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Conjugated polymers based on 2,6-azulene have been synthesized and their electronic and optical properties characterized. Two of them showed the ability to disperse single-walled carbon nanotubes (SWNTs).

In this article, a new series of conjugated polymers based on a low-cost, easily accessible vat dye called Vat orange 1 or 2,9-dibromo-dibenzo[b,def]chrysene-7,14-dione have been prepared. This compound was made electron-donating by reducing and alkylating the ketone groups into alkoxy groups, allowing the introduction of solubilizing, branched alkyl chains at the 7 and 14 positions. Polymerization reactions using Suzuki–Miyaura coupling with 6,6′-isoindigo, 3,6-di-2-thienyl-pyrrolo[3,4-c]pyrrole-1,4-dione (DPP) and 4,7-dithieno-2,1,3-benzothiadiazole (TBT) yielded three donor–acceptor polymers with bandgap values ranging from 1.61 to 1.86 eV. Field-effect transistors (OFETs) and organic solar cells (OSCs) were fabricated and hole mobility values of up to 3.62 × 10−4 cm2 V−1 s−1 and a maximum power conversion efficiency of 1.2% were measured, respectively.

Carbon nanoparticles (CNPs) have emerged as one of the most promising nanomaterials due to their distinct optoelectronic properties for a diverse range of applications in the area of electronics, energy conversion and storage, and bio-imaging. Their functions and properties can be changed by varying their shape, size and dimensionality. The synthetic methods reported until now involve high-temperature (>100 °C) processes, which often result in uncontrolled shape, size and polydispersity. In this work, we focus on the development of a low-temperature synthetic method for the preparation of fluorescent carbon nanoparticles and modulation of properties. Our method, based on the dispersion Glaser-Hay polymerization of acetylene followed by decomposition into a carbonaceous material, yields CNPs with sizes varying from 30 nm to 60 nm. The shape and size of the resulting carbon nanoparticles are influenced by changing different reaction parameters such as temperature, reaction time and pressure. The control over the different reaction parameters allows us to obtain monodisperse CNPs in spherical shapes. After isolation, CNPs were characterized by microscopy and spectroscopy techniques. The residual alkynes in the CNPs’ structure were exploited for further post-functionalization/ graphitization to yield multifunctional CNPs, which were fluorescent in the blue region.

We report the successful synthesis and spectroscopic characterization of a novel, water soluble anthanthrene-based derivative, 6,12-bis(TEG)anthanthrene 3. The presence of the two long ethylene glycol side chains gives this large, six-membered polycyclic aromatic compound a high aqueous solubility. It exhibits UV–vis absorption properties similar to those of anthanthrene itself, indicating that the side chains do not have a significant effect on the electronic structure of the central chromophore. The compound exhibits strong, polarity-sensitive fluorescence in aqueous solution in the blue–green region of the spectrum, with a fluorescence quantum yield of 0.13 and a polarity sensitivity factor (PSF) of 2.0. The utility of this new fluorescent molecule as a probe of supramolecular complexation was demonstrated by its inclusion into the molecular host hydroxypropyl-β-cyclodextrin in aqueous solution. Strictly 1:1 inclusion was observed, with a moderately strong binding constant K of 650 M−1. This new fluorescence probe has significant potential applications in fluorescence-based studies of aqueous biochemical and supramolecular systems.

Objectives This article aims to contextualize and review interventions for patients with a clinical high-risk (CHR) state for psychosis. Method This review explores the literature on the CHR state and focuses more precisely on the development of its defining criteria, the evolution of CHR patients, the main interventions studied so far, and the clinical services implemented to date. Results The CHR criteria were developed from observations on the prodrome of psychotic disorders to prevent or delay the onset of psychosis. These criteria help defining three distinct groups of patients who seek help because of significant distress and functional impairments. The diagnostic evaluation remains a critical step that represents a challenge for clinicians. A significant proportion of CHR patients will not develop a psychotic disorder. And the course can be unfavorable even if there is no conversion to a psychotic disorder. In order to improve the clinical conditions of CHR patients, several interventions have been developed and studied. They fall into two main categories: psychosocial approaches and pharmacotherapy. Clinical initiatives to assess and provide support to these patients have emerged around the world, including in Switzerland, in France, and in Canada. The implementation and the integration of these services within existing health care system are influenced by several factors, including the organization of health care structures. Knowing that only a small proportion of CHR patients will progress to a psychotic disorder, it is relevant to offer these interventions in non-stigmatizing and youth-friendly places. These services would possibly be distinct from first-episode psychosis programs. Conclusion Interventions for CHR patients go well beyond the prevention of psychosis. They meet legitimate clinical needs. We must think about how to deploy them adequately in the most appropriate places.

