Search

A new series of 4-methyl-2-{2-[(aryl)methylidene]hydrazinyl}-1,3-thiazole (2a-i), N-(4-acetyl-5-aryl)4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamides (3a-b) and N-(5-(4-(substituted phenyl)-1,3,4-thiadiazol-2-yl)acetamides (3c-i) were synthesized by the reaction of 2-((aryl)methylene)hydrazine-1-carbothioamides (1a-i) and acetic anhydride or chloroacetone. The cytotoxic activities of the products were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay against Hela cervical cancer, MCF-7 breast carcinoma and HT-29 colorectal cancer cell lines. Thiazole based compounds 2a, 2b, 2f and 2i, bearing 4-bromothiophen-2-yl, naphthalen-2-yl, 2,5-difluorophenyl and 4-(trifluoromethoxy)phenyl moieties, respectively; also N-(4-acetyl-5-(naphthalen-2-yl)-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide (3b) and N-(5-(2,6-difluorophenyl)-1,3,4-thiadiazol-2-yl)acetamide (3d) exhibited significant anticancer activity against three cancer cell lines. Moreover, these active compounds were further evaluated by apoptotic protein levels. The results showed that these thiazole and thiadiazole compounds induced apoptosis of cancer cells.

Gut microbiota of the gastrointestinal tract provide health benefits to the human host via bacterial metabolites. Bacterial butyrate has beneficial effects on intestinal homeostasis and is the preferred energy source of intestinal epithelial cells, capable of inducing differentiation. It was previously observed that changes in the expression of specific proteins as well as protein glycosylation occur with differentiation. In this study, specific mucin O-glycans were identified that mark butyrate-induced epithelial differentiation of the intestinal cell line CaCo-2 (Cancer Coli-2), by applying porous graphitized carbon nano-liquid chromatography with electrospray ionization tandem mass spectrometry. Moreover, a quantitative proteomic approach was used to decipher changes in the cell proteome. It was found that the fully differentiated butyrate-stimulated cells are characterized by a higher expression of sialylated O-glycan structures, whereas fucosylation is downregulated with differentiation. By performing an integrative approach, we generated hypotheses about the origin of the observed O-glycome changes. These insights pave the way for future endeavors to study the dynamic O-glycosylation patterns in the gut, either produced via cellular biosynthesis or through the action of bacterial glycosidases as well as the functional role of these patterns in homeostasis and dysbiosis at the gut-microbiota interface.

Mass spectrometry imaging (MSI) of lipids within tissues has significant potential for both biomolecular discovery and histopathological applications. Conventional MSI technologies are, however, challenged by the prevalence of phospholipid regioisomers that differ only in the location(s) of carbon-carbon double bonds and/or the relative position of fatty acyl attachment to the glycerol backbone (i.e., sn position). The inability to resolve isomeric lipids within imaging experiments masks underlying complexity, resulting in a critical loss of metabolic information. Herein, ozone-induced dissociation (OzID) is implemented on a mobility-enabled quadrupole time-of-flight (Q-TOF) mass spectrometer capable of matrix-assisted laser desorption/ionization (MALDI). Exploiting the ion mobility region in the Q-TOF, high number densities of ozone were accessed, leading to similar to 1000-fold enhancement in the abundance of OzID product ions compared to earlier MALDI-OzID implementations. Translation of this uplift into imaging resulted in a 50-fold improvement in acquisition rate, facilitating large-area mapping with resolution of phospholipid isomers. Mapping isomer distributions across rat brain sections revealed distinct distributions of lipid isomer populations with region-specific associations of isomers differing in double bond and sn positions. Moreover, product ions arising from sequential ozone- and collision-induced dissociation enabled double bond assignments in unsaturated fatty acyl chains esterified at the noncanonical sn-1 position.

International audience; Tremolite is one of the most common amphibole species and, in the fibrous form (i.e., characterized by crystals/particles consisting of fibres with length > 5 µm, width 3), one of the six asbestos minerals. Until now the attention of crystallographers has focused only on samples from continental environment. Here we report the first chemical and structural data of a tremolite asbestos found along the Mid Atlantic Ridge (MAR) at the eastern intersection of the Romanche Transform Fault (Equatorial MAR). Tremolite is associated with chlorite and lizardite and was formed through the green shale facies lower than zeolite in a predominantly fluid system. MAR tremolite asbestos shows very slight deviations from the ideal crystal structure of tremolite. Differences in cation site partitioning were found with respect to tremolite asbestos from ophiolitic complexes, attributed to the different chemical–physical conditions during the mineral formation. In particular, oceanic tremolite asbestos is enriched in Al and Na, forming a trend clearly distinct from the continental tremolites.

Lignocellulosic biomass is an abundant byproduct from cereal crops that can potentially be valorized as a feedstock to produce biomaterials. Zea mays CINNAMYL ALCOHOL DEHYDROGENASE 2 (ZmCAD2) is involved in lignification, and is a promising target to improve the cellulose‐to‐glucose conversion of maize stover. Here, we analyzed a field‐grown zmcad2 Mutator transposon insertional mutant. Zmcad2 mutant plants had an 18% lower Klason lignin content, whereas their cellulose content was similar to that of control lines. The lignin in zmcad2 mutants contained increased levels of hydroxycinnamaldehydes, i.e. the substrates of ZmCAD2, ferulic acid and tricin. Ferulates decorating hemicelluloses were not altered. Phenolic profiling further revealed that hydroxycinnamaldehydes are partly converted into (dihydro)ferulic acid and sinapic acid and their derivatives in zmcad2 mutants. Syringyl lactic acid hexoside, a metabolic sink in CAD‐deficient dicot trees, appeared not to be a sink in zmcad2 maize. The enzymatic cellulose‐to‐glucose conversion efficiency was determined after 10 different thermochemical pre‐treatments. Zmcad2 yielded significantly higher conversions compared with controls for almost every pre‐treatment. However, the relative increase in glucose yields after alkaline pre‐treatment was not higher than the relative increase when no pre‐treatment was applied, suggesting that the positive effect of the incorporation of hydroxycinnamaldehydes was leveled off by the negative effect of reduced p‐coumarate levels in the cell wall. Taken together, our results reveal how phenolic metabolism is affected in CAD‐deficient maize, and further support mutating CAD genes in cereal crops as a promising strategy to improve lignocellulosic biomass for sugar‐platform biorefineries.

N-Heterocyclic carbenes (NHCs) are nowadays ubiquitous in organometallic chemistry and catalysis. Recently, a synthetic method which makes use of weak bases and desirable solvents has emerged as a simple, widely applicable and cost-effective pathway to well defined M-NHC complexes. Herein, recent studies devoted to the weak base approach are examined in detail, in order to showcase the simplicity, scope and variations of the method with regards to the azolium salts, bases and the metal sources, as well as the reaction conditions used. Mechanistic investigations are presented, illustrating the formation of intermediates which are air and moisture stable, prior to the metallation step. Finally, the importance, limitations and future prospects of the weak base route are discussed.

