• Title/Summary/Keyword: C-C Cross-coupling reaction

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Synthesis of Graphene Oxide Based CuOx Nanocomposites and Application for C-N Cross Coupling Reaction

  • Choi, Jong Hoon;Park, Joon B.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.176.1-176.1
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    • 2014
  • Graphene has attracted an increasing attention due to its extraordinary electronic, mechanical, and thermal properties. Especially, the two dimensional (2D) sheet of graphene with an extremely high surface to volume ratio has a great potential in the preparation of multifunctional nanomaterials, as 2D supports to host metal nanoparticles (NPs). Copper oxide is widely used in various areas as antifouling paint, p-type semiconductor, dry cell batteries, and catalysts. Although the copper oxide(II) has been well known for efficient catalyst in C-N cross-coupling reaction, copper oxide(I) has not been highlighted. In this research, CuO and Cu2O nanoparticles (NPs) dispersed on the surface of grapehene oxide (GO) have been synthesized by impregnation method and their morphological and electronic structures have been systemically investigated using TEM, XRD, and XAFS. We demonstrate that both CuO and Cu2O on graphene presents efficient catalytic performance toward C-N cross coupling reaction. The detailed structural difference between CuO and Cu2O NPs and their effect on catalytic performance are discussed.

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Graphene Based Cu Oxide Nanocomposites for C-N Cross Coupling Reaction

  • Choi, Jong Hoon;Park, Joon B.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.138.2-138.2
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    • 2013
  • Copper oxide is a multi-functional material being used in various research areas including catalysis, electrochemical materials, oxidizing agents etc. Among these areas, we have synthesized and utilized graphene based copper oxide nanocomposites (CuOx/Graphene) for the catalytic applications (C-N cross coupling reaction). Briefly, Cu precursors were anchored on the graphite oxide(GO) sheets being exfoliated and oxidized from graphite powder. Two different crystalline structures of Cu2O and CuO on graphene and GO were prepared by annealing them in Ar and O2 environments, respectively. The morphological and electronic structures were systemically investigated using FT-IR, XRD, XPS, XAFS, and TEM. Here, we demonstrate that the catalytic performance was found to depend on oxidative states and morphological structures of CuOx graphene nanocomposites. The relationship between the structure of copper oxides and catalytic efficiency toward C-N cross coupling reaction will be discussed.

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Palladium-Catalyzed Coupling between Quinolone Moieties and Heteroaryl Stannes - Synthesis of C-7 heteroaryl Quinolone Derivatives - (팔라듐 촉매를 이용한 퀴놀론핵과 Heteroaryl Stannes의 결합 - C-7 heteroaryl 쿼놀론 유도체의 합성 -)

  • 남상훈;함원훈;김기수;임태균;양재권
    • YAKHAK HOEJI
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    • v.37 no.6
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    • pp.615-620
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    • 1993
  • The cross-coupling reaction of organo tin reagents with a variety of organic halides, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. We used this method for the antibacterial agents, and synthesis of new quinolone derivatives which have carbon-carbon bond at C-7 position of general quinolone moieties. Aryl tin, quinolone moieties, and palladium catalyst were refluxed in DMF to afford new quinolone derivatives. This palladium catalyzed coupling reactions have capacity for further synthetic elaboration.

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Functionalization of Organotrifluoroborates via Cu-Catalyzed C-N Coupling Reaction

  • Lee, Jung-Hyun;Kim, Heejin;Kim, Taejung;Song, Jung Ho;Kim, Won-Suk;Ham, Jungyeob
    • Bulletin of the Korean Chemical Society
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    • v.34 no.1
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    • pp.42-48
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    • 2013
  • Potassium N-heterobiaryltrifluoroborates were successfully prepared via a selective Cu-catalyzed C-N coupling reaction. The $BF_3K$ moiety was well tolerated under the reaction conditions involving CuI and dimethyl-ethylenediamine (DMEDA) in the presence of DMSO. The Pd-catalyzed Suzuki-Miyaura cross couplings of potassium N-heterobiaryltrifluoroborates with bromoarenes were studied to prepare the N-heterotriaryl compounds. Moreover, homocoupling, iodination, and hydroxylation of potassium N-heterobiaryltrifluoroborates provided the corresponding products in high yields.

