نتایج جستجو برای: cocatalyst
تعداد نتایج: 432 فیلتر نتایج به سال:
Overall water splitting was achieved on a simple perovskite oxynitride photocatalyst, CaTaO2N, with an absorption edge at 510 nm. This photocatalyst, modified with a Rh-Cr bimetallic oxide cocatalyst, produced stoichiometric H2 and O2 steadily under UV and visible light irradiation after coating of the photocatalyst particles with amorphous Ti oxyhydroxide.
Chiral CuF-catalyzed asymmetric allylation of ketones and ketimines is described. Nucleophile activation via transmetallation (allylboronate to allylcopper), which is facilitated by a cocatalyst [La(OPr)3 or LiO iPr], is key for these reactions. A CuOTf–3KOtBu–DUPHOS complex is a comparably effective catalyst that reduces the required amount of chiral phosphines.
Covalent organic frameworks (COFs) are a new class of crystalline organic polymers that have garnered significant recent attention as highly promising H2 evolution photocatalysts. This Perspective discusses the advances in this field of energy research while highlighting the underlying peremptory factors for the rational design of readily tunable COF photoabsorber-cocatalyst systems for optimal...
Multinuclear aluminum cocatalysts have been obtained by the reaction of various phenols, alcohols or diols with trimethylaluminum and were used in situ or as isolated, well-defined species, for the activation of an iron(ii) or an iron(iii) pre-catalyst for the oligomerization of ethylene. The best cocatalyst candidate involves 2,2'-biphenol () in a /AlMe3 ratio of 2/3.
A method using quinidine and optically active binol-derived phosphoric acid as a cocatalyst to catalyze the asymmetric semipinacol rearrangement of 2,3-allenols forming optically active 3-bromo-3-enals that contain an all-carbon quaternary stereocenter has been developed. After some further treatments, the products with practical enantiomeric purity could be prepared.
[reaction: see text] We describe methodology for the in situ generation of reactive monosubstituted ketenes from acid chlorides through a shuttle deprotonation process using NaH as an inexpensive stoichiometric base and a crown ether cocatalyst. We have successfully applied this new procedure to the catalytic, asymmetric synthesis of beta-lactams and alpha-haloesters.
Photocatalytic hydrogen evolution over semiconducting niobate nanosheets is synergistically improved by coexisting photochemically inactive additives of clay particles and sodium chloride without precise nanoscopic structural regulation. In addition, the Pt cocatalyst loaded on the clay particles works better than that photodeposited on the photocatalytic nanosheets.
Graft poly(ε-caprolactone)s (PCLs) with high graft density were synthesized by using random copolymer poly(ethylene-co-vinyl alcohol) (EVOH) to initiate ring-opening polymerization of ε-caprolactone, with and without cocatalyst Sn(Oct)2. The graft copolymer were characterized by IR, 1H and 13C NMR. The solution property and the crystallization behavior were also investigated.
The application of chiral sulfinamides and achiral sulfonic acids as a cocatalyst system for enantioselective protonation reactions is described. Structurally simple, easily accessible sulfinamides were found to induce moderate-to-high ee's in the formation of 2-aryl-substituted cycloalkanones from the corresponding trimethylsilyl enol ethers.
The Mn-oxide/Nb:SrTiO3 photoelectrode for oxygen evolution reaction was investigated by in situ Mn K-edge XAFS spectroscopy under UV irradiation. The oxidization of the Mn oxide was observed via photoexcited carrier transfer, which results in the positive potential shift of the Mn oxide cocatalyst toward oxygen evolution reaction.
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