• Bulletin of the Korean Chemical Society
• /
• v.32 no.5
• /
• pp.1669-1678
• /
• 2011

Six new binuclear copper(II) complexes have been prepared by template condensation of the dialdehydes 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-l,4,8,11-tetraazacyclotetradecane (PC-a) and 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclotetradecane (PC-b) with appropriate aliphatic diamines, and copper(II) perchlorate. The structural features of the complexes have been confirmed by elemental analysis, IR, UV-vis and mass spectra etc. The electrochemical behavior of all the copper(II) complexes show two irreversible one electron reduction process. The room temperature magnetic moment studies depict the presence of an antiferromagnetic interaction in the binuclear complexes. The catechol oxidation and hydrolysis of 4-nitrophenylphosphate were carried out by using the complexes as catalyst. The antimicrobial screening data show good results. The binding of the complexes to calf thymus DNA (CT DNA) has been investigated with absorption and emission spectroscopy. The complex [$Cu_2L^{1a}$] displays significant cleavage property of circular plasmid pBR322 DNA in to linear form. Spectral, electrochemical, magnetic and catalytic studies support the distortion of the copper ion geometry that arises as the macrocyclic ring size increases.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.9
• /
• pp.2609-2615
• /
• 2013

A series of fluorene-carbazole copolymers containing the pendant phosphor chromophore $Ir(absn)_2(acac)$ (absn: 2-(1-naphthyl)benzothiazole; acac: acetylacetone) were designed and synthesized via Yamamoto coupling. In the film state, these copolymers exhibited absorption and emission peaks at approximately 389 and 426 nm, respectively, which originated from the fluorene backbone. However, in electroluminescent (EL) devices, a significantly red-shifted emission at approximately 611 nm was observed, which was attributed to the pendant iridium(III) complex. Using these copolymers as a single emission layer, polymer light-emitting devices with ITO/PEDOT:PSS/polymer:DNTPD/TmPyPb/LiF/Al configurations exhibited a saturated red emission at 611 nm. The attached iridium(III) complex had a significant effect on the EL performance. A maximum luminous efficiency of 0.85 cd/A, maximum external quantum efficiency of 0.77, maximum power efficiency of 0.48 lm/W, and maximum luminance of 883 $cd/m^2$ were achieved from a device fabricated with the copolymer containing the iridium(III) complex in a 2% molar ratio.

• Corrosion Science and Technology
• /
• v.12 no.2
• /
• pp.65-78
• /
• 2013

The present investigation deals with the corrosion inhibition of mild steel in 1M $H_2SO_4$ with 1, 4-dihydro pyridine and its derivatives prepared using microwave activation method. The synthesis of inhibitor was confirmed by IR spectra. The effect of 1, 4-dihydropyridine derivatives on the corrosion inhibition of mild steel in 1M $H_2SO_4$ was studied using weight loss and electrochemical polarization techniques. Influence of temperature (303-333K) and synergistic effect of halide ions ($I^-$, $Br^-$ and $Cl^-$) on the inhibition behaviour was also studied. Corrosion products on the metal surface were analyzed by scanning electron microscopy (SEM) and a possible mechanism of inhibition by the compounds is suggested. Thermodynamic parameters were calculated using weight loss data in order to elaborate the mechanism of corrosion inhibition. Polarization measurements revealed that the studied compounds acted as mixed type inhibitor but slightly anodic in nature. Electrochemical impedance measurements revealed that the compounds were adsorbed onto the carbon steel surface and the adsorption obeyed the Langmuir adsorption isotherm. The synergistic effect of halide ions on the IE increases with increase in concentration. The IE obtained from atomic absorption spectrophotometric studies was found to be in good agreement with that obtained from the conventional weight loss method. SEM revealed the information of a smooth, dense protective layer in presence of the inhibitors.

