Synthesis of Cyclic Phosphates in Hot,Concentrated Phosphoric Acid

The synthesis of transition metal phosphates in hot, concentrated phosphoric acid medium leads to highly crystalline materials and to increased condensation of the phosphate at higher temperatures. Aluminum extraction from the porcelain crucible is also observed in some circumstances. Two new compounds were produced: (Al_3.28Cr_0.72)(P₄O₁₂)₃ a = 13.512(8) Å, cubic, I-43d, V = 2470(3) ų, Z = 6, density = 2.887 mg/m³, R = 0.055, GOF = 1.29 for 254 data points, was prepared at 748 K whereas (Al_1.97Cr_1.03)P₉O₂₇ a = b = 11.170(6), c = 9.412(9) Å, trigonal P – 3c1, V = 1017(1) ų, Z = 2, density = 2.669 mg/m³, R = 0.0581, GOF = 0.87 for 676 data points, was produced at 798 K from the heating of Cr₂O₃ in H₃PO₄ in a porcelain crucible. Crystal structures of both materials show mixed metal sites containing Al and Cr.     

Lanthanides benzimidinates: initiators or real catalysts for the ε‐caprolactone polymerization

Lanthanides (samarium and ytterbium) tris and monobenzimidinates are efficient for the polymerization of ε‐caprolactone, the systems remaining active after consumption of the monomer. Nevertheless it is not a living polymerization because the benzimidinates are recovered. Evidence for support of the proposed catalytic cycle was obtained by NMR studies.     

Diméthyl 3-benzyl-2-(4-méthyl-2,5-dioxoimidazolidin-1-yl)butanedioate

There are two symmetry-independent formula units of the title compound, dimethyl 3-benzyl-2-(4-methyl-2,5-di­oxo­imid­azol­idin-1-yl)­butane­dioate, C₁₇H₂₀N₂O₆, per cell. The two symmetry-independent molecules differ in their configuration and are diastereomers. This structural study confirms a new side reaction during the synthesis of seven-membered cyclopeptides. The stereochemistry of both diastereomers has been established.     

Development and characterization of biodegradables packaging obtained from biopolymers mixture

The aim of this work is the development and the characterization of biodegradables films obtained from a mixture of soluble starch and sodium alginate. The influence of sodium alginate ratio on the behavior of these films is also studied in order to use them as new formulations to produce food packaging. The obtained films are generally homogeneous, thin, smooth and having a good coherence with no visual defects. The results of the FITR, SEM and XRD tests have shown the existence of a good compatibility, between alginate and starch due to both kind of strong interactions like hydrogen bonds and ionic interactions. Water sorption isotherm, water vapor permeability, and mechanical tests were strongly influenced by the addition of sodium alginate in the different formulations. This influence is caused by the plasticization effect of sodium alginate.     

Semi-empirical correlation of solid solute solubility in supercritical carbon dioxide: Comparative study and proposition of a novel density-based model

A comprehensive data set on experimental solubility of 210 solid solutes in supercritical CO₂ counting 5550 data points has been used for comparison of the correlation performance of 21 empirical models. On the basis of the comparison results a new eight-parameter density-based model has been proposed. The comparison shows that the three-parameter models are the least accurate. The results also show that models that relate the logarithm of the solubility to the logarithm of solvent density and temperature are more accurate than models that include the pressure. When comparing the overall correlating performance in terms of average absolute relative deviation the proposed model is by far the best with an average absolute relative deviation lying in the range 0.17–81.99% and an average value of 8.88%.     

Solventless lactam synthesis by intramolecular cyclizations of alpha-iminoester derivatives under microwave irradiation

We have previously reported a new synthesis of amides from esters and amines under microwave irradiation, offering much higher yields than those achieved with conventional heating [1]. We have now extended these studies to the ring closure of neat iminoesters I2, I3 and I4-I6 to give five- and six-membered ring lactams L5, L6 and larger lactams L7-L9 (where I means imine and L means lactam), respectively, under both classical heating conditions and microwave irradiation.     

Glyphosate and glufosinate detection at electrogenerated NiAl-LDH thin films

An amperometric sensor based on Ni_1−xAl_x(OH)₂NO_3x·nH₂O layered double hydroxide (LDH) has been developed for the electrochemical analysis in one step of two herbicides: glyphosate (N-(phosphonomethyl)glycine, Glyp) and glufosinate ((DL-homoalanine-4-yl)-methylphosphinic acid, Gluf). NiAl-LDH was prepared by coprecipitation or by electrodeposition at the Pt electrode surface. Inorganic films were fully characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Adsorption isotherms of Glyp onto this inorganic lamellar material have been established. Electrocatalytic oxidation of Glyp and Gluf is possible at the Ni³⁺ centres of the structure. The electrochemical responses of the NiAl-LDH modified electrode were obtained by cyclic voltammetry and chronoamperometry at 0.49 V/SCE as a function of herbicide concentration in 0.1 M NaOH solution. The electrocatalytic response showed a linear dependence on the Glyp concentration ranging between 0.01 and 0.9 mM with a detection limit of 1 μM and sensitivity 287 mA/M cm². The sensitivity found for Gluf was lower (178 mA/M cm²).     

ortho-Lithium/magnesium carboxylate-driven aromatic nucleophilic substitution reactions on unprotected naphthoic acids

Substitution of an ortho-fluoro or methoxy group in 1- and 2-naphthoic acids furnishing substituted naphthoic acids occurs in good to excellent yields upon reaction with alkyl/vinyl/aryl organolithium and Grignard reagents, in the absence of a metal catalyst without the need to protect the carboxyl (CO(2)H) group. This novel nucleophilic aromatic substitution is presumed to proceed via a precoordination of the organometallic with the substrate, followed by an addition/elimination.     

Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse

Background  

The expression of retinal CaMKII is up-regulated in the retina of the rdta mouse in which rod photoreceptors are genetically ablated. As ionotropic glutamate receptors are known substrates of CAMKII, this study set out to determine if the protein levels of ionotropic glutamate receptors in the rdta mouse retina are also affected.