Stéven Renault

Evaluation of polyketones with N-cyclic structure as electrode material for electrochemical energy storage: case of pyromellitic diimide dilithium salt

Pyromellitic diimide dilithium salt was selected to complete our database on redox-active polyketones with a N-cyclic structure. Although never reported to date, such a lithiated salt was readily synthesized making its electrochemical evaluation in a Li battery possible. Preliminary data show that this novel material reversibly inserts two Li per formula unit at a relatively low potential giving a stable capacity value of 200 mAh g(-1).

Leucettines, a Class of Potent Inhibitors of cdc2-Like Kinases and Dual Specificity, Tyrosine Phosphorylation Regulated Kinases Derived from the Marine Sponge Leucettamine B: Modulation of Alternative Pre-RNA Splicing

We here report on the synthesis, optimization, and biological characterization of leucettines, a family of kinase inhibitors derived from the marine sponge leucettamine B. Stepwise synthesis of analogues starting from the natural structure, guided by activity testing on eight purified kinases, led to highly potent inhibitors of CLKs and DYRKs, two families of kinases involved in alternative pre-mRNA splicing and Alzheimers disease/Down syndrome. Leucettine L41 was cocrystallized with CLK3. It interacts with key residues located within the ATP-binding pocket of the kinase. Leucettine L41 inhibits the phosphorylation of serine/arginine-rich proteins (SRp), a family of proteins regulating pre-RNA splicing. Indeed leucettine L41 was demonstrated to modulate alternative pre-mRNA splicing, in a cell-based reporting system. Leucettines should be further explored as pharmacological tools to study and modulate pre-RNA splicing. Leucettines may also be investigated as potential therapeutic drugs in Alzheimers disease (AD) and in diseases involving abnormal pre-mRNA splicing.

Evaluation of polyketones with N-cyclic structure as electrode material for electrochemical energy storage: case of tetraketopiperazine unit

Pursuing the electrochemical evaluation vs. Li of carbonyl-based cyclic structures deriving from the oxocarbon family, polyketones with N-cyclic structure are investigated to probe the potential modifications. In this communication, we specifically report on the electrochemical investigation of our first selected family of heterocycles based on the 2,3,5,6-tetraketopiperazine unit. Working in a systematic way, a series of tetraketopiperazine molecules with quite different R groups as substituents (i.e., phenyl, allyl and propyl functions) have been synthesized and characterized. Such small molecules were found to rapidly solubilise in commonly used electrolytes. To bypass this issue, we have prepared an oligomeric form via acyclic diene metathesis (ADMET). Preliminary results on the poly-N,N′-diallyl-2,3,5,6-tetraketopiperazine oligomer show a sustained reversible capacity of 110 mAh g−1 at near 2.45 V. The insight gained from this work is the fact that two intracyclic nitrogen atoms or a lithiated ene–diolate functionality in the C6-based polyketone cyclic structure induces a similar tuning of the redox potential.

Improving the electrochemical performance of organic Li-ion battery electrodes.

Dilithium benzenediacrylate was prepared and investigated as an example of a readily available organic electrode material for lithium-ion batteries. Its poor conductive properties were overcome by a method of carbon-coating in the liquid state, resulting in enhanced cycling performance, displaying a reversible capacity of 180 mA h g(-1).

A green Li–organic battery working as a fuel cell in case of emergency

The routine access to electricity always means a drastic change in terms of quality of life making it easier and safer. Consequently, the global electric demand both on and off-the-grid is growing and calls for ongoing innovation to promote reliable, clean and safe power supplies. In this context, the development of new chemistries for batteries and fuel cells could play a critical role. From our prospects aiming at fostering the concept of sustainable organic batteries, we report in this article on the peculiar properties of dilithium (2,5-dilithium-oxy)-terephthalate salt, a novel redox-active material. Based on an oriented retrosynthetic analysis, we have succeeded in elaborating this organic electrode material through an original and low-polluting synthesis scheme, which includes both chemical and biochemical CO2 sequestration in conjunction with a closed-loop solution for recycling products. Beyond its remarkable electrochemical performance vs. Li, especially as a lithiated cathode material, this compound behaves also like an oxygen scavenger. This dual electrochemical/chemical reactivity makes the self-recharging of a Li cell based on this organic salt possible by opening it to air ensuring an electrical power reserve when a conventional electrical recharge is not possible. In such a case, the pristine rechargeable Li–organic battery operates as a sort of “Li/O2 fuel cell”.

