligomerization under mild conditions with methylaluminoxane (MAO) as co-catalyst.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1801-1806
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• 2004

Ligand-based quantitative structure-activity relationship (QSAR) studies were performed on indolinones derivatives as a potential inhibitor of the protein tyrosine kinase of fibroblast growth factor receptor (FGFR) by comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) implemented in the SYBYL packages. The initial X-ray structure of docked ligand (Su5402) to FGFR was used to minimize the 27 training set molecules using TRIPOS force field. Seven models were generated using CoMFA and CoMSIA with grid spacing 2 ${\AA}$. After the PLS analysis the best predicted CoMSIA model with hydrophobicity, hydrogen bond donor and acceptor property showed that a leave-one out(LOO) cross validated value $({r^2}_{cv})^$ and non-cross validated conventional value $({r^2}_{ncv})^$ are 0.543 and 0.938, respectively.