Coating photoanodes with transition‐metal hydroxides (TMH) is a promising approach for improving photoelectrochemical (PEC) water oxidation. However, the present system still suffers from high charge recombination and sluggish surface reactions. Herein, effective charge separation is achieved at the same time as boosting the surface catalytic reaction for PEC water splitting through decoration of plasmon metal (Ag) in a semiconductor/TMH coupling system. The kinetic behavior at the semiconductor/TMH and TMH/electrolyte interfaces is systematically evaluated by employing intensity modulated photocurrent spectroscopy, scanning photoelectrochemical microscopy, and oxygen evolution reaction model. It is found that both charge transfer and surface catalysis dynamics are enhanced through local surface plasmon resonance of Ag nanoparticles. The as‐prepared BiVO4/Co(OH)x‐Ag exhibits remarkable activity (≈4.64 times) in PEC water splitting in comparison with pure BiVO4. Notably, this smart approach can be also applied to other TMH (Ni(OH)2), reflecting its universality. This work provides a guiding design method for solar energy conversion with the semiconductor‐TMH system.
Proteolysis targeting chimeras (PROTACs) have emerged as useful chemical probes and potential therapeutics by taking advantage of the ubiquitin−proteasome system to degrade intracellular disease-associated proteins. PROTACs are heterobifunctional molecules composed of a target protein ligand, E3 ubiquitin ligase ligand, and a linker between them. The generation of efficient PROTACs requires screening of many parameters, especially the lengths and types of the linkers. We report our proof-ofconcept study using a two-stage strategy to facilitate the development of PROTACs against the estrogen receptor (ER). In stage one, a library of close to 100 PROTACs was synthesized by simply mixing a library of ERα ligands containing a hydrazide functional group at different positions with a preassembled library of E3 ligase ligands bearing different types and lengths of linkers with a terminal aldehyde group in a 1:1 ratio. Cell-based screening occurred without further purification, because the formation of the acylhydrazone linkage is highly efficient and produces water as the only byproduct. Compound A3 was the most potent ER degrader in two ER+ cell lines (DC 50 = ∼ 10 nM, D max = ≥ 95%). Stage two involved transformation to a more stable amide linker to generate a more drug-like molecule. The new compound, AM-A3, showed comparable biological activity (DC 50 = 1.1 nM, D max = 98%) and induced potent antiproliferation (IC 50 = 13.2 nM, I max = 69%) in MCF-7. This proof-of -concept study demonstrates that the two-stage strategy can significantly facilitate the development of PROTACs against ER without the tedious process of making large numbers of PROTACs one by one. It has the potential to be expanded to many other targets.
The control of the stereochemistry at the anomeric position is still one of the major challenges of synthetic carbohydrate chemistry. We have developed a new strategy consisting of a chiral catalyst-directed acylation followed by a palladium-catalyzed glycosidation to achieve high α- and β-stereoselectivity on the anomeric position. The former process involves a dynamic kinetic diastereoselective acylation of lactols derived from Achmatowicz rearrangement, while the latter is a stereospecific palladium-catalyzed allylic alkylation.
Figure 3. a) Plausible mechanism. b) Scheme of the TCPP-Fe/Fe ultra-thin metallized film catalyzed oxidative dehydrogenation of aromatic hydrazides reactions. c) Catalytic efficiency in the reaction over the five cycles. 7 of 7) www.advancedsciencenews.com
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