• Title/Summary/Keyword: Organometallic

Search Result 114, Processing Time 0.029 seconds

Coordination Polymerization of Carbon Double Bond Catalyzed by Organometallic Compounds (유기금속화합물 촉매에 의한 탄소이중결합의 배위중합)

  • Lee Dong-ho
    • Polymer(Korea)
    • /
    • v.29 no.4
    • /
    • pp.321-330
    • /
    • 2005
  • In 1990's the Korean polyolefin industry boomed up through the development of magnificient polymerization catalysts. To understand the general situation of polymerization catalyst R & D, the various experimental results had been summarized for the investigation of not only the supported Ziegler-Natta catalyst used presently in polyolefin industry but also the metallocene catalysts applied for the preparation of special grade of polyolefin. In addition, it had been shown that the new polymeric materials were prepared by new developed catalyst, and the polymer in-situ nanocomposites could be obtained with the application of catalyst heterogenization procedures.

Screening of Antineoplastic Immunomodulator from Herbal Medicines (천연물로부터 항암면역증강물질 탐색연구)

  • Song, Jie-Young;Yang, Hyun-Ok;Pyo, Suhk-Neung;Park, Sin-Young;Kim, Ki-Hwan;Son, Eun-Hwa;Kang, Nam-Sung;Yun, Yeon-Sook
    • YAKHAK HOEJI
    • /
    • v.42 no.2
    • /
    • pp.132-139
    • /
    • 1998
  • Currently, cancer is the primary cause of death and 50% of cancer patients are incurable by surgery, radiotherapy and chemotherapy. Therefore, immunotherpy is interested as the fourth remedy. Biological response modifier (BRM), such as organometallic compounds, glycoproteins, polysaccharides and other natural products. Is the one which can enhance the immune response against cancer cell. To develop new BRM from natural sources, we investigated 63 species Korean traditional medicines by observing the mitogenic activity to splenocytes, generation of activated killer cells and activation of macrophages. Finally, we selected 9 species including Angelicae gigantis Radix, Mori Cortex Radicis, Arisaematis Tuber, Salviae Radix, Cnidii Rhizoma, Ligusti Fructus, Pasoraliae Semen, Loranthi Ramulus, Ginseng Radix. Bioassay-guided fractionation and purification is undergoing.

  • PDF

Reactions of Trimethyl-and Triphenyl-Metal(Ⅳ) Methoxide with Phenylisocyanate (Trimethyl- 및 Triphenyl-metal(Ⅳ) methoxide와 phenylisocyanate의 반응)

  • Ghap-Ju Kim;Bae Seok Seo;Myung Jae Lee;Sung Woo Park;Il-Kyu Lee
    • Journal of the Korean Chemical Society
    • /
    • v.31 no.1
    • /
    • pp.79-83
    • /
    • 1987
  • Trimethyl-and triphenyl-metal (IVA) methoxides were reacted with phenylisocyanate at various temperatures. Even at 100$^{\circ}C$, methyltrimethylsilyl ether, methyltriphenylsilyl ether and triphenyltin methoxide produced the cyclic dimer of phenylisocyanate, N,N'-diphenyluretidine-2,4-dione. But the other compounds produced only the cyclic trimer of phenylisocyanate, phenylisocyanurate. And above 200$^{\circ}C$, considerable amounts of diphenylcarbodiimide was formed by all the organometallic compounds. From these results, the mechanism of cyclic polymerization of phenylisocyanate by the organometal catalysts, and the correlation of substituents with the reactivity were discussed.

  • PDF

The Photodegradation Effect of Organic Dye for Metal Oxide (Cr2O3, MgO and V2O3) Treated CNT/TiO2 Composites

  • Chen, Ming-Liang;Bae, Jang-Soon;Yoon, Hee-Seung;Lim, Chang-Sung;Oh, Won-Chun
    • Bulletin of the Korean Chemical Society
    • /
    • v.32 no.3
    • /
    • pp.815-820
    • /
    • 2011
  • Three kinds of organometallic compounds (chromium acetylacetonate, magnesium acetate and vanadyl acetylacetonate) were used as transition metal precursor, titanium n-butoxide and multi-walled carbon nanotube as titanium and carbon precursor to prepare metal oxide-CNT/$TiO^2$ composites. The surface properties and morphology of metal oxide-CNT/$TiO^2$ composites were by Brauer-Emett-Teller (BET) surface area measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The photocatalytic activity of prepared metal oxide-CNT/$TiO^2$ composites was determined by the degradation effect of methylene blue in an aqueous solution under irradiation of visible light.

