scholarly journals An efficient Pd–NHC catalyst system in situ generated from Na2PdCl4 and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

2017 ◽  
Vol 13 ◽  
pp. 1735-1744 ◽  
Author(s):  
Nan Sun ◽  
Meng Chen ◽  
Liqun Jin ◽  
Wei Zhao ◽  
Baoxiang Hu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Imidazole Ring ◽  
Catalyst System ◽  
Water Soluble ◽  
Imidazolium Salts ◽  
Heck Reactions ◽  
Imidazolium Salt ◽  
Simple Method ◽  
Wide Range

Three PEG-functionalized imidazolium salts L1–L3 were designed and prepared from commercially available materials via a simple method. Their corresponding water soluble Pd–NHC catalysts, in situ generated from the imidazolium salts L1–L3 and Na2PdCl4 in water, showed impressive catalytic activity for aqueous Mizoroki–Heck reactions. The kinetic study revealed that the Pd catalyst derived from the imidazolium salt L1, bearing a pyridine-2-methyl substituent at the N3 atom of the imidazole ring, showed the best catalytic activity. Under the optimal conditions, a wide range of substituted alkenes were achieved in good to excellent yields from various aryl bromides and alkenes with the catalyst TON of up to 10,000.

Niobium(v) chloride and imidazolium bromides as efficient dual catalyst systems for the cycloaddition of carbon dioxide and propylene oxide

2014 ◽  
Vol 4 (6) ◽  
pp. 1638-1643 ◽  
Author(s):  
Michael E. Wilhelm ◽  
Michael H. Anthofer ◽  
Robert M. Reich ◽  
Valerio D'Elia ◽  
Jean-Marie Basset ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Catalytic Activity ◽  
Propylene Oxide ◽  
Catalyst System ◽  
Cyclic Carbonates ◽  
Imidazolium Salt ◽  
Catalyst Systems

Imidazolium bromides combined with niobium(v) choride were used as catalyst system for the reaction of CO2 with epoxides to cyclic carbonates. The variation of the cation structure strongly affects the properties of the imidazolium salt and therefore the catalytic activity.

scholarly journals Water-soluble gold nanoparticles: recyclable catalysts for the reduction of aromatic nitro compounds in water

RSC Advances ◽  
2020 ◽  
Vol 10 (26) ◽  
pp. 15065-15071 ◽  
Author(s):  
Gustavo A. Monti ◽  
N. Mariano Correa ◽  
R. Darío Falcone ◽  
Gustavo F. Silbestri ◽  
Fernando Moyano
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Pure Water ◽  
Nitro Compounds ◽  
Water Soluble ◽  
Imidazolium Salts ◽  
Aromatic Nitro Compounds ◽  
Recyclable Catalysts ◽  
Aromatic Nitro

A structure/catalytic activity study of water-soluble gold nanoparticles, stabilized by zwitterionic ligands derived from imidazolium salts, in the reduction of aromatic nitro compounds in pure water, as well as their recyclability, was performed.

C-H bond Activation/Arylation over Arene-Ruthenium(II)-picolinate Complexes: Synthesis, Structure and Catalytic Activity

2017 ◽  
Author(s):  
Chinky Binnani ◽  
Rohit K. Rai ◽  
Deepika Tyagi ◽  
Shaikh M Mobin ◽  
Sanjay Kumar Singh
Keyword(s):  
Catalytic Activity ◽  
Bond Activation ◽  
Ruthenium Catalysts ◽  
Molecular Structures ◽  
Water Soluble ◽  
Aryl Halides ◽  
Donor Ligands ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Wide Range

<p>A series of water soluble arene-ruthenium(II) complexes [(<i>η</i><sup>6</sup>-arene)RuCl(κ<sup>2</sup>-L)]<sup>n+</sup> (n = 0, 1) (<b>[Ru]-1</b> – <b>[Ru]-12</b>) containing pyridine based N,O or N,N ligands (<b>L1-L6</b>) were synthesized and employed for the catalytic C-H bond activation/ arylation of 2-phenylpyridine with aryl halides in water. Efficient C-H bond activation/ arylation of a wide range of substituted 2-phenylpyridines and aryl halides were achieved to afford corresponding mono and biarylated products. Exploring the reactivity of the synthesized complexes, our investigation with ruthenium catalysts inferred that pyridine based N,O donor ligands afforded enhanced catalytic activity compared to those obtained with the iminopyridine (N,N donor) ligands. Further, mass spectrometric investigations, during the catalytic and controlled reaction conditions, evidenced the presence of the crucial cycloruthenated species {(<i>η</i><sup>6</sup>-<i>p</i>-cymene)Ru(<i>κ</i><sup>2</sup>-<i>CN</i>-phenylpyridine)}<sup>+</sup> (m/z [M<sup>+</sup>] 390.0), along with a ligand coordinated species, {(<i>η</i><sup>6</sup>-<i>p</i>-cymene)Ru(<b>L1</b>)(<i>κ</i><sup>2</sup>-<i>CN</i>-phenylpyridine)}<sup>+</sup> (m/z [M<sup>+</sup>]+Na 539.0), suggesting the important role such intermediate species in C-H bond activation reactions. Moreover, molecular structures for few of the representative complexes were also authenticated by single crystal X-ray diffraction studies.</p>

