• Bulletin of the Korean Chemical Society
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• 제21권11호
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• pp.1119-1124
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• 2000

$\beta-Cyclodextrin$ derivatives connected with diaza-18-crown-6 through flexible bridges (R) at the secondary face 1a-c (1a: R = $-(CH_2)4-;$ 1b: R = $-CH_2CH_2OCH_2CH2-;$ 1c: R = $-(CH_2)8-)$ have been prepared. The associa tion constants of 1 with (2-naphthoxy)alkylammonium ions (2a: alkyl = butyl; 2b: alkyl = octyl) were determined by induced circular dichroism (ICD) spectroscopy and it was found that the derivatization of $\beta-CD$ with the diazacrown resulted in enhanced binding with 2, compared to the native $\beta-CD.$ ICD Characteristics of the host-guest complexes indicate that a part of the alkylammonium moiety of 2 is protruded from the secondary side of the $\beta-CD$ cavity, and the guest molecules 2a and 2b move to the secondary and primary side, respectively, to make the binding of the ammonium group with the diaza-18-crown-6 moiety more feasible. The energy accompanied by the relocation of the guest molecules inside $\beta-CD$ moiety is compensated by the interaction energy between the ammonium ion and diazacrown ether.

• Mass Spectrometry Letters
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• 제6권1호
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• pp.17-20
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• 2015

Sesamin, one of the lignans in sesame seed, was a labile compound in MS and it was reported that the protonated molecule of sesamin decomposed easily in ES ionization process and it cannot be detected (G. Yan, et al., Rapid Commun Mass Spectrom. 2007, 21, 3613-3620). To protect labile compounds, an amino-cyclodextrin (NCyD) was added to the sample to promote the host-guest interaction complex in ESI-MS. As a result, sesamin was ionized as the NCyD-sesamin-NCyD (1:2) complex without undesired decomposition, suggesting that the amino-CyDs assist the ionization of the labile molecules capped with CyDs by host-guest interaction and these compounds were ionized without their decomposition, those are like amino-CyD complex-assisted ionization. The amino-CyD complexes of sesamin and sesamolin were also analyzed by their ion-mobility MS.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.232-237
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• 2014

We have fabricated white organic light-emitting diodes (OLEDs) by co-doping of red and blue phosphorescent guest emitters into the single host layer. Tris(2-phenyl-1-quinoline) iridium(III) [$Ir(phq)_3$] and iridium(III)bis[(4,6-di-fluorophenyl)-pyridinato-$N,C^{2^{\prime}}$]picolinate (FIrpic) were used as red and blue dopants, respectively. The effects of dopant concentration on the emission, carrier conduction and external quantum efficiency characteristics of the devices were investigated. The emissions on the guest emitters were attributed to the energy transfer to the guest emitters and direct excitation by trapping of the carriers on the guest molecules. The white OLED with 5% FIrpic and 2% $Ir(phq)_3$ exhibited a maximum external quantum efficiency of 19.9% and a maximum current efficiency of 45.2 cd/A.

• 상하수도학회지
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• 제30권6호
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• pp.635-643
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• 2016

Gas hydrate (GH)-based desalination process have a potential as a novel unit desalination process. GHs are nonstoichiometric crystalline inclusion compounds formed at low temperature and a high pressure condition by water and a number of guest gas molecules. After formation, pure GHs are separated from the remaining concentrated seawater and they are dissociated into guest gas and pure water in a low temperature and a high pressure condition. The condition of GH formation is different depending on the type of guest gas. This is the reason why the guest gas is a key to success of GH desalination process. The salt rejection of GH based desalination process appeared 60.5-93%, post treatment process is needed to finally meet the product water quality. This study adopted reverse osmosis (RO) as a post treatment. However, the test about gas rejection by RO process have to be performed because the guest gas will be dissolved in a GH product (RO feed). In this research, removal potential of dissolved gas by RO process is performed using lab-scale RO system and GC/MS analysis. The relation between RO membrane characteristics and gas removal rate were analyzed based on the GC/MS measurement.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2005년도 추계학술연구발표회 및 정기총회
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• pp.20-20
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• 2005

• Korean Chemical Engineering Research
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• 제48권2호
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• pp.232-243
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• 2010

