54737-75-6Relevant academic research and scientific papers
Ruthenium-Catalyzed E-Selective Partial Hydrogenation of Alkynes under Transfer-Hydrogenation Conditions using Paraformaldehyde as Hydrogen Source
Fetzer, Marcus N. A.,Tavakoli, Ghazal,Klein, Axel,Prechtl, Martin H. G.
, p. 1317 - 1325 (2021/02/11)
E-alkenes were synthesized with up to 100 % E/Z selectivity via ruthenium-catalyzed partial hydrogenation of different aliphatic and aromatic alkynes under transfer-hydrogenation conditions. Paraformaldehyde as a safe, cheap and easily available solid hydrogen carrier was used for the first time as hydrogen source in the presence of water for transfer-hydrogenation of alkynes. Optimization reactions showed the best results for the commercially available binuclear [Ru(p-cymene)Cl2]2 complex as pre-catalyst in combination with 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP) as ligand (1 : 1 ratio per Ru monomer to ligand). Mechanistic investigations showed that the origin of E-selectivity in this reaction is the fast Z to E isomerization of the formed alkenes. Mild reaction conditions plus the use of cheap, easily available and safe materials as well as simple setup and inexpensive catalyst turn this protocol into a feasible and promising stereo complementary procedure to the well-known Z-selective Lindlar reduction in late-stage syntheses. This procedure can also be used for the production of deuterated alkenes simply using d2-paraformaldehyde and D2O mixtures.
Nonmonotonic dependence of intramolecular charge-transfer sidechain interactions for triazole containing phenylene-ethynylene grafted Co-Polyoxetane brushes
Gon, Masayuki,Chujo, Yoshiki,Zolotarskaya, Olga,Wynne, Kenneth J.
, (2021/03/04)
This research explores effects of introduction of the rigid phenylene ethynylene (PEy) moiety as a side chain in polyoxetanes. The synthesis of PEy-grafted polyoxetanes was carried out via Huisgen copper (I) catalyzed alkyne-azide cycloaddition. These polymers have a flexible main chain (low Tg polyoxetane) and rigid side chains (phenylene ethynylene). Compositions for copolyoxetanes with PEy and alkynyl side chains were determined by 1H-NMR spectroscopy. Mole percents PEy, designated P-%, were P-21, P-44, P-69 and P-100. UV-VIS spectra for P-21, P-44, P-69, P-100 at 330 nm showed differentiation based on assignments to intramolecular charge-transfer (ICT) interactions between triazole and phenylene ethylene moieties. Interestingly, instead of a monotonic increase, absorption intensity is in the order P-69 ~ P-44 > P-100 > P-21. Low substitution and mainchain flexibility and account for P-21 having the lowest UV-VIS absorption at 330 nm. P-44 and P-69 have similar strong absorptions at 330 nm with overlapping curves. Steric effects culminate in P-100, which has the highest PEy content but a lower absorption at 330 nm than P-69 but higher than P-21. A model for optical absorptions for PEy copolyoxetanes is described that includes the effect of the rigid PEy side chain in decreasing molecular mobility.
Benzimidazolium salts prevent and disrupt methicillin-resistant: Staphylococcus aureus biofilms
Schmitzer, Andreea R.,Tessier, Jérémie
, p. 9420 - 9430 (2020/03/19)
Emergence of resistant bacteria encourages us to develop new antibiotics and strategies to compensate for the different mechanisms of resistance they acquire. One of the defense mechanisms of resistant bacteria is the formation of biofilms. Herein we show
Sulphonic acid functionalized porphyrin anchored with a: Meso -substituted triazolium ionic liquid moiety: A heterogeneous photo-catalyst for metal/base free C-C cross-coupling and C-N/C-H activation using aryl chloride under visible light irradiation
Bhansali, Karan,Raut, Subodh,Barange, Shital,Bhagat, Pundlik
, p. 19690 - 19712 (2020/12/04)
We report an easy process to synthesize sulphonic acid functionalized porphyrin, anchored with a meso-substituted triazolium ionic liquid moiety (SAFPTILM) for metal/base free C-C cross-coupling and C-N/C-H activation using aryl chloride under visible light irradiation. The acid strength has been measured based on the Hammett indicator. The SAFPTILM photocatalyst comprising 18 π-conjugated electronic systems with the chromophore substituents in the meso-position can provide rapid electronic conducting channels during photocatalysis under the irradiation of visible light. It was found that SAFPTILM is an efficient photocatalyst for the Heck, Sonogashira, Buchwald, Ullmann/Fittig coupling and C-H activation of phenols with different aryl chlorides in the absence of a base/noble metal, using 5 W LED (yellow) light under ambient conditions. The photocatalyst with low band gap (1.55 eV) comprising conjugation, favors coupling reaction of unactivated aryl chlorides, by easy excitation of electrons and transfer to the conjugated benzimidazolium based phenylenediamine support delaying the recombination of photoinduced electron-hole pairs.
Diaminodiphosphine tetradentate ligand and ruthenium complex thereof, and preparation methods and applications of ligand and complex
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Paragraph 0316-0319, (2019/11/04)
The invention discloses a diaminodiphosphine tetradentate ligand and a ruthenium complex thereof, and preparation methods and applications of the ligand and the complex, and provides a ruthenium complex represented by a formula I, wherein L is a diaminodiphosphine tetradentate ligand represented by a formula II, and X and Y are respectively and independently chlorine ion, bromine ion, iodine ion,hydrogen negative ion or BH4. According to the present invention, the ruthenium complex exhibits excellent catalytic activity in the catalytic hydrogenation reactions of ester compounds, has high yield and high chemical selectivity, is compatible with conjugated and non-conjugated carbon-carbon double bond, carbon-carbon triple bond, epoxy, halogen, carbonyl and other functional groups, and hasgreat application prospects.
