201011-40-7Relevant academic research and scientific papers
Catalysis with gold complexes immobilised on carbon nanotubes by π-π Stacking interactions: Heterogeneous catalysis versus the boomerang effect
Vriamont, Charles,Devillers, Michel,Riant, Olivier,Hermans, Sophie
, p. 12009 - 12017 (2013)
A new pyrene-tagged gold(I) complex has been synthesised and tested as a homogeneous catalyst. First, a simple 1,6-enyne was chosen as a model substrate for cyclisation by using different solvents to optimise the reaction conditions. The non-covalent immobilisation of our pyrene-tagged gold complex onto multi-walled carbon nanotubes through π-π stacking interactions was then explored to obtain a supported homogeneous catalyst. The heterogenised catalyst and its homogeneous counterpart exhibited similar activity in a range of enyne cyclisation reactions. Bearing in mind that π-π interactions are affected by temperature and solvent polarity, the reuse and robustness of the supported homogeneous catalyst was tested to explore the scope and limitations of the recyclability of this catalyst. Under the optimised conditions, recyclability was observed by using the concept of the boomerang effect. Copyright
Covalently and non-covalently immobilized clusters onto nanocarbons as catalysts precursors for cinnamaldehyde selective hydrogenation
Vriamont, Charles,Haynes, Tommy,McCague-Murphy, Emily,Pennetreau, Florence,Riant, Olivier,Hermans, Sophie
, p. 389 - 400 (2015/06/30)
Abstract Ru-based nanoparticles were deposited on carbon nanotubes and graphene via an organometallic approach involving mixed-metal clusters modified with appropriate ligands. These ligands allowed either covalent or non-covalent π-π interactions with the carbonaceous surfaces. The immobilized clusters were then coalesced at different temperatures to give carbon-supported nanoparticles of different sizes. The obtained catalysts were tested in the selective hydrogenation of cinnamaldehyde. It was found that the nature of the metal(s), support nature, incorporation method and activation temperature all had a profound influence on activity and selectivity. Interestingly, the selectivity could be shifted from cinnamyl alcohol (COL) to hydrocinnamaldehyde (HCAL) by changing the reaction solvent. The best catalysts gave a very high selectivity in cinnamyl alcohol, which is not the more thermodynamically favored product, and could be reused several times without loss of activity or selectivity.
'Click' Dendritic phosphines: Design, synthesis, application in Suzuki coupling, and recycling by nanofiltration
Janssen, Michele,Mueller, Christian,Vogt, Dieter
supporting information; experimental part, p. 313 - 318 (2009/10/20)
A new synthetic route towards stable molecular-weight enlarged monodentate phosphine ligands via 'click' chemistry was developed. These ligands were applied in the Pd-catalyzed Suzuki-Miyaura coupling of aryl halides and phenyl boronic acid. The supported systems show very similar activities compared to the unsupported analogues. Moreover, recycling experiments by means of nanofiltration using ceramic nanofiltration membranes demonstrate that these systems can be recovered and reused efficiently.
Phosphorus functionalized dendrimers and hyperbranched polymers: Is there a need for perfect dendrimers in catalysis?
Ribaudo, Fabrizio,Van Leeuwen, Piet,Reek, Joost
experimental part, p. 79 - 98 (2010/03/03)
In this paper we describe the facile and straightforward covalent functionalization of commercially available dendritic poly(propylenimine) and hyperbranched poly(ethylenimine) with P-containing functional groups. The P-functionalized macromolecules have been applied as multivalent ligands in the Pd-catalyzed allylic substitution reactions (batch and continuous process) using either morpholine or thiophenol as nucleophile. Palladium complexes of all described molecules are active in allylic substitution reactions. The PEI functionalized polymers appear more sensitive to small changes in the P/Pd ratio than the PPI analogues, but form catalysts that are more active. When used in a continuous flow process the macromolecules are completely retained by the nanofiltration membrane, while the catalytic activity decreases with time because of palladium depletion. This is more severe for the allylic thiolation, probably because of the stronger affinity of sulfur for palladium, facilitating palladium leaching.