In situ synthesis of ultra-small platinum nanoparticles using a water soluble polyphenolic polymer with high catalytic activity

RSC Advances ◽  
2014 ◽  
Vol 4 (93) ◽  
pp. 51745-51753 ◽  
Author(s):  
Tanmoy Maji ◽  
Sanjib Banerjee ◽  
Mrinmoy Biswas ◽  
Tarun K. Mandal
Keyword(s):  
Catalytic Activity ◽  
Organic Solvent ◽  
Platinum Nanoparticles ◽  
In Situ Synthesis ◽  
Reduction Technique ◽  
Water Soluble ◽  
High Catalytic Activity

Ultra-small platinum nanoparticles are generated by in situ polymer reduction technique which shows high catalytic activity in water and in organic solvent.

C-H bond Activation/Arylation over Arene-Ruthenium(II)-picolinate Complexes: Synthesis, Structure and Catalytic Activity

2017 ◽  
Author(s):  
Chinky Binnani ◽  
Rohit K. Rai ◽  
Deepika Tyagi ◽  
Shaikh M Mobin ◽  
Sanjay Kumar Singh
Keyword(s):  
Catalytic Activity ◽  
Bond Activation ◽  
Ruthenium Catalysts ◽  
Molecular Structures ◽  
Water Soluble ◽  
Aryl Halides ◽  
Donor Ligands ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Wide Range

<p>A series of water soluble arene-ruthenium(II) complexes [(<i>η</i><sup>6</sup>-arene)RuCl(κ<sup>2</sup>-L)]<sup>n+</sup> (n = 0, 1) (<b>[Ru]-1</b> – <b>[Ru]-12</b>) containing pyridine based N,O or N,N ligands (<b>L1-L6</b>) were synthesized and employed for the catalytic C-H bond activation/ arylation of 2-phenylpyridine with aryl halides in water. Efficient C-H bond activation/ arylation of a wide range of substituted 2-phenylpyridines and aryl halides were achieved to afford corresponding mono and biarylated products. Exploring the reactivity of the synthesized complexes, our investigation with ruthenium catalysts inferred that pyridine based N,O donor ligands afforded enhanced catalytic activity compared to those obtained with the iminopyridine (N,N donor) ligands. Further, mass spectrometric investigations, during the catalytic and controlled reaction conditions, evidenced the presence of the crucial cycloruthenated species {(<i>η</i><sup>6</sup>-<i>p</i>-cymene)Ru(<i>κ</i><sup>2</sup>-<i>CN</i>-phenylpyridine)}<sup>+</sup> (m/z [M<sup>+</sup>] 390.0), along with a ligand coordinated species, {(<i>η</i><sup>6</sup>-<i>p</i>-cymene)Ru(<b>L1</b>)(<i>κ</i><sup>2</sup>-<i>CN</i>-phenylpyridine)}<sup>+</sup> (m/z [M<sup>+</sup>]+Na 539.0), suggesting the important role such intermediate species in C-H bond activation reactions. Moreover, molecular structures for few of the representative complexes were also authenticated by single crystal X-ray diffraction studies.</p>

Pd(II) Complexes of N-Allyl Substituted N-Heterocyclic Carbenes

2004 ◽  
Vol 59 (11-12) ◽  
pp. 1519-1523 ◽  
Author(s):  
F. Ekkehardt Hahn ◽  
Beate Heidrich ◽  
Thomas Lügger ◽  
Tania Pape
Keyword(s):  
Allyl Bromide ◽  
Heterocyclic Carbenes ◽  
Ethyl Bromide ◽  
Imidazolium Salts ◽  
Imidazolium Salt ◽  
Butyl Lithium ◽  
X Ray ◽  
Square Planar