Wood is increasingly used in construction for the benefits it brings to occupants and for its ecological aspect. Indoor wood products are frequently subject to mechanical aggressions, their abrasion and scratch resistance thus need to be improved. The coating system ensures the wood surface protection, which is, for wood flooring, a multilayer acrylate UV-curable 100% solid system. To increase the service life of wood flooring, a new property is studied: self-healing. The objective of this study is to observe the impact of monomer structure on self-healing efficiency and the effect of self-healing parameters. A previous formulation was developed using hydrogen bond technology to generate the self-healing property. In this paper, the assessment of the formulation and the self-healing parameters’ impact on self-healing efficiency as well as the physicochemical properties are presented. The composition of the monomer part in the formulations was varied, and the effect on the conversion yield (measured by FT-IR), on the Tg and crosslinking density (measured by DMA) and on mechanical resistance (evaluated via hardness pendulum, indentation, and reverse impact) was analyzed. The self-healing efficiency of the coatings was determined by gloss and scratch depth measurements (under constant and progressive load). It was proven that monomers with three acrylate functions bring too much crosslinking, which inhibits the chain mobility necessary to observe self-healing. The presence of the AHPMA monomer in the formulation permits considerably increasing the crosslinking density (CLD) while keeping good self-healing efficiency. It was also observed that the self-healing behavior of the coatings is different according to the damage caused. Indeed, the self-healing results after abrasion and after scratch (under constant or progressive load) are different. In conclusion, it is possible to increase CLD while keeping self-healing behavior until a certain limit and with a linear monomer structure to avoid steric hindrance. Moreover, the selection of the best coatings (the one with the highest self-healing) depends on the damage.

Carbon nanoparticles (CNPs) have emerged as one of the most promising nanomaterials due to their distinct optoelectronic properties for a diverse range of applications in the area of electronics, energy conversion/ storage, and bio-imaging. The uniqueness in terms of functions and properties of the CNPs gets more interesting as it changes distinctly with a change in the shape, size, and dimensionality of these nanoparticles. The synthetic methods reported until now involves high-temperature (>100 °C) processes, which often results in uncontrolled shape, size, and polydispersity. In this work, we focus on the development of a low-temperature synthetic method for the preparation of fluorescent carbon nanoparticles allowing precise control over the shape, size, and properties by dispersion polymerization of acetylene as a precursor. The shape- and size-tunable nanoparticles were synthesized in a single step with dispersion polymerization by Glaser-Hay coupling. The shape and size of the resulting carbon nanoparticles are controlled by changing different reaction parameters such as temperature, reaction time and pressure. The control over the different reaction parameters allows us to obtain monodisperse CNPs in spherical (and tubular) shape with a size in the range of 25 nm to 250 nm. The use of low-temperature methods (RT < T < 70 °C) also allows us to overcome the limitations associated with current methods. After isolation, CNPs were characterized by microscopy techniques to analyze their shape and size. The nanoparticles were further characterized to by various techniques for chemical composition, structure, morphology, and optical properties. The residual alkynes in the CNPs' structure were exploited for further post-functionalization/graphitization to yield multifunctional CNPs, which were fluorescent in the blue region.