The valorisation of the plant biopolymer lignin is now recognised as essential to enabling the economic viability of the lignocellulosic biorefining industry. In this context, the “lignin-first” biorefining approach, in which lignin valorisation is considered in the design phase, has demonstrated the fullest utilisation of lignocellulose. We define lignin-first methods as active stabilisation approaches that solubilise lignin from native lignocellulosic biomass while avoiding condensation reactions that lead to more recalcitrant lignin polymers. This active stabilisation can be accomplished by solvolysis and catalytic conversion of reactive intermediates to stable products or by protection-group chemistry of lignin oligomers or reactive monomers. Across the growing body of literature in this field, there are disparate approaches to report and analyse the results from lignin-first approaches, thus making quantitative comparisons between studies challenging. To that end, we present herein a set of guidelines for analysing critical data from lignin-first approaches, including feedstock analysis and process parameters, with the ambition of uniting the lignin-first research community around a common set of reportable metrics. These guidelines comprise standards and best practices or minimum requirements for feedstock analysis, stressing reporting of the fractionation efficiency, product yields, solvent mass balances, catalyst efficiency, and the requirements for additional reagents such as reducing, oxidising, or capping agents. Our goal is to establish best practices for the research community at large primarily to enable direct comparisons between studies from different laboratories. The use of these guidelines will be helpful for the newcomers to this field and pivotal for further progress in this exciting research area.

In the meat industry, hydrocolloids and phosphates are used to improve the quality attributes of meat products. However, latest research results revealed that the usage of exopolysaccharide (EPS)-forming lactic acid bacteria (LAB), which are able to produce EPS in situ during processing could be an interesting alternative. The current review aims to give a better understanding of bacterial EPS production in food matrices with a special focus on meat products. This includes an introduction to microbial EPS production (homopolysaccharides as well as heteropolysaccharides) and an overview of parameters affecting EPS formation and yield depending on LAB used. This is followed by a summary of methods to detect and characterize EPS to facilitate a rational selection of starter cultures and fermentation conditions based on desired structure-function relationships in different food matrices. The mechanism of action of in situ generated EPS is then highlighted with an emphasis on different meat products. In the process, this review also highlights food additives currently used in meat production that could in the future be replaced by in situ EPS-forming LAB. ispartof: COMPREHENSIVE REVIEWS IN FOOD SCIENCE AND FOOD SAFETY vol:19 issue:6 pages:2932-2954 ispartof: location:United States status: published

We have investigated the reactions of chalcogenoureas derived from N-heterocyclic carbenes, referred to here as [E(NHC)], with halogens. Depending on the structure of the chalcogenourea and the identity of the halogen, a diverse range of reactivity was observed and a corresponding range of structures were obtained. Cyclic voltammetry was carried out to characterize the oxidation and reduction potentials of these [E(NHC)] species; selenoureas were found to be easier to oxidize than the corresponding thioureas. In some cases, a correlation was found between the oxidation potential of these compounds and the electronic properties of the corresponding NHC moiety. The reactivity of these chalcogenoureas with different halogenating reagents (Br2, SO2Cl2, I2) was then investigated, and products were characterized using NMR spectroscopy and single-crystal X-ray diffraction. X-ray analyses elucidated the solid-state coordination types of the obtained products, showing that a variety of possible adducts can be obtained. In some cases, we were able to extrapolate a structure/activity correlation to explain the observed trends in reactivity and oxidation potentials.

In this study, Schiff base ligand was obtained from the condensation reaction of benzene-1,2-diamine and 5-fluoropyrimidine-2,4(1H,3H)-dione (5-FU). Metal(II) complexes were synthesized with Fe(II), Co(II) and Ni(II) chloride salts. The synthesized ligand and metal complexes were characterized by FT-IR, UV-vis, H-1-C-13 NMR, elemental analyses, mass spectroscopy, magnetic moments, molar conductivity and thermogravimetric analysis studies. With the help of different techniques reveal Fe(II), Co(II) and Ni(II) complexes have exhibited tetrahedral and octahedral geometry. Ligand acted as bidentate and it binds metal(II) ions through deprotonated-NH, imine-N atom and carbonyl-O atom, respectively. DPPH, ABTS, FRAP, CUPRAC and total antioxidant activity methods were used to determine the antioxidant properties of ligand and metal complexes. According to the results, the synthesized compounds showed very high antioxidant activity compared to 5-FU. The cytotoxicities of the synthesized compounds were performed on MCF-7 (human breast cancer) and L-929 (fibroblast) cell lines using the MTT assay. In addition, the effect of electroporation (EP) on the cytotoxicity of the compounds was investigated. Our results demonstrated that novel Co(II) and Ni(II) complexes show potential as new anticancer agents and ECT may be a viable treatment option for breast cancer.

The five new Ru(II)(eta(6)-p-cymene) complexes (1-5 ) were successfully synthesized, characterized by FT-IR, elemental analysis, electronic spectra, proton and carbon NMR, mass spectra and thermal analysis, and applied in the transfer hydrogenation of ketones. In addition, enzyme inhibitory and antioxidant activities of novel Ru(II)(eta(6)-p-cymene) complexes were evaluated using several in vitro methods. The stabilities of complexes were checked by UV-Vis. spectroscopy. The results of enzyme assays showed that novel Ru(II)(eta(6)-p-cymene) complexes had effective inhibitions against the tyrosinase and pancreatic lipase enzymes. The IC50 values of five different (1-5) for tyrosinase were found as 34.65 +/- 1.2 mu M, 31.51 +/- 1.7 mu M, 49.50 +/- 3.1 mu M, 19.25 +/- 0.9 mu M, and 63.01 +/- 3.3 mu M, respectively. Furthermore, ABTS, CUPRAC, DPPH, and FRAP in vitro methods were utilized to assess the antioxidant capabilities of the compounds. The powerful antioxidant potentials of the synthesized compounds were detected compared to the standards, such as BHA, BHT, ascorbic acid, and a-tocopherol. This study provides a valuable potential of the novel Ru(II)(eta(6)-p-cymene) complexes for pharmacological studies with further analytical experiments to explore their full properties. (C) 2022 Elsevier B.V. All rights reserved.