First fluorescent photoinduced electron transfer (PET) reagent for hydroperoxides
Onoda, Maki,Uchiyama, Seiichi,Endo, Atsushi,Tokuyama, Hidetoshi,Santa, Tomofumi,Imai, Kazuhiro
, p. 1459 - 1461 (2007/10/03)
(Matrix presented) A novel fluorescent reagent for hydroperoxides, 4-(2-diphenylphosphinoethylamino)-7-nitro-2,1,3-benzoxadiazole (1), was developed on the basis of the method for designing photoinduced electron transfer (PET) reagents having a benzofurazan skeleton. Compound 1 was quantitatively reacted with hydroperoxides to give its fluorescent derivative, 2. In acetonitrile, the Φ value (0.44) of 2 was 31 times greater than that of 1. The long excitation (458 nm) and emission (520 nm) wavelengths of 2 are suitable for the determination of hydroperoxides, especially in biosamples.
Palladium-catalyzed biaryl-coupling reaction of arylboronic acids in water using hydrophilic phosphine ligands
Nishimura, Masato,Ueda, Masato,Miyaura, Norio
, p. 5779 - 5787 (2007/10/03)
Hydrophilic phosphine ligands possessing a carbohydrate side-chain, such as N-(4-diphenylphosphinophenyl)methyl gluconamide (9), N-[4-(2′-dicyclohexylphosphinobiphenyl)phenylmethyl] gluconamide (10), and N-[4-(2′-di-t-butylphosphinobiphenyl)]phenylmethyl gluconamide (11), were newly synthesized to carry out palladium-catalyzed biaryl coupling of arylboronic acids in a single aqueous medium. The catalyst prepared in situ from Pd(OAc)2 and 10 exhibited a higher efficiency than that of 9, 11, Ph2P(m-C6H4SO3Na) (TPPMS) or P(m-C6H4SO3Na)3 (TPPTS) for representative aryl bromides, chlorides, or triflates. The catalyst prepared in situ from Pd(OAc)2 (0.001mol%) and 10 (0.002mol%) achieved 96,000 TON in the reaction of p-tolylboronic acid with 4-bromoacetophenone in water.
A palladium-catalyzed biaryl coupling of arylboronic acids in aqueous media using a gluconamide-substituted triphenylphosphine (GLCAphos) ligand
Ueda, Masato,Nishimura, Masato,Miyaura, Norio
, p. 856 - 858 (2007/10/03)
A water-soluble phosphine ligand, N-(4-diphenyl-phosphino)phenylmethyl gluconamide (GLCAphos), was newly synthesized to perform the palladium- catalyzed biaryl coupling of arylboronic acids in a single aqueous media. The catalyst prepared from GLCAphos revealed higher activity than that synthesized from Ph2P(m-C6H4SO3Na) or P(m-C6H4SO3Na)3 for various haloarenes.
Nucleophilic phosphanylation of fluoroaromatic compounds with carboxyl, carboxymethyl, and aminomethyl functionalities - An efficient synthetic route to amphiphilic arylphosphanes
Hingst, Martin,Tepper, Michael,Stelzer, Othmar
, p. 73 - 82 (2007/10/03)
Chiral- and multiply-carboxylated phosphanes and phosphanyl derivatives of benzoic and phthalic acids (1-9) are accessible in high yields by nucleophilic phosphanylation of potassium or lithium salts of commercially available fluorobenzoic and 3-fluorophthalic acids with Ph2PH, Ph2PK, PhPLi2, Ph(K)P-(CH2)3-P(K)Ph in superbasic media (DMSO/KOH) or in THF and DME. The hitherto unknown phosphanylphenylacetic acids (10-13) and phosphanylbenzylamines RR′P-C6H4-CH2-NH2 (14-19, R, R′ = H, Me, Ph) with unsubstituted amino groups were also synthesized by this method. The diphenylphosphanyl derivatives 14-16 (R, R′ = Ph) are accessible by an alternative method involving LiAlH4 reduction of the phosphanylbenzonitriles (20-22), which were obtained in high yields by nucleophilic phosphanylation of the corresponding fluoro- or chlorobenzonitriles. The novel bidentate phosphanylbenzonitrile 23 has also been obtained using this synthetic route. All compounds were completely characterized by elemental analysis, NMR spectroscopy, and mass spectrometry.
