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Enhanced Carbon Dioxide Adsorption on Post-Synthetically Modified Metal-Organic Frameworks
고낙은,김자헌 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.8
Four MOFs functionalized with 1-Me, 1-Pr, 1-Ph, and 1-PhCF_3 were prepared through post-synthetic modifications of a metal-organic framework (MOF), UMCM-1-NH_2 (1) with acetic, butyric, benzoic, and 4-(trifluoromethyl)benzoic anhydrides, respectively. Methane adsorption measurements between 253 and 298 K at pressures up to 1 bar indicated that both 1-Ph and 1-PhCF_3 adsorbed more CH_4 than the parent MOF, 1. All the functionalized MOFs adsorbed more CO_2 than 1 under conditions similar to the CH_4 test. The introduction of functional groups promoted adsorption of both CH_4 and CO_2 despite significantly reducing Brunauer-Emmet-Teller (BET) surface area: 4170 (1), 3550 (1-Me), 2900 (1-Pr), 3680 (1-Ph), and 3520 m2/g (1-PhCF_3). Electron-withdrawing aromatic groups (1-Ph, 1-PhCF_3) more effectively enhanced CO_2 adsorption than electron-donating alkyl groups (1-Me, 1-Pr). In particular, 1-Ph adsorbed 23% more CO_2 at 298 K and 50%more at 253 K than 1.
Theoretical Studies on Pillared Covalent Organic Frameworks for a Hydrogen Storage Material
Daejin Kim,김자헌,최기항,Dong Hyun Jung,Seung-Hoon Choi 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4
Pillared covalent organic frameworks (PCOFs) have been studied with density functional theory (DFT) calculations. Based on the covalent organic framework-1 (COF-1) structure, one of the COFs synthesized by using the condensation reactions of phenyl diboronic acid C6H₄[B(OH)₂]₂, we inserted pillar molecules between the organic layers to improve the physisorption ability for hydrogen molecules. Pyridine, pyrazine and 1,4-diaza-bicyclo[2.2.2]octane (DABCO) could be considered as the candidates for the pillar molecules and pyridine wad used as the pillar in this study. The binding sites and the orientations of the pillar molecules were investigated on cluster models of COFs. From the calculations, we observed puckering in the cluster model of the COF, which were caused by binding of pyridine molecules.
Simple Preparation of Anatase Titanium Dioxide Nanoparticles by Heating Titanium-Organic Frameworks
임지혁,강은영,양승재,박혜정,김자헌,박종래 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
Thermal degradation of titanium–containing metal-organic frameworks (MOFs; MIL-125 and MIL-125-NH2 at 350 °C for 6 h in air produced TiO2 nanoparticles of ca. 10 nm in diameter. Scanning electron and transmission electron microscope analyses indicated that those nanoparticles were aggregated randomly within each crystalline particle of their MOF precursors. The TiO2 nanoparticles prepared from MIL-125-NH2 exhibited higher activity for the degradation of 4-chlorophenol under visible light.
벌독으로 인한 혈청병 양상의 두드러기 및 맥관부종 치험 1례
김정현,강다혜,김지영,임해원,김자헌,권강,Kim, Jung-Hyun,Kang, Da-Hae,Kim, Jee-Young,Lim, Hae-Won,Kim, Ja-Heon,Kwon, Kang 대한한방안이비인후피부과학회 2011 한방안이비인후피부과학회지 Vol.24 No.3
Objective : This study was performed to prove the effect of the oriental medical treatments on urticaria and angioedema caused from serum sickness reaction by bee venom. Method : We treated one case of urticaria and angioedema with oriental medical treatments such as 8 constitution acupuncture, herbal medicine, venesection therapy and facial pack therapy. We took pictures through the treatment to evaluate the improvement. Six items, itching, burning sensation, pain, wheal, redness, edema were used to diagnose urticaria and angioedema. Result & Conclusion : After treatments the urticaria and angioedema were improved. The symptom of itching, heating, pain, wheal, redness of whole body and facial edema disappeared.
IRMOF-3 의 수소 흡착 실험 및 Organic Linker 의 작용기에 따른 분자모델링 연구
이은성,오유진,윤지혜,김자헌,최승훈,이준,조성준,김대진,이태범 한국수소및신에너지학회 2004 한국수소 및 신에너지학회논문집 Vol.15 No.2
To find out rational design and synthetic strategies toward efficient hydrogen storage materials, molecular modeling and quantum mechanical studies have been carried out on the MOFs(Metal-Organic Frameworks) having various organic linkers and nanocube frameworks. The calculation results about the free volume ratio, surface area, and electron density variation of the frameworks indicated that the capacity of the hydrogen storage of MOFs was largely dependent on the specific surface area and electron localization around benzene ring rather than the free volume of MOFs. The prediction of the modeling study could be supported by the hydrogen adsorption experiments using IRMOF-1 and -3, which showed more enhanced hydrogen storage capacities of IRMOF-3 compared with the IRMOF-1's at both experimental conditions, 77K, ∠H2 1 atm and ambient temperature, ∠H2 35 atm.
Density Functional Study on Metal Decoration onto a Metal-Organic Framework
Dong Hyun Jung,김자헌,최기항,Daejin Kim,Seung-Hoon Choi 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4
We carried out density functional theory calculations on the adsorption of a Ti atom at the Zn-O3, Zn-O2 and Hex sites in one of isoreticular metal-organic frameworks (IRMOFs). The binding energy is largest at the Hex site and smallest at the Zn-O3 site. Through the analyses of the orbitals and then density of states plots, we also found that the binding at the Hex site was due to direct orbital overlap between the Ti atom and the carbon atoms of the phenyl ring. When a Ti atom binds to the Zn-O3 site, the interactions of the d orbitals of the Ti atom with the adjacent oxygen atoms have anti-bonding characters. At the Zn-O2 site, however, the d orbitals of the Ti atom have bonding interactions with the oxygen atoms of the carboxylate groups. Thus, the binding energy is larger at the Zn-O2 site than at the Zn-O3 site.