27 páginas.- 7 figuras.- 2 tablas.- 157 referencias.- Supplementary data The following supplementary data are available at JXB online., Phenolic metabolism is rewired during internode development and in response to cinnamyl alcohol dehydrogenase perturbation in sorghum, with different sets of genes and accumulating compounds. The molecular mechanisms associated with secondary cell wall (SCW) deposition in sorghum remain largely uncharacterized. Here, we employed untargeted metabolomics and large-scale transcriptomics to correlate changes in SCW deposition with variation in global gene expression profiles and metabolite abundance along an elongating internode of sorghum, with a major focus on lignin and phenolic metabolism. To gain deeper insight into the metabolic and transcriptional changes associated with pathway perturbations, a bmr6 mutant [with reduced cinnamyl alcohol dehydrogenase (CAD) activity] was analyzed. In the wild type, internode development was accompanied by an increase in the content of oligolignols, p-hydroxybenzaldehyde, hydroxycinnamate esters, and flavonoid glucosides, including tricin derivatives. We further identified modules of genes whose expression pattern correlated with SCW deposition and the accumulation of these target metabolites. Reduced CAD activity resulted in the accumulation of hexosylated forms of hydroxycinnamates (and their derivatives), hydroxycinnamaldehydes, and benzenoids. The expression of genes belonging to one specific module in our co-expression analysis correlated with the differential accumulation of these compounds and contributed to explaining this metabolic phenotype. Metabolomics and transcriptomics data further suggested that CAD perturbation activates distinct detoxification routes in sorghum internodes. Our systems biology approach provides a landscape of the metabolic and transcriptional changes associated with internode development and with reduced CAD activity in sorghum., This work was supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) via the BIOEN Young Investigators Awards research grant (FAPESP no. 2015/02527-1). This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES) -Finance Code 001, by FEDER/Agencia Estatal de Investigacion with the Spanish Projects AGL2017-83036-R and PID2020-118968RB-I00, and by Junta de Andalucia (Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades, project P20_00017). IC is indebted to Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for the research fellowship 302927/2018-2. SSF was funded for a post-doctoral fellowship (FAPESP n0. 2016/06917-1). MSS was funded for a master's fellowship (FAPESP no. 2015/18361-5). AVAP was funded for a scientific initiation fellowship (FAPESP no. 2016/06714-3). LGAL was funded for a scientific initiation fellowship (FAPESP no. 2019/14604-1).

Transition metal complexes bearing N-heterocyclic carbene ligands (NHCs) have gained a place of crucial importance in numerous areas of research such as medicinal chemistry, material sciences, and homogeneous/heterogeneous catalysis. In the present review, an updated overview of the main synthetic routes used for the preparation of this broad class of compounds along with their main applications are reported. Particular attention will be paid to the synthesis of late transition metal-NHC complexes using weak bases, eco-friendly solvents, and mild operating conditions. This simple synthetic approach, also known as the 'weak base route', represents a recent development with yet unrealized potential.

The role of sodium acetate in the synthesis of [Au(NHC)Cl] complexes was examined. The use of this base was also investigated for the activation of C-H and S-H bonds by experimental and computational methods. The synthetic use of NaOAc to assemble these complexes is applicable to a wide range of NHCs and proceeds under air, under mild conditions and using technical grade green solvents.

This study involves the modeling of rheological behavior of the gum solution obtained from cold-pressed chia seed (CSG), flaxseed (FSG), and rocket seed (RSG) oil by-products and the application of these gums in a low-fat vegan mayonnaise formulation as fat replacers and emulsifier. CSG, FSG, and RSG solutions showed shear-thinning flow behavior at all concentrations. The K values ranged between 0.209 and 49.028 Pa·sn for CSG, FSG, and RSG solutions and significantly increased with increased gum concentration. The percentage recovery for the G′ was significantly affected by gum type and concentrations. CSG, FSG, and RSG showed a solid-like structure, and the storage modulus (G′) was higher than the loss modulus (G″) in all frequency ranges. The rheological characterization indicated that CSG, FSG, and RSG could be evaluated as thickeners and gelling agents in the food industry. In addition, the rheological properties, zeta potential, and particle size and oxidative stability (at 90 °C) of low-fat vegan mayonnaise samples prepared with CSG, FSG, and RSG were compared to samples prepared with guar gum (GG), Arabic gum (AG), and xanthan gum (XG). As a result, CSG, FSG, and RSG could be utilized for low-fat vegan mayonnaise as fat and egg replacers, stabilizers, and oxidative agents. The results of this study indicated that this study could offer a new perspective in adding value to flaxseed, chia seed, and rocket seed cold-press oil by-product.

The present paper describes a capillary zone electrophoresis method which relies on a multi-layered water-alkali solvent stacking with on-line ionization to enhance detection of mannose, arabinose, and their oligosaccharides, which are used as the migration profile standards but are also the distinctive structural components of lipoarabinomannan. Lipoarabinomannan is detected in patients having tuberculosis. The CE method with ionization of the whole saccharides without degradation in alkaline solution inside the capillary is based structural deprotonation of the molecules under ultrahigh pH conditions. The validation of the CE parameters revealed that the 15-fold electrolyte - water -injection plug allowed detection of one third lower concentrations than detected without on-line concentration. For the first time, the better detectability was seen especially for highly polymerized, but otherwise poorly ionized, arabino-octaose. The applicability of the method for detecting whole large biological saccharide complexes was confirmed by the glycolipid lipoarabinomannan. For the first time also, the migration of the indestructible lipoarabinomannan was detected together with oligosaccharides used representing the capping units, namely mannose, mannobiose and mannotriose. The myo-inositol-phosphate-lipid unit was seen to migrate separately from the arabinomannan, since it was hydrolyzed from one lipoarabinomannan product under alkaline conditions in CE. This article is protected by copyright. All rights reserved The present article describes a capillary zone electrophoresis method which relies on a multilayered water-alkali solvent stacking with online ionization to enhance detection of mannose, arabinose, and their oligosaccharides, which are used as the migration profile standards but are also the distinctive structural components of lipoarabinomannan. Lipoarabinomannan is detected in patients having tuberculosis. The capillary electrophoresis method with ionization of the whole saccharides without degradation in alkaline solution inside the capillary is based on the structural deprotonation of the molecules under ultrahigh pH conditions. The validation of the capillary electrophoresis parameters revealed that the 15-fold electrolyte–water-injection plug allowed detection of one-third lower concentrations than detected without online concentration. For the first time, the better detectability was seen especially for highly polymerized, but otherwise poorly ionized, arabinooctaose. The applicability of the method for detecting whole large biological saccharide complexes was confirmed by the glycolipid lipoarabinomannan. For the first time also, the migration of the indestructible lipoarabinomannan was detected together with oligosaccharides used representing the capping units, namely mannose, mannobiose, and mannotriose. The myo-inositol-phosphate-lipid unit was seen to migrate separately from the arabinomannan, since it was hydrolyzed from one lipoarabinomannan product under alkaline conditions in capillary electrophoresis.