가스 하이드레이트는 고압과 저온 조건에서 객체분자(guest molecule)인 저 분자량의 가스와 주체분자(host molecule)인 물 분자가 결합하여 고체상으로 형성된 화합물을 일컫는다. 물과 가스에 의해서 형성이 된다는 점, 포집 가스의 종류에 따라 다양한 결정구조가 형성되며 선택적으로 가스를 포획할 수 있는 장점으로 인하여 이를 지구온난화 가스 저감을 위한 산업공정에 활용하는 연구가 최근 활발히 진행되고 있다. 본 논문에서는 $CO_2$ 또는 $CO_2-N_2$ 하이드레이트에 관한 전반적인 최근 연구 동향을 파악하여 이를 실제 산업 현장에 적용하는 경우에 대한 기술적 가능성을 모색해 본다. 특히 대규모 $CO_2$가 배출되면서도 이에 해당하는 연구가 활발히 진행되지 않았던 제철 공정에 대한 적용성을 중점적으로 검토하였다.

• Journal of Photoscience
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• 제10권1호
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• pp.127-148
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• 2003

Zeolite is a porous highly interactive matrix. Zeolitic cations help to generate triplets from molecules that possess poor intersystem crossing efficiency. Certain zeolites act as electron acceptors and thus can spontaneously generate radical cations. Zeolites also act as proton donors and thus yield carbocations without any additional reagents. These reactive species, radical cations and carbocations, have long lifetime within a zeolite and thus lend themselves to be handled as ‘regular’ chemicals. Internal structure of zeolites is studded with cations, the counter-ions of the anionic framework. The internal constrained structure and the cations serve as handles for chemists to control the behavior of guest molecules included within zeolites.

• Macromolecular Research
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• 제14권6호
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• pp.603-609
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• 2006

Tricyanopyrrolidene chromophores were prepared in order to compare their macroscopic nonlinear optical (NLO) properties with a conjugated structure through the long molecular axis. A thiophene or phenyl ring was tethered to an ethylenic bond; it may act as a lateral moiety to disrupt the planarity of a chromophore and lessen the electrostatic interaction. Thin film composites of these chromophores dissolved in amorphous polycarbonate (APC) were fabricated. Real time pole and probe method was employed to investigate the change of electro-optic (EO) signal during poling. The EO properties and their relaxation behaviors of the guest-host systems containing newly synthesized chromophores were investigated in detail.

• 공업화학
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• 제30권2호
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• pp.186-189
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• 2019

폴리피롤(polypyrrole)은 전기를 전도하는 고분자로 뛰어난 전기적 신호 전달을 지니며, 사이클로덱스트린(cyclodextrin)은 환형다당류(cyclic oligosaccharide) 분자들로서 저분자량 물질을 포획할 수 있는 친환경 물질로 널리 활용되고 있다. 따라서 이들 두 가지 물질을 혼합하여 혼성체를 제조할 수 있다면 사이클로덱스트린이 host가 되어 guest 물질을 포획하였을 때 발생하는 전기 신호를 폴리피롤이 민감하게 전달할 수 있게 되어 우수한 감지 능력을 갖게 된다. 따라서 본 연구에서는 폴리피롤/사이클로덱스트린 혼성체를 간단한 수용액 방식으로 제조하여, 제조된 혼성체를 하이드로젤(hydrogel)에 도입하여 건조한 후 금 전극 위에 적용하여 대표적인 유해성 분자인 메틸파라벤(methyl paraben)을 검출할 수 있는지에 대해서 살펴보았다. 그리고 폴리피롤만으로 이루어진 물질과 비교해 봤을 때, 사이클로덱스트린의 도입효과는 존재하는 것으로 나타났다. 이 연구는 전도성 고분자와 친환경 분자 혼성체를 유해물질 감지에 활용할 수 있는 가능성을 제시하고 있다.

• Mass Spectrometry Letters
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• 제7권1호
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• pp.16-20
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• 2016

Characterization of intact protein structures in the gas phase using electrospray ionization combined with ion mobility mass spectrometry has become an important tool of research. However, the biophysical properties that govern the structures of protein ions in the gas phase remain to be understood. Here, we investigated the impact of host-guest complexation of ubiquitin (Ubq) with macrocyclic host molecules, cucurbit[n]urils (CB[n]s, n = 6, 7), on its structure in the gas phase. We found that CB[n] complexation induces the formation of compact Ubq ions. Both CB[6] and CB[7] exhibited similar effects despite differences in their binding properties in solution. In addition, CB[n] attachment prevented Ubq from unfolding by collisional activation. Based on the experimental results, we suggest that CB[n]s prevent unfolding of Ubq during transfer to the gas phase to promote the formation of compact protein ions. Furthermore, interaction with positively charged residues per se is suggested to be the most important factor for the host-guest complexation effect.