Synthesis and Characterization of Graphene and Graphene Oxide Based Palladium Nanocomposites and Their Catalytic Applications in Carbon-Carbon Cross-Coupling Reactions

  • Lee, Minjae;Kim, Bo-Hyun;Lee, Yuna;Kim, Beom-Tae;Park, Joon B.
    • Bulletin of the Korean Chemical Society
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    • v.35 no.7
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    • pp.1979-1984
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    • 2014
  • We have developed an efficient method to generate highly active Pd and PdO nanoparticles (NPs) dispersed on graphene and graphene oxide (GO) by an impregnation method combined with thermal treatments in $H_2$ and $O_2$ gas flows, respectively. The Pd NPs supported on graphene (Pd/G) and the PdO NPs supported on GO (PdO/GO) demonstrated excellent carbon-carbon cross-coupling reactions under a solvent-free, environmentally-friendly condition. The morphological and chemical structures of PdO/GO and Pd/G were fully characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). We found that the remarkable reactivity of the Pd/G and PdO/GO catalysts toward the cross-coupling reaction is attributed to the high degree of dispersion of the Pd and PdO NPs while the oxidative states of Pd and the oxygen functionalities of graphene oxide are not critical for their catalytic performance.

Palladium-Catalyzed Coupling between Quinolone Moieties and Heteroacyl Stannes - Synthesis of C-7 Heteroacyl Quinolone Derivatives

  • 함원훈;양재권;임태균
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.221-221
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    • 1994
  • The cross-coupling reaction of organo tin reagents with a variety of organic halides, catalyzed by palladium, provides a novel method for generating a carbon-carbon bond. We use this method for antibacterial agents, and synthesis of new quinolone derivatives which have carbon-carbon bond at C-7 position of general quinolone moieties. Aryl tin, quinolone moieties, and palladium catalyst were refluxed in DMF to afford new quinolone derivatives. This palladium catalyzed coupling reactions have capacity for further synthetic elaboration.

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Ligand Effect in Recycled CNT-Pd Heterogeneous Catalyst for Decarboxylative Coupling Reactions

  • Kim, Ji Dang;Pyo, Ayoung;Park, Kyungho;Kim, Gwui Cheol;Lee, Sunwoo;Choi, Hyun Chul
    • Bulletin of the Korean Chemical Society
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    • v.34 no.7
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    • pp.2099-2104
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    • 2013
  • We present here an efficient and simple method for preparation of highly active Pd heterogeneous catalyst (CNT-Pd), specifically by reaction of dichlorobis(triphenylphosphine)palladium ($Pd(PPh_3)_2Cl_2$) with thiolated carbon nanotubes (CNTs). The as-prepared CNT-Pd catalysts demonstrated an excellent catalytic activity for the carbon-carbon (C-C) cross-coupling reactions (i.e. Suzuki, Stille, and decarboxylative coupling reactions) under mild conditions. The CNT-Pd catalyst could easily be removed from the reaction mixture; additionally, in the decarboxylative coupling of iodobenzene and phenylpropiolic acid, it showed a six-times recyclability, with no loss of activity. Moreover, once its activity had decreased by repeated recycling, it could easily be reactivated by the addition of phosphine ligands. The remarkable recyclability of the decarboxylative coupling reaction is attributable to the high degree of dispersion of Pd catalysts in CNTs. Aggregation of the Pd catalysts is inhibited by their strong adhesion to the thiolated CNTs during the chemical reactions, thereby permitting their recycling.