• Journal of dental hygiene science
• /
• v.8 no.3
• /
• pp.109-115
• /
• 2008

Two t-amines, N,N-dimethylaniline (MA), N,N-dimethyl-p-toluidine (MPT), were investigated as new visible light amine initiators for a dental resin composite of UDMA in order to improve photopolymerization effect. Three t-amines mixed with three photosensitizers, camphorquinone(CQ), 1-phenyl-1,2-propane dione(PD) and diacetyl (DA), respectively. And then this mixtures are added to resin monomer, UDMA. Photopolymerization efficiency of UDMA was studied through the use of FT-IR absorption spectroscopy. The photopolymerization effect of amine initiators were compared with that of 4-(dimethylamino)ethyl methacrylate (AEM), the most widely used photoinitiator. The photopolymerization efficiency of UDMA containing the amine initiator increased with irradiation time. The relative polymerization efficiency containing the CQ photosensitizer increase was in the order: AEM < MPT < MA. And the relative polymerization efficiency containing the PD photosensitizer increase was in the order: MPT < AEM < MA. This result shows that MA is most efficient amine initiator with CQ and PD.

• Journal of the Korean Chemical Society
• /
• v.61 no.4
• /
• pp.191-196
• /
• 2017

One-phase method to prevent the initial formation of Ag(I) thiolate layered materal from the mixture of $AgNO_3$ and thiols was previously developed to generate TP (Thiolate-Protected)-nanosilver. In this modified method, $AgNO_3$ is added to the mixtures of $NaBH_4$ and thiols in ethanol. This method was so successful that it was applied to synthesize TP-nanogold and nanoplatinum. The synthesis and characterization of these nanoparticles by ultraviolet-visible (UV-vis) absorption spectra, transmission electron microscopy (TEM) pictures, X-ray powder differaction (XRD) patterns and infrared(IR) spectra are described. The results show that colloidal nanoparticles are spherical or oval shape and the mean sizes for TP-nanogold and nanoplatinum are about 3~7 nm and below 2 nm, respectively. The conformation of polymethylene [$-(CH_2)_7-$] sequence in octanethiolate attached to nanogold was elucidated as trans.

• Journal of the Korean Ceramic Society
• /
• v.45 no.8
• /
• pp.459-463
• /
• 2008

$P_2O_5-SnO_2$ system $0.5SnO_2-xP_2O_5-(0.5-x)B_2O_3$(x=0.1, 0.2, 0.3, 0.4, 0.5) glasses have been prepared for Pb-free low temperature glass frit. A investigation about the effect of $B_2O_3$ substitution on properties of $P_2O_5$ glasses, including glass structure properties, thermal properties, and mechanical properties was presented. Substance that is responsible for in moisture absorption existing circumstances supposes by phosphate, and excess moisture tolerance that state funeral's structure is improved breaking does not affect in state funeral bond that only most single bond remains, and can know that does not suffer big impact in boric oxide anomaly present state. This phenomenon estimates that connect with structure change. It is thought according to link this result the phosphoric acid happened structural change. $B_2O_3$ displacement quantity 0.3 mole put out $BO_4$ structures, but above 0.3 mole it changed with the case $BO_3$ structure which it displaces.

• Particle and aerosol research
• /
• v.7 no.3
• /
• pp.79-85
• /
• 2011

Porous $TiO_2-SiO_2$ particles were synthesized by co-assembly of nanoparticles of $TiO_2$ and $SiO_2$ in evaporating aerosol droplets. Poly styrene latex (PSL) particles were employed as a template of porous particles. Flowrate of dispersion gas, weight ratio of $TiO_2/SiO_2$ and $SiO_2$ concentration in the precursor, and PSL size were chosen as process variables. The morphology, crystal structure, chemical bonding, and pore size distribution were analyzed by FE-SEM, XRD, FT-IR, BET. The morphology of porous $TiO_2-SiO_2$ particles was spherical and the average particle size range were from 1 to $10{\mu}m$. The particles were composed of meso and macro pores. The average particle diameter and pore volume of the as prepared particles were dependant on process variables. It was found that UV-Vis absorption of the porous particles was comparable with pure $TiO_2$ nanoparticles even though $TiO_2/SiO_2$ ratio is low in the porous particles.

