Bruno Andrioletti

This study explores the use of reline (choline chloride–urea combination), a deep eutectic solvent (DES), in the synthesis of polyhydroxyurethanes through step‐growth polymerization between a polycarbonate and a diamine. The performance of reline was compared to that of ZnCl ₂ /urea DES and MeCN as a typical conventional solvent, demonstrating its superiority in both conversion efficiency (Conv. > 99%) and molar mass ( M _n 10% higher than that obtained with the two other solvents) of the resulting polymer. The versatility of the method was evaluated by testing various bis‐cyclic carbonates and primary diamines, revealing differences in reactivity, number‐average molar mass, and glass transition temperature values of the obtained polymers. Finally, a representative reaction was successfully scaled up, demonstrating the practical applicability of the methodology, albeit with some challenges related to heat transfer.

The development of more sustainable and eco-friendly polymers has attracted much attention from researchers over the past decades. Among the different strategies that can be implemented towards this goal, the substitution of the toxic reagents/monomers often used in polyurethane chemistry has stimulated much innovation leading to the development of the hydroxylated version of PURs, namely, the poly(hydroxyurethane)s (PHURs). However, some PHURs remain far from being sustainable as their synthesis may involve monomers and/or solvents displaying poor environmental impacts. Herein, we report on the use of more sustainable conditions to synthesize the biobased polycarbonates involved in the aminolysis reaction. In addition, we demonstrate that the use of renewable deep eutectic solvents (DESs) can act both as excellent solvents and organocatalysts to promote the aminolysis reaction.

Triazole-Appended Dipyrromethenes (TADs) constitute a highly tunable and versatile family of ligands. Thus, well designed 1:1 / Zn:L complexes incorporating a macrocyclic TAD member were proven very efficient in the carbonation of epoxides at low CO₂ pressure (1 bar) and 100 [ ]. Interestingly, the non-macrocyclized analogue was catalytically inactive in the presence of Zn(OAc)₂ and dimerized instantly. Hence, engineering a structure preventing the dimerization was proven critical to restore the catalytic activity of the zinc complex.

The identification of the intermediates and by-products produced during the oxidative cleavage of cycloalkenes in the presence of H₂O₂ and a tungsten-based catalyst for the production of dicarboxylic acids has been carried out under various experimental conditions. On the basis of this mechanistic investigation and previous studies from the literature, a complete reaction scheme for the formation of the reaction products and by-products is proposed. In this hypothetical mechanism, the production of a hydroperoxyalcohol intermediate accounts for the two pathways proposed by Noyori and Venturello for the formation of the targeted dicarboxylic acid. In addition, Baeyer–Villiger oxidation of the mono-aldehyde intermediate allows explaining the formation of short chain diacids observed as by-products during the reaction. Hence, the proposed mechanism constitutes a real tool for scientists looking for a better understanding and those heading to set up environmentally friendly conditions for the oxidative cleavage of cycloalkenes.

Because BF₄⁻ is a labile, non- or weakly coordinating anion, it is generally chosen by chemists who do not want the anion to interfere with the associated cation. Herein, we demonstrate that BF₄⁻ actually strongly binds to triazole-appended dipyrromethenes (TADs). In particular, HETCOR NMR experiments and DFT calculations were used to rationalize the results observed with anion titrations. Hence, special care should be taken when considering that BF₄⁻ is innocent.

The synthesis and characterization of unusual silver triazolylidene‐containing dipyrromethene complexes are described. The carbeneTAD‐N₃C‐Hobtained from its parent Triazole‐Appended Dipyrromethene (TAD‐N₄) is an excellent ligand for the complexation of silver, thanks to the proximity between the dipyrromethene scaffold and the triazolylidene. The effect of silver salt stoichiometry on the structure of the complexes was clearly evidenced by¹H‐NMR spectroscopy and mass spectrometry. Furthermore, an unexpected argentophilic interaction was proved by different analytical techniques, including X‐ray diffraction analysis and fluorescence spectroscopy. The potentiality of using the unprecedented DPM‐triazolydene silver complexes for the preparation of dipyrromethene‐based metallocomplexes displaying unusual coordination mode was further demonstrated with palladium.

A graphical resume of the hydrothermal decomposition of d-glucose at 150 °C in the presence of ammonium sulfate.

Dicarboxylic acids constitute one of the most important oxygenated intermediates in the chemical industry providing a wide range of daily products: fibers, pharmaceuticals, cosmetics, lubricants, pesticides and plasticizers. A major part of their large-scale production relies on the oxidative cleavage processes of unsaturated acids and cyclic olefins but suffers from severe drawbacks such as the use of harmful compounds, the need of specific set-ups to produce oxidants, expensive catalysts and energy-consuming conditions. In the context of the development of sustainable oxidation reactions, hydrogen peroxide has attracted growing interest thanks to its multiple benefits to replace conventional oxidants: low toxicity, no need of energetic conditions to perform catalytic oxidation and generation of benign H₂O as a by-product. The present review aims at bringing a critical view on the development of catalytic systems for the H₂O₂-mediated oxidative cleavage of cycloalkenes toward green chemistry criteria. Different transition metal-based catalysts investigated for the reaction will be discussed with a special emphasis on tungsten. Next, the performance of different heterogeneous and homogeneous W-based systems on the oxidative cleavage of various cycloolefins will be presented. More specifically, their relevance towards sustainable oxidation will be assessed by studying key reaction features: solvent, H₂O₂ amount, reaction time and catalyst synthesis, recoverability and activity. The main challenges regarding the oxidative cleavage of medium-sized cycloalkenes with W–H₂O₂ systems will also be exposed. Finally, the potential of ultrasound as an unconventional activation method will be pointed out to overcome the limits encountered with the conventional thermal heating leading to even more environmentally-friendly cycloalkene oxidative cleavage.