Carbon nanoparticles (CNPs) have emerged as one of the most promising nanomaterials due to their distinct optoelectronic properties for a diverse range of applications. These unique properties arise from the network of hybridized sp2 carbon atoms as it allows delocalization of the electrons over the entire surface of the molecule. These surface groups help CNPs emit strong fluorescence in visible region. The significant fluorescence of CNPs combined with low toxicity, and photostability makes them suitable for various applications in biosensing, bio-imaging, and OLEDs. Despite several advantages and unique properties, the transformation from laboratory to industrial products has been slow for carbon nanoparticles. The synthetic methods reported until now chemically inert nanoparticles, increasing the difficulty to modulate their morphological, optical, and electronic properties. The organic synthesis methods for synthesizing CNPs often involve several synthesis steps, long reaction time, low yield, non-scalable and inefficient purification methods. Most of these synthesis methods involve several catalysts and removal of catalysts is always a challenge. Resulting nanoparticles also need functionalization using another synthesis step to give them properties such as fluorescence and making them soluble. Therefore, a synthesis method with minimum steps, minimum catalysts which could result in soluble and fluorescence nanoparticles is desired. This work investigates the use of highly reactive sp-carbon rich precursors for polymerization with microwave heating with minimum use of catalysts resulting in fluorescent CNPs. The sp-carbon rich precursors such as TMS-Benzene, butadiyne and acetylene were used as starting material. These alkynes are highly reactive and reacts to other alkynes present in the system in the presence of heat and form polyyne intermediates which are thermodynamically unstable in the form of long chains and decompose to provide us with CNPs. The plan is to use the high reactivity with microwave heating for polymerization without catalysts and further investigate the use of oxidants or minimum catalysts to increase the rate of polymerization and conversion into CNPs. The resulting nanoparticles required minimum purification in centrifuge and were isolated easily as there were no catalysts involved. The resulting nanoparticles were characterized with various techniques to study the morphology, structure, composition, and optical properties of CNPs. The resulting nanoparticles had blue fluorescence under the UV lamp. The single step synthesis of blue fluorescence CNPs was performed with microwave assisted polymerization of sp-carbon rich precursors without any catalysts. Further investigation of this method will provide a single step synthesis method for fluorescent CNPs which would be suitable for application in sensing and OLEDs.

Use of edible insects as an alternative source of proteins in food and feed is increasing. These last years, numerous companies in Europe have started producing insects for food and feed purposes. In the European Union, the use of edible insects for human consumption falls within Regulation (EU) No. 2015/2283 on novel foods. For feed, Commission Regulation (EU) 2017/893 authorizes seven insect species as processed animal proteins for aquaculture. Methods of authentication are required to check the conformity of the products. In this study, we propose a real-time polymerase chain reaction (PCR) method for the specific detection of the lesser mealworm (

Since the discovery of graphene in the early 2000's, polycyclic aromatic hydrocarbons (PAHs) have been resurrected and new synthetic tools have been developed to prepare unprecedented structures with unique properties. One application that has been overlooked for this class of molecules is organic solar cells (OSCs). In this account, we present the recent development in the preparation of moderate to low band gap PAHs that could potentially be used as semiconducting materials in OSCs. Our focus is directed toward all-carbon PAHs as well as their polymeric analogs.

We report the synthesis of π-extended ullazine derivatives annulated with either electron-poor pyridine or electron-rich thiophene units through a metal-free, photochemical cyclodehydrochlorination (CDHC) reaction. The strongest electron-donor derivative, 7-tetradecylthieno[3′,2′:7,8]indolizino[6,5,4,3-ija]thieno[2,3-c]quinolone, was copolymerized with electron-deficient thienopyrroledione (TPD), isoindigo (IID), and diketopyrrolopyrrole (DPP) derivatives to provide three donor–acceptor conjugated polymers (D–A CPs). Their photophysical, electrochemical and photovoltaic (PV) properties were investigated. The polymers showed broad UV-vis-NIR absorption bands with λmax values of 612 nm, 698 nm, 788 nm in chloroform and exhibited optical bandgap (Eoptg) of 1.58 eV, 1.41 eV, 1.24 eV measured as films. Inverted bulk heterojunction polymer solar cells (BHJ-PSCs) were fabricated using these polymers as host and light-harvesting materials. The device based on P3:PC70BM blends shows the best power conversion efficiency (PCE) of 2.23% (Voc = 0.55 V, Jsc = 7.86 mA cm−2, FF = 52%). These promising results demonstrate that π-extended ullazine derivatives can be used as electron-rich building blocks for the construction of D–A CPs for efficient PSCs applications.

