• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.1033-1037
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• 2008

A copper cyclam-type complex was successfully immobilized onto mesoporous silica SBA-16. Characterization by NIR spectroscopy and TGA analysis confirmed that copper cyclam complex is immobilized onto mesoporous SBA-16. The Cu(II)-Cyclam-SBA-16 was proven to be a good catalyst for oxidation reaction of cyclohexene with conversion up to 77.8% after 13 h reaction and providing a high selectivity to cyclohexenol and 3-hydroperoxycyclohex-1-ene. The results suggest that the copper species play a major role as catalyst via reversible redox cycles as proven by cyclic voltammetry analysis.

• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.715-720
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• 2014

A Cu(II) complex with an three nitrogens and one sulfur coordination environment was synthesized and characterized. Its redox potential was observed at 0.483 V vs. NHE, very similar to that of a Cu-containing fungal enzyme, galactose oxidase, which catalyzes the oxidation of alcohols to corresponding aldehydes with the concomitant reduction of molecular oxygen to water. The Cu(II) complex selectively oxidizes the benzylic alcohols using TEMPO/$O_2$ under mild reaction conditions to corresponding aldehydes without forming any over-oxidation product. Moreover, the catalyst can be recovered and reused multiple times for further oxidation reactions, thus minimizing the waste generation.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.221-222
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• 2005

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

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.176.1-176.1
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• 2014

Graphene has attracted an increasing attention due to its extraordinary electronic, mechanical, and thermal properties. Especially, the two dimensional (2D) sheet of graphene with an extremely high surface to volume ratio has a great potential in the preparation of multifunctional nanomaterials, as 2D supports to host metal nanoparticles (NPs). Copper oxide is widely used in various areas as antifouling paint, p-type semiconductor, dry cell batteries, and catalysts. Although the copper oxide(II) has been well known for efficient catalyst in C-N cross-coupling reaction, copper oxide(I) has not been highlighted. In this research, CuO and Cu2O nanoparticles (NPs) dispersed on the surface of grapehene oxide (GO) have been synthesized by impregnation method and their morphological and electronic structures have been systemically investigated using TEM, XRD, and XAFS. We demonstrate that both CuO and Cu2O on graphene presents efficient catalytic performance toward C-N cross coupling reaction. The detailed structural difference between CuO and Cu2O NPs and their effect on catalytic performance are discussed.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.394-399
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• 2015

In this study, the Cu catalyst decorated with activated carbon fibers were prepared for improving $SO_2$ adsorption properties. Flame retardant and heat treatments of Lyocell fibers were carried out to obtain carbon fibers with high yield. The prepared carbon fibers were activated by KOH solution for the high specific surface area and controlled pore size to improve $SO_2$ adsorption properties. Copper nitrate was also used to introduce the Cu catalyst on the activated carbon fibers (ACFs), which can induce various reactions in the process; i) copper nitrate promotes the decomposition reaction of oxygen group on the carbon fiber and ii) oxygen radical is generated by the decomposition of copper oxide and nitrates to promote the activation reaction of carbon fibers. As a result, the micro and meso pores were formed and Cu catalysts evenly distributed on ACFs. By Cu-impregnation process, both the specific surface area and micropore volume of carbon fibers increased over 10% compared to those of ACFs only. Also, this resulted in an increase in $SO_2$ adsorption capacity over 149% than that of using the raw ACF. The improvement in $SO_2$ adsorption properties may be originated from the synergy effect of two properties; (i) the physical adsorption from micro, meso and specific surface area due to the transition metal catalyst effect appeared during Cu-impregnation process and ii) the chemical adsorption of $SO_2$ gas promoted by the Cu catalyst on ACFs.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.425-430
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• 2016

p-Phenylenediamine (PPD) was synthesized by aromatic amination of p-diiodobenzene (PDIB) using liquid ammonia and Cu-catalysts. The effects of the catalyst, reductant, ammonia quantity and reaction temperature on PPD production were investigated. Cu(I) compounds and Cu powder were selected as catalyst due to a higher selectivity than Cu(II) compounds. As the catalyst quantity increased, rate of PPD production as well as side reaction of aniline decreased with increasing the quantity of ammonia. Reductants such as ascorbic acid, hydrazine and dihydroxyfumaric acid were tested to lower the catalyst loading. The use of reductants resulted in increasing the reaction rate but also increased the amount of aniline The rate of reaction using ascorbic acid or dihydroxyfumaric acid was faster than that using hydrazine. The lowest side reaction of aniline was found in dihydroxyfumaric acid of reductants investigated.

• Macromolecular Research
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• v.17 no.4
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• pp.240-244
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• 2009

High molecular weight(MW), 3-arm star poly(methyl methacrylate)(PMMA) with a narrow MW distribution($M_n$=570,000 g/mol, PDI=1.36) was successfully synthesized by activators regenerated by electron transfer(ARGET) atom transfer radical polymerization(ATRP). The polymerization was carried out with a trifunctional initiator/$CuBr_2$/N,N,N',N",N"-pentamethyldiethy lenetriamine(PMDETA) initiator/catalyst system in the presence of a tin(II) 2-ethylhexanoate [$Sn(EH)_2$] reducing agent at $90^{\circ}C$. The concentration of the copper catalyst was as low as 30 ppm, and a high initiation efficiency of the initiating sites was obtained. The chain-end functionality of the high MW, 3-arm star PMMA was confirmed by a chain extension experiment with styrene via ARGET ATRP, using the same catalyst system.

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.357-360
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• 2013

Sustainable development is a balance between environment and development. Sustainable development requires sustainable supplies of clean, affordable, and renewable energy sources that do not cause negative impact to the society. This article introduces a green chemistry method to synthesize 2-amino-4H-chromenes that reduces or eliminates the use and generation of hazardous substances in the design, manufacture, and application of chemical products. This method is described using copper (II) sulfate pentahydrate, as a green and reusable catalyst on water. The products were obtained at very good yields, short reaction time, and at lower cost than other reported procedures.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.639-644
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• 2011

A simple and highly sensitive chemiluminescence method to determine norfloxacin (NFLX) has been proposed by measuring the chemiluminescence (CL) intensities using a flow injection (FI) system. The CL intensity of the luminol-$H_2O_2$ system is strongly enhanced by the addition of Cu (II) in alkaline condition. The CL intensity is substantially increased after the injection of NFLX into the luminol-$H_2O_2$-Cu (II) system. The enhancement effect is attributed to a catalytic effect of Cu (II) due to the interaction with NFLX which forms a complex with the catalyst. Under the optimal conditions, the sensitizing effect of the CL intensity is proportional to the concentration of NFLX in the range of $1.5{\times}10^{-9}-5.9{\times}10^{-7}molL^{-1}$ (r = 0.9994) with a detection limit ($3{\sigma}$) of $2.98{\times}10^{-10}molL^{-1}$. The proposed method had good reproducibility with the relative standard deviation (RSD, n = 5) of 1.6% for $1{\times}10^{-7}molL^{-1}$ of NFLX. The possible reaction mechanism of the CL reaction is also discussed. This method has been successfully applied for the determination of trace amount of NFLX in pharmaceutical preparations and serum samples.