• Journal of Photoscience
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• v.12 no.2
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• pp.109-111
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• 2005

It was found that 1,4-diketones such as 1,4-diphenyl-l,4-butanediones containing N,N-dimethylaminophenyl (pDPB) and N,N-dimethylaminonaphthyl (nDPB) at C2 are converted into 3-(4-dimethylaminoaryl)-1-phenylpropan-lones (pPPA and nPPA) by treatment with $Ca(OH)_2$ in methanol, which was easily oxidized to enone, i.e., 3-(4-dimethylaminophenyl)-l-phenylpropenones (pPPE and nPPE), when treated with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) in dichloromethane.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.355-358
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• 1987

The reaction of t-butylithium with chlorodiphenylvinylsilane at low temperatures in hexane gave a 52% yield of the two isomeric 1,1,3,4-tetraphenyl-2,4-dineopenty-1,3-disilacyclo butanes mixture, formed by a head-to-tail dimerization of 1,1-diphenyl-2-neopentylsilene intermediate. In the presence of the trapping agents such as trimethylmethoxysilane and anthracene, the expected trapped adducts, 1-methoxy-l,l-diphenyl-2-trimethylsilyl-4,4-dimethyl-1-silapentane and 2,2-diphenyl-3-neopentyl-(5,6 : 7,8)-dibenzo-2-silabicyclo-(2.2.2)-octane, were obtained in 74% and 46% yields, respectively. These products were separated and their stereochemistry were assigned on the basis of $^1H$- and $^{13}C$-NMR data.

• Journal of Applied Biological Chemistry
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• v.55 no.4
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• pp.201-205
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• 2012

The present study was conducted to evaluate of the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) radical scavenging effect, cytotoxicity and tyrosinase inhibition activities using methanol extracts from different parts of four herb plants. The results showed that whole and root extracts of yarrow the highest total polyphenol and flavonoid contents as well as whole of yarrow revealed the highest DPPH radical scavenging effect. In cytotoxicity test against three cancer cell lines, HeLa (uterus), SK-Hep-1 (liver), and YD-15 (oral), the whole extract of feverfew showed the highest toxicity with $IC_{50}$ values of $102.58-138.68{\mu}g/mL$. Also, mallow root extract ($71.24{\mu}g/mL$) exhibited potent tyrosinase inhibitory activity comparable to arbutin ($69.56{\mu}g/mL$), which was used as the control.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.383-388
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• 2009

Rates of solvolyses of diphenyl thiophosphorochloridate ($(PhO)_2$PSCl, 1) in ethanol, methanol, and aqueous binary mixtures incorporating ethanol, methanol, acetone and 2,2,2-trifluoroethanol (TFE) are reported. For four representative solvents, studies were made at several temperatures and activation parameters were determined. The 30 solvents gave a reasonably precise extended Grunwald-Winstein plot, correlation coefficient (R) of 0.989. The sensitivity values (l = 1.29 and m = 0.64) of diphenyl thiophosphorochloridate ($(PhO)_2$PSCl, 1) were similar to those obtained for diphenyl phosphorochloridate ($(PhO)_2$POCl, 2), diphenylphosphinyl chloride ($Ph_2$POCl, 3) and diphenylthiophosphinyl chloride ($Ph_2$PSCl, 4). As with the previously studied of 3~4 solvolyses, an $S_N$ pathway is proposed for the solvolyses of diphenyl thiophosphorochloridate (1). The activation parameters, ${\Delta}H^{\neq}\;(=11.6{\sim}13.9\;kcal{\cdot}mol^{-1})\;and\;{\Delta}S^{\neq}\; (=\;-32.1\;{\sim}\;-42.7\;cal{\cdot}mol^{-1}{\cdot}K^{-1})$, were determined, and they were in line with values expected for an $S_N$2 reaction. The large kinetic solvent isotope effects (KSIE, 2.44 in MeOH/MeOD and 3.46 in $H_2O/D_2$O) are also well explained by the proposed $S_N$2 mechanism.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.16-19
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• 2002

In this study, a novel red emitting organic electroluminescent (EL) device was fabricated with the bis(8-oxyquinolino)zinc II (Znq2) doped dye as an emitting layer. The Znq2 was synthesized successfully from zinc chloride (ZnC1$_2$) as an initial material. Then, we fabricated the red organic EL device with a dye (DCJTB) doped and inserted Znq2 between emission layer and cathode for increasing EL efficiency. The hole transporting layer is a N,N'-diphenyl-N,N'-bis-(3-methylphenyl)-1,1'-diphenyl-4,4-diamine (TPD), and the host material of emission layer is Znq2. And the electrical and luminance characteristics of the device were measured. We found that the EL device with Znq2 inserting layer results in the increasing luminance efficiency.

• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.205-210
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• 1999

The Mo(V) $di-{\mu}-oxo$ type $[Mo_2O_4(H_2O)_2L]Cl_2$ complexes(L: 4,4'-Diphenyl-2,2'-dipyridyl, 4,4'-Dimethyl-2,2'-dipyridyl, 4,7-Diphenyl-1,10-phenanthroline) have been prepared by the reaction of $[Mo_2O_4(H_2O)_6]^{2+}$ with a series of chelate ligands. These complexes are completed by two terminal oxygens arranged trans to one another and each ligand forms a chelate types. In $Mo_2O_4(H_2O)_2L$ two $H_2O$ coordinated at trans site of terminal oxgens. The prepared complexes have been characterized by elemental analysis, infrared spectra, electronic spectra, $^1H$ nuclear magnetic resonance spectra, and thermal analysis(TG-DTA). In the potential range -0.00V to -1.00V at scan rate of $50mVs^{-1}$, a cathodic peak at -0.83V ${\sim}$ -0.88V (vs SCE) and an anodic peak at -0.54V ${\sim}$ -0.88V (vs SCE) have been observed in aquous solution. The ratio of the cathodic to anodic current(Ipc/Ipa) is almost 2, we infer that redox is irreversible as dimer forms broken.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.1-4
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• 2003

Two antioxidative compounds in Chrysanthemum boreale were isolated by a bioassay using a 2, 2-diphenyl-1-picrydrazyl(DPPH) free radical. They were identified as apigenin, linarin(acacetin-7-O-rutinoside) on the basis of $^1H\;and\;^{13}C-NMR$ and MS data. The DPPH radical scavenging activity$(RC_{50}:\;13.3{\mu}g)$ of apigenin was similar to that of ${\alpha}-tocopherol\;(12.1{\mu}g)$ and L-ascorbic acid$(13.1{\mu}g)$

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1103-1107
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• 2007

Highly efficient organic electroluminescent devices (OLEDs) based on 4,7- diphenyl-1, 10- phenanthroline (BPhen) as the electron transport layer (ETL), tris (8-hydroxyquinoline) aluminum ($Alq_3$) as the emission layer (EML) and N,$\acute{N}$-bis-[1-naphthy(-N,$\acute{N}$diphenyl-1,1´-biphenyl-4,4´-diamine)] (NPB) as the hole transport layer (HTL) were developed. The typical device structure was glass substrate/ ITO/ NPB/$Alq_3$/ BPhen/ LiF/ Al. Since BPhen possesses a considerable high electron mobility of $5\;{\times}\;10^{-4}\;cm^2\;V^{-1}\;s^{-1}$, devices with BPhen as ETL can realize an extremely high luminous efficiency. By optimizing the thickness of both HTL and ETL, we obtained a highly efficient OLED with a current efficiency of 6.80 cd/A and luminance of $1361\;cd/m^2$ at a current density of $20\;mA/cm^2$. This dramatic improvement in the current efficiency has been explained on the principle of charge balance.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1466-1468
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• 2001

For the full color organic electro-luminescent device, essentially, red, green, and blue emissions are required. But red emission is not to reach minimum level of practical use 31[lm/W]. In order to optimize color purity and power consumption requirements, it is important for the materials development efforts to search for improvements in red emission effisiency. In this study, the bis(8-oxyquinolino)zinc II ($Znq_2$) were synthesized successfully from zinc chloride($ZnCl_2$) as a initial material. Then, we fabricated red organic electroluminescent device with a dye(DCJTB)-doped and inserted $Znq_2$ between emission layer and cathode layer for increasing EL efficiency. The hole transfer layer is a N,N'-diphenyl-N,N'-bis-(3-methyl phenyl) -1,1'-diphenyl-4.4'-diamine(TPD), and the host material of emission layer is $Znq_2$. For the inserting of $Znq_2$, efficiency increased.

• Bulletin of the Korean Chemical Society
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• v.12 no.6
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• pp.686-691
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• 1991

Emission quenching of photoexcited tris(${\alpha},{\alpha} '$-diimine)-ruthenium(II) complex cations, $RuL_3^{2+}$ (L: 2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine; 4,4'-diphenyl-2,2'-bipyridine; 1,10-phenanthroline; 5-methyl-1,10-phenanthroline; 5,6-dimethyl-1,10-phenanthroline or 4,7-diphenyl-1,10-phenanthroline) by $Cu^{2+}$, dimethylviologen $(MV^{2+})$, nitrobenzene (NB), and oxygen was studied in aqueous homogeneous and sodium dodecyl sulfate (SDS) micellar solutions. The apparent bimolecular quenching rate constants $k_q$ were determined from the quenching data and life-times of $^{\ast}RuL_3^{2+}$. In homogeneous media, the quenching rate was considerably slower than that for the diffusion-controlled reaction. The decreasing order of quenching activity of quenchers was $NB>O_2>MV^{2+}>Cu^{2+}$. The rate with $Cu^{2+}$ was faster as the reducing power of $^{\ast}RuL_3^{2+}$ is greater. On the other hand, the rates with NB and $O_2$ were faster as the ligand is more hydrophobic. This was attributed to the stabilization of encounter pair by van der Waals force. The presence of SDS enhanced the rate of quenching reactions with $Cu^{2+}$ and $MV^{2+}$, whereas it attenuated the quenching activity of NB and $O_2$ toward $RuL_3^{2+}$. The binding affinity of quenchers to SDS micelle and binding sites of the quenchers and $RuL_3^{2+}$ in micelle appear to be important factors controlling the micellar effect on the quenching reactions.