Pressure Effect of Various Inert Gases on the phase Behavior of Polystyrene-<i>block</i>-Poly(n-pentyl methacrylate) Copolymer

Kim, Hye Jeong,Moon, Hong Chul,Kim, Hyunuk,Kim, Kimoon,Kim, Jin Kon,Cho, Junhan American Chemical Society 2013 Macromolecules Vol.46 No.2

<P>We investigated the pressure effect of three inert gases (nitrogen, helium, and argon) on the phase behavior of polystyrene-<I>block</I>-poly(<I>n</I>-pentyl methacrylate) copolymer (PS-<I>b</I>-PnPMA) showing closed-loop phase behavior and baroplasticity. Helium gas pressure enhanced the miscibility between PS and PnPMA blocks similar to the hydrostatic pressure. Thus, the closed-loop size decreased with increasing helium gas pressure. Very interestingly, with increasing nitrogen and argon gas pressure, the miscibility between the two blocks decreased even though these two are also considered as inert gases. To explain these unexpected results, we measured the amount of gas absorption into each block. Helium gas showed almost no absorption in both PS and PnPMA; thus it simply acts as hydrostatic pressure. On the other hand, nitrogen and argon gases were more selectively absorbed into PnPMA compared with PS, which increased the free volume disparity between two blocks and enlarged closed-loop size with increasing gas pressure. The experimentally measured gas absorption results are consistent with the theoretical ones based on the Sanchez–Lacombe theory. The results in this study imply that well-known and widely employed inert gases such as nitrogen and argon could significantly affect the phase behavior of a weakly interacting block copolymer at high pressures.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2013/mamobx.2013.46.issue-2/ma302155j/production/images/medium/ma-2012-02155j_0007.gif'></P>

Functionalized cucurbiturils and their applications

Kim, Kimoon,Selvapalam, Narayanan,Ko, Young Ho,Park, Kyeng Min,Kim, Dongwoo,Kim, Jeeyeon Royal Society of Chemistry 2007 Chemical Society reviews Vol.36 No.2

<P>Cucurbit[<I>n</I>]uril (CB[<I>n</I>], <I>n</I> = 5–10), a new family of molecular hosts comprising <I>n</I> glycoluril units, have gained much attention in the new millennium for their exceptional molecular recognition ability. The CB homologues have brought dynamism to CB chemistry, as witnessed by the heightened interest in the field for the last several years. Compared to the chemistry of cyclodextrins and calixarenes, however, that of CB[<I>n</I>] has developed slowly until recently, which may be attributed mainly to their poor solubility in common solvents, and inability to functionalize these molecules. The direct functionalization method of CB[<I>n</I>] propelled CB chemistry to a new height as this new method not only solved the solubility problem but also opened up the gateway to the generation of tailor-made CB[<I>n</I>] derivatives. The functionalization of CB[<I>n</I>] led us to investigate numerous applications including artificial ion channels, vesicles, stationary phases in chromatography, ISEs, polymers, nanomaterials, and many others. This tutorial review describes the recent advances and challenges in the functionalization of CBs along with the applications of functionalized CBs.</P> <P>Graphic Abstract</P><P>The recent advances and challenges in the functionalization of cucurbiturils (CBs) along with the applications of functionalized CBs are described. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b603088m'> </P>

Synthesis of phase-pure interpenetrated MOF-5 and its gas sorption properties.

Kim, Hyunuk,Das, Sunirban,Kim, Min Gyu,Dybtsev, Danil N,Kim, Yonghwi,Kim, Kimoon American Chemical Society 2011 Inorganic Chemistry Vol.50 No.8

