Gold nanoparticles (AuNPs) stabilized by N‐heterocyclic carbenes (NHCs) represent robust alternatives to thiol‐protected counterparts owing to the NHCs’ strong AuC bonds that provide enhanced stability. While NHC‐capped AuNPs with a single type of carbene have been reported many times, strategies to introduce multiple NHC ligands on the same nanoparticle remain unexplored. Here, we investigate NHC‐for‐NHC ligand exchange on AuNPs stabilized either by benzimidazol‐2‐ylidene or by mesoionic triazolylidene scaffolds, employing an in situ generated free carbene route. Prior to ligand exchange, the formation and stability of the studied NHCs from the corresponding azolium salts were examined and characterized by NMR spectroscopy. In situ NMR studies of the exchange reaction showed no evidence of ligand substitution under argon, the conventional atmosphere for free NHC intermediates. Although no exchange was detected by NMR, X‐ray photoelectron spectroscopy (XPS) analysis of the purified AuNPs revealed that ligand substitution had in fact occurred. Further investigation indicated that oxygen plays a key role in promoting the exchange, and that its involvement is also associated with oxidation of the gold core and the formation of NHC‐Au(I) complexes. Taken together, our results highlight the complexity of NHC‐for‐NHC exchange on AuNPs by the free carbene route and point to the need for alternative strategies to achieve controlled ligand substitution.

Mixtures of anionic and cationic surfactants, often referred to as catanionics, can possess synergistic properties, e.g. lower surface tension compared to their individual components. However, they usually precipitate close to equimolar ratios, and they form vesicles. Surprisingly, we observe that catanionics of the anionic biosurfactants, rhamnolipid or sophorolipid, form micelles instead of vesicles and precipitates. More importantly, the results suggest that specific carbohydrate-carbohydrate interactions between biosurfactant headgroups can overcome electrostatic repulsion and drive nanoscopic phase separation within the aggregates, leading to a heterogeneous internal structure. For this reason, we aim to investigate the limited miscibility and structure of these mixtures using a range of experimental and theoretical methods. We use pulsed field-gradient spin-echo NMR spectroscopy, molecular dynamics simulations, small-angle X-ray scattering and contrast variation by small-angle neutron scattering to study the partially mixed micelles on different length scales and to gain an understanding of the interactions between the surfactants. The peculiar properties of catanionics with biosurfactants compared to typical catanionic systems can be rationalized by the complex, asymmetric, hydrophilic and (non)ionic character of the biosurfactants, exerting strong hydrogen-bonding interactions.

How can energy transfer catalysis move beyond fragile molecular light absorbers toward more robust and tunable systems? Here we show that tiny gold nanostructures can act as universal energy donors to activate otherwise inactive gold-based catalysts using light. By introducing a molecular mediator, we demonstrate that the localized energy within the nanoparticles can be passed along through a two-step mechanism, ultimately creating a reactive excited state in the gold complex, even when the light does not directly match its energy levels. Spectroscopic measurements confirm the formation and lifetime of this state and provide clear evidence of successful energy transfer. These results establish how plasmonic materials can drive catalytic reactions through controlled energy flow, opening new opportunities for designing durable and versatile systems for light-driven chemistry. This papers finds that gold nanostructures can act as universal energy donors to activate otherwise inactive gold-based catalysts using light. Introducing a molecular mediator enables localized energy within the nanoparticles to be passed along through a two-step mechanism, creating a reactive excited state in the gold complex.

The controlled fabrication of mixed-ligand monolayers on gold nanoparticles (AuNPs) remains of broad interest in materials chemistry, yet current strategies rely predominantly on thiol-for-thiol exchange processes. However, strategies to post-synthetically...

The production and widespread use of synthetic pigments and dyes have significant environmental and health impacts. Despite this, synthetic colorants remain dominant due to their wide color range, high stability, strong tinting power, and lower cost compared to natural alternatives. Therefore, to offer sustainable and competitive substitutes, eco-friendly methods for producing bio-based pigments with similar performance are essential. Herein, a methodology has been developed to extract the entire colored organic fraction occluded within seashell biomineral waste, which comprises pigments and pigment-macromolecule complexes. This process involves an optimized cleaning procedure of the biomineral soft tissues, a tailored biochemical extraction, and detailed characterization of the extracted fraction. Applied to sea urchin skeletons, this method successfully isolates polyhydroxylated naphthoquinone (PHNQ)-macromolecule complexes. These complexes show superior pH stability in purple hues compared to free PHNQ, which shifts from red to purple in basic conditions. Notably, the approach enhances colorant yield by up to five times. These results, together with mineral pigment synthesis and fabric dyeing assays performed with the extracted colored organic fraction, contribute to a better understanding of the origin of color in biominerals and reveal the versatility of these natural pigments for environmentally friendly coloring of both organic and inorganic materials.

