pISSN : 0253-2964 / eISSN : 1229-5949
About BKCS
A Message from our Editor-in-Chief
Papers since 2015 are available from Wiley.
(Bulletin of the Korean Chemical Society: List of Issues - Wiley Online Library)
The Bulletin of the Korean Chemical Society (BKCS) is a monthly journal and publishes communications, articles, accounts and reviews in all fields of chemistry, including analytical, electro-, industrial, inorganic, life-science, macromolecular, organic, physical and materials chemistry. The BKCS is published on behalf of the Korean Chemical Society (KCS).
A Message from our Editor-in-Chief
Prof. Wonwoo Nam is the Editor-in-Chief of the flagship journal of the Korean Chemical Society, which provides the opportunity to share new findings in all chemical sciences.
Our BKCS editorial teams also continue our publishing services. Thus, if you have any concerns about the publishing process, please contact the corresponding editorial office without hesitation.
Papers since 2015 are available from Wiley.
(Bulletin of the Korean Chemical Society: List of Issues - Wiley Online Library)
Latest Publication (Vol. 35, No. 12, Dec. 2014)
Fabrication of Mesoporous Hollow TiO2 Microcapsules for Application as a DNA Separator
Sang Gweon Jeon Jin Young Yang Keun Woo Park Geon-Joong Kim
This study evaluated a simple and useful route to the synthesis of mesoporous TiO2 microcapsules with a hollow macro-core structure. A hydrophilic precursor sol containing the surfactants in the hydrophobic solvents was deposited on PMMA polymer surfaces modified by non-thermal plasma to produce mesoporous shells after calcination. The surface of the PMMA polymer spheres was coated with NH4F and CTAB to control the interfacial properties and promote the subsequent deposition of inorganic sols. These hollow type mesoporous TiO2 microcapsules could be applied as an efficient substrate for the immobilization of DNA oligonucleotides.
Heteroleptic Phosphorescent Iridium(III) Compound with Blue Emission for Potential Application to Organic Light–Emitting Diodes
Sihyun Oh Narae Jung Jongwon Lee Jinho Kim Ki-Min Park Youngjin Kang
Blue phosphorescent (dfpypy)2Ir(mppy), where dfpypy = 2',6'-difluoro-2,3'-bipyridine and mppy = 5-methyl- 2-phenylpyridine, has been synthesized by newly developed effective method and its solid state structure and photoluminescent properties are investigated. The glass-transition and decomposition temperature of the compound appear at 160 oC and 360 oC, respectively. In a crystal packing structure, there are two kinds of intermolecular interactions such as hydrogen bonding (C-HF) and edge-to-face C-Hπ(py) interaction. This compound emits bright blue phosphorescence with λmax = 472 nm and quantum efficiencies of 0.23 and 0.32 in fluid and the solid state. The emission band of the compound is red-shifted by 40 nm relative to homoleptic congener, Ir(dfpypy)3. The ancillary ligand in (dfpypy)2Ir(mppy) has been found to significantly destabilize HOMO energy, compared to Ir(dfpypy)3, (dfpypy)2Ir(acac) and (dfpypy)2Ir(dpm), without significantly changing LUMO energy.
Investigation of Gold and Silver Nanoparticles as Acid–base pH Indicators and Their Transition pH Ranges
Byoung Gue Jung Jihee Jo Jin Won Yu Jong Kuk Lim
Monitoring of pH, especially under highly alkaline conditions, is necessary in various processes in the industrial, biotechnological, agricultural, and environmental fields. However, few pH indicators that can function at highly alkaline levels are available, and most of which are organic-based pH indicators. Several years ago, it was reported that gold nanoparticles prepared using trisodium citrate dihydrate were rapidly aggregated at pH values higher than ~12.7. A shift of surface plasmon resonance for such aggregated gold nanoparticles can be applied to pH indicators, allowing for the substitution of traditional organic-based pH indicators. The most important characteristic of pH indicators is the transition pH range. Herein, gold and silver nanoparticles are prepared using different reducing agents, and their transition pH ranges are examined. The results showed that all nanoparticles prepared in this study exhibit similar transition pH ranges spanning 11.9– 13.0, regardless of the nanoparticle material, reducing agents, and concentration.
