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Deep Red Phosphorescence of Cyclometalated Iridium Complexes by <i>o</i>-Carborane Substitution
Bae, Hye Jin,Chung, Jin,Kim, Hyungjun,Park, Jihyun,Lee, Kang Mun,Koh, Tae-Wook,Lee, Yoon Sup,Yoo, Seunghyup,Do, Youngkyu,Lee, Min Hyung American Chemical Society 2014 Inorganic chemistry Vol.53 No.1
<P>Heteroleptic (C<SUP>∧</SUP>N)<SUB>2</SUB>Ir(acac) (C<SUP>∧</SUP>N = 5-MeCBbtp (<B>5a</B>); 4-BuCBbtp (<B>5b</B>); 5-BuCBbtp (<B>5c</B>); 5-(<I>R</I>)CBbtp = 2-(2′-benzothienyl)-5-(2-<I>R</I>-<I>ortho</I>-carboran-1-yl)-pyridinato-C<SUP>2</SUP>,N, R = Me and <I>n</I>-Bu; 4-BuCBbtp = 2-(2′-benzothienyl)-4-(2-<I>n</I>-Bu-<I>ortho</I>-carboran-1-yl)-pyridinato-C<SUP>2</SUP>,N, acac = acetylacetonate) complexes supported by <I>o</I>-carborane substituted C<SUP>∧</SUP>N-chelating ligand were prepared, and the crystal structures of <B>5a</B> and <B>5b</B> were determined by X-ray diffraction. While <B>5a</B> and <B>5c</B> exhibit a deep red phosphorescence band centered at 644 nm, which is substantially red-shifted compared to that of unsubstituted (btp)<SUB>2</SUB>Ir(acac) (<B>6</B>) (λ<SUB>em</SUB> = 612 nm), <B>5b</B> is nonemissive in THF solution at room temperature. In contrast, all complexes are emissive at 77 K and in the solid state. Electrochemical and theoretical studies suggest that the carborane substitution leads to the lowering of both the HOMO and LUMO levels, but has higher impact on the LUMO stabilization than the HOMO, resulting in the reduction of the triplet excited state energy. In particular, the LUMO stabilization in the 4-substituted <B>5b</B> is more contributed by carborane than that in the 5-substituted <B>5a</B>. The solution-processed electroluminescent device incorporating <B>5a</B> as an emitter displayed deep red phosphorescence (CIE coordinate: 0.693, 0.290) with moderate performance (max η<SUB>EQE</SUB> = 3.8%) whereas the device incorporating <B>5b</B> showed poor performance, as well as weak luminance.</P><P>The introduction of an <I>o</I>-carborane to the 4- or 5-position of the pyridine ring of a btp ligand in heteroleptic (C<SUP>∧</SUP>N)<SUB>2</SUB>Ir(acac) complexes leads to deep red phosphorescence, which is substantially red-shifted compared to that of (btp)<SUB>2</SUB>Ir(acac). The solution processed PhOLED devices incorporating the 5-carborane substituted Ir(III) complex as an emitter display moderate performance with deep red phosphorescence.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-1/ic401755m/production/images/medium/ic-2013-01755m_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic401755m'>ACS Electronic Supporting Info</A></P>
Ryu, Jungho,Kim, Soonhyun,Hong, Hye-Jin,Hong, Jeongsik,Kim, Minsun,Ryu, Taegong,Park, In-Su,Chung, Kang-Sup,Jang, Jum Suk,Kim, Byoung-Gyu Elsevier 2016 Chemical engineering journal Vol.304 No.-
<P><B>Abstract</B></P> <P>Strontium ion (Sr<SUP>2+</SUP>) separation from seawater has attracted attention for radioactive pollutants removal and for Sr<SUP>2+</SUP> recovery. Herein, we synthesized titanate nanotubes (TiNTs) via a simple hydrothermal reaction, characterized their physicochemical properties, and systematically evaluated Sr<SUP>2+</SUP> sorption behavior under various reaction conditions corresponding to seawater environments. The synthesized TiNTs exhibited a fibril-type nanotube structure with a high specific surface area (260m<SUP>2</SUP>/g). Sr<SUP>2+</SUP> adsorption on TiNTs rapidly occurred following a pseudo-second-order kinetic model and was in good agreement with the Langmuir isotherm model, indicating a maximum adsorption capacity of 97mg/g. Based on the Sr<SUP>2+</SUP> uptake and Na<SUP>+</SUP> release with a stoichiometric balance, the Sr<SUP>2+</SUP> sorption mechanism on TiNTs was ion exchange between Na<SUP>+</SUP> in the TiNT lattice and Sr<SUP>2+</SUP> in the solution phase, as confirmed by XRD and Raman analysis. Among the competitive ions, Ca<SUP>2+</SUP> significantly hindered Sr<SUP>2+</SUP> sorption on TiNTs, whereas Na<SUP>+</SUP> only slightly affected Sr<SUP>2+</SUP> sorption, despite the Na<SUP>+</SUP> exchange sorption mechanism. The effect of Ca<SUP>2+</SUP> on Sr<SUP>2+</SUP> sorption was evaluated by introducing a distribution coefficient (<I>K<SUB>d</SUB> </I>) as a critical factor in determining the selectivity, which revealed a slightly higher selectivity for Sr<SUP>2+</SUP>. The Sr<SUP>2+</SUP> adsorption-desorption test in a real seawater medium enabled the determination of <I>K<SUB>d</SUB> </I> and the concentration factor (CF) for co-existing matrix ions in seawater; these values were evaluated for Sr<SUP>2+</SUP> removal and recovery from seawater. TiNTs were regenerated by acid