<P>For the first time, phase-pure interpenetrated MOF-5 (1) has been synthesized and its gas sorption properties have been investigated. The phase purity of the material was confirmed by both single-crystal and powder X-ray diffraction studies and TGA analysis. A systematic study revealed that controlling the pH of the reaction medium is critical to the synthesis of phase-pure 1, and the optimum apparent pH (pH*) for the formation of 1 is 4.0-4.5. At higher or lower pH*, [Zn(2)(BDC)(2)(DMF)(2)] (2) or [Zn(5)(OH)(4)(BDC)(3)] (3), respectively, was predominantly formed. The pore size distribution obtained from Ar sorption experiments at 87 K showed only one peak, at ~6.7 ?, which is consistent with the average pore size of 1 revealed by single crystal X-ray crystallography. Compared to MOF-5, 1 exhibited higher stability toward heat and moisture. Although its surface area is much smaller than that of MOF-5 due to interpenetration, 1 showed a significantly higher hydrogen capacity (both gravimetric and volumetric) than MOF-5 at 77 K and 1 atm, presumably because of its higher enthalpy of adsorption, which may correlate with its higher volumetric hydrogen uptake compared to MOF-5 at room temperature, up to 100 bar. However, at high pressures and 77 K, where the saturated H(2) uptake mostly depends on the surface area of a porous material, the total hydrogen uptake of 1 is notably lower than that of MOF-5.</P>

Galactosylated cucurbituril-inclusion polyplex for hepatocyte-targeted gene delivery

Kim, Soo Kyung,Park, Kyeng Min,Singha, Kaushik,Kim, Jeeyeon,Ahn, Youngjoo,Kim, Kimoon,Kim, Won Jong Royal Society of Chemistry 2010 Chemical communications Vol.46 No.5

<P>The work demonstrates a judicious approach to achieve hepatocyte cell-targeted highly efficient gene delivery by utilizing a supramolecular complex of galactosylated cucurbituril and dextran–spermine conjugates.</P> <P>Graphic Abstract</P><P>Judicious utilization of a biocompatible, nontoxic supramolecular assembly of galactosylated cucurbit[6]uril and dextran–spermine conjugate enables asialoglycoprotein receptor mediated efficient hepatocyte-targeted gene delivery. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b920753h'> </P>

Smart SERS Hot Spots: Single Molecules Can Be Positioned in a Plasmonic Nanojunction Using Host-Guest Chemistry

Kim, Nam Hoon,Hwang, Wooseup,Baek, Kangkyun,Rohman, Md. Rumum,Kim, Jeehong,Kim, Hyun Woo,Mun, Jungho,Lee, So Young,Yun, Gyeongwon,Murray, James,Ha, Ji Won,Rho, Junsuk,Moskovits, Martin,Kim, Kimoon American Chemical Society 2018 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.140 No.13

<P>Single-molecule surface-enhanced Raman spectroscopy (SERS) offers new opportunities for exploring the complex chemical and biological processes that cannot be easily probed using ensemble techniques. However, the ability to place the single molecule of interest reliably within a hot spot, to enable its analysis at the single-molecule level, remains challenging. Here we describe a novel strategy for locating and securing a single target analyte in a SERS hot spot at a plasmonic nanojunction. The “smart” hot spot was generated by employing a thiol-functionalized cucurbit[6]uril (CB[6]) as a molecular spacer linking a silver nanoparticle to a metal substrate. This approach also permits one to study molecules chemically reluctant to enter the hot spot, by conjugating them to a moiety, such as spermine, that has a high affinity for CB[6]. The hot spot can accommodate at most a few, and often only a single, analyte molecule. Bianalyte experiments revealed that one can reproducibly treat the SERS substrate such that 96% of the hot spots contain a single analyte molecule. Furthermore, by utilizing a series of molecules each consisting of spermine bound to perylene bisimide, a bright SERS molecule, with polymethylene linkers of varying lengths, the SERS intensity as a function of distance from the center of the hot spot could be measured. The SERS enhancement was found to decrease as 1 over the square of the distance from the center of the hot spot, and the single-molecule SERS cross sections were found to increase with AgNP diameter.</P> [FIG OMISSION]</BR>