The intricate architecture of cell walls and the complex cross-linking of their components hinders some industrial and agricultural applications of plant biomass. Xylan is a key structural element of grass cell walls, closely interacting with other cell wall components such as cellulose and lignin. The main branching points of grass xylan, 3-linked l-arabinosyl substitutions, can be modified by ferulic acid (a hydroxycinnamic acid), which cross-links xylan to other xylan chains and lignin. XAX1 (Xylosyl arabinosyl substitution of xylan 1), a rice (Oryza sativa) member of the glycosyltransferase family GT61, has been described to add xylosyl residues to arabinosyl substitutions modified by ferulic acid. In this study, we characterize hydroxycinnamic acid-decorated arabinosyl substitutions present on rice xylan and their cross-linking, in order to decipher the role of XAX1 in xylan synthesis. Our results show a general reduction of hydroxycinnamic acid-modified 3-linked arabinosyl substitutions in xax1 mutant rice regardless of their modification with a xylosyl residue. Moreover, structures resembling the direct cross-link between xylan and lignin (ferulated arabinosyl substitutions bound to lignin monomers and dimers), together with diferulates known to cross-link xylan, are strongly reduced in xax1. Interestingly, apart from feruloyl and p-coumaroyl modifications on arabinose, putative caffeoyl and oxalyl modifications were characterized, which were also reduced in xax1. Our results suggest an alternative function of XAX1 in the transfer of hydroxycinnamic acid-modified arabinosyl substitutions to xylan, rather than xylosyl transfer to arabinosyl substitutions. Ultimately, XAX1 plays a fundamental role in cross-linking, providing a potential target for the improvement of use of grass biomass.

Wheat bran incorporation into biscuits may increase their nutritional value, however, it may affect dough rheology and baking performance, due to the effect of bran particles on dough structure and an increase in water absorption. This study analyzed the enrichment effect of wheat bran and arabinoxylans, the most important non-starch polysaccharides found in whole wheat flour, on dough rheology and thermal behaviour during processing of rotary-moulded biscuits. The objective was to understand the contribution of arabinoxylans during biscuit-making and their impact when incorporated as wheat bran. Refined flour was replaced at 25, 50, 75, or 100% by whole flour with different bran particle sizes (fine: 4% &gt, 500 μm, coarse: 72% &gt, 500 μm). The isolated effect of arabinoxylans was examined by preparing model flours, where refined flour was enriched with water-extractable and water-unextractable arabinoxylans. Wheat bran had the greatest impact on dough firmness and arabinoxylans had the greatest impact on the elastic response. The degree of starch gelatinization increased from 24 to 36% in biscuits enriched with arabinoxylans or whole flour and coarse bran. The microstructural analysis (SEM, micro-CT) suggested that fibre micropores may retain water inside their capillaries which can be released in a controlled manner during baking.

O-methyltransferases are ubiquitous enzymes involved in biosynthetic pathways for secondary metabolites such as bacterial antibiotics, human catecholamine neurotransmitters, and plant phenylpropanoids. While thousands of putative O-methyltransferases are found in sequence databases, few examples are functionally characterized. From a pathway engineering perspective, however, it is crucial to know the substrate and product ranges of the respective enzymes to fully exploit their catalytic power.In this study, we developed anin vitroprototyping workflow that allowed us to screen ~30 enzymes against five substrates in three days with high reproducibility. We combinedin vitrotranscription/translation of the genes of interest with a microliter-scale enzymatic assay in 96-well plates. The substrate conversion was indirectly measured by quantifying the consumption of the S-adenosyl-L-methionine co-factor by time-resolved fluorescence resonance energy transfer rather than time-consuming product analysis by chromatography. This workflow allowed us to rapidly prototype thus-far uncharacterized O-methyltransferases for future use as biocatalysts.

Density functional theory calculations on neutral sheet models for methylaluminoxane (MAO) indicate that these structures, containing 5‐coordinate and 4‐coordinate Al, are likely precursors to ion‐pairs seen during the hydrolysis of trimethylaluminum (Me3Al) in the presence of donors such as octamethyltrisiloxane (OMTS). Ionization by both methide ([Me]−) and [Me2Al]+ abstraction, involving this donor, were studied by polarizable continuum model calculations in fluorobenzene (PhF) and o‐difluorobenzene (DFB) media. These studies suggest that low MW, 5‐coordinate sheets ionize by [Me2Al]+ abstraction, while [Me]− abstraction from Me3Al‐OMTS is the likely process for higher MW 4‐coordinate sheets. Further, comparison of anion stabilities per mole of aluminoxane repeat unit (MeAlO)n, suggest that anions such as [(MeAlO)7(Me3Al)4Me]−=[7,4]− are especially stable compared to higher homologues, even though their neutral precursors are unstable., Hydrolysis of trimethylaluminum (Me3Al): Viewed through the lenses of electrospray ionization mass spectrometry and density functional theory, methylaluminoxane activators adopt sheet structures while the larger sheets form chelated anions on reaction with neutral donors. Calculated ion‐pair stabilities in polar media agree well with experimental spectra collected during formation of activators.

In this study, we have designed, synthesized and full characterized a novel biological based acidic nano organocatalyst via condensations reaction of uric acid and phosphorous acid. The obtained compound was named theacrine tetrakis(phosphonic acid) (TTPA) and prepared under refluxing ethanol. This new nano organocatalyst was applied as an efficient and recyclable catalyst for the preparation of novel pyridines with indole moieties via a cooperative vinylogous anomeric based oxidation with good to excellent yields.

Conjugated organic photochromes such as azobenzene derivatives can show remarkable nonlinear optical (NLO) properties and rapid responses, two essential requirements for the realization of optoelectronic switching devices. These applications also require the control of the molecular organization over the micrometric scale, which in principle can be achieved by arranging chromophore units in self-assembled monolayers (SAMs). To rationalize the interplay between the NLO responses of isolated molecules and those of photoresponsive materials, we implement here a computational approach combining molecular dynamics simulations and DFT calculations for predicting the contrast NLO responses of azobenzene-based SAMs with different surface densities. We show that collective switching of the chromophores is indeed possible, even though trans -> cis photoisomerization yields decrease when increasing the chromophore concentration. The magnitude of the second-order NLO response of trans SAMs is dominated by the component normal to the surface, which is considerably larger than the parallel one and significantly increases with the packing density. Photoswitching has the neat effect of halving the first hyperpolarizability, allowing for large NLO contrasts exploitable for storing and reading information in selected portions of the surface.

The impact of various degrees of acetylation on improving the thermal stability of xylan isolated from different botanical source has been studied; methylglucuronoxylan from birch and eucalyptus, arabinoglucuronoxylan from spruce and glucuronoarabinoxylan from sugarcane bagasse and straw. The lower molecular weight of nonacetylated methylglucuronoxylan (17.7-23.7 kDa) and arabinoglucuronoxylan (16.8 kDa) meant that they were more soluble in water than glucuronoarabinoxylan (43.0-47.0 kDa). The temperature at the onset of degradation increased by 17-61 degrees C and by 75-145 degrees C for low and high acetylated xylans respectively, as a result of acetylation. A glass transition temperature in the range of 121-132 degrees C was observed for the samples non-acetylated and acetylated at low degree of acetylation (0.0-0.6). The acetylation to higher degrees (1.4-1.8) increased the glass transition temperature of the samples to 189-206 degrees C. Acetylation proved to be an efficient method for functionalization of the xylan to increase the thermal stability.