The unsymmetrically substituted imidazolium salt 1-ethyl-3-allyl-imidazolium bromide 1 was synthesized by treatment of imidazole with one equivalent each of n-butyl lithium and ethyl bromide followed by treatment with one equivalent of allyl bromide. The symmetrically substituted derivatives 1,3-diallyl-imidazolium bromide 2 and 1,3-bis(3-methyl-2-butenyl)-imidazolium bromide 3 were obtained from imidazole and two equivalents of allyl bromide or 4-bromo-2-methyl-2-butenyl bromide, respectively, in the presence of sodium hydrogencarbonate as a base. The imidazolium bromides 1- 3 react with Pd(OAc)2 to afford the palladium(II) dicarbene complexes trans-[PdBr2(L)2] (L = 1- ethyl-3-allyl-imidazolin-2-ylidene, 4; L = 1,3-diallyl-imidazolin-2-ylidene, 5; L = 1,3-di(3-methyl-2- butenyl)imidazolin-2-ylidene, 6) by in situ deprotonation of the imidazolium salts. The X-ray structure analyses of 4- 6 show all three complexes to be mononuclear with palladium(II) coordinated in a square-planar fashion by two carbene and two bromo ligands.

scholarly journals Pd-catalyzed decarboxylative Heck vinylation of 2-nitrobenzoates in the presence of CuF2

2010 ◽  
Vol 6 ◽  
Author(s):  
Lukas J Gooßen ◽  
Bettina Zimmermann ◽  
Thomas Knauber
Keyword(s):  
Carbon Dioxide ◽  
Catalyst System ◽  
Benzoic Acids ◽  
Wide Range

A new protocol for the decarboxylative Heck vinylation of benzoic acids is disclosed. In the presence of a catalyst system generated in situ from Pd(OAc)2 (2 mol %), CuF2 (2 equiv), and benzoquinone (0.5 equiv) in NMP, a wide range of olefins were coupled with various 2-nitrobenzoates at 130 °C with the release of carbon dioxide to afford the corresponding vinyl arenes in good yields.

scholarly journals Synthesis and Characterization of Amphiphilic Diblock Copolymer by Reverse Iodine Transfer Polymerization (RITP)

2019 ◽  
Vol 27 (2) ◽  
pp. 185-202 ◽  
Author(s):  
Wahiba Chaibi ◽  
Lamia Bennabi ◽  
Imene Boukhouya ◽  
Kaddour Guemra
Keyword(s):  
Diblock Copolymer ◽  
Self Assembly ◽  
Molecular Iodine ◽  
Water Soluble ◽  
H Nmr ◽  
Wide Range ◽  
Dynamic Light Scattering Technique ◽  
Ft Ir ◽  
Iodine Transfer

Abstract Iodine transfer radical homo- and diblock copolymerization of N-[3-(dimethylamino)propyl] methacrylamide (DMAPMA) with methyl methacrylate (MMA) were carried out in the presence of iodine I2 and 2,2′-azobis(isobutyronitrile) (AIBN) as chain transfer agent and initiator, respectively. Using reverse iodine transfer polymerization (RITP) method based on the in situ generation of transfer agents using molecular iodine I2. The homopolymer and copolymer were characterized by FT-IR and 1H NMR. The self-assembly behaviours of diblock copolymer in water are studied by viscosity and tensiometry techniques. The water-soluble fraction of P(DMAPMA-b-MMA) block copolymer formed micelles which were investigated at 25°C in water at 0.2 mg.mL−1 concentration using a tensiometry device. Dynamic light scattering technique (DLS) was performed over a wide range of concentration to determine hydrodynamic size of the aggregates.

Basic Properties of Calcium Phosphate Cement Scaffold

2012 ◽  
Vol 531 ◽  
pp. 354-357 ◽  
Author(s):  
Hua Liu ◽  
Xi Qing Liu ◽  
Jin Shuang Liang
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Volume Fraction ◽  
Bone Ingrowth ◽  
Clinical Applications ◽  
Water Soluble ◽  
Implant Fixation ◽  
Wide Range ◽  
Early Strength

Calcium phosphate cement (CPC) sets in situ to form hydroxyapatite and is highly promising for a wide range of clinical applications. However, its low strength limits its use to only non-stress applications, and its lack of macroporosity hinders cell infiltration, bone ingrowth and implant fixation. The aim of this study was to develop strong and macroporous CPC scaffolds by incorporating chitosan and water-soluble mannitol. The incorporation of chitosan could improve the handling properties of CPC. Mannitol provided the needed early strength of CPC and then dissolved to create macropores for tissue ingrowth. This study investigated the effects of mannitol volume fraction (0-70%) on CPC composite mechanical properties and macroporosity of the scaffold after mannitol dissolution.

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