Study the Mechanism of Formation of Different Products of the Reaction Between Propargyl and Methyl Radicals

The mechanism of the reaction between propargyl radical (C3H3) and methyl radical (CH3) has been studied by the quantum chemical method using the M06-2X functional in conjunction with the aug-cc-pVTZ basis set. The potential energy surface (PES) for the C3H3 + CH3 system has been established. The calculated results indicate that the C3H3 + CH3 reaction has two main entrance channels leading to two stabilized intermediates, buta-1,2-diene and but-1-yne, which become the major intermediate products of the reaction system. From these two intermediate states, 19 different bimolecular products can be formed. For which, C2H2 + C2H4 is the most thermodynamically favorable product.

Maternal methionine supplementation in mice affects long-term body weight and locomotor activity of adult female offspring

Methionine is a precursor of s-adenosylmethionine (SAM), the main donor of methyl radicals for methylation of DNA and other compounds. Previous studies have shown that reduced availability of methyl radicals during pregnancy/lactation decreased offspring perigonadal white adipose tissue (PWAT) and body weight. Therefore, we aimed to evaluate the effects of methionine supplementation during early development, a time of great ontogenic plasticity, by assessing the biometric, biochemical, and behavioral parameters of the offspring of adult Swiss female mice supplemented with 1% methionine in water one month before pregnancy, and during pregnancy or pregnancy/lactation. After birth, the offspring were distributed into three groups: control (CT), methionine supplementation during pregnancy (SP) and methionine supplementation during pregnancy and lactation (SPL), and were followed until postnatal day (PND) 300. No changes were observed in offspring birth weight in both sexes. At PND 5, 28, 90 no differences in body weight were found in females, however, at PND 300 SP and SPL females showed an increase in body weight when compared to the control group. This increase in body weight was accompanied by a total and relative increase in PWAT, and a decrease in locomotor activity in these groups. No differences in the body and organ weights were found in male offspring. In conclusion, the increased availability of methyl radicals during pregnancy and lactation impacted long-term body composition and locomotor activity in female offspring.

Mixed-Halide Triphenyl Methyl Radicals for Site-Selective Functionalization and Polymerization

<p>Derivatives of the stable, luminescent tris-2,4,6-trichlorophenylmethyl (TTM) radical exhibit unique doublet spin properties that are of interest for applications in optoelectronics, spintronics, and energy storage. However, the synthesis and variety of TTM-type donor-acceptor molecules with high quantum yields are limited by the symmetric chloride decoration and poor reactivity of chlorides in metal-catalyzed C-C cross-coupling reactions. Therefore, only few donor-acceptor molecules have been successfully coupled to the TTM radical motif. Here, we present a synthetic pathway to obtain mixed-halide derivatives of TTM, partly carrying bromo- instead of chloro-substituents, leading to improved reactivity and enabling site-specific cross-coupling reactions. These highly stable mixed-halide triphenyl methyl radicals represent a powerful tool to obtain complex, and so far inaccessible open-shell small molecules, as well as polymers.</p>

Mixed-Halide Triphenyl Methyl Radicals for Site-Selective Functionalization and Polymerization

<p>Derivatives of the stable, luminescent tris-2,4,6-trichlorophenylmethyl (TTM) radical exhibit unique doublet spin properties that are of interest for applications in optoelectronics, spintronics, and energy storage. However, the synthesis and variety of TTM-type donor-acceptor molecules with high quantum yields are limited by the symmetric chloride decoration and poor reactivity of chlorides in metal-catalyzed C-C cross-coupling reactions. Therefore, only few donor-acceptor molecules have been successfully coupled to the TTM radical motif. Here, we present a synthetic pathway to obtain mixed-halide derivatives of TTM, partly carrying bromo- instead of chloro-substituents, leading to improved reactivity and enabling site-specific cross-coupling reactions. These highly stable mixed-halide triphenyl methyl radicals represent a powerful tool to obtain complex, and so far inaccessible open-shell small molecules, as well as polymers.</p>

C(sp3)–H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling

The “magic methyl” effect describes the change in potency, selectivity, and/or metabolic stability of a drug candidate associated with addition of a single methyl group. We report a synthetic method that enables direct methylation of C(sp3)–H bonds in diverse drug-like molecules and pharmaceutical building blocks. Visible light–initiated triplet energy transfer promotes homolysis of the O–O bond in di-tert-butyl or dicumyl peroxide under mild conditions. The resulting alkoxyl radicals undergo divergent reactivity, either hydrogen-atom transfer from a substrate C–H bond or generation of a methyl radical via β-methyl scission. The relative rates of these steps may be tuned by varying the reaction conditions or peroxide substituents to optimize the yield of methylated product arising from nickel-mediated cross-coupling of substrate and methyl radicals.

Alkali-Added Catalysts Based on LaAlO3 Perovskite for the Oxidative Coupling of Methane

In this study, we aimed to enhance the catalytic activity of perovskite catalysts and elucidate their catalytic behavior in the oxidative coupling of methane (OCM), using alkali-added LaAlO3 perovskite catalysts. We prepared LaAlO3_XY (X = Li, Na, K, Y = mol %) catalysts and applied them to the OCM reaction. The results showed that the alkali-added catalysts’ activities were promoted compared to the LaAlO3 catalyst. In this reaction, ethane was first synthesized through the dimerization of methyl radicals, which were produced from the reaction of methane and oxygen vacancy in the perovskite catalysts. The high ethylene selectivity of the alkali-added catalysts originated from their abundance of electrophilic lattice oxygen species, facilitating the selective formation of C2 hydrocarbons from ethane. The high COx (carbon monoxide and carbon dioxide) selectivity of the LaAlO3 catalyst originated from its abundance of nucleophilic lattice oxygen species, favoring the selective production of COx from ethane. We concluded that electrophilic lattice oxygen species play a significant role in producing ethylene. We obtained that alkali-adding could be an effective method for improving the catalytic activity of perovskite catalysts in the OCM reaction.