Zinc phenoxide complexes (LZnOAr)-Zn-1 1-4 (L-1=Me2NC2H4NC(Me)CHC(Me)O) and (LZnOAr)-Zn-2 5-8 (L-2=Me2NC3H6NC(Me)CHC(Me)O) with donor-functionalized beta-ketoiminate ligands (L-1/2) and OAr substituents (Ar=Ph 1, 5; 2,6-Me-2-C6H3 2, 6; 3,5-Me-2-C6H3 3, 7; 4-Bu-C6H4 4, 8) with tuneable electronic and steric properties were synthesized and characterized. 1-8 adopt binuclear structures in the solid state except for 5, while they are monomeric in CDCl3 solution. 1-8 are active catalysts for the ring opening polymerization (ROP) of lactide (LA) in CH2Cl2 at ambient temperature and the catalytic activity is controlled by the electronic and steric properties of the OAr substituent, yielding polymers with high average molecular weight (M-n) and moderately controlled molecular weight distribution (MWDs). 1 and 5 showed a living polymerization character and kinetic studies on the ROP of L-LA with 1 and 5 proved first order dependencies on the monomer concentration. Homonuclear decoupled H-1-NMR analyses of polylactic acid (PLA) formed with rac-LA proved isotactic enrichment of the PLA microstructure.

A simple deoxygenation reagent prepared in situ from commercially available Mo(CO)6 and ortho-quinone has been developed for the synthesis of indoline and indole derivatives. The Mo/quinone complex efficiently deoxygenates carbonyl compounds bearing a neighboring dialkylamino group and effects intramolecular cyclizations with the insertion of a deoxygenated carbonyl carbon into a C(sp3)–H bond, in which a carbonyl group acts as a carbene equivalent. The reaction also proceeds with a catalytic amount of Mo/quinone in the presence of disilane as an oxygen atom acceptor.

Snake venom L-amino acid oxidases (LAAOs) are flavoproteins, which perform diverse biological activities in the victim such as edema, myotoxicity and cytotoxicity, contributing to the development of clinical symptoms of envenomation. LAAO cytotoxicity has been described, but the temporal cascade of events leading to cell death has not been explored so far. This study evaluates the involvement of LAAO in dermonecrosis in mice and its cytotoxic effects in normal human keratinocytes, the major cell type in the epidermis, a tissue that undergoes extensive necrosis at the snakebite site. Pharmacological inhibition by the antioxidant NAC (N-acetyl cysteine) prevented B. atrox venom-induced necrosis. Consistent with the potential role of oxidative stress in wounding, treatment with purified LAAO decreased keratinocyte viability with an Effective Concentration (EC50) of 5.1 μg/mL. Cytotoxicity caused by LAAO was mediated by H2O2 and treated cells underwent autophagy, followed by apoptosis and necrosis. LAAO induced morphological alterations that precede cell death. Our results show the chronological events leading to cell death and the temporal resolution from autophagy, apoptosis and necrosis as distinct mechanisms triggered by LAAO. Fluorescently-labelled LAAO was efficiently and rapidly internalized by keratinocytes, suggesting that catalysis of intracellular substrates may contribute to LAAO toxicity. A better understanding of LAAO cytotoxicity and its mechanism of action will help to identify potential therapeutic strategies to ameliorate localized snake envenomation symptoms.

Reaction of Me3Al with HB[N(H)DIPP](2) (DIPP = 2,6-iPr(2)-C6H3) in hexane gave a complex mixture of compounds instead of HB(N-DIPP)(2)AlMe. After addition of THF, one of the products could be trapped in trace amounts and was characterized by crystal structure determination: DIPP-N(H)B(H)(N-DIPP)AlMe2 center dot THF (1). Heating a hexane or fluorobenzene solution of HB[N(H)DIPP](2) and Me3Al in the absence of THF gave a relatively clean conversion and allowed for the isolation of [(DIPPNH)AlMe2(mu-H)AlMe2](2) (2), a product that was formed through B/Al ligand exchange. Complex 2 contains protic and hydridic hydrogen atoms in close vicinity. The compound remains intact upon heating, however, it readily releases H-2 when dissolved in THF forming DIPPN(AlMe2 center dot THF)(2) (3). The latter bimetallic complex contains two THF stabilized Lewis acidic central aluminum atoms in close proximity.

Photosystem I of the moss Physcomitrella patens has special properties, including the capacity to undergo non-photochemical fluorescence quenching. We studied the organization of photosystem I under different light and carbon supply conditions in wild-type moss and in moss with the Ihcb9 (light-harvesting complex) knockout genotype, which lacks an antenna protein endowed with red-shifted absorption forms. Wild-type moss, when grown on sugars and in low light, accumulated LHCB9 proteins and a large form of the photosystem I supercomplex, which, besides the canonical four LHCI subunits, included a LHCII trimer and four additional LHC monomers. The Ihcb9 knockout produced an angiosperm-like photosystem I supercomplex with four LHCI subunits irrespective of the growth conditions. Growth in the presence of sublethal concentrations of electron transport inhibitors that caused oxidation or reduction of the plastoquinone pool prevented or promoted, respectively, the accumulation of LHCB9 and the formation of the photosystem I megacomplex. We suggest that LHCB9 is a key subunit regulating the antenna size of photosystem I and the ability to avoid the over-reduction of plastoquinone: this condition is potentially dangerous in the shaded and sunfleck-rich environment typical of mosses, whose plastoquinone pool is reduced by both photosystem II and the oxidation of sugar substrates.

Biofilm composition from fish myofibrillar protein (FMP) and chitosan solution (CS) incorporated with rosemary extract (RE) was developed and applied to monitor the freshness of fish fillets. The effects of different concentrations of RE as well as physical, mechanical, structural and functional properties of FMP/CS films were investigated. Films containing RE showed reduced water solubility and water vapor permeability and enhanced tensile strength and elongation at break. Results also showed good compatibility of the components and good dispersion of RE in the matrix. However, the content of RE (0.2%, v/v) added in the composite films produced aggregations and had negative effects on their film-forming properties. The antioxidant capacity of composite films was related to the level of RE and demonstrated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. Chilled grass carp fillets wrapped with different films to evaluate the preservative effect. Results of thiobarbituric acid reactive substances, pH value, Free amino acid and total volatile basic nitrogen indicated that FMP/CS/RE composite film could protect the fish fillet well and inhibit the lipid oxidation. The developed FMP/CS/RE composite films possess the potential to be applied as edible films in the food packaging industry and food cold chain transportation., Fundamental Research Funds for the Central Universities of China [2662019PY031]; National Natural Science Foundation of China [31772047], This work was funded by the Fundamental Research Funds for the Central Universities of China (No. 2662019PY031) and the National Natural Science Foundation of China (No. 31772047) .

