Efficient organic Li‐ion batteries require air‐stable lithiated organic structures that can reversibly deintercalate Li at sufficiently high potentials. To date, most of the cathode materials ...reported in the literature are typically synthesized in their fully oxidized form, which restricts the operating potential of such materials and requires use of an anode material in its lithiated state. Reduced forms of quinonic structures could represent examples of lithiated organic‐based cathodes that can deintercalate Li+ at potentials higher than 3 V thanks to substituent effects. Having previously recognized the unique electrochemical properties of the C6O6‐type ring, we have now designed and then elaborated, through a simple three‐step method, lithiated 3,6‐dihydroxy‐2,5‐dimethoxy‐p‐benzoquinone, a new redox amphoteric system derived from the tetralithium salt of tetrahydroxy‐p‐benzoquinone. Electrochemical investigations revealed that such an air‐stable salt can reversibly deintercalate one Li+ ion on charging with a practical capacity of about 100 mAh g−1 at about 3 V, albeit with a polarization effect. Better capacity retention was obtained by simply adding an adsorbing additive. A tetrahydrated form of the studied salt was also characterized by XRD and first‐principles calculations. Various levels of theory were probed, including DFT with classical functionals (LDA, GGA, PBEsol, revPBE) and models for dispersion corrections to DFT. One of the modified dispersion‐corrected DFT schemes, related to a rescaling of both van der Waals radii and s6 parameter, provides significant improvements to the description of this kind of crystal over other treatments. We then applied this optimized approach to the screening of hypothetical frameworks for the delithiated phases and to search for the anhydrous structure.
A new redox amphoteric system, derived from the tetralithium salt of tetrahydroxy‐p‐benzoquinone, reversibly deintercalates one Li+ on charging and has a practical capacity of about 100 mAh g−1 at an average potential of 3 V versus Li+/Li0 (see figure). A solvated form of the studied salt (Li2DHDMQ⋅4 H2O) was also characterized by X‐ray diffraction and first‐principles calculations.
The present study reports superior electrochemical performance with capacity doubled for organic positive electrodes based on a small redox-active molecule when using the Lithium Metal Polymer (LMP) ...technology. Particularly, the simple use of the regular solid polymer electrolyte currently employed in commercial LMP cells allows obtaining for the first time an efficient two-electron cycling of tetramethoxy-p-benzoquinone with high-rate capability at temperatures as high as 100°C. With no optimization, the restored capacity represents 80% of the theoretical value (190mAh/g) after 20cycles operated at a C rate. On the contrary, when cycled in conventional carbonate-based electrolytes, this quinone compound exhibits quite poor electrochemical features such as a very limited depth of discharge (~50% of the theoretical capacity in the first cycle) followed by rapid capacity decay. After cycling, preliminary post-mortem characterizations did not evidence any obvious degradation in the cell. Although the adverse effect of the diffusion of the active material is not fully inhibited, the coulombic efficiency is close to 100% while the Li/electrolyte interface appears stable.
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•The electroactive material was a fairly soluble quinone molecule in polar solvents.•A solid and dry polymer electrolyte was used in place of a liquid electrolyte.•Full capacity (2e−/quinone ring) can be reached even at intermediate rates.•Good cyclability and power performance were obtained at 100°C.
Pregnant women and children are especially vulnerable to exposures to food contaminants, and a balanced diet during these periods is critical for optimal nutritional status.
Our objective was to ...study the association between diet and measured blood and urinary levels of environmental contaminants in mother-child pairs from six European birth cohorts (
mothers and 1,288 children).
We assessed the consumption of seven food groups and the blood levels of organochlorine pesticides, polybrominated diphenyl ethers, polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFAS), and heavy metals and urinary levels of phthalate metabolites, phenolic compounds, and organophosphate pesticide (OP) metabolites. Organic food consumption during childhood was also studied. We applied multivariable linear regressions and targeted maximum likelihood based estimation (TMLE).
Maternal high (
) versus low (
) fish consumption was associated with 15% higher PCBs geometric mean (GM)
; 95% confidence interval (CI): 1.02, 1.29, 42% higher perfluoroundecanoate (PFUnDA) (
; 95% CI: 1.20, 1.68), 89% higher mercury (Hg) (
; 95% CI: 1.47, 2.41) and a 487% increase in arsenic (As) (
; 95% CI: 2.57, 9.23) levels. In children, high (
) versus low (
) fish consumption was associated with 23% higher perfluorononanoate (PFNA) (
; 95% CI: 1.08, 1.40), 36% higher PFUnDA (
; 95% CI: 1.12, 1.64), 37% higher perfluorooctane sulfonate (PFOS) (
; 95% CI: 1.22, 1.54), and
higher Hg and As
(95% CI: 1.91, 4.31) and
(95% CI: 2.23, 3.21) concentrations. Using TMLE analysis, we estimated that fish consumption within the recommended 2-3 times/week resulted in lower PFAS, Hg, and As compared with higher consumption. Fruit consumption was positively associated with OP metabolites. Organic food consumption was negatively associated with OP metabolites.
Fish consumption is related to higher PFAS, Hg, and As exposures. In addition, fruit consumption is a source of exposure to OPs. https://doi.org/10.1289/EHP5324.
Switch over: All the disulfide moieties in the cations of an iodoplumbate display the same chiral conformation in a single crystal; however, during a phase transition (75 °C) half of these molecules ...undergo a conformational change, from the left‐ to the right‐handed helical form, and a true racemate is formed. This transition is reversible, and thus this compound can act as a second harmonic generation switch.
Prenatal caffeine exposure may influence offspring health via DNA methylation, but no large studies have tested this.
