Copper-catalyzed coupling reactions of alkyl halides are believed to prominently involve copper(II) species and alkyl radicals as pivotal intermediates, with their exact interaction mechanism being the subject of considerable debate. In this study, a visible light-responsive fluoroalkylcopper(III) complex, [(terpy)Cu(CF3)(2)((CH2CO2Bu)-Bu-t)] Trans-1, was designed to explore the mechanism. Upon exposure to blue LED irradiation, Trans-1 undergoes copper-carbon bond homolysis, generating Cu(II) species and carbon-centered radicals, where the carbon-centered radical then recombines with the Cu(II) intermediate, resulting in the formation of Cis-1, the Cis isomer of Trans-1. Beyond this, a well-defined fluoroalkylcopper(II) intermediate ligated with a sterically hindered ligand was isolated and underwent full characterization and electronic structure studies. The collective experimental, computational, and spectroscopic findings in this work strongly suggest that organocopper(II) engages with carbon-centered radicals via an oxidative substitution mechanism, which is likely the operational pathway for copper-catalyzed C-H bond trifluoromethylation reactions.

Developing olefin polymerization catalytic systems for both high activity and high chain transfer efficiency by using coordinative chain transfer polymerization (CCTP) is critical for the controlled synthesis of various novel high-value polyolefin materials. While the limited choice of chain transfer agents (CTAs) makes it a challenge to achieve highly efficient CCTP as well as chain propagation due to their competition during the polymerization. Here we report using the combination of R3Al 3 Al and R2Zn 2 Zn in equal amount for tetradentate amine-bis(phenolate) Ti complex and tridentate ketoiminate Ti complex catalyzed ethylene polymerization and observed significantly enhanced CCTP catalytic performance in terms of activity, chains/cat, fill ratio, and k ct / k p vs. using R3Al 3 Al as CTA. The role of R3Al 3 Al and R2Zn 2 Zn during ethylene polymerization were probed by preliminary control experiments studies and a possible mechanistic scenario was proposed.

AimsWe evaluated the potential of Parkinson's disease (PD) fecal microbiota transplantation to initiate or exacerbate PD pathologies and investigated the underlying mechanisms. MethodsWe transplanted the fecal microbiota from PD patients into mice by oral gavage and assessed the motor and intestinal functions, as well as the inflammatory and pathological changes in the colon and brain. Furthermore, 16S rRNA gene sequencing combined with metabolomics analysis was conducted to assess the impacts of fecal delivery on the fecal microbiota and metabolism in recipient mice. ResultsThe fecal microbiota from PD patients increased intestinal inflammation, deteriorated intestinal barrier function, intensified microglia and astrocyte activation, abnormal deposition of alpha-Synuclein, and dopaminergic neuronal loss in the brains of A53T mice. A mechanistic study revealed that the fecal microbiota of PD patients stimulated the TLR4/NF-kappa B/NLRP3 pathway in both the brain and colon. Additionally, multiomics analysis found that transplantation of fecal microbiota from PD patients not only altered the composition of the gut microbiota but also influenced the fecal metabolic profile of the recipient mice. ConclusionThe fecal microbiota from PD patients intensifies inflammation and neurodegeneration in A53T mice. Our findings demonstrate that imbalance and dysfunction in the gut microbiome play significant roles in the development and advancement of PD.

A six-cyclic crown ether-type pillar[5]arene was synthesized, and the five ethylene oxide loops were located outside the cavity and not affected by temperature changes which was confirmed by variable-temperature NMR experiment in DMSO-d6 and CDCl3 and 2D 1H-1H NOESY experiment in CDCl3. The six-cyclic pillar[5]-crown also showed greater binding ability of host-guest with bis(pyridinium) derivatives than conventional alkoxy pillar[5]arenes that illustrated through 1H NMR titration spectroscopic experiment in acetone-d6/CDCl3 (1 : 1) and UV-vis titration experiments in CHCl3 at room temperature. The five benzocrown ethers at the periphery were able to bind metal cations by 1H NMR titration spectroscopic experiment in CD2Cl2/methanol-d4(9 : 1). A new six-cyclic crown ether-type pillar[5]arene was synthesized, and the five ethylene oxide loops at the periphery were able to bind metal cations and the cavity of pillararene skeleton showed greater binding ability of host-guest with bispyridinium derivatives than conventional alkoxy pillar[5]arenes. image

The oxyalkynylation of alkenes offers a valuable strategy for constructing C-C and C-O bonds, generating beta-alkynyl alcohols frequently found in bioactive molecules. This work presents a photocatalytic approach for the oxyalkynylation of readily available unactivated alkenes using hypervalent iodine(III) reagents, acetoxylbenziodoxole (BI-OAc) and alkynylbenziodoxole (BI-alkyne), to afford anti-Markovnikov beta-alkynyl alcohols. Mechanistic studies reveal a unique energy transfer process between BI-OAc and the photocatalyst, leading to the efficient generation of aryl carboxyl radicals. The aryl carboxyl radicals initiate atom-economical addition reactions with a broad range of commercially available mono-, di-, and trisubstituted alkenes, achieving anti-Markovnikov regioselectivity with BI-alkynes. The reaction can be readily scaled up to the gram scale, demonstrating its potential for late-stage modification of natural products and drug molecules. This method represents a significant advance in leveraging hypervalent iodine(III) reagents for radical generation and opens exciting avenues for future reaction design and development.