Summary Sentinel species are playing an indispensable role in monitoring environmental pollution in aquatic ecosystems. Many pollutants found in water prove to be endocrine disrupting chemicals that could cause disruptions in lipid homeostasis in aquatic species. A comprehensive profiling of the lipidome of these species is thus an essential step toward understanding the mechanism of toxicity induced by pollutants. Both the composition and spatial distribution of lipids in freshwater crustacean Gammarus fossarum were extensively examined herein. The baseline lipidome of gammarids of different sex and reproductive stages was established by high throughput shotgun lipidomics. Spatial lipid mapping by high resolution mass spectrometry imaging led to the discovery of sulfate-based lipids in hepatopancreas and their accumulation in mature oocytes. A diverse and dynamic lipid composition in G. fossarum was uncovered, which deepens our understanding of the biochemical changes during development and which could serve as a reference for future ecotoxicological studies., Graphical Abstract, Highlights • Baseline lipidome profiling of G. fossarum of different sex and reproductive stages • Spatial localization of lipids in gammarid tissue by mass spectrometry imaging • SIMS imaging guided discovery of sulfate-based lipids in hepatopancreas epithelium • Disclosure of a dynamic lipid composition in maturing female oocytes, Environmental Science; Lipidomics; Metabolomics; Pollution; Zoology

The pyrolytic sugar fraction, obtained by an aqueous extraction of pyrolysis oil, is an attractive source for sugar-derived platform chemicals. However, solids (humin) formation occurs to a significant extent during hydrolysis and subsequent acid-catalyzed conversion processes. In this study, we report investigations on possible conversion routes (pyrolysis, liquefaction) of such humin byproducts to biobased chemicals. Experiments were carried out with a model humin made from a representative technical pyrolytic sugar and the product was characterized by elemental analysis, GPC, TGA, HPLC, GC-MS, FT-IR and NMR. The obtained humin sample is soluble in organic solvents (dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and isopropanol (IPA)), in contrast to typical more condensed humins from glucose and fructose, allowing characterization using NMR and GPC. All analyses reveal that the humins are oligomeric in nature (M-w of about 900 g/mol) and consist of sugar and furanic fragments linked with among others (substituted) aliphatic, ester units and, in addition, phenolic fragments with methoxy groups. The humins were used as a feed for catalytic pyrolysis and catalytic liquefaction experiments. Catalytic pyrolysis experiments (mg scale, programmable temperature vaporizer (PTV)-GC-MS, 550 degrees C) with HZSM-5 50 as the catalyst gave benzene-toluene-xylene-naphthalene-ethylbenzene mixtures (BTXNE) in 5.1 wt% yield based on humin intake. Liquefaction experiments (batch reactor, 350 degrees C, 4 h, isopropanol as both the solvent and hydrogen donor and Pt/CeO2 (4.43 wt% Pt) catalyst) resulted in 80 wt% conversion of the humin feed to a product oil with considerable amounts of phenolics and aromatics (ca. 24.7 % based on GC detectables in the humin oil). These findings imply that the techno-economic viability of pyrolysis oil biorefineries can be improved by converting humin type byproducts to high value, low molecular weight biobased chemicals.

The present article examines recently published literature on lipids, mainly focusing on research involving glycero-, glycerophospho- and sphingo-lipids. The primary aim is identification of distinct profiles in biologic lipidomic systems by ultra-high-performance liquid chromatography (UHPLC) coupled with mass spectrometry (MS, tandem MS) with multivariate data analysis. This review specifically targets lipid biomarkers and disease pathway mechanisms in humans and artificial targets. Different specimen matrices such as primary blood derivatives (plasma, serum, erythrocytes, and blood platelets), faecal matter, urine, as well as biologic tissues (liver, lung and kidney) are highlighted.

In this communication, we investigate the reaction between seleno- and thiourea, derived from N-heterocyclic carbenes, with the interhalogen iodine monochloride. The formation of all three products was confirmed by NMR spectroscopy, while single-crystal X-ray analyses were able to establish a charge-transfer coordination type, which showed a linear Se/S-I-Cl arrangement, for all adducts formed. Based on a detailed crystallographic analysis, we can deduce the zwitterionic character of these compounds.

Graphical abstract, Highlights • The oxovanadium(IV) and nickel(II) complexes were synthesized with the “template effect”. • The synthesized complexes were characterized by X-ray diffraction of the compounds. • Electrochemical characterization and total antioxidant capacity measurements were determined., 2,2′-Dihydroxybenzophenone-S-methyl-thiosemicarbazone and 3-methoxy-salicylaldehyde were reacted in the presence of oxovanadium(IV) or nickel(II) ions to yield the N2O2-type-chelate complex. The synthesized complexes were characterized by employing elemental analysis, electronic and infrared spectra, 1H NMR spectra, magnetic measurements, and thermogravimetric analyses. The expected structures of oxovanadium(IV) and nickel(II) complexes were confirmed by using the single-crystal X-ray diffraction method. The presence of π-π stacked dimeric structures provided stronger crystalline formations. The optimized geometries and vibrational frequencies of the compounds were obtained using the DFT/ωB97XD method with the 6-31G (d,p) basis set and compared with the experimental data. The electrochemical characterization of the oxovanadium(IV) and nickel(II) complexes were carried out by using the cyclic voltammetry (CV) method. The oxovanadium(IV) complex gives a ligand-centered oxidation and a metal-centered one electron reduction and oxidation peaks corresponding to the VIV/IIIO and VIV/VO, respectively. The nickel(II) complex gives a ligand-centered oxidation and metal-centered (NiII/I) reduction peaks in a dimethyl sulfoxide (DMSO) solution. The redox potentials were calculated in terms of Gibbs free energy change of the redox reaction at the theory level of M06-L/LANL2DZ/PCM. In addition, the energy gap, HOMO and LUMO distributions were calculated. The total antioxidant capacities of the compounds were determined by using cupric reducing antioxidant capacity (CUPRAC) method, in which the oxovanadium(IV) complex was found to be powerful as an antioxidant agent.

Hydrogels find application in many areas of technology and research due to their ability to combine responsiveness and robustness. A detailed understanding of their molecular structure and dynamics (which ultimately underpin their functional properties) is needed for their design to be optimized and these hydrogels to be exploited effectively. In this review, we shed light on the unique capabilities of solid-state NMR spectroscopy to reveal this information in molecular detail. We review recent literature on the advancements in solid-state NMR techniques in resolving the structure, degree of grafting, molecular organization, water-biopolymer interactions and internal dynamical behavior of hydrogels. Among various solid-state NMR techniques, 13C cross polarization (CP) magic angle spinning (MAS) NMR is examined for its ability to probe the hydrogel and its trapped solvent. Although widely applicable to many types of polymeric and supramolecular hydrogels, the current review focuses on polysaccharide-based hydrogels.

