Recently published reactions of group 4 metallocene bis(trimethylsilyl)acetylene (btmsa) complexes from the last two years are reviewed. Complexes like Cp' Ti(η -Me SiC SiMe ) and Cp Zr(py)(η -Me SiC SiMe ) with Cp' as Cp (cyclopentadienyl) and Cp* (pentamethylcyclopentadienyl) have been considered (py=pyridine). These complexes can liberate a reactive low-valent titanium or zirconium center by dissociation of the ligands and act as ''masked'' M complexes (M=Ti, Zr). They represent excellent sources for the clean generation of the reactive coordinatively and electronically unsaturated complex fragments [Cp' M]. This is the reason why they were used for many synthetic and catalytic reactions during the last years. As an update to several review articles on this topic, this contribution provides an update with recent examples of preparative organometallic and organic chemistry of these complexes, acting as reagents for a wide range of coordinating and coupling reactions. In addition, applications and investigations concerning reaction products derived from this chemistry are mentioned, too.
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http://dx.doi.org/10.1002/open.202100258 | DOI Listing |
J Am Chem Soc
January 2025
Molecular Synthesis Center, Key Laboratory of Marine Drugs of Ministry of Education, Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
2-Deoxy-β-glycosides are essential components of natural products and pharmaceuticals; however, the corresponding 2-deoxy-β-glycosidic bonds are challenging to chemically construct. Herein, we describe an efficient catalytic protocol for synthesizing 2-deoxy-β-glycosides via either IPrAuNTf-catalyzed activation of a unique 1,2--positioned C2--propargyl xanthate (OSPX) leaving group or (PhO)PAuNTf-catalyzed activation of a 1,2--C2--alkynylbenzoate (OABz) substituent of the corresponding thioglycosides. These activation processes trigger 1,2-alkyl/arylthio-migration glycosylation, enabling the synthesis of structurally diverse 2-deoxy-β-glycosides under mild reaction conditions.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
Organic redox systems that can undergo oxidative and reductive (ambipolar) electron transfer are elusive yet attractive for applications across synthetic chemistry and energy science. Specifically, the use of ambipolar redox systems in proton-coupled electron transfer (PCET) reactions is largely unexplored but could enable "switchable" reactivity wherein the uptake and release of hydrogen atoms are controlled using a redox stimulus. Here, we describe the synthesis and characterization of an ambipolar functionalized terthiophene (TTH) bearing methyl thioether and phosphine oxide groups that exhibits switchable PCET reactivity.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
State Key Laboratory of Advanced Chemical Power Sources (Chongqing University), Chongqing 400044, China.
Investigating how the size of carbon support pores influences the three-phase interface of platinum (Pt) particles in fuel cells is essential for enhancing catalyst utilization. This study employed molecular dynamics simulations and density functional theory calculation to examine the effects of mesoporous carbon support size, specifically its pore diameter, on Nafion ionomer distribution, as well as on proton and gas/liquid transport channels, and the utilization of Pt active sites. The findings show that when Pt particles are located within the pores of carbon support (Pt/PC), there is a significant enhancement in the spatial distribution of Nafion ionomer, along with a reduction in encapsulation around the Pt particles, compared to when Pt particles are positioned on the surface or in excessively large pores of the carbon support.
View Article and Find Full Text PDFRev Esc Enferm USP
January 2025
Universidade Federal de Viçosa, Departamento de Medicina e Enfermagem, Viçosa, MG, Brazil.
Objective: To compare the effectiveness of ear acupuncture with laser and needles in the treatment of anxiety in university students in the post-pandemic context of Covid-19, as well as to evaluate the possible symptoms or adverse reactions triggered by the interventions.
Method: Randomized clinical trial carried out with 126 university students, allocated to the "Needle" (control) and "Laser" (experimental) groups. Five ear acupuncture sessions were performed.
PLoS One
January 2025
Departamento de Psicología Evolutiva y Comunicación, Campus Universitario de Vigo, University of Vigo, Vigo, Spain.
The main purpose of this study was to examine the age-related changes in inhibitory control of 450 children at the ages of 7-8, 11-12, and 14-16 when controlling for working memory capacity (WMC) and processing speed to determine whether inhibition is an independent factor far beyond its possible reliance on the other two factors. This examination is important for several reasons. First, empirical evidence about age-related changes of inhibitory control is controversial.
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