Synthesis and Characterization of an Organometallic Ruthenium Complex Bearing 4-Picolinic Acid Ligands for Dye-Sensitized Solar Cells (DSSCs) (피콜리닉산 리간드를 갖는 염료감응형 태양전지용 루테늄 염료 합성과 특성분석)

  • Jung, Hye-In;An, Byeong-Kwan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.3
    • /
    • pp.192-197
    • /
    • 2016
  • A novel heteroleptic ruthenium(II) complex bearing a 4-picolinic acid unit as anchoring ligands (trans-dithiocyanato bis(4-picolinic acid)ruthenium(II) (trans-H1)) was synthesized and its chemical structure was identified by $^1H$-NMR, FT-IR and mass spectroscopy. The optical, thermal, electrochemical and dye adsorption properties of trans-H1 dye were investigated and compared with those of the gold standard ruthenium complex, Ru(4,4'-dicarboxy-2,2'-bipyridine)$_2cis(NCS)_2$ (N3). DSSCs based on trans-H1 dyes were examined under the illumination of AM 1.5 G, $100mWcm^{-2}$ and exhibited typical photovoltaic properties with an open-circuit voltage ($V_{OC}$) of 0.46 V, a short-circuit current ($J_{SC}$) of $4.10mA{\cdot}cm^{-2}$, a fill factor (FF) of 60.4%, and a conversion efficiency (PCE) of 1.14%.

Investigation of GaAs Tilt Grain Boundaries by High-resolution Transmission Electron Microscopy (HITEM을 이용한 GaAs 기울임입계 구조 연구)

  • ;C. B. Carter
    • Korean Journal of Crystallography
    • /
    • v.6 no.2
    • /
    • pp.69-74
    • /
    • 1995
  • GaAs tilt grain boundaries were propared by growing GaAs epilayers on Ge bicrystals by an organometallic vapor phase epitaxy (OMVPE) method ∑ =9 tilt grain boundaries were produced when two different first-order twin boundaries interacted with one another in GaAs epilayers. Structural investigations were performed for the coherent and second-order twin boundaries of GaAs by high-resolution transmission electron microscopy (HRTEM). Polarities of cross-boundary bondings were determined from the high-order Laue zone (HOLZ) lines in the (200) convergent beam disks : these were recorded from the two grains on either side of the boundaries, respectively, at particular diffraction conditions.

  • PDF

Synthesis and Characterization of Fe-fullerene/TiO2 Photocatalysts Designed for Degradation of Methylene Blue

  • Meng, Za-Da;Zhang, Kan;Oh, Won-Chun
    • Korean Journal of Metals and Materials
    • /
    • v.48 no.7
    • /
    • pp.674-682
    • /
    • 2010
  • Fe-fullerene/$TiO_2$ composite photocatalysts were prepared with titanium (IV) n-butoxide (TNB) by a sol-gel method. The samples were characterized by scanning electron microscopy (SEM), Transmission electron microscope (TEM), specific surface area (BET), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities were evaluated by the photocatalytic degradation of methylene blue (MB) solution. XRD patterns of the composites showed that the Fe-fullerene/$TiO_2$ composite contained a typical single and clear anatase phase. The surface properties shown by SEM present a characterization of the texture on Fe-fullerene/$TiO_2$ composites and showed a homogenous composition in the particles for the titanium sources used. The EDX spectra for the elemental identification showed the presence of C and Ti with strong Fe peaks for the Fe-fullerene/$TiO_2$ composite. From the photocatalytic results, the excellent activity of the Fe-fullerene/$TiO_2$ composites for degradation of methylene blue under UV light irradiation could be attributed to both the effects between photocatalytic reaction of the supported $TiO_2$, decomposition of the organometallic reaction by the Fe compound and energy transfer effects such as electron and light of the fullerene.