New mononuclear complexes [Mn(NO3)(sac)(H2O)(bzimpy)]center dot 2DMF (Mn), [Fe(sac)(2)(H2O)(bzimpy)]center dot 2H(2)O (Fe), [Co(bzimpy)(2)](sac)(2)center dot 2H(2)O (Co), [Ni(bzimpy)(2)](sac)(2)center dot H2O center dot i-PrOH (Ni) and [Cu(sac)(2)(bzimpy)]center dot 3DMF (Cu) (sac = saccharinate and bzimpy = 2,6-bis(2-benzimidazolyl)pyridine) were synthesized and structurally characterized by elemental analysis, UV-Vis, IR, ESI-MS and X-ray diffraction. The anticancer activity of the metal complexes against A549 (lung), MCF-7 (breast), HT29 (colon) cancer cells and MCF10A (normal human breast epithelial) cells was tested and compared with those of cisplatin and bzimpy. The complexes displayed potent cytotoxic activity especially in MCF-7 and A549 cell lines, but they were practically inactive against the normal cells. Mechanistic studies with Mn and Cu complexes on A549 cells indicated that the complexes induced G0/G1 arrest. Both complexes increased intracellular ROS (reactive oxygen species) levels and successfully caused both mitochondrial dysfunction and doublestrand DNA breaks. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-3/7 activation and reduced Fas expression indicated that Mn and Cu induced ROS-dependent mitochondria-mediated intrinsic apoptosis in A549 cells. (C) 2020 Elsevier Masson SAS. All rights reserved.

Bacillus aryabhattai GYC2-3 strain, capable of synthesizing EPS, was isolated from the rhizosphere of Taraxacum spp. plant. The EPS was identified as levan by C-13 NMR spectroscopy and methylation analysis. The levan produced had a high weight average molecular weight of 5.317 x 10(7) Da and degree of branching 5.19%. Thin layer chromatography and high-performance anion-exchange chromatography revealed that it is capable of producing broad range of fructooligosaccharides (FOS) and higher levels of FOS synthesis were observed with increasing sucrose concentrations. The optimum temperature, initial pH and sucrose concentration for levan biosynthesis were studied to be 30 degrees C, 8.0 and 250 g/L, respectively. Levan production was increased by similar to 38% (26 g/L) when provided aeration as compare to static cultures. To the best of our knowledge, this is the first report on biosynthesis of levan and FOS by a B. aryabhattai strain.

Polylactide (PLA) is a high potential bioplastic that can replace oil‐based plastics in a number of applications. To date, in spite of its known toxicity, a tin catalyst is used on industrial scale which should be replaced by a benign catalyst in the long run. Germanium is known to be unharmful while having similar properties as tin. Only few germylene catalysts are known so far and none has shown the potential for industrial application. We herein present Ge complexes in combination with zinc and copper, which show amazingly high polymerization activities for lactide in bulk at 150 °C. By systematical variation of the complex structure, proven by single‐crystal XRD and DFT calculations, structure–property relationships are found regarding the polymerization activity. Even in the presence of zinc and copper, germanium acts as the active site for polymerizing probably through the coordination–insertion mechanism to high molar mass polymers., On the route towards a benign production of PLA, we came across Germanium. With its similar properties to tin due to its close position in the periodic table, germanium, being completely nontoxic, is a promising, but so far rather neglected candidate for an alternative catalyst for industrial lactide polymerization. With high molar masses after 1 h of polymerization at 150 °C in bulk, these examples show the high efficiency germanium catalysts can reach (see scheme).

The discovery of sustainable and scalable synthetic protocols leading to gold-aryl compounds bearing N-heterocyclic carbene (NHC) ligands sparked an investigation of their reactivity and potential utility as organometallic synthons. The use of a mild base and green solvents provide access to these compounds, starting from widely available boronic acids and various [Au(NHC)Cl] complexes, with reactions taking place under air, at room temperature and leading to high yields with unprecedented ease. One compound, (N,N'-bis[2,6-(di-isopropyl)phenyl]imidazol-2-ylidene)(4-methoxyphenyl)gold, ([Au(IPr)(4-MeOC6 H4 )]), was synthesized on a multigram scale and used to gauge the reactivity of this class of compounds towards C-H/N-H bonds and with various acids, revealing simple pathways to gold-based species that possess attractive properties as materials, reagents and/or catalysts.

Deoxynivalenol is one of the most ubiquitous mycotoxins in the Western diet through its presence in cereals and cereal products. A vast amount of studies indicate the worrying level of exposure to this toxin, while even high percentages of the population exceed the tolerable daily intake. To evaluate and assess dietary exposure, analysis of urinary levels of deoxynivalenol and its glucuronides has been proposed as a reliable methodology. An indirect preliminary method was used based on the cleavage of deoxynivalenol glucuronides through the use of enzymes (β-glucuronidase) and subsequent determination of "total deoxynivalenol" (sum of free and released mycotoxins by hydrolysis). Next, a direct procedure for quantification of deoxynivalenol-3-glucuronide and deoxynivalenol-15-glucuronide was developed. As deoxynivalenol glucuronides reference standards are not commercially available, the indirect method is widely applied. However, to not underestimate the total deoxynivalenol exposure in urine, the direct and indirect methodologies need to be compared. Urinary samples (n = 96) with a confirmed presence of deoxynivalenol and/or deoxynivalenol glucuronides were analysed using both approaches. The indirect method clarified that not all deoxynivalenol glucuronides were transformed to free deoxynivalenol during enzymatic treatment, causing an underestimation of total deoxynivalenol. This short communication concludes on the application of direct or indirect assessment of urinary deoxynivalenol.

Mass spectrometry imaging (MSI) enables the spatial distributions of molecules possessing different mass‐to‐charge ratios to be mapped within complex environments revealing regional changes at the molecular level. Even at high mass resolving power, however, these images often reflect the summed distribution of multiple isomeric molecules, each potentially possessing a unique distribution coinciding with distinct biological function(s) and metabolic origin. Herein, this chemical ambiguity is addressed through an innovative combination of ozone‐induced dissociation reactions with MSI, enabling the differential imaging of isomeric lipid molecules directly from biological tissues. For the first time, we demonstrate both double bond‐ and sn‐positional isomeric lipids exhibit distinct spatial locations within tissue. This MSI approach enables researchers to unravel local lipid molecular complexity based on both exact elemental composition and isomeric structure directly from tissues.

Since the commercial introduction of Ion Mobility coupled with Mass Spectrometry (IM-MS) devices in 2003, a large number of research laboratories have embraced the technique. IM-MS is a fairly rapid experiment used as a molecular separation tool and to obtain structural information. The interpretation of IM-MS data is still challenging and relies heavily on theoretical calculations of the molecule's collision cross section (CCS) against a buffer gas. Here, a new software (HPCCS) is presented, which performs CCS calculations using high perfomance computing techniques. Based on the trajectory method, HPCCS can accurately calculate CCS for a great variety of molecules, ranging from small organic molecules to large protein complexes, using helium or nitrogen as buffer gas with considerable gains in computer time compared to publicly available codes under the same level of theory. HPCCS is available as free software under the Academic Use License at https://github.com/cepid-cces/hpccs. © 2018 Wiley Periodicals, Inc.