Studies on the Michael Addition Reaction between Secondary Amino Groups on the Silica Surface with Poly(ethylene glycol) Diacrylates (실리카 나노입자 표면에 결합된 2차 아미노기와 Poly(ethylene glycol) Diacrylate의 마이클 부가반응에 대한 연구)

  • Jeon, Ha Na;Ha, KiRyong
    • Polymer(Korea)
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    • v.36 no.6
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    • pp.822-830
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    • 2012
  • We used dipodal type bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to modify silica nanoparticles to introduce secondary amino groups on the silica surface. These N-H groups were reacted with three different molecular weights (M.W. = 258, 575, and 700) of poly(ethylene glycol) diacrylates to introduce different attached layer thicknesses on the silica surface by Michael addition reaction. After Michael addition reaction, we used several analytical techniques such as fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state $^{13}C$ cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy to characterize introduced structures. We found almost complete Michael addition reaction of both two acrylate groups of PDGDA with N-H groups of BTMA modified silica to form ${\beta}$-amino acid esters. Between equimolar ratio of pure BTMA and pure PEGDA reaction, only one acrylate group of two acrylate groups of PEGDA reacted with N-H groups of pure BTMA to form ${\beta}$-amino acid ester and the other remaining acrylate group can be used to form a polymer later.

Study on Mixing Condition of the Rubber Composite Containing Functionalized S-SBR, Silica and Silane : II. Effect of Mixing Temperature and Time (변성 S-SBR Silica-Silane 고무복합체의 배합조건에 대한 연구 : II. 배합온도와 시간의 영향)

  • Jang, Suk-Hee;Kim, Wook-Soo;Kang, Yong-Gu;Han, Min-Hyun;Chang, Sang-Mok
    • Elastomers and Composites
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    • v.48 no.2
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    • pp.103-113
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    • 2013
  • The properties of the rubber composites containing a silane and silica were evaluated by changing the mixing time and temperature, in order to find the optimum mixing conditions. Characteristics of the compounds were evaluated after mixing at $120^{\circ}C$, $140^{\circ}C$, and $160^{\circ}C$ with various mixing time. With increasing of mixing time, mooney viscosity decreased while the bound rubber contents of the compounds increased. Viscosity rise by increased mixing time was bigger at low temperature and the higher the mixing temperature the faster in the formation of bound rubber. With lower mixing temperature of $120^{\circ}C$, cross-linking rate was almost constant. Dynamic viscoelastic properties and dispersity of the compound showed that dispersion of ingredients and reaction was not sufficient with the mixing time of less than 10min. On the contrary, with high temperature, it was obvious that good dynamic and physical properties could be obtained due to sufficient coupling reaction, however it was thought this high temperature is not optimum because of sensitive cross-linking rate and physical properties and excessive formation of bound rubber. Consequently, it was confirmed that the mixing condition of 10min at $140^{\circ}C$ was optimum for the silane coupling reaction and dispersion of functionalized S-SBR containing silica and silane.

Low Temperature Vulcanization of Chlorosulfonated Polyethylene (Chlorosulfonated Polyethylene의 저온가황반응(低溫加黃反應))

  • Park, Keun-Sik;Park, Sung-Ha;Choi, Sei-Young
    • Elastomers and Composites
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    • v.27 no.4
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    • pp.255-261
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    • 1992
  • Chlorosulfonated polyethylene(CSM) was moisture-cure after treating them with silane coupling agents such as ${\gamma}-mercapto$ propyl trimethoxy silane, ${\gamma}-glycidoxy$ propyl triethoxy silane and methyl triethoxy silane, 3-(trimethoxy silyl) propyl methacrylate and 3-thiocyanopropyl triethoxy silane. The cure reaction is composed two steps. The first is the reaction between chlorosulfonyl groups of CSM and silane coupling agents. The second is the formation of cross-links which are siloxane linkage. The linkage is formed by the condensation of silanol groups which are produced by the hydrolysis of alkoxysilyl groups. CSM was mixed with MPS etc., and dilaurate dilaurate as catalyst on two open mill and the compounds were lured in hot water at $70^{\circ}C$ Physical properties of moisture-cured CSM was measured. CSM was effectively moisture-cured and r-mercapto propyl trimethoxy silane and r-glycidoxy propyl trimethoxy silane were capable of the vulcanizing agents.

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