Ionene-based physical hydrogels have been investigated here in terms of the changes of the local environment for ionene polyelectrolyte chains and their counterions upon the liquid-gel transition. These changes were probed via1H and 19F NMR chemical shifts, peak intensities and peak broadening. Further, chain and counterion dynamics was studied by means of PFG-NMR. Properties of ionene-based hydrogels being highly sensitive to the nature of the chain counterion, we compare here two systems, with F- and Cl- counterions. An important observation is the significant loss of signal intensity for the ionene chains and counterions upon the liquid-gel transition. This is a consequence of the immobilisation of a proportion of the chains and counterions as they start taking part in the cross-linked chain network and become invisible to solution/liquid state NMR. For the counterions (measured only in the case of 19F nuclei), the liquid-gel transition leads also to a sudden deshielding effect (peak shift by 3 ppm) and a large increase in the peak width (decrease in the 19F transverse relaxation time). This clearly attests to the involvement of the counterions in the formation of chain cross-links in ionene-based hydrogels. For all solution/liquid and gel phases, the diffusion coefficients of NMR-visible chains are consistently higher in the case of Cl-gels, in comparison to F-gels (a factor of ≈ 2). This reflects the increased rigidity of the F-ionene chains due to strong dissociation of the strongly hydrating F- ions from the ionene backbone.

How can energy transfer catalysis be extended beyond molecular photosensitizers to more robust, tunable systems? In this study, we investigate whether plasmonic nanostructures can serve as universal energy donors to activate redox-inert gold(I) complexes relevant to photo-driven catalysis. Using a molecular mediator, we demonstrate that localized energy from gold nanoparticles can be transferred through a two-step Dexter-type mechanism to generate the reactive first triplet metal-to-ligand charge-transfer state of the gold complex, even under non-resonant excitation. Spectroscopic analyses confirm the formation and lifetime of this excited state and reveal emission-based signatures of successful energy transfer. These results establish a mechanistic foundation for plasmon-enabled activation and open new possibilities for designing catalytic systems where precise energetic control and compatibility with a broad range of substrates are critical.

Significant progress has been made over the last decades in surface functionalization of coinage metals using thiols and more recently N-heterocyclic carbenes. As shown in this work, mesoionic carbenes (MICs) provide straightforward access to a novel class of surface ligands and thus materials. Importantly, MICs are easily accessed from triazolium salts (TS) onto which functional groups may be attached with little synthetic effort. Here, we present a library of TS that were further converted into MICs, in situ, and grafted to gold surfaces. The modified surfaces were thoroughly characterized by advanced spectroscopic methods and electrochemistry for MICs bearing electroactive moieties. We also prepared mixed MIC/thiol self-assembled monolayers, which opens the route to multifunctional surfaces.

Poly(ethylene glycol) methyl ether methacrylate polymer networks (PEO-based networks), with or without anionic bis(trifluoromethanesulfonyl)imide (TFSI)-grafted groups, are promising electrolytes for Li-metal all solid-state batteries. Nevertheless, there is a need to enhance our current understanding of the physicochemical characteristics of these polymer networks to meet the mechanical and ionic conductivity property requirements for Li battery electrolyte materials. To address this challenge, our goal is to investigate the impact of the cross-linking density of the PEO-based network and the ethylene oxide/lithium ratio on mechanical properties (such as glass transition temperature and storage modulus) and ionic conductivity. We have synthesized a series of cross-linked PEO-based polymers (si-SPE for single ion solid polymer electrolyte) via solvent-free radical copolymerization. These polymers are synthesized by using commercially available lithium 3-[(trifluoromethane)sulfonamidosulfonyl]propyl methacrylate (LiMTFSI), poly(ethylene glycol)methyl ether methacrylate (PEGM), and [poly(ethylene glycol) dimethacrylate] (PEGDM). In addition, we have synthesized a series of cross-linked PEO-based polymers (SPE for solid polymer electrolyte) using LiTFSI as the ionic species. Most of the resulting polymer films are amorphous, self-standing, flexible, homogeneous, and thermally stable. Interestingly, our research has revealed a correlation between ionic conductivity and mechanical properties in both the SPE and si-SPE series. Ionic conductivity increases as glass transition temperature, alpha relaxation temperature, and storage modulus decrease, suggesting that Li+ transport is influenced by polymer chain flexibility and Li+/EO interaction.