There are numerous reports demonstrating the heterogeneous spatial distributions of lipids throughout biology using mass spectrometry imaging (MSI). However, despite these and the biological significance of lipid alterations there remains a surprising lack of understanding regarding the underlying origins of the spatial distributions detected with MSI. With the rapid improvements in analytical capabilities of MSI instrumentation, it is now at the point that these biological questions can begin to be addressed. In this review we focus on (i) work providing insight into the biochemical origins of lipid spatial distributions, with an emphasis on the role of localised enzymatic processes in determining lipid compositions; (ii) use of stable isotope labelling to spatially-resolve the kinetics of lipid synthesis; and (iii) current challenges faced by the lipid MSI community and new analytical methods to overcome them. Combined, these topics highlight the added biological information that can be acquired from the MSI of lipids. (c) 2018 Elsevier B.V. All rights reserved.

Samarocene sandwich complexes with superbulky penta-arylcyclopentadienyl ligands have been prepared and were structurally characterized: [(4-EtC6H4)(5)C-5](2)Sm (1) and [(4-iPrC(6)H(4))(5)C-5](2)Sm (2). Analogous to the previously reported synthesis of [(4-nBuC(6)H(4))(5)C-5](2)Sm, reaction of (DMAT)(2)center dot Sm(THF)(2) (DMAT = 2-Me2N-alpha-Me3Si-benzyl) and the appropriate Ar5C5H ligand gave 1 (66% yield) and 2 (59% yield). In contrast to the high reactivity of Cp*Sm-2, complex 1 has been shown to be surprisingly stable toward reaction with a large variety of reagents. Even under forcing conditions, no reaction with N-2, CO, CO2, pyrazine, trans-stilbene, pyridine, P-4, and benzophenone was observed. Complex 1 reacts with cuminil ArC(O)C(O)Ar (Ar = 4-iPrC(6)H(4)) to yield the Sm(III) sandwich complex [(4-EtC6H4)(5)C-5](2)Sm[ArC(O)C(O)Ar] (3), which could be isolated in 83% yield as a dark-red crystalline material. Complex 2 reacts with oxygen in the presence of phenazine to yield the bimetallic Sm(III) complex [(4-iPrC(6)H(4))(5)C5Sm(eta(1)-phenazine)]2(mu:eta(2)-eta(2)-O-2)(2) (4) in 25% yield as dark-red crystals. The unusually high redox-stability of deca-arylsamarocenes originates from steric hindrance of the Sm metal center.

International audience; Herein we report the synthesis of new ditopic ligands, which consist of a phenoxy group and N,N,N'trisubstituted amidines linked by a methylene spacer (L1-L4). Their coordination chemistry has been studied/investigated with Zn(II) and Al(III). Alkane elimination route between the phenol-amidine proligands (L1H-L4H) and Et2Zn led to dinuclear complexes [(L1-L4)ZnEt]2 (1a-4a) in which the Zn centers are chelated by phenoxyamidine ligands and bridged through the oxygen atom of the phenoxy groups. Salt metathesis reaction between two equivalents of the sodium amidine phenate L1Na and ZnCl2 led to a bis-chelate chiral spiro-complex (L12Zn) 1a'. Analogous alkane elimination route between AlMe3 and the phenol-amidine proligands L1H-L4H allowed the preparation of the mononuclear complexes [(L1-L4)AlMe2] (1b-4b). The phenoxyamidine-Al and Zn complexes have been characterized by NMR spectroscopy, elemental analysis and/or high resolution ESI-MS. The solid state structures of the proligands [L1H2][Br] and L2H as well as of six complexes have been established by single crystal X-ray diffraction analysis. Fluxional properties of the proligands L1H-L2H and of the complexes 1a and 2b have been investigated by VT NMR experiments. In the presence of an alcohol source, complexes 1a-4a and 1b-4b were used as initiators for the controlled ring-opening polymerization (ROP) of rac-lactide to afford atactic polylactic acid (PLA).

Lipids are a large and highly diverse family of biomolecules, which play essential structural, storage and signalling roles in cells and tissues. Although traditional mass spectrometry (MS) approaches used in lipidomics are highly sensitive and selective, lipid analysis remains challenging due to the chemical diversity of lipid structures, multiple isobaric species and incomplete separation using many forms of chromatography. Ion mobility (IM) separates ions in the gas phase based on their physicochemical properties. Addition of IM to the traditional lipidomic workflow both enhances separation of complex lipid mixtures, beneficial for lipid identification, and improves isomer resolution. Herein, we discuss the recent developments in IM-MS for lipidomics.

International audience; A series of bis(pyridine)cobalt corroles with one or three nitrophenyl groups on the meso positions of the corrole macrocycle were synthesized and characterized as to their electrochemical and spectroscopic properties in dichloromethane, benzonitrile, and pyridine. The potentials for each electrode reaction were measured by cyclic voltammetry and the electron-transfer mechanisms evaluated by analysis of the electrochemical data combined with UV-visible spectra of the neutral, electroreduced, and electroxidized forms of the corroles. The proposed electronic configurations of the initial compounds and the prevailing redox reactions involving the electroactive central cobalt ion, the electroactive conjugated macrocycle, and the electroactive meso-nitrophenyl groups are all discussed in terms of solvent binding and the number of the nitrophenyl groups and other substituents on the meso-nitrophenyl rings of the compounds.

Copper(I) species exhibit various coordination modes as a function of surrounding ligands. Complexes bearing N-heterocyclic carbenes as ligands are usually monomeric species with the copper adopting a linear geometry. Contrarily to the parent phosphine complexes, in which the presence of species of higher nuclearity is well established, fewer examples of such copper(I)–NHC species are reported and, interestingly, their number is growing. Moreover, these are no longer a mere curiosity from a coordination perspective since they have been shown successful in catalysis. The aim of this review is to present a summary of the synthesis and structural properties of dinuclear copper(I)–NHC complexes. It is our hope that by centralizing all information available on such species, future efforts aimed at exploiting their full potential can be facilitated.

A series of novel 4-ferrocenyl-1,2,3,4-tetrahydroquinolines were synthesized in high-to-excellent yields (up to 99%) starting from the corresponding ferrocenoylethyl aryl amines. These Mannich bases were reduced (NaBH4) to the corresponding 3-(arylamino)-1-ferrocenylpropan-1-ols and submitted to an intramolecular cyclization prompted by acetic acid, proceeding via the corresponding alpha-ferrocenyl carbenium ion intermediates. Subsequently, the obtained tetrahydroquinolines were smoothly oxidized (aromatized) by means of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to provide the corresponding 4-ferrocenylquinolines (up to 93%). (C) 2017 Elsevier Ltd. All rights reserved.