Frédéric-Georges Fontaine

Electrochemical CO ₂ reduction at catalytic liquid metal (LM) surfaces offers a promising route for sustainable carbon conversion, yet suboptimal electrolyte formulations limit its practical implementation. We demonstrate CO ₂ reduction at a cerium‐containing liquid metal (LM‐Ce) using, for the first time, an ionic liquid‐based electrolyte that combines high CO ₂ solubility, electrochemical stability, and high solution conductivity. Using 1 M 1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate (EMIM‐TfO) with 2 M H ₂ O in N,N‐dimethylformamide (DMF), and under an applied potential of –1.44 V versus standard hydrogen electrode (SHE), the system achieves a high current density while CO ₂ reduction to graphite proceeds with an overall faradaic efficiency of 73.2 ± 3.3% and a high degree of graphitization (I _G /I _D ≈ 5). These results demonstrate that ionic liquids (ILs) function not only as excellent supporting media but may also serve as active and potentially tunable components to improve CO ₂ reduction rates at LM‐Ce interfaces.

Triphenylphosphonium salts incorporating tetrazolylmethyl (1) and pyrimidinylmethyl (2) substituents were synthesized via nucleophilic substitution of the corresponding chloromethyl-heterocycles with triphenylphosphine, followed by selective protonation of 2 to yield pyrimidinium 3. These catalysts were systematically evaluated for the cycloaddition of CO ₂ to epoxides under mild, solvent- and co-catalyst-free conditions (0.1 MPa atmospheric pressure, 80–120 °C). Protonated catalyst 3 demonstrated superior performance, delivering quantitative conversion (96% yield) of styrene oxide to the corresponding cyclic carbonate within 6 h at 2 mol.% loading. In situ FT-IR monitoring provided mechanistic insights, revealing that protonation accelerates initial ring-opening rates, and confers stability by mitigating phosphine oxide (P=O) degradation pathways prevalent in 1 (complete conversion to P=O). A factorial design of experiments delineated parameter effects, temperature exerted dominant influence, followed by loading and time, establishing optimized conditions (120 °C, 2 mol.%, 6 h) with factorial convergence at 96%–98% yields, indicative of operational robustness for scale-up. Substrate scope validation encompassed structurally diverse epoxides, achieving 98%–99% yields for halogenated, unsaturated, sterically encumbered, aliphatic, and aromatic derivatives, confirming high functional group tolerance without elevated pressures or additives. These economical metal-free catalysts versus conventional organometallics establish critical protonation–stability relationships, providing a scalable platform for sustainable CO ₂ valorization into commodity cyclic carbonates from renewable feedstocks.

Control of borane speciation through Me2PhN·BH3 formation enables HBcat-mediated, metal-free C–H borylation of (hetero)arenes via an electrophilic aromatic substitution pathway. The process operates without external catalysts or additives and provides a sustainable platform for accessing organoboron motifs, highlighting the untapped potential of simple hydroboranes in selective C–H functionalization.

Electrochemical CO₂ reduction reactions (CO₂RR) offer a viable approach to mitigating anthropogenic CO₂ while simultaneously generating value-added chemicals. Among diverse electrocatalyst classes, metal–organic framework (MOF)-based materials have been extensively explored owing to their excellent tunability of chemical structure, high surface area, and the ability to tailor the coordination/electronic environment of active centers. This state-of-the-art review provides a critical assessment of recent progress in the development of pristine Cu-based MOFs, Cu MOF-derived catalysts, and hybrid Cu@MOFs for the selective production of C₁ products such as CO, CH₄, and formate/formic acid. Theoretical investigations into the roles of the copper center, ligands, pore structures, and interfacial effects reveal that product selectivity is influenced by more than just the oxidation state of Cu sites. Mixed-valence Cu⁺/Cu⁰ junctions, defect-rich surfaces, conductive frameworks, and coordination site tuning constitute fundamental design strategies for steering CO₂ reduction pathways. In addition to electrocatalytic performance, this review emphasizes the importance of life cycle assessment (LCA). Current studies identify electricity demand, separation steps, and operational lifetime as the dominant environmental impact factors in LCA analyses. Combining molecular-level catalyst design with systems-level sustainability considerations, this review highlights key challenges and future prospects for advancing Cu-MOF electrocatalysts toward efficient and sustainable C₁ formation from CO₂.

Building on our recent homogeneous catalyst system, this work explores heterogenization by formation of covalent organic frameworks to enhance durability.

Commercial ammonium-grafted silica in micropacked microreactors enables sub-second, low-pressure CO ₂ –epoxide cycloaddition, overcoming mass-transfer limits.