High-Potential Reversible Li Deintercalation in a Substituted Tetrahydroxy-p-benzoquinone Dilithium Salt: An Experimental and Theoretical Study

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 C(6)O(6)-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 s(6) 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.

Benzenediacrylates as organic battery electrode materials: Na versus Li

This paper discusses investigations of a novel Na-based organic battery electrode material, disodium benzenediacrylate (Na2BDA) in comparison with its Li-ion homologue. Li2BDA has previously shown promising battery properties, such as stable cycling and good capacity retention. Na2BDA and Li2BDA are here successfully synthesized and characterized, and investigated as anode materials in prototype Na- and Li-ion battery cells. Moreover, different electrolytes are screened for the Na-battery material, and a useful operating voltage window is explored. Na2BDA is shown to possess a higher initial coulombic efficiency (91%) than the Li-homologue, which is uncommon for sodiated organic electrode materials. The Na-compound shows an initial capacity of 177.7 mA h g−1, which however decreases to ca. 50 mA h g−1 after 20–100 cycles depending on the cycling rate; a significantly lower capacity retention then that observed for Li2BDA. The capacity loss can primarily be explained by a decomposition mechanism of the Na2BDA compound.

Synthesis and preliminary biological evaluation of new derivatives of the marine alkaloid leucettamine B as kinase inhibitors.

New derivatives of the marine alkaloid leucettamine B were prepared in five steps with overall yields ranging from 23 to 30%. The key step of our strategy has been the sulfur/nitrogen displacement under solvent-free microwave irradiation of (5Z) 5-benzo[1,3]-dioxo-5-ylmethylene-2-ethylsulfanyl-3,5-dihydroimidazol-4-one 3 with a mono-protected ethylenediamine 2. After deprotection of the N-Boc group, the amino derivative of leucettamine B 5 was subjected to reductive amination in two steps with retention of configuration of the double bond, to lead to eight new analogs of leucettamine B. The effect of these compounds on CK1alpha/beta, CDK5/p25, and GSK-3alpha/beta were investigated.

Sustainable Materials for Sustainable Energy Storage: Organic Na Electrodes

In this review, we summarize research efforts to realize Na-based organic materials for novel battery chemistries. Na is a more abundant element than Li, thereby contributing to less costly materials with limited to no geopolitical constraints while organic electrode materials harvested from biomass resources provide the possibility of achieving renewable battery components with low environmental impact during processing and recycling. Together, this can form the basis for truly sustainable electrochemical energy storage. We explore the efforts made on electrode materials of organic salts, primarily carbonyl compounds but also Schiff bases, unsaturated compounds, nitroxides and polymers. Moreover, sodiated carbonaceous materials derived from biomasses and waste products are surveyed. As a conclusion to the review, some shortcomings of the currently investigated materials are highlighted together with the major limitations for future development in this field. Finally, routes to move forward in this direction are suggested.

Environmentally‐Friendly Lithium Recycling From a Spent Organic Li‐Ion Battery

A simple and straightforward method using non-polluting solvents and a single thermal treatment step at moderate temperature was investigated as an environmentally-friendly process to recycle lithium from organic electrode materials for secondary lithium batteries. This method, highly dependent on the choice of electrolyte, gives up to 99% of sustained capacity for the recycled materials used in a second life-cycle battery when compared with the original. The best results were obtained using a dimethyl carbonate/lithium bis(trifluoromethane sulfonyl) imide electrolyte that does not decompose in presence of water. The process implies a thermal decomposition step at a moderate temperature of the extracted organic material into lithium carbonate, which is then used as a lithiation agent for the preparation of fresh electrode material without loss of lithium.