Four new copolymers based on anthanthrene for the dispersion of semiconducting SWNTs of various diameters have been synthesized. After optimization of the dispersion parameters, it has been observed that fluorene- and carbazole-based copolymers lead to a sc-SWNT enrichment with low amount of residual m-SWNTs for HiPCO nanotubes. For larger diameter Plasma torch SWNTs, phenyl-based and pyrene-based copolymers yield high concentration dispersions (0.08 mg ml−1), but no selectivity for either SWNT species. Our work opens up the use of large polycyclic aromatic hydrocarbon units such as anthanthrene derivatives for SWNT wrapping process.

We demonstrate the preparation of anthanthrene derivatives with fused five-membered rings. These new derivatives are prepared by a palladium catalyzed cyclopentannulation reaction from precursors derived from the low-cost dye Vat Orange 3 (4,10-dibromoanthanthrone). The new cyclopenta-anthanthrene compounds possess reduced optical and electrochemical gaps (~0.9 eV) compared to anthanthrene derivatives and are electron acceptors with lowest unoccupied molecular orbital energies of ~ -3.4 eV to -3.9 eV.

International audience; Linear and helical graphene nanoribbons (L-PyGNR and H-PyGNR) bearing electron-rich pyrrole units have been synthesized by using the photochemical cyclodehydrochlorination (CDHC) reaction. The pyrrole units in the polymer backbone make the polymer electron-rich with moderate bandgap values and relatively high HOMO energy levels. The planarization of the pyrrole unit through cyclization yields a bandgap value almost 0.5 eV lower than that measured for polypyrrole. Conductivity values in the thin film up to 0.12 S/cm were measured for the chemically oxidized L-PyGNR (four-point method). Both GNRs showed excellent fluorescence sensing properties for TNT in solution with K SV values up to 6.4 × 10 6 M −1 .

Self-assembly of organic macrocycles has been exploited as a preliminary step in the synthesis of soluble and tailorable carbon-based nanostructures. Functionalized nanotubes have been prepared using, as core building blocks, nearly planar ring structures containing several alkyne units, exploiting the geometry achieved in the spontaneous preassembling step driven by π interaction. Covalent cross-linking between these units was achieved by thermal or photochemical activation with UV light. Here, we apply a moderate pressure in a sapphire anvil cell (1.0 GPa) to facilitate the preassembling and induce the cross-linking under pressure either with visible light, absorbed by two-photon absorption, or thermally. We observe a high yield of enhanced quality cross-linked nanotubes in a sample, showing, at ambient pressure, only side-chain decomposition. These results show that moderate pressures, easily achievable in large volume cells, are able to selectively favor topochemical reactions in such complex organic ...

Three new and stable diradical dications based on the 4,10-dibromoanthanthrone have been synthesized and characterized. In their dicationic state, the amines show a biradical character in the ground state. Their magnetic properties have been investigated by NMR and EPR spectroscopies. The dicationic salts shows strong and broad optical absorption in the near-infrared region. The main driving force to obtain a ground state biradical is the high steric hindrance that prevents planarization of the diphenylamines with the anthanthrone aromatic core. The radical cations are isolated in two perpendicular π-systems as demonstrated by X-ray diffraction structures. This work provides a new bridging unit in the search for biradical bis(triarylamines) salts.

Supramolecular self-assembly is an increasingly popular approach to design and prepare functional materials, for various applications such as organic electronics and sensing. Despite allowing for a precise organization of photo- and electro-active building blocks, supramolecular assemblies often show poor kinetic stability, which limits their application. Among the recent strategies developed to circumvent this issue, the covalent stabilization of supramolecular self-assembly with polydiacetylene moieties is a particularly attractive approach to well-defined nanomaterials. In this review, we present the most recent examples of covalent rigidification of supramolecualr self-assemblies through the photopolymerization of diacetylene moieties. This approach has not only shown great promise for the stabilization of supramolecular assemblies through covalent bond formation, but also showed great promise for the rational design and preparation of well-defined carbon-rich materials.