CAN 네트워크를 위한 내장형 ORB 프로토콜의 설계

김기문(Kimoon Kim),김선일(Sunil Kim),김태형(Taehyung Kim),전광일(Gwangil Jeon),홍성수(Seongsoo Hong) 한국정보과학회 1999 한국정보과학회 학술발표논문집 Vol.26 No.2Ⅲ

많은 내장형 시스템이 분산 제어 방식을 채용하고 있는 현재, 소프트웨어 개발자들이 이기종으로 구성된 시스템의 설계 및 관리에 많은 어려움을 겪고 있다. 이에 따라 범용 통신 미들웨어인 CORBA, DCOM 등을 내장형 시스템에 사용하고자 하는 요구가 높아지고 있으나 이들은 분산 내장형 시스템의 고유한 제약 조건을 만족하지 못해 내장형 시스템에 사용된 전례가 드물다. 본 논문은 표준 CORBA의 ORB 프로토콜인 GIOP가 CAN 네트워크와 같은 내장형 콘트롤러 네트워크에 적용되었을 때 드러나는 문제점을 살펴보고, 이러한 고찰의 결과에 근거해 내장형 시스템 환경에 최적화된 새로운 ORB 프로토콜, EIOP (Embedded Inter-ORB Protocol)을 제안한다.

The guest-dependent thermal response of the flexible MOF Zn₂(BDC)₂(DABCO)

Kim, Yonghwi,Haldar, Ritesh,Kim, Hyunuk,Koo, Jaehyoung,Kim, Kimoon The Royal Society of Chemistry 2016 Dalton Transactions Vol.45 No.10

<P>The guest-dependent thermal response of the flexible MOF Zn-2(BDC)(2)(DABCO) (1) has been studied. A series of temperature-dependent single crystallographic analyses revealed inherent structural thermal responses of 1. The guest-free framework 1 exhibited interesting thermal responses including anisotropic thermal expansion (negative thermal expansion (NTE) along the a- and b-axes, positive thermal expansion (PTE) along the c-axis) and disorder-order phase transition. In addition, inclusion of guest molecules (DMF and benzene) brought distinct thermal responses to 1 from host-guest interactions. 1.4DMF showed altered thermal responses, presenting disorder-order phase transitions at a higher temperature and PTE along the a- and b-axes. Meanwhile, 1.3benzene displayed a quite different type of thermal response such as a hinge like motion (breathing) without a symmetry change.</P>

Complexation of Aliphatic Ammonium Ions with a Water-Soluble Cucurbit[6]uril Derivative in Pure Water: Isothermal Calorimetric, NMR, and X-ray Crystallographic Study

Kim, Youngkook,Kim, Hyunuk,Ko, Young Ho,Selvapalam, Narayanan,Rekharsky, Mikhail V.,Inoue, Yoshihisa,Kim, Kimoon WILEY-VCH Verlag 2009 Chemistry Vol.15 No.25