Arylation of Terminal Alkynes by Aryl Iodides Catalyzed by a Parts-per-Million Loading of Palladium Acetate
Hamasaka, Go,Roy, David,Tazawa, Aya,Uozumi, Yasuhiro
, p. 11640 - 11646 (2019/12/02)
Arylation of terminal alkynes (16 varieties) by aryl iodides (28 varieties) was achieved with a mol ppm loading level of palladium catalyst, where a variety of functional groups including heteroarenes were tolerated. Thus, the arylations were carried out in the presence of palladium acetate at ppm loadings and potassium carbonate in ethanol at 80 °C to give the corresponding internal alkynes in good to excellent yields. Synthesis of 2-phenyl-3-(phenylalkynyl)benzofuran was achieved by iterative use of the alkyne arylation under mol ppm catalytic conditions. Reaction-rate analysis, transmission electron microscopic (TEM) examination of the reaction mixture, and mercury-amalgamation test were performed to gain insight into the active species of the highly active ppm catalytic species. TEM examination of the reaction mixture revealed that palladium nanoparticles were generated in situ under the reaction conditions, and their cluster size was variable during the catalytic reaction. A variation in size of palladium particles suggested that the composition-decomposition process of Pd aggregates should take place in situ via monomeric palladium(0) species and/or fine palladium(0) clusters, which might be real catalytic species in this reaction.
A Highly Active Manganese Catalyst for Enantioselective Ketone and Ester Hydrogenation
Widegren, Magnus B.,Harkness, Gavin J.,Slawin, Alexandra M. Z.,Cordes, David B.,Clarke, Matthew L.
supporting information, p. 5825 - 5828 (2017/05/12)
A new hydrogenation catalyst based on a manganese complex of a chiral P,N,N ligand has been found to be especially active for the hydrogenation of esters down to 0.1 mol % catalyst loading, and gives up to 97 % ee in the hydrogenation of pro-chiral deactivated ketones at 30–50 °C.
Hydrogenation of Carbonyl Derivatives with a Well-Defined Rhenium Precatalyst
Wei, Duo,Roisnel, Thierry,Darcel, Christophe,Clot, Eric,Sortais, Jean-Baptiste
, p. 80 - 83 (2017/01/17)
The first efficient and general rhenium-catalyzed hydrogenation of carbonyl derivatives was developed. The key to the success of the reaction was the use of a well-defined rhenium complex bearing a tridentate diphosphinoamino ligand as the catalyst (0.5 mol %) at 70 °C in the presence of H2 (30 bar). The mechanism of the reaction was investigated by DFT(PBE0-D3) calculations.
E-selective semi-hydrogenation of alkynes with dinuclear iridium complexes under atmospheric pressure of hydrogen
Higashida, Kosuke,Mashima, Kazushi
supporting information, p. 866 - 868 (2016/08/13)
Semi-hydrogenation of alkynes was catalyzed by halide-bridged dinuclear iridium complexes, yielding (E)-alkenes with high selectivity. Mechanistic studies conducted with monohydride dinuclear species, dihydride mononuclear species, and trihydride dinuclear species led us to propose a mechanism involving dual cycles.
On the Functional Group Tolerance of Ester Hydrogenation and Polyester Depolymerisation Catalysed by Ruthenium Complexes of Tridentate Aminophosphine Ligands
Fuentes, José A.,Smith, Samuel M.,Scharbert, M. Theresa,Carpenter, Ian,Cordes, David B.,Slawin, Alexandra M. Z.,Clarke, Matthew L.
, p. 10851 - 10869 (2015/07/20)
The synthesis of a range of phosphine-diamine, phosphine-amino-alcohol, and phosphine-amino-amide ligands and their ruthenium(II) complexes are reported. Five of these were characterised by X-ray crystallography. The activities of this collection of catalysts were initially compared for the hydrogenation of two model ester hydrogenations. Catalyst turnover frequencies up to 2400 h-1 were observed at 85 °C. However, turnover is slow at near ambient temperatures. By using a phosphine-diamine RuII complex, identified as the most active catalyst, a range of aromatic esters were reduced in high yield. The hydrogenation of alkene-, diene-, and alkyne-functionalised esters was also studied. Substrates with a remote, but reactive terminal alkene substituent could be reduced chemoselectively in the presence of 4-dimethylaminopyridine (DMAP) co-catalyst. The chemoselective reduction of the ester function in conjugated dienoate ethyl sorbate could deliver (2E,4E)-hexa-2,4-dien-1-ol, a precursor to leaf alcohol. The monounsaturated alcohol (E)-hex-4-en-1-ol was produced with reasonable selectivity, but complete chemoselectivity of C=O over the diene is elusive. High chemoselectivity for the reduction of an ester over an alkyne group was observed in the hydrogenation of an alkynoate for the first time. The catalysts were also active in the depolymerisation reduction of samples of waste poly(ethylene terephthalate) (PET) to produce benzene dimethanol. These depolymerisations were found to be poisoned by the ethylene glycol side product, although good yields could still be achieved. A simple catalyst for difficult reductions: Ruthenium complexes of P,N,N and P,N,O ligands catalyse the reduction of esters with high activities. The Ru complex of a phosphine-diamine ligand (see scheme) has been found to be a good catalyst for reducing alkene-, diene-, and alkyne-functionalised esters, displaying good activity and chemoselectivity. This catalyst was also active in the hydrogenation of waste poly(ethylene terephthalate) (PET).