Significant achievements have been reported in the last few years regarding the stabilization and functionalisation of gold nanoparticles (AuNPs), mainly through the use of thiols and imidazolylidene N-heterocyclic carbenes capping ligands. Herein, we report that mesoionic carbenes (MICs) ligands, based on the 1,2,3-triazol-5-ylidene scaffold, allow the expeditive preparation of AuNPs of exceptional stability through a simple and straightforward one-pot protocol directly from triazolium salts and discrete Au(III) sources. Control over the size of the AuNPs has been achieved by varying the Au/ligand ratio as well as the nature of the triazolium salts, the latter being facilitated by the ease of synthesis of the MIC precursors through click chemistry. Characterisation of these MIC-AuNPs by X-ray photoelectron spectroscopy (XPS) hints at the exclusive presence of MICs on the nanoparticle surface.

To reduce the environmental impact of supported catalyst production in compliance with the recommendations of the UN's 12th objective, which encourages more sustainable consumption and production patterns, we propose to revisit solgel chemistry in a more frugal mode. The principle of frugal innovation is to simplify products and processes, eliminate complexities to make solutions easier to understand and use, and reduce production costs. By this way, the synthesis of rutheniumbased catalysts supported on gamma-AlOOH and gamma-Al2O3 is revised via solvent-free sol-gel chemistry. Such catalysts are successfully prepared in one-pot preparation of the active phase and the support using Ru(acac)(3)/Al alkoxide that requires no sacrificial organic pore-generating agent, no washing, and no filtration and produces no liquid waste. The mixed Ru/Al precursor is hydrolyzed with a stoichiometric amount of water without any solvent. The obtained materials containing 1 and 3% Ru/Al molar ratios have high specific surface areas, from 300 to 690 m(2)center dot g(-1) and exhibit well dispersed NPs of 1-4 nm on.-AlOOH with interesting CO2 methanation activity and 100% CH4 selectivity. This proves that a frugal synthesis approach can do as well as traditional synthesis methods while having a much lower environmental impact (cE-factor, water consumption, and energy consumption are 24, 69, and 24 to 42 times lower, respectively) than the standard multistep protocol..

Hydrosilylation reactions are commonly used for the reduction of carbonyl bonds in fine chemistry, catalyzed by transition metal complexes. The current challenge is to expand the scope of metal-free alternative catalysts, including in particular organocatalysts. This work describes the organocatalyzed hydrosilylation of benzaldehyde with a phosphine, introduced at 10 mol%, and phenylsilane at room temperature. The activation of phenylsilane was highly dependent on the physical properties of the solvent such as the polarity, and the highest conversions were obtained in acetonitrile and propylene carbonate with yields of 46 % and 97 %, respectively. The best results of the screening over 13 phosphines and phosphites were obtained with linear trialkylphoshines (PMe3 , Pn Bu3 , POct3 ), indicating the importance of their nucleophilicity, with yields of 88 %, 46 % and 56 %, respectively. With the help of heteronuclear 1 H-29 Si NMR spectroscopy, the products of the hydrosilylation (PhSiH3-n (OBn)n ) were identified, allowing a monitoring of the concentration in the different species, and thereby of their reactivity. The reaction displayed an induction period of ca. 60 min, followed by the sequential hydrosilylations presenting various reaction rates. In agreement with the formation of partial charges in the intermediate state, we propose a mechanism based on a hypervalent silicon center via the Lewis base activation of the silicon Lewis acid.

N-Heterocyclic carbenes (NHCs) have drawn considerable interest in the field of nanomaterials chemistry as highly stabilizing ligands enabling the formation of strong and covalent carbon-metal bonds. Applied to gold nanoparticles synthesis, the most common strategy consists of the reduction of a preformed NHC-Au-I complex with a large excess of a reducing agent that makes the particle size difficult to control. In this paper, we report the straightforward synthesis of NHC-coated gold nanoparticles (NHC-AuNPs) by treating a commercially available gold(I) precursor with an easy-to-synthesize NHC-BH3 reagent. The latter acts as both the reducing agent and the source of surface ligands operating under mild conditions. Mechanistic studies including NMR spectroscopy and mass spectrometry demonstrate that the reduction of gold(I) generates NHC-BH2Cl as a by-product. This strategy gives efficient control over the nucleation and growth of gold particles by varying the NHC-borane/gold(I) ratio, allowing unparalleled particle size variation over the range of 4.9 & PLUSMN;0.9 to 10.0 & PLUSMN;2.7 nm. Our strategy also allows an unprecedented precise and controlled seeded growth of gold nanoparticles. In addition, the as-prepared NHC-AuNPs exhibit narrow size distributions without the need for extensive purification or size-selectivity techniques, and are stable over months.