Functionalized Organometallic Ligand (1) Synthesis of Some Ferrocene Derivatives of Cyclohexyl- and Cyclopentadienyl-phosphines

  • Kim Tae-Jeong;Kim Yong-Hoon;Kim Hong-Seok;Shim Sang-Chul;Kwak Young-Woo;Cha Jin-Soon;Lee Hyung Soo;Uhm Jae-Kook;Byun Sang-In
    • Bulletin of the Korean Chemical Society
    • /
    • v.13 no.6
    • /
    • pp.588-592
    • /
    • 1992
  • A series of new ferrocene derivatives containing cyclohexylphosphines have been prepared from the reactions of lithioferrocenes with corresponding chlorodicyclohexylphosphines. 1-diphenylphosphino-1'-dicyclohexylphosphinoferro cene has been prepared from [1]-ferrocenophane via a ring cleavage reaction. Chiral ferrocenylaminophosphines incorporating cyclohexyl-and cyclopentadienylphosphines have also been prepared from the chiral template 2-N,N-dimethylaminoethylferrocene (FA) via stereoselective lithiation followed by phosphination with corresponding $R_2PCl$(R= $C_6H_{11}$, $C_5H_5$). The synthesis of cyclopentadienylphosphine derivative of (R)-FA (6b) led to the formation of a mixture of four diastereomers due to the presence of three chiral sources in the final product in addition to the fluxional behavior of the $η^1$-$C_5H_5$ group attached to the phosphorus. All these new compounds have been characterized by analytical and spectroscopic techniques.

Looking through the Mass-to-Charge Ratio: Past, Present and Future Perspectives

  • Shin, Seung Koo
    • Mass Spectrometry Letters
    • /
    • v.12 no.4
    • /
    • pp.126-130
    • /
    • 2021
  • The mass spectrometry (MS) provides the mass-to-charge ratios of atoms, molecules, stable/metastable complexes, and their fragments. I have taken a long journey with MS to address outstanding issues and problems by experiments and theory and gain insights into underlying principles in chemistry. By looking through the mass-to-charge ratio, I have studied thermochemical problems in silicon chemistry, the infrared multiphoton dissociation spectroscopy of organometallic intermediates, unimolecular dissociations of halotoluene radical cations, and the kinetics of association/dissociation of alkali halide triple ions with Lewis bases. Various MS platforms have been used to characterize non-covalent interactions between porphyrins and fullerenes and those between the group IIB ions and trioctylchalcogenides, and to examine the binding of the group IA, IIA and porphyrin ions to G-quadruplex DNA. Recently, I have focused on mass-balanced H/D isotope dipeptide tags for MS-based quantitative proteomics, a simple chemical modification method for MS-based lipase assay, and the kinetics and dynamics of energy-variable collision-induced dissociation of chemically modified peptides. Now, I see an important role of MS in global issues in the post-COVID era, as the society demands high standards for indoor air quality to contain the airborne-pathogen transmission as well as in-situ monitoring and tracking of carbon emissions to reduce global warming.

Synthesis of Fe/SiO2 Core-Shell Nanoparticles by a Reverse Micelle and Sol-Gel Processes

  • Son, Jeong-Hun;Bae, Dong-Sik
    • Korean Journal of Materials Research
    • /
    • v.22 no.6
    • /
    • pp.298-302
    • /
    • 2012
  • Fe/$SiO_2$ core-shell type composite nanoparticles have been synthesized using a reverse micelle process combined with metal alkoxide hydrolysis and condensation. Nano-sized $SiO_2$ composite particles with a core-shell structure were prepared by arrested precipitation of Fe clusters in reverse micelles, followed by hydrolysis and condensation of organometallic precursors in micro-emulsion matrices. Microstructural and chemical analyses of Fe/$SiO_2$ core-shell type composite nanoparticles were carried out by TEM and EDS. The size of the particles and the thickness of the coating could be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TEOS within the micro-emulsion. The water/surfactant molar ratio influenced the Fe particle distribution of the core-shell composite particles, and the distribution of Fe particles was broadened as R increased. The particle size of Fe increased linearly with increasing $FeNO_3$ solution concentration. The average size of the cluster was found to depend on the micelle size, the nature of the solvent, and the concentration of the reagent. The average size of synthesized Fe/$SiO_2$ core-shell type composite nanoparticles was in a range of 10-30 nm and Fe particles were 1.5-7 nm in size. The effects of synthesis parameters, such as the molar ratio of water to TEOS and the molar ratio of water to surfactant, are discussed.