A novel and convenient strategy for the synthesis of phthalazines from an aryne precursor

A novel three-step entry toward phthalazine derivatives has been elaborated. A strategy based on a sequential acyl-alkylation/diazo transfer reaction/Diaza-Wittig reaction led to the desired analogues in moderate to good yields from an aryne precursor. Various aryl groups were introduced on the annulated pyridazine, moreover the presence of an ester group allows further modifications.     

Physico-chemical properties of Tecoma stans Linn. seed oil: a new crop for vegetable oil

Tecoma stans Linn. is known to have various medicinal and therapeutic properties. However, to our knowledge, no information is available regarding their seed oils. In this study, the fatty acid (FA) compositions, physico-chemical properties and antioxidant capacities of T. stans seed oils (TSOs) were investigated. The oil content of the seeds was 15%. The FAs of the TSOs were analysed by GC–MS. α-Linolenic (45.47%), oleic (23.56%), linoleic (11.48%), palmitic (6.09%) and stearic (4.12%) acids were the major detected FAs. γ-Linolenic acid and stearidonic acid, unusually FAs, were also present (1.04% and 6.65%, respectively). The total tocol content in the TSOs was found to be 266.06 mg/100 g. The main component was γ-tocopherol (78.93%). The total phenolic content (168.69 mg GAE/100 g oil) and total flavonoid content (5.54 mg CE/g oil) were also determined in the TSOs.     

Synthesis and X-ray crystal structure of a new μ-hydroxo dinuclear cobalt complex containing one cis-β folded and one planar salen moiety

The reduction of [Co(III)(tmsalen)(py)₂]⁺ with NaBH₄/PdCl₂ and the successive oxidative addition of CH₂ClI, carried out in neutral methanolic solution and followed by the addition of NaOH, afford a new dinuclear complex. The molecular structure reveals that it is formed by an octahedral [Co(tmsalen)(py)(OH)] unit connected to a β-folded [Co(tmsalenCH₂)]⁺ fragment, in such a way that the latter metal completes the coordination sphere with the hydroxo group and a tmsalen oxygen from the former unit.     

Optimization of the separation conditions of tetracyclines on a preselected reversed-phase column with embedded urea group

The use of a C12 stationary phase with embedded polar group has been investigated for the separation of seven tetracyclines. The influence of pH, organic modifier, buffer, and temperature on the peak shape and analyte separation was discussed. It appears that all the chromatographic conditions had a great effect on both the resolution and peak shape whereas the elution order was not affected. The baseline separation with symmetrical peaks of the seven tetracyclines can be obtained with a mobile phase containing either 5 mM phosphate buffer pH 2.5/ACN (84:16 v/v) or 5 mM perchlorate buffer pH 2.5/ACN (75:25 v/v) at a temperature not exceeding 20 degrees C. This study reveals that the retention mechanism is ion-pairing.     

Symbiotic signaling in actinorhizal symbioses

Actinorhizal symbioses are mutualistic associations between plants belonging to eight angiosperm families and soil bacteria of the genus Frankia. These interactions lead to the formation of new root organs, actinorhizal nodules, where the bacteria are hosted and fix atmospheric nitrogen thus providing the plant with an almost unlimited source of nitrogen for its nutrition. It involves an elaborate signaling between both partners of the symbiosis. In recent years, our knowledge of this signaling pathway has increased tremendously thanks to a series of technical breakthroughs including the sequencing of three Frankia genomes [1] and the implementation of RNA silencing technology for two actinorhizal species. In this review, we describe all these recent advances, current researches on symbiotic signaling in actinorhizal symbioses and give some potential future research directions.     

Hybrid nanocomposites for optical applications

Incorporating inorganic particles into conjugated polymer matrices is an area of current interest in the fields of optoelectronics and solar energy. The hybrid nanocomposites exhibit interesting physical properties thanks to good optical properties of polymers and to high carrier mobility of inorganic semiconductors. A judicious combination of organic/inorganic can therefore provide materials of low cost, ease processing, high stability, with specific electrical and optical properties.In the present study, we briefly review the composite materials that have been successfully utilized in the field of optoelectronics and photovoltaic conversion. We shall describe in particular a family of nanocomposites using polyhedral oligomeric silsesquioxanes (POSS) of general formula (RSiO_3/2)n where R is an organic group as a core. The composites are made by grafting functional polymer groups to the core, which allows the control of their optical properties. Such composites have high mechanical resistance and stability because of the special structure of the core. For illustration, we present a study of polyfluorene (PF)/POSS materials used as an active layer in organic light emitting diodes, with improved performance as compared to those using polymer only, and we discuss the role of the particles in the transport and emission processes in the devices studied.     

Correction to: A comprehensive review on radioactive waste cycle from generation to disposal

Journal of Radioanalytical and Nuclear Chemistry - A correction to this paper has been published: https://doi.org/10.1007/s10967-021-07815-8     

Synthesis of core-shell material rich in carboxyl groups and its application in the selective adsorption of cationic peptides

The ability to extract peptides and proteins from biological samples with excellent reusability, high adsorption capacity, and great selectivity is essential in scientific research and medical applications. Inspired by the advantages of core-shell materials, we fabricated a core-shell material using amino-functionalized silica as the core. Benzene-1,3,5-tricarbaldehyde and 3,5-diaminobenzoic acid were used as model organic ligands to construct a shell coating by alternately reacting the two monomers on the surface of silica microspheres. The resultant material featured an outstanding capability for the adsorption of cationic peptides, most likely owing to its porous structure, a large number of carboxylic functional groups, and low mass-transfer resistance. The maximum saturated adsorption capacity reached 833.3 mg/g and the adsorption process took only 20 min. Under optimized adsorption conditions, the core-shell material was used to selectively adsorb cationic peptides from the tryptic digestive solution of lysozyme and bovine serum albumin, Specifically, the analysis results showed seven cationic peptides in the eluate and twenty anionic peptides in the supernatant, which indicates the efficient trap of most cationic peptides in the digestive solution.     

Crystal structure of monomethylammonium monochlorodibromomercurate(II)

The crystal structure of monomethylammonium monochlorodibromomercurate (II) was refined from single crystal X-ray data including the fractional contribution of centrosymmetric domains. The refinement converged toR=0.05 in space groupC2. The fraction of structure and its inverse were detected in the refinement. The structure is one-dimensional consisting of distorted tetrahedra (HgCl₂Br₂) connected together by chlorine atoms, The CH₃NH ₃ ⁺ groups are connected to the chains by hydrogen bonds to the halogen atoms contributing to the cohesion of the crystal.