The mechanism of borylation of N-methylindole (1aH) with aryl catecholboranes (2Bcat), mediated by the N-aryl-1,3-imidazole-2-thione organocatalyst (3aH), has been investigated using a combination of in situ 1H and 19F NMR reaction monitoring, titration experiments, kinetic analysis, kinetic modeling, and computational studies. The study shows that rapid and unproductive catalytic protodeboronation removes trace impurities of water, boronic acid, and catechol prior to the catalytic arene C−H borylation. The catalytic cycles for protodeboronation and arene C−H borylation are linked to one another, with differences in their catalyst resting states resulting in different kinetics. The catalyst resting state for protodeboronation is dominated by a rapid and thermodynamically favorable dimerization equilibrium of the protonated species (3aH). The dimer acts as a reservoir, with irreversible protonation of the C−B bond occurring at the monomeric species through a cyclic concerted transition state. The rates of catalytic protodeboronation are independent of water and catechol concentrations, and correlation of experimental and computational linear free-energy relationships within a series of (2-anisyl)catecholboranes suggests mechanistic continuity across electronic variations in the arene, with important contributions of resonance substituent effects (ρ+ = −2.1). The subsequent electrophilic C−H borylation step involves the monomeric borylated catalyst species (3aBcat), with reaction kinetics influenced by the reversible and thermodynamically favored self-aggregation of 3aBcat. The protodeboronation of the newly formed borylated indole (1aBcat) is faster compared to the organoboron reagent (2Bcat), which causes a stark and progressive rate inhibition. These findings provide a mechanistic basis for the observed choice of reagents, stoichiometry, high temperatures, and narrow scope of approaches relying on transfer borylation, while informing key targets that can assist the design of improved FLP-based organocatalytic C−H borylations.

Recent advances in liquid chromatography–mass spectrometry (LC-MS) have accelerated the adoption of high-throughput workflows that deliver deep proteome coverage using minimal sample amounts. This trend is largely driven by clinical and single-cell proteomics, where sensitivity and reproducibility are essential. Here, we extend our previous benchmark dataset (PXD028735) using next-generation LC-MS platforms optimized for rapid proteome analysis. We generated an extensive DDA/DIA dataset using a human-yeast- E. coli hybrid proteome. The proteome sample was distributed across multiple laboratories together with standardized analytical protocols specifying two short LC gradients (5 and 15 min) and low sample input amounts. This dataset includes data acquired on four different platforms, and features new scanning quadrupole-based implementations, extending coverage across different instruments and acquisition strategies. Our comprehensive evaluation highlights how technological advances and reduced LC gradients may affect proteome depth, quantitative precision, and cross-instrument consistency. The release of this benchmark dataset via ProteomeXchange (PXD070049 and PXD071205), allows for the acceleration of cross-platform algorithm development, enhance data mining strategies, and supports standardization of short-gradient, high-throughput LC-MS-based proteomics.

A series of pyridine‐grafted triphenylphosphonium salts [Ph ₃ P ⁺ R]Cl ⁻ (R = benzyl ( 1 ), pyridine‐2‐ylmethyl ( 2 ), pyridine‐3‐ylmethyl ( 3 ), and pyridine‐4‐ylmethyl ( 4 )) were synthesized and evaluated for their catalytic efficiency in the cycloaddition of CO ₂ to epoxides under mild and solvent‐free conditions. The para ‐substituted pyridyl catalyst ( 4 ) exhibited the highest performance. High yields (up to 99.9%) were obtained within 3 h (at 100°C and 6 mol% loading under 0.1 MPa CO ₂ pressure) for a range of epoxides, including styrene oxide (SO), epichlorohydrin (ECH), epibromohydrin (EBR), 2‐butyloxirane, glycidol, phenyl glycidyl ether, allyl glycidyl ether, cyclohexene oxide and three bulky terpene‐based epoxides: α‐pinene oxide, limonene oxide, and limonene dioxide. DFT calculations on catalyst 4 reveal that the nucleophilic attack by the nitrogen of pyridine lowers the epoxide ring‐opening barrier by about 4.6 kcal mol ⁻¹ compared to the halide‐mediated pathway, rationalizing the superior performance of the para ‐substituted analog. As demonstrated by independent synthesis of the protonated and alkylated pyridine analogs, the pyridine ring can be protonated during catalysis, generating a dicationic intermediate that exhibits high activity but low durability. This outcome underscores the critical influence of the pyridine substituent's position on catalytic performance. These findings reveal structure–activity relationships critical for catalyst design and demonstrate the viability of tailored phosphonium salts for scalable and sustainable CO ₂ valorization, including for challenging bio‐based feedstocks.