We studied structure, molecular orientation, morphology, and electrostatic properties of mixed self-assembled monolayers (SAMs) comprised of alkanethiolates (ATs) which are modified by a dipolar ester group embedded into the alkyl backbone at two different orientations, namely, with the dipole directed upward and downward from the substrate. The packing density and molecular orientation in these SAMs were found to be similar to those of the “parent” single-component monolayers. Applying X-ray photoelectron spectroscopy (XPS) as a morphology tool, we could estimate that the mixed SAMs represent homogeneous intermolecular mixtures of both components, down to the molecular level, excluding existence of “hot spots” for charge injection. The analysis of the C 1s XPS spectra and the work function data suggests that the composition of the mixed SAMs fully mimicked the mixing ratio of both components in the solutions from which these SAMs were prepared, which suggests a minor role of the dipole–dipole interaction...

Alkanethiolates (ATs) forming self-assembled monolayers (SAMs) on coinage metal and semiconductor substrates have been used successfully for decades for tailoring the properties of these surfaces. Here, we provide a detailed analysis of a highly promising class of AT-based systems, which are modified by one or more dipolar carboxylic acid ester groups embedded into the alkyl backbone. To obtain comprehensive insight, we study nine different embedded-dipole monolayers and five reference nonsubstituted SAMs. We systematically varied lengths of the alkyl segments, ester group orientations, and number of ester groups contained in the chain. To understand the structural and electronic properties of the SAMs, we employ a variety of complementary experimental techniques, namely, infrared reflection absorption spectroscopy (IRS), high-resolution X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), atomic force microscopy (AFM), and Kelvin probe (KP) AFM. These experiments are comp...

Graphene is a zero-gap, semiconducting 2D material that exhibits outstanding charge-transport properties. One way to open a band gap and make graphene useful as a semiconducting material is to confine the electron delocalization in one dimension through the preparation of graphene nanoribbons (GNR). Although several methods have been reported so far, solution-phase, bottom-up synthesis is the most promising in terms of structural precision and large-scale production. Herein, we report the synthesis of a well-defined, helically coiled GNR from a polychlorinated poly(m-phenylene) through a regioselective photochemical cyclodehydrochlorination (CDHC) reaction. The structure of the helical GNR was confirmed by 1H NMR, FT-IR, XPS, TEM, and Raman spectroscopy. This Riemann surface-like GNR has a band gap of 2.15 eV and is highly emissive in the visible region, both in solution and the solid state.

Le depistage de la trisomie 21 par les marqueurs seriques maternels repose sur un calcul de risque incluant la chaine libre de l’hormone chorionique gonadotrophique (hCGβ) et la pregnancy associated placenta protein de type A (PAPP-A). Cette etude a pour objectif de preciser les conditions pre-analytiques de stabilite de ces marqueurs en sang total a 15-25 C et dans le serum conserve a 4-8 C ; 158 patientes ont ete incluses dans l’etude. Deux techniques, Cobas 8000e602, Roche Diagnostics (58 patientes) et DelfiaXpress, PerkinElmer (100 patientes) ont ete etudiees. La stabilite des marqueurs a ete etudiee dans le sang total (15-25 C) 2, 4, 6 et 8 heures apres le prelevement et dans le serum conserve a 4-8 C a 24, 72 et 120 heures. Les variations relatives ont ete definies par le rapport (CT – C2)/C2, C2 etant la concentration du marqueur au temps 2 heures, et CT la concentration aux temps etudies. En sang total conserve 8 heures a 15-25 C, on observe une augmentation moyenne de 2,4 % pour l’hCGβ et inferieure a 1 % pour la PAPP-A. Dans le serum conserve 5 jours a 4-8 C, l’hCGβ augmente en moyenne de 4,2 % et la PAPP-A reste stable. L’impact de ces augmentations sur le calcul de risque de trisomie 21 est faible. En conclusion, des delais de conservation de 8 heures du sang total a 15-25 C et de 5 jours apres centrifugation et separation du serum (gel separateur ou decantation) et conservation a 4-8 C peuvent etre consideres comme acceptables.