Although the presence of silica in many living organisms offers advanced properties including cell protection, the different in vitro attempts to build living materials in pure silica never favoured the cells viability. Thus, little attention has been paid to host-guest interactions to modify the expected biologic response. Here we report the physiological changes undergone by Escherichia coli K-12 in silica from colloidal solution to gel confinement. We show that the physiological alterations in growing cultures are not triggered by the initial oxidative Reactive Oxygen Species (ROS) response. Silica promotes the induction of alternative metabolic pathways along with an increase of growth suggesting the existence of rpoS polymorphisms. Since the functionality of hybrid materials depends on the specific biologic responses of their guests, such cell physiological adaptation opens perspectives in the design of bioactive devices attracting for a large field of sciences.

Fabrication of precursor-derived ceramic fibers as electrodes for energy storage applications remains largely unexplored. Within this work, three little known polymer-derived ceramic (PDC)-based fibers are being studied systemically as potential high-capacity electrode materials for electrochemical energy devices. We report fabrication of precursor-derived SiOC fibermats via one-step spinning from various compositions of siloxane oligomers followed by stabilization and pyrolysis at 800 °C. Electron microscopy, Raman, FTIR, XPS, and NMR spectroscopies reveal transformation from polymer to ceramic stages of the various SiOC ceramic fibers. The ceramic samples are a few microns in diameter with a free carbon phase embedded in the amorphous Si-O-C structure. The free carbon phase improves the electronic conductivity and provides major sites for ion storage, whereas the Si-O-C structure contributes to high efficiency. The self-standing electrodes in lithium-ion battery half-cells deliver a charge capacity of 866 mA h gelectrode -1 with a high initial coulombic efficiency of 72%. As supercapacitor electrode, SiOC fibers maintain 100% capacitance over 5000 cycles at a current density of 3 A g-1.

New functional nanobuilding blocks have been successfully synthesized by hydrosilylation of unsaturated alcohols with dimethylsiloxy isobutyl-POSS and further acylation with methacryloylchloride. The solvent influence on the reaction pathway has been studied, and reaction steps and final nano-objects have been characterized using multinuclear NMR and FTIR spectroscopy. The organic spacer chain length between the inorganic cage and the reactive methacrylate function has been changed in order to modify the reactivity of the final functional nanobuilding block in the polymerization process.

The race for developing Li-ion batteries positive electrodes with always greater energy density has recently renewed interest towards understanding the formation of the so-called cathode electrolyte interface (CEI) forming upon cycling at high potential. In this work, we used an approach combining electrochemical measurements with physical characterizations to study the different anodic events occurring for the state-of-the-art EC:DMC 1M LiPF6 (LP30) electrolyte. Doing so, we could find that EC-related species are first oxidized before the oxidation of DMC-related species at greater potential which forms a film relatively rich in organic polycarbonates species. Using a soluble redox probe, we could then demonstrate that while this organic layer is partially passivating, it is unstable with time and cycling. In fact, only reaching a potential as high as 5.4V vs. Li+/Li for several hours leads to the formation of a perfectly stable and passivating CEI.

N-Heterocyclic carbene (NHC)-stabilized copper nanoparticles (NPs) were synthesized from an NHC-borane adduct and mesitylcopper(I) under thermal conditions (refluxing toluene for 2.5 h). NPs with a size distribution of 11.6 +/- 1.8 nm were obtained. The interaction between Cu NPs and NHC ligands was probed by X-ray photoelectron spectroscopy, which showed covalent binding of the NHC to the surface of the NPs. Mechanistic studies suggested that NHC-borane plays two roles: contributing to the reduction of [CuMes](2) to release Cu-0 species and providing NHC ligands to stabilize the copper NPs.

New nuclear glass compositions, able to immobilize highly active liquid wastes arising from high burn-up UO2 fuel reprocessing, are being studied. Investigations are being performed on rare earthrich glasses, known as durable matrices. After a preliminary study, a basic glass composition was selected (Glass A, wt. %) : 51.0 SiO2 – 8.5 B2O3 – 12.2 Na2O – 4.3 Al2O3 – 4.8 CaO – 3.2 ZrO2 – 16.0 Nd2O3. The aim of this study is to determine the local environment of the rare earth in this glass and its evolution according to neodymium. To achieve this objective, glasses were prepared from the baseline Glass A with variable neodymium oxide amounts (from 0 to 30 wt. % Nd2O3). By coupling characterization methods such as EXAFS (Extended X-Ray Absorption Fine Structure) spectroscopy at the neodymium LIII-edge, optical absorption spectroscopy, B, Al MAS-NMR and Raman spectroscopy, pieces of information on the rare earth surroundings in the glass were obtained.