treatment and reused through consecutive adsorption-desorption experiments. While most studies addressing Sr<SUP>2+</SUP> sorption using TiNTs aimed for extraction from wastewater and radioactive wastewater, this study elucidated Sr<SUP>2+</SUP> sorption behavior under seawater conditions and provided insights into developing the removal and recovery processes from seawater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Titanate nanotubes (TiNTs) were synthesized by a simple hydrothermal reaction. </LI> <LI> The sorption of strontium (Sr) on TiNTs rapidly occurred, achieving Sr uptake 97mg/g. </LI> <LI> Na had little effect on Sr sorption despite the sorption mechanism of the Na exchange. </LI> <LI> Ca significantly hindered Sr sorption on TiNTs among co-existing cations in seawater. </LI> <LI> TiNTs could be easily regenerated by acid treatment and reused for repeated cycles. </LI> </UL> </P>
Chung, Kang-Sup,Lee, Jae-Chun,Kim, Kun-Han,Han, Tae-Sam,Kil, Dae-Sup,Kim, Eun-Jin,Hwang, Taek-Sung 공주대학교 자원재활용신소재지역협력센터 2000 2차년도 센터 사업 성과집 Vol.2000 No.1
On-line determination of trace uranium in sea water by flow injection-inductively coupled plasma-mass spectrometry(FI-ICP-MS) has been investigated. The method of flow injection equipped wth microcolumn was used for on-line separation and enrichment of uranium prior to determination by ICP-MS because the influences of concomitant matrix in sea water are serious problem in introducing to ICP-MS. In order to take high accuracy and precision, flow injection parameters such as time response, acid concentration, sampling volume, flow rate, etc., and other instrumental conditions were optimized. A sampling volume of 3mL resulted in a preconcentration factor of about 30, and precision at the 3 ng/mL level was 3.5%(RSD). Developed method was applied to natural sea water samples off the coast of Young Kwang nuclear power plant in Korea and the results were assessed through either analysis of synthetic sea water reference sample or recovery experiment
Inhibition of Human Malignant Glioma Growth in Vivo by Human Recombinant Plasminogen Kringles 1-3
Chung, Dong-Sup,Hong, Yong-Kil,Lee, Youn-Soo,Lee, Hyo-Sil,Kang, Joon-Ki,Yang, Youn-Joo,Joe, Young A.,Chung, Soo-Il 가톨릭 의과학연구원 1999 가톨릭 의과학연구원 국제학술대회 Vol.3 No.-
Human malignant gliomas are highly vascularized and aggressive tumors. Angiogenesis inhibitors have been shown to induce regression of a variety of primary and metastatic tumors in vivo. However, their usefulness in treating brain tumors is not well understood. Angiostatin, a multiple kringle (1-4 out of 5) containing fragment of plasminogen, is one of the highly effective natural cryptic angiogenesis inhibitors. In this study, the theraperutic efficacy of a non-glycosylated and small molecular size recombinant kringles 1-3 (rPK1-3) was examined in the treatment of brain tumors generated by stereotactic intracerebral implantation of U-87 human glioma cells in nude mice. Mice bearing tumors, post-7 day implant, were treated with rPK1-3 (100 ㎎/㎏/day) s.c. for 21 days. The treated animals showed suppressed brain tumor growth by greater than 71.2% along with a 3-fold increase of apoptotic index and suppressed vascularization by 78.9%, without any observable signs of toxicity. Analysis of bFGF and VEGF expression in the tumors of the treated animals using immunohistochemical methods showed near complete absence of growth factors. Our results indicate that a non-glycosylated, small molecular size rPK1-3 is an efficient tumoristatic agent for the treatment of intracranial human glioma xenograft in mice and might provide new strategies for the treatment of brain tumors.
Cation Transport Properties of Li-M-silicate(M=Mg, Ai, Ti) Composite Compounds
Chung, Kang-Sup,Lee, Jae-Chun,Jeong, Jin-Ki,Kim, Eun-Jin,Lee, Kyung-Chul,Lee, Si-Hoon,Kim, Yang-Soo 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.5
Various crystalline Li-M-Silicate (M=Mg, Al, Ti) composite compounds were prepared and their cation transport properties examined. The extent of reaction was tested under the fixed M:Si molar ratio of 1 by changing the Li molar ratios from 0.1, 0.3, 0.5, 0.7 to 1. The physiochemical properties of the materials obtained were analyzed by using ICP-AES, XRD, TG/DTA and SEM and conductivity measurements were carried out with an LCR meter. According to the results found in the substituted polyvalent M^n+ ion and the added lithium contents, each polycrystalline sample showed various crystal structures and conductivity. The highest conductivity was obtained from Li-Al-Silicate compound (Li:Al:Si=O.3:1:1), which contains the Al_6Si_2O_13-LiAlSiO_4 transient phase to facilitate free space for the lithium ions mobility in the crystal lattice.