<P>Without interference: The complexation of aliphatic ammonium ions with a water-soluble cucurbit[6]uril (CB[6]) derivative, CB*[6] (see picture), in pure water is investigated by isothermal titration calorimetry, NMR spectroscopy, and X-ray crystallography. The binding affinity of the host in pure water is 2–5 orders of magnitude higher than that in the presence of interfering ions, such as protons and alkali metal ions. <img src='wiley_img/09476539-2009-15-25-CHEM200900305-content.gif' alt='wiley_img/09476539-2009-15-25-CHEM200900305-content'> </P><P>Complexation of a water-soluble cucurbituril (CB) derivative, cyclohexanocucurbit[6]uril (CB*[6]), the cavity dimensions of which are essentially the same as those of CB[6], with various organic mono- and diammonium ions has been studied by isothermal titration calorimetry and <SUP>1</SUP>H NMR spectroscopy. The binding affinity of CB*[6] with the guest molecules in water is 3–5 and 2–3 orders of magnitude higher than those of CB[6] in 50 % formic acid and in 0.05 m NaCl solution, respectively, which is mainly due to the larger enthalpic gains upon complex formation in the absence of interfering ions, such as protons and Na<SUP>+</SUP>. In particular, the binding constant (K) of spermine to CB*[6] was measured to be 3.4×10<SUP>12</SUP> m<SUP>−1</SUP>, which is the highest binding constant ever reported for CB[6] or its derivatives. We also obtained the X-ray crystal structures of α,ω-alkanediammonium ions (C<SUB>n</SUB>DA<SUP>2+</SUP>, n=4–8) and spermine complexes with CB[6], in which the aliphatic chains of the guest molecules take an extended or partially bent conformation inside the CB[6] cavity, depending on the chain length. The hexamethylene chain of C<SUB>6</SUB>DA<SUP>2+</SUP> takes a twisted conformation, which not only allows strong ion–dipole interactions between the ammonium groups and the carbonyl groups at the portals, but also increases hydrophobic interactions between the alkyl part of the guest and the inner wall of the host, which results in the largest enthalpic gain among α,ω-alkanediammonium ions. The thermodynamic parameters associated with the complexation are discussed in relation to the binding modes and conformations of the aliphatic chain of the guest molecules inside the host, which were investigated by <SUP>1</SUP>H NMR spectroscopy and X-ray crystallography.</P> <B>Graphic Abstract</B> <P>Without interference: The complexation of aliphatic ammonium ions with a water-soluble cucurbit[6]uril (CB[6]) derivative, CB*[6] (see picture), in pure water is investigated by isothermal titration calorimetry, NMR spectroscopy, and X-ray crystallography. The binding affinity of the host in pure water is 2–5 orders of magnitude higher than that in the presence of interfering ions, such as protons and alkali metal ions. <img src='wiley_img/09476539-2009-15-25-CHEM200900305-content.gif' alt='wiley_img/09476539-2009-15-25-CHEM200900305-content'> </P>

Ultraviolet-Enduring Performance of Flexible Pentacene TFTs with SnO[sub 2] Encapsulation Films

Kim, Woo Jin,Koo, Won Hoe,Jo, Sung Jin,Kim, Chang Su,Baik, Hong Koo,Hwang, D. K.,Lee, Kimoon,Kim, Jae Hoon,Im, Seongil The Electrochemical Society 2006 Electrochemical and solid-state letters Vol.9 No.7

Direct Profiling the Post-Translational Modification Codes of a Single Protein Immobilized on a Surface Using Cu-free Click Chemistry

Kim, Kyung Lock,Park, Kyeng Min,Murray, James,Kim, Kimoon,Ryu, Sung Ho American Chemical Society 2018 ACS central science Vol.4 No.5

<▼1><P/><P>Combinatorial post-translational modifications (PTMs), which can serve as dynamic “molecular barcodes”, have been proposed to regulate distinct protein functions. However, studies of combinatorial PTMs on single protein molecules have been hindered by a lack of suitable analytical methods. Here, we describe erasable single-molecule blotting (eSiMBlot) for combinatorial PTM profiling. This assay is performed in a highly multiplexed manner and leverages the benefits of covalent protein immobilization, cyclic probing with different antibodies, and single molecule fluorescence imaging. Especially, facile and efficient covalent immobilization on a surface using Cu-free click chemistry permits multiple rounds (>10) of antibody erasing/reprobing without loss of antigenicity. Moreover, cumulative detection of coregistered multiple data sets for immobilized single-epitope molecules, such as HA peptide, can be used to increase the antibody detection rate. Finally, eSiMBlot enables direct visualization and quantitative profiling of combinatorial PTM codes at the single-molecule level, as we demonstrate by revealing the novel phospho-codes of ligand-induced epidermal growth factor receptor. Thus, eSiMBlot provides an unprecedentedly simple, rapid, and versatile platform for analyzing the vast number of combinatorial PTMs in biological pathways.</P></▼1><▼2><P>An <U>e</U>rasable <U>si</U>ngle <U>m</U>olecule <U>blot</U> (eSiMBlot) assay provides an unprecedentedly simple and versatile platform for analyzing the combinatorial post-translational modifications in biological pathways.</P></▼2>