Organic-based nanoparticles hold great potential for optoelectronics and biomedicine as they may provide optical properties in the visible range and notable advantages over inorganic counterparts. In this report, we exploit aggregation-induced emission (AIE) from the well-known tetraphenylethene (TPE) to yield photoluminescent polymer particles by a dispersion polymerization route. 1,1-Bis(4-ethynylphenyl)-2,2-diphenylethene is polymerized by a Glaser-type dispersion polymerization, providing nanoparticles of 170–600 nm with low polydispersity by simply varying monomer loadings. Optical characterization reveals emission bands at 500 nm and 600 nm, where UV irradiation of the particles causes the 500 nm band to increase relative to the 600 nm one. Structural characterization by 13C MAS-NMR allows confirming that this change upon UV irradiation is not induced by a chemical modification, thus suggesting a physical change in the particle's morphology. Altogether, the results of this work allow enlarging the library of TPE-comprising particles, but also enhance the variety of particles synthesized from Glaser-type dispersion polymerization. The study also allows gaining insight into the photochemical stability of TPE-containing particles, where the non-destructive UV irradiation lets us plan the development of new polyyne/TPE hybrid systems.

A new alkyne-based macrocycle that combines monoyne, diyne and tetrayne is reported. Despite its unusual trapezoid shape, the bending of the tetrayne unit allows the macrocycle to be unstrained. The macrocycle is synthesized by a combination of selective deprotection of silylated alkyne, Castro–Stephen–Sonogashira coupling and copper-mediated oxidative homocoupling. The final intramolecular cyclization proceeded in surprisingly high yield (72%) using modified Eglinton conditions in moderate dilution.

The two-dimensional (2D) surface-directed self-assembly of dibenzonitrile diacetylene (DBDA) on Ag(111) under ultrahigh vacuum (UHV) conditions was investigated by combining scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and theoretical simulations based on density functional theory (DFT) calculations. The molecule consists of two benzonitrile groups (–C6H4–CN) on each side of a diacetylene (–CC–CC–) backbone. The terminating nitrile (–CN) groups at the meta position of the phenyl rings lead to cis and trans stereoisomers. The trans isomer is prochiral and can adsorb in the R or S configuration, leading to the formation of enantiomeric self-assembled networks on the surface. We identify two simultaneously present supramolecular networks, termed parallel and chevron phases, as well as a less frequently observed butterfly phase. These networks are formed from pure R (or S) domains, racemic mixtures (RS), and cis isomers, respectively. Our complementary data illustrates that the formation of the 2D supramolecular networks is driven by intermolecular hydrogen bonding between nitrile and phenyl groups (–CN⋯H–C6H3). This study illustrates that the molecular arrangement of each network depends on the geometry of the isomers. The orientation of the nitrile group controls the formation of the most energetically stable network via intermolecular hydrogen bonding.

This review presents an overview of the recent developments in the area of vat dye chemistry for the preparation of π-conjugated molecules and polymers for organic electronic applications. Vat dyes are well-established molecules in the textile colouring and painting industry as they are inexpensive and highly stable. Their optical properties in the visible region are attributed to their highly conjugated sp2 carbon networks and the presence of functional groups, especially ketones that allow the formation of “leuco” species. In this review, we will show how the presence of functional groups on these highly conjugated scaffolds can be used to modify their electronic and optical properties to make them useful building blocks for semiconducting organic materials.

Singlet and triplet excited‐state dynamics of anthanthrene and anthanthrone derivatives in solution are studied. Triisopropylsilyl‐ (TIPS) or H‐terminated ethynyl groups are used to tune the singlet and triplet energies to enable their potential applications in singlet fission and triplet fusion processes. Time‐resolved optical and electron paramagnetic resonance (EPR) spectroscopies are used to obtain a mechanistic understanding of triplet formation. The anthanthrene derivatives form triplet states efficiently at a rate (ca. 107 s−1) comparable to radiative singlet fluorescence processes with approximately 30 % triplet yields, despite their large S1‐T1 energy gap (>1 eV) and the lack of carbonyl groups. In contrast, anthanthrone has a higher triplet yield (50±10 %) with a faster intersystem crossing rate (2.7urn:x-wiley:21926506:media:cplu201900410:cplu201900410-math-0001 108 s−1) because of the n‐π* character of the S1←S0 transition. Analysis of time‐resolved spin‐polarized EPR spectra of these compounds reveals that the triplet states are primarily generated by the spin‐orbit‐induced intersystem crossing mechanism. However, at high concentrations, the EPR spectrum of the 4,6,10,14‐tetrakis(TIPS‐ethynyl) anthanthrene triplet state shows a significant contribution from a non‐Boltzmann population of the ms=0 spin sublevel, which is characteristic of triplet formation by singlet fission.