• Textile Coloration and Finishing
• /
• v.22 no.2
• /
• pp.132-139
• /
• 2010

Sericin pulverization process was applied by freezing-thawing of sericin protein concentration solution and physicochemical properties of sericin/chitosan blended films were investigated. In sericin pulverization process by freezing-thawing method, the refrigeration storage at $4^{\circ}C$ maximized gelling between sericin molecules, which increased 10% of recovery ratio from sericin concentration solution that using ultrafiltration procedure. In physicochemical properties of sericin/chitosan blended films, the maximum load of chitosan (6.7kgf) had higher than that of sericin (1.2kgf), and the elongation of sericin and chitosan had 96% and 34%, respectively. Also FT-IR analysis of sericin/chitosan blended films showed that both sericin and chitosan films had amide I peak (N-H bond) in $1,521cm^{-1}$ and amide II peak (C=O bond) in $1,630cm^{-1}$. In addition, it could confirm compatibility between both materials as indicated by the decrease in the amide I peak's absorption value as chitosan content increases.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.1
• /
• pp.64-73
• /
• 2010

This study was conducted to modify the surface properties of papers by formation of hydrophobic self-assembled monolayer(SAM) on paper surface with silanes. A base paper I(0.5% AKD) and base paper II(1.0-1.5% AKD) were reacted with silanes(PFDTES, DMDCS, MODDCS) by immersion method and vapor deposition method. Hydrophobic SAMs(contact angle value>$120^{\circ}C$) were obtained on all papers after treatment with $10^{\mu}l$ PFDTES for 15min, with $50^{\mu}l$ DMDCS for 30min, with $50^{\mu}l$ MODDCS for 300min. When applying PFDTES to paper surface, lower silane concentration and shorter reaction time were required, whereas MODDCS with long alkyl chain required the longest reaction time of 300min. The st$\ddot{o}$ckight sizing degree of silane treated papers were increased between 105sec(base paper I) and 130sec(base paper II). The wet tensile strength of PFDTES-treated base papers(I, II) increased by 10-34% after SAM formation. However, the wet tensile strength of the DMDCS-treated base paper(I) was found to decrease from 0.067kN/m to 0.038kN/m; this may due to the cellulose degrading as a result of generated hydrogen chloride when hydroxyl group of cellulose were reacted with DMDCS. No apparent changes of PPS roughness on silane-treated papers are observed. The ATR-IR spectrum showed absorption peak located at 465 and 1200cm-1 which can be assigned to the Si-O-C asymmetric stretching and Si-O-C bonds, respectively.

• Microbiology and Biotechnology Letters
• /
• v.9 no.2
• /
• pp.51-57
• /
• 1981

1,2-propanediol-utilizing yeast, Y-1-4, was isolated from sludge sample by the enrichment culture technique. The product produced from 1,2-propanediol by the selected strain was identified as lactic acid by paper chromatography and infrared absorption spectrum. The strain assimilated ethanol, 1,2-propanediol, glycerine and glucose, but it produced lactic acid from 1,2-propanediol used as the sole carbon source. Under optimal conditions, the strain Y-1-4 was cultured with shaking at 3$0^{\circ}C$ for 4days in the medium containing 1,2-propanediol 20.0g, NH$_4$Cl 5.0g, KH$_2$PO$_4$ 1.0g, MgSO$_4$.7$H_2O$ 0.5g, FeSO$_4$.7$H_2O$ 0.25g, yeast extract 0.4g, CaCO$_3$ 3. 0g and tap water to one liter, and then the yield of lactic acid was about 12. 1g per liter of the culture broth.