Epigenome-wide association studies and differentially methylated regions in cord ...blood (450k or EPIC Illumina arrays) were meta-analyzed across six European cohorts (n = 3725). Differential methylation related to self-reported caffeine intake (mg/day) from coffee, tea and cola was compared with assess whether caffeine is driving effects.
One CpG site (cg19370043,
) was associated with caffeine and another (cg14591243,
) with cola intake. A total of 12-22 differentially methylated regions were detected with limited overlap across caffeinated beverages.
We found little evidence to support an intrauterine effect of caffeine on offspring DNA methylation. Statistical power limitations may have impacted our findings.
We report on the structures of three dibromothiophene compounds (4, 5, and 12) and the analysis of the patterns of self‐assembly in the solid state by CBr⋅⋅⋅BrC halogen bonds of a selected set of ...16 di‐ or poly‐bromine(poly)thiophene monomers sorted according to the dimensionality of their halogen‐bonded, extended frameworks thereby identifying syn‐ or anti‐strings and layers. We conclude that in 1, 2, 9, and 10, the antiparallel orientation of successive CBr⋅⋅⋅BrC halogen‐bonded dibromothiophene units along extended anti‐strings is linked to the occurrence of solid‐state polymerization.
In the search for low-polluting electrode materials for batteries, the use of redox-active organic compounds represents a promising alternative to conventional metal-based systems. In this article we ...report a combined experimental and theoretical study of tetramethoxy-p-benzoquinone (TMQ). In carbonate-based electrolytes, electrochemical behaviour of this compound is characterized by a reversible insertion process located at approximately 2.85 V vs.Li super(+)/Li super(0 ). This relatively high potential reactivity, coupled with our effort to develop computational methodologies in the field of organic electrode materials, prompted us to complement these experimental data with theoretical studies performed using density functional theory (DFT). Single crystals of TMQ were synthesized and thoroughly characterized showing that this quinonic species crystallised in the P2 sub(1)/nspace group. The experimental crystal structure of TMQ was then used to assess various DFT methods. The structural features and vibrational spectra were thus predicted by using as a whole five common density functionals (PBE, LDA, revPBE, PBEsol, B3PW91) with and without a semi-empirical correction to account for the van der Waals interactions using either Grimme's (DFT-D2) or Tkatchenko-Scheffler (TS) scheme. The most reliable combination of the DFT functional and the explicit dispersion correction was chosen to study the Li-intercalated molecular crystal (LiTMQ) with the view of indentifying Li insertion sites. A very close agreement with the experiment was found for the average voltage by using the most stable relaxed hypothetical LiTMQ structure. Additionally, a comparison of vibrational spectra gained either for TMQ molecule and its dimer in gas phase or through periodic calculation was undertaken with respect to the experimentally measured infrared spectra. The topological features of the bonds were also investigated in conjunction with estimates of net atomic charges to gain insight into the effect of chemical bonding and intermolecular interaction on Li intercalation. Finally, pi -electron delocalization of both quinone and alkali salts of p-semiquinone were determined using the Harmonic Oscillator model of Aromaticity (HOMA) or aromatic fluctuation index (FLU) calculations.
A template-free approach is described for the synthesis of expanded foams of mesoporous carbon exhibiting high surface areas ranging from 550 to 1100m2g−1. The procedure is based on the exceptional ...carbonization reaction that occurs with squaric acid (H2C4O4), a strained four-membered carbocycle belonging to the oxocarbon acids. Indeed the pyrolysis reaction proceeds just above 300°C through an amazing one-step and sharp exothermic phenomenon coupled with a weight loss of 90%, thereby promoting a porous structure. This massive gas release behaves also as a “fluid” template during the carbon production, which explains the formation of expanded foams. This particular thermal behaviour seems related to the phase transition that occurs in H2C4O4 crystals at Tc=121°C. Below Tc the planar squaric acid molecules exhibit a fully ordered structure in a monoclinic system whereas for T>Tc the structure undergoes a disordered tetragonal structure where all CO bonds of squaric acid become statistically equivalent in a perfect square, making a discrete thermal decomposition reaction possible.
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•An original template-free approach was found for producing mesoporous carbon foams.•The foam morphology is related to an outstanding carbonization reaction.•Squaric acid pyrolysis involves 90% of sacrificial mass.
Urinary metabolic profiling is a promising powerful tool to reflect dietary intake and can help understand metabolic alterations in response to diet quality. Here, we used
H NMR spectroscopy in a ...multicountry study in European children (1147 children from 6 different cohorts) and identified a common panel of 4 urinary metabolites (hippurate,
-methylnicotinic acid, urea, and sucrose) that was predictive of Mediterranean diet adherence (KIDMED) and ultra-processed food consumption and also had higher capacity in discriminating children's diet quality than that of established sociodemographic determinants. Further, we showed that the identified metabolite panel also reflected the associations of these diet quality indicators with C-peptide, a stable and accurate marker of insulin resistance and future risk of metabolic disease. This methodology enables objective assessment of dietary patterns in European child populations, complementary to traditional questionary methods, and can be used in future studies to evaluate diet quality. Moreover, this knowledge can provide mechanistic evidence of common biological pathways that characterize healthy and unhealthy dietary patterns, and diet-related molecular alterations that could associate to metabolic disease.
The behavior of G3 factor and of its methylated or fluorinated analogues G3Me and G3F, was studied under Fe(II) conditions. Degradation products were isolated and characterized in each case. The use ...of labelled compounds allowed us to propose mechanisms in which a tertiary radical is involved. This radical rearranges by 5-exo-trig cyclization, or disproportionates in the case of G3Me. A correlation between antiplasmodial activity and stability of this radical is proposed.
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