RGB Light Emissions from ZnSe Based Nanocrystals: ZnSe, ZnSe:Cu, and ZnSe:Mn
Byungkwan Song Jeongho Heo Cheong-Soo Hwang
RGB light emitting ZnSe based nanocrystals: ZnSe (blue), ZnSe:Cu (green) and ZnSe:Mn (red) were synthesized by capping the surface of the nanocrystals with oleic acid. The obtained nanocrystal powders were characterized by using XRD, HR-TEM, ICP-AES, FT-IR, and FT-Raman spectroscopies. The optical properties were also measured by UV/Vis and photoluminescence (PL) spectroscopies. The PL spectra showed broad emission peaks at 471 nm (ZnSe), 530 nm (ZnSe:Cu) and 665 nm (ZnSe:Mn), with relative PL efficiencies in the range of 0.7% to 5.1% compared to a reference organic dye standard. The measured average particle sizes from the HR-TEM images for those three nanocrystals were 4.5 nm on average, which were also supported well by the Debye-Scherrer calculations. The elemental compositions of the ZnSe based nanocrystals were determined by ICP-AES analyses. Finally, the drawn CIE diagram showed the color coordinates of (0.15, 0.16) for ZnSe, (0.22, 0.57) for ZnSe:Cu, and (0.62, 0.35) for ZnSe:Mn respectively, which were fairly well matched to that of the RGB color standards.
Microwave Assisted Synthesis of 1,3,4-Oxadiazole/Thiohydantoin Hybrid Derivatives via Dehydrative Cycliztion of Semicarbazide
Seung-Ju Yang Jae-Min Lee Gee-Hyung Lee NaYeon Kim Yong-Sang Kim Young-Dae Gong
A series of compounds containing both 1,3,4-oxadiazole and thiohydantoin were synthesized as a promising scaffold for application in medicinal chemistry. The key step of the synthesis is a microwave-assisted cyclization of semicarbazides possessing a thiohydantoin moiety at one of the acyl termini using POCl3 as a dehydrating reagent. A wide range of semicarbazides were prepared through the substitution of hydrazides with an N-acylated thiohydantoin derived from the cyclization of the corresponding isothiocyanate with an amino acid and subsequent N-acylation of the resultant thiohydrantion. Consequently, the 58 number of 1,3,4- oxadiazole derivatives having a thiohydantoin substituent were prepared in good overall yields.
Expeditious Synthesis of Natural Benzofuran, Eupomatenoid-6 by Umpolung of α-Aminophosphonates
Kongara Damodar Jong-Gab Jun
Simple and practical synthesis of natural benzofuran derivative eupomatenoid-6 via Horner-Emmons type condensation as the key step is described. The umpolung property of aldehyde derivative, α-aminophosphonate was efficiently employed in this reaction. α-Aminophosphonate of anisaldehyde subjected to Horner-Emmons type condensation with 5-bromo-2-methoxybenzaldehyde to yield the deoxybenzoin, which was further methylated and then underwent tandem demethylation-cyclodehydration to afford the benzofuran scaffold in excellent yield. Finally Suzuki coupling with propenyl boronic acid afforded eupomatenoid-6 with an overall yield of 56.8%.
Synthesis and Biological Evaluation of Novel IM3829 (4-(2-Cyclohexylethoxy)aniline) Derivatives as Potent Radiosensitizers
Jiyeon Ahn Ky-Youb Nam Sae-lo-oom Lee Hwani Ryu Hyun Kyung Choi Jie-Young Song
Nuclear factor-erythroid 2-related factor 2 (Nrf2) regulates the expression of over 200 genes of antioxidant and phase II drug-metabolizing enzymes, and is highly expressed in non-small cell lung cancer (NSCLC). Nine derivatives of 4-(2-cyclohexylethoxy)aniline were designed. Our previous study demonstrated that IM3829 increases radiosensitivity of several lung cancer cells in vitro and in vivo. Here, biological effects of IM3829 derivatives (2a-2i) were evaluated. Compound 2g derivative effectively inhibits mRNA and protein expression of Nrf2 and HO-1. In addition, we observed over two fold enhancement in IR-induced cell death, from 2.90 ± 0.22 to 6.02 ± 0.87, in H1299 cancer cell-line. Among the nine derivatives, compound 2g derivative exhibited the highest enhancement of radiosensitizing effect via inhibition of Nrf2 activity.