The solution-phase synthesis is one of the most promising strategies for the preparation of well-defined graphene nanoribbons (GNRs) in large scale. To prepare high quality, defect-free GNRs, cycloaromatization reactions need to be very efficient, proceed without side reaction and mild enough to accommodate the presence of various functional groups. In this Minireview, we present the latest synthetic approaches for the synthesis of GNRs and related structures, including alkyne benzannulation, photochemical cyclodehydrohalogenation, Mallory and Pd- and Ni-catalyzed reactions.

Polycyclic aromatic hydrocarbons (PAHs) are interesting building blocks for the preparation of conjugated polymers due to their extended π surface and planar conformation. However, their use as comonomer in conjugated polymers often leads to nonplanar main chains as a consequence of high steric hindrance at the linking point. Herein, we report the synthesis of a ladderized anthanthrene unit using an sp3 carbon bridge. Three conjugated copolymers with fluorene, isoindigo, and bithiophene derivatives have been synthesized and characterized to study the effect of such ladderization on the electronic properties. The dihedral angle between the ladderized anthanthrene and adjacent units has been significantly reduced by the formation of the sp3 carbon bridge, thus eliminating the steric hindrance with the proton at the peri position of the anthanthrene unit and red-shifting the absorption spectrum by 25 nm.

Le logiciel de calcul de risque de trisomie 21 fœtale, Fast Screen Pre I Plus, de la Societe Thermo Fisher Scientific, convertit les concentrations des marqueurs seriques maternels du premier trimestre de la grossesse (PAPP-A et hCGβ) en degres d’extreme (DoE). Afin de repondre aux exigences de la reglementation francaise ainsi qu’a celles des biologistes agrees, un outil de conversion des DoE en multiples de la mediane (MoM), valeur intermediaire de reference pour le depistage, a ete developpe. En l’absence de tout polynome median, permettant une obtention facile de ces MoM, les calculs ont d’abord ete realises sur la base des polynomes centiles du logiciel. Les revisions successives des algorithmes de calcul ont montre la fragilite de cette approche reposant sur l’hypothese gaussienne. Des generateurs de medianes, calcules a partir des donnees des biologistes du club Kryptor, ont ete etablis.

Novel nanographenes were prepared by a photochemical cyclodehydrochlorination (CDHC) reaction. Chlorinated precursors were irradiated in acetone in the presence of a base or in pure benzene and underwent multiple (up to four) regioselective cyclization reactions to provide rigid π-conjugated molecules. Pure compounds were recovered in good yields by simple filtration at the end of the reaction. The CDHC reaction showed compatibility with both electron-poor and electron-rich substrates, thus allowing the synthesis of pyridine- and thiophene-fused nanographenes. It also enabled the synthesis of sterically hindered contorted π-conjugated molecules without causing full aromatization. A kinetic study showed that the CDHC reaction under the conditions used is a very fast process, and some reactions are completed within minutes. The CDHC reaction thus shows great potential as an alternative to other reactions involving harsher conditions for the preparation of nanographenes.

This report describes the design and development of functionalized silica particles using tethered Schiff base ligands for uranium extraction from rare earth element leach liquors. We evaluated different grafting approaches (both one- and two-sided tethering); and found the maximum U(VI) adsorption capacity for the functionalized silica was 95 ± 2 mg g −1 . The functionalized particles demonstrated a very high degree of affinity for the uranyl and thorium ions with K d values at pH 6 exceeding 19,000 and 900,000 mL g −1 , respectively. This selectivity for these ions is better than most metal ions present in leach liquors, and the extraction kinetics are faster than pure Schiff base crystals. The Schiff-base-functionalized silica particles also exhibited a high degree of reusability over five cycles of loading-elution in the conditions tested.