نتایج جستجو برای: tri aryl structure

تعداد نتایج: 1593907  

Journal: :journal of chemical and petroleum engineering 2014
nastaran hazrati ali mohammadalizadeh seyed hamed mousavi fatemeh babaie

in this study, bimodal meso-porous silica (uvm-7) synthesized and fabricated amino silane modified supports were characterized by powder x-ray diffraction (xrd), n2 adsorption/desorption, transmission electron microscope (tem), elemental analysis and titration. capacity of co2 capture on modified bimodal pore structure silica at 70°c was calculated using breakthrough curves; and it was found th...

2000
John F. Hartwig

Studies on the palladium-catalyzed formation of aryl amines, aryl ethers and a-aryl carbonyl compounds from aryl halides are reported. These studies range from synthetic methodology, to detailed mechanistic analysis, to new methods one can use to screen for catalytic covalent bond formation. Improved methods for formation of aryl ethers and room temperature amination chemistry have resulted fro...

Journal: :Journal of chromatography. A 2009
Naoya Kishikawa Kimiko Kubo Sherin Farouk Hammad Mokhtar Mohamed Mabrouk Ahmed Habib Hamed Elfatatry Kaname Ohyama Kenichiro Nakashima Naotaka Kuroda

The fluorogenic derivatization method for aryl halide was developed for the first time. This method was based on the formation of fluorescent biphenyl structure by Suzuki coupling reaction between aryl halides and non-fluorescent phenylboronic acid (PBA). We measured the fluorescence spectra of the products obtained by the reaction of p-substituted aryl bromides (i.e., 4-bromobenzonitrile, 4-br...

Journal: :Molecules 2017
Dongjun Lv Mingjie Zhang

Two polymer catalysts (Pd-OCMCS and Ni-OCMCS) with good reusability were synthesized by coordinating Pd and Ni onto O-carboxymethyl chitosan (OCMCS). The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR) spectra, Energy Dispersive Spectrometer (EDS)analysis, X-ray diffraction (XRD), and thermogravimetric analyzer (TG-DTG), and t...

Journal: :Organic & biomolecular chemistry 2011
Jadwiga Gajewy Jacek Gawronski Marcin Kwit

Chiral hexamine macrocycle derived from trans-1,2-diaminocyclohexane (DACH) in a complex with diethylzinc efficiently catalyzes the asymmetric hydrosilylation of N-phosphorylated aryl-alkyl or aryl-aryl ketimines in protic media with enantiomeric excess of the product approaching 100%. The cyclic structure of the trianglamine ligand increases the enantioselectivity and/or the yield of the react...

2017
Dengfeng Chen Qingyuan Feng Yunqin Yang Xu-Min Cai Fei Wang Shenlin Huang

hemistry 2017 been widely used to construct important families of target molecules, aryl ethers, suldes and sulfoxides. Traditionally, these reactions are carried out in organic solvents (e.g., THF, CH3CN, DMSO, and DMF), which may cause potential health, safety, and waste disposal issues. Therefore, transition-metalfree C–O and C–S coupling reactions under greener conditions are desirable, es...

Journal: :Zeitschrift für Kristallographie - New Crystal Structures 2001

Journal: :Science 2016
Dmitry E Agafonov Berthold Kastner Olexandr Dybkov Romina V Hofele Wen-Ti Liu Henning Urlaub Reinhard Lührmann Holger Stark

The U4/U6.U5 triple small nuclear ribonucleoprotein (tri-snRNP) is a major spliceosome building block. We obtained a three-dimensional structure of the 1.8-megadalton human tri-snRNP at a resolution of 7 angstroms using single-particle cryo-electron microscopy (cryo-EM). We fit all known high-resolution structures of tri-snRNP components into the EM density map and validated them by protein cro...

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