3602-55-9Relevant articles and documents
Size effect of gold nanoparticles supported on carbon nanotube as catalysts in selected organic reactions
Jawale, Dhanaji V.,Gravel, Edmond,Geertsen, Valérie,Li, Haiyan,Shah, Nimesh,Kumar, Rahul,John, Jubi,Namboothiri, Irishi N.N.,Doris, Eric
, p. 6140 - 6145 (2014)
Carbon nanotube-supported gold nanoparticles of different sizes (diameter of 3 or 20 nm) were evaluated as catalysts in four selected organic transformations. The nanohybrids were shown to efficiently catalyze the investigated reactions, regardless of the size of the supported gold nanoparticles. However, some differences were observed as regards turnover frequency values although size effect turned out to be less significant when only gold surface atoms were considered.
Simple homopolymer-incarcerated gold nanoclusters prepared by self-assembled encapsulation with aluminum reagents as crosslinkers: Catalysts for aerobic oxidation reactions
Yasukawa, Tomohiro,Miyamura, Hiroyuki,Kobayashi, Shu
, p. 50 - 52 (2015)
Simple homopolymer-incarcerated gold nanocluster catalysts were developed using a self-assembled encapsulation strategy. In this method, Red-Al acting as a reductant also played the role of an inter-crosslinker via the formation of tetraalkoxyaluminate with the hydroxy groups in a homopolymer. Gold nanoclusters could be immobilized at high loadings without aggregation, and high catalytic activities were observed in several aerobic oxidation reactions.
Aerobic Oxidation of Dihydroxyarenes Substrates Catalyzed by Polymer-Supported RuII-Pheox/Silica-Gel: A Beneficial Route for Purification of Industrial Water
Abu-Elfotoh, Abdel-Moneim
supporting information, p. 236 - 243 (2022/04/09)
A broad class of dihydroxyarenes were easily oxidized by aerobic oxygen to quinone products in excellent yields under the catalytic effect of polymer-supported RuII-Pheox/silica-gel catalyst. By using this combined catalyst, hydroquinone and catechol derivatives with electron-donating groups were easily oxidized by molecular oxygen to quinone products in 90% to >99% yield, while in the case of electron-withdrawing group, only 70% was obtained. The biologically useful 1,4-Naphthoqinone products were obtained in 83% to 90%. The catalyst was easily obtained and reused many times without a significant decrease in reactivity. Interestingly, a sample of industrial water contaminated with phenolic compounds was subjected to aerobic oxidation by using this catalyst, and the resultant quinones were detected within one day and the catalyst was removed and reused several times with different contami-nating samples with the same efficiency. Other catalytic oxidations by using this promising catalyst were investigated.
Benzoquinone Cocatalyst Contributions to DAF/Pd(OAc)2-Catalyzed Aerobic Allylic Acetoxylation in the Absence and Presence of a Co(salophen) Cocatalyst
Kozack, Caitlin V.,Tereniak, Stephen J.,Jaworski, Jonathan N.,Li, Bao,Bruns, David L.,Knapp, Spring M. M.,Landis, Clark R.,Stahl, Shannon S.
, p. 6363 - 6370 (2021/05/29)
Palladium(II)-catalyzed allylic acetoxylation has been the focus of extensive development and investigation. Methods that use molecular oxygen (O2) as the terminal oxidant typically benefit from the use of benzoquinone (BQ) and a transition-metal (TM) cocatalyst, such as Co(salophen), to support oxidation of Pd0 during catalytic turnover. We previously showed that Pd(OAc)2 and 4,5-diazafluoren-9-one (DAF) as an ancillary ligand catalyze allylic oxidation with O2 in the absence of cocatalysts. Herein, we show that BQ enhances DAF/Pd(OAc)2 catalytic activity, nearly matching the performance of reactions that include both BQ and Co(salophen). These observations are complemented by mechanistic studies of DAF/Pd(OAc)2 catalyst systems under three different oxidation conditions: (1) O2 alone, (2) O2 with cocatalytic BQ, and (3) O2 with cocatalytic BQ and Co(salophen). The beneficial effect of BQ in the absence of Co(salophen) is traced to the synergistic roles of O2 and BQ, both of which are capable of oxidizing Pd0 to PdII. The reaction of O2 generates H2O2 as a byproduct, which can oxidize hydroquinone to quinone in the presence of PdII. NMR spectroscopic studies, however, show that hydroquinone is the predominant redox state of the quinone cocatalyst in the absence of Co(salophen), while inclusion of Co(salophen) maintains oxidized quinone throughout the reaction, resulting in better reaction performance.
Oxidative radical coupling of hydroquinones and thiols using chromic acid: One-pot synthesis of quinonyl alkyl/aryl thioethers
Adarsh Krishna, T. P.,Chinnasamy, Suresh,Ilangovan, Andivelu,Pandaram, Sakthivel
, p. 19454 - 19462 (2020/06/04)
An efficient, simple and practical protocol for one-pot sequential oxidative radical C-H/S-H cross-coupling of thiols with hydroquinones (HQs) and oxidation leading to the formation of quinonyl alkyl/aryl thioethers using H2CrO4was developed. This cross-coupling of thiyl and aryl radicals offers mono thioethers in good to moderate yield and works well with a wide variety of thiols. Similarly, this method works well for coupling of 2-amino thiophenol and HQs to form phenothiazine-3-ones5a-c. C-S bond formationviathioether synthesis was observed using a chromium reagent for the first time. Theoretical studies on the pharmacokinetic properties of compounds5a-crevealed that due to drug-like properties, compound5bstrongly binds with Alzheimer's disease (AD) associated AChE target sites.