Effective α-Helix Stabilization via Hexenyl Propionate Cross-Link
Jiyeon Yoo Young-Woo Kim
In this study we examined two ester-containing cross-links, hex-2-enyl acetate and hex-2-enyl propionate, as new cross-linking systems for helix stabilization of short peptides. We demonstrated that these hexenyl ester cross-links can be readily installed via a ruthenium-mediated ring-closing metathesis reaction of L-aspartic acid 4-allyl ester or L-glutamic acid 5-allyl ester at position i and (S)-2-(4'-pentenyl)alanine at position i+4 using second generation Hoveyda-Grubbs catalyst at 60 oC. Between these two cross-links, we found that the hex-2- enyl propionate significantly stabilizes the α-helical conformations of short model peptides. The helixstabilizing effects of the hex-2-enyl propionate tether appear to be as powerful as Verdine’s i,i+4 allhydrocarbon stapling system, which is one of the most widely used and the most potent helix-stabilizing crosslinking systems. Furthermore, the hex-2-enyl propionate bridge is reasonably robust against non-enzymatic hydrolytic cleavage at a physiological pH. While extended studies for probing its chemical scopes and biological applications are needed, we believe that this new helix-stabilizing system could serve as a useful chemical tool for understanding protein folding and designing conformationally-constrained peptide drugs.
De Novo Design and Their Antimicrobial Activity of Stapled Amphipathic Helices of Heptapeptides
Thuy T. T. Dinh Do-Hee Kim Bong-Jin Lee Young-Woo Kim
In this study we designed and synthesized several heptapeptides that are enforced to form an amphipathic helix using all-hydrocarbon stapling system and evaluated their antimicrobial and hemolytic activities. The antimicrobial activity showed clear structure-activity relationships, confirming the importance of helicity and amphipathicity. Some stapled heptapeptides displayed a moderate antimicrobial activity along with a low hemolytic activity. To our best knowledge, although not highly potent, these stapled peptides represent the shortest helical amphipathic antimicrobial peptides reported to date. The preliminary data obtained in this work would serve as a good starting point for further developing short analogs of amphipathic helical antimicrobial peptides.
Prediction of the Toxicity of Dimethylformamide, Methyl Ethyl Ketone, and Toluene Mixtures by QSAR Modeling
Ki-Woong Kim Yong Lim Won Mun Ki Hong Jihoon Jo Sung Kwang Lee
In this study, we analyzed the toxicity of mixtures of dimethylformamide (DMF) and methyl ethyl ketone (MEK) or DMF and toluene (TOL) and predicted their toxicity using quantitative structure-activity relationships (QSAR). A QSAR model for single substances and mixtures was analyzed using multiple linear regression (MLR) by taking into account the statistical parameters between the observed and predicted EC50. After preprocessing, the best subsets of descriptors in the learning methods were determined using a 5-fold cross-validation method. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP), flash point (FP), low explosion limit (LEL), and octanol/ water partition coefficient (Pow) were observed between the single substances and the mixtures. The EC50 of the mixture of DMF and TOL was significantly lower than that of DMF. The mixture toxicity was directly related to the mixing ratio of TOL and MEK (MLR EC50 equation = 1.76997 − 1.12249 × TOL + 1.21045 × MEK), as well as to SG, VP, and LEL (MLR equation EC50 = 15.44388 − 19.84549 × SG + 0.05091 × VP + 1.85846 × LEL). These results show that QSAR-based models can be used to quantitatively predict the toxicity of mixtures used in manufacturing industries.
ISSN(Print) 0253-2964
ISSN(Online) 1229-5949
