Crystal structure of {4-[10,15,20-tris(4-methoxy-phenyl)porphyrin-5-yl]benzyl 2-diazoacetato}-zinc(II)

International audienceIn the title compound, [Zn(CHNO)], the Zn cation is chelated by four pyrrole N atoms of the porphyrinate anion and coordinated by a symmetry-generated keto O atom of the diazo-ester group in a distorted square-pyramidal geometry. The mean Zn-N(pyrrole) bond length is 2.058 Å and the Zn-O(diazo-ester) bond length is 2.179 (4) Å. The zinc cation is displaced by 0.2202 (13) Å from the NC mean plane of the porphyrinate anion toward the O atom; the involvement of this atom leads to a [100] polymeric chain in the crystal

Synthesis, crystal structure, catalytic dimerization and S-H insertion of new porphyrin diazoketones

International audiencePorphyrin diazoketones were synthesized from the corresponding porphyrin acetyl chloride by treatment with trimethylsilyldiazomethane in 60-80% yield. The solid-state structure of one of the two bisdiazo derivatives (trans isomer) was determined by single-crystal X-ray diffraction analysis. Thiol insertion and cis-selectivity in the coupling reactions of porphyrin diazoketones catalyzed by ruthenium porphyrin were observed

Porphyrin symmetry and chiral catalysis in water

International audienceChiral metalloporphyrins (ruthenium, iron and manganese) have been developed in solution. Both effective chiral recognition and asymmetric catalysis using optically active macrocycles were observed. Asymmetric oxidation and carbene transfer showed potential pharmaceutical applications

Cinnamaldehyde loaded-microparticles obtained by complex coacervation: Influence of the process parameters on the morphology and the release of the core material

International audienceEncapsulation by complex coacervation includes several steps that have been developed in order to attain a better control over the whole process and to achieve an important delayed effect. This has been carried out for the encapsulation of cinnamaldehyde (CN) by the classical gelatin/acacia gum pair of coacervating polymers. This preparation was performed in different conditions (stirring speeds, cooling rate, emulsion and coacervate time, use of surfactant, and polymer concentration) in order to investigate their effect on the encapsulation efficiency and drug release kinetics. Optical microscopy studies showed spherical microcapsules. The yield of the encapsulation attains more than 88% of all prepared microcapsules. The mean Sauter diameter (d 32) of obtained microparticles was in the range from 124 to 200 µm. The microspheres were also characterized by the FTIR method; showing the presence of core and polymers in the microparticles. The release of cinnamaldehyde was performed in heterogeneous medium (Water / ethanol, v/v: 30/70) at 25±0.5°C using UV–Vis analysis. It was demonstrated that the drug release followed the Fickian diffusion mechanism. The data were best fitted to the Fick's law with high correlation coefficients (R²)

Halterman Corroles and Their Use as a Probe of the Conformational Dynamics of the Inherently Chiral Copper Corrole Chromophore

International audienceHalterman corroles have been synthesized for the first time from pyrrole and Halterman's aldehyde via Gryko's "water-methanol method". These were derivatized to the corresponding copper complexes and subsequently to the β-octabromo complexes. Electronic circular dichroism spectra were recorded for the enantiopure copper complexes, affording the first such measurements for the inherently chiral Cu corrole chromophore. Interestingly, for a given configuration of the Halterman substituents, X-ray crystallographic studies revealed both P and M conformations of the Cu-corrole core, proving that the substituents, even in conjunction with β-octabromination, are unable to lock the Cu-corrole core into a given chirality. The overall body of evidence strongly indicates a dynamic equilibrium between the P and M conformations. Such an interconversion, which presumably proceeds via saddling inversion, provides a rationale for our failure so far to resolve sterically hindered Cu corroles into their constituent enantiomers by means of chiral HPLC

Variabilité spatio-temporelle de la teneur en carbone du sol en milieu agricole carbonaté : exemples d'apports de la spectroscopie proche infrarouge

Effective protection of environmental resources requires an understanding of spatial and temporalvariation of soil properties, and its causes and its consequences. However, the acquisition of data on thisvariability requires datasets whose achievement is limited by the cost of physico-chemical analyses, and also insome cases by the amount of material available. For studies related to carbon sequestration in soils and theirvulnerability to land use and climate changes, additional limitations appear in carbonate soils as organic formsand inorganic carbon must be distinguished. Assuming that the near-infrared spectroscopy (NIRS) could helpovercome these limitations, this paper presents some results obtained with NIRS through two examples ofstudies in carbonate environment, one in the watershed the Rheraya (High Atlas of Morocco) and the other inthe plain of Languedoc (France). These examples show that depending on the particular case studied andphysicochemical methods implemented a procedure for prediction by NIRS may be efficient to predict the Corgand inefficient for predicting carbonates or moderately efficient in predicting the Corg and very efficient to predictthe carbonates.La protection efficace des ressources environnementales nécessite une bonne connaissancedes variations spatiales et temporelles des propriétés des sols, ainsi que de ses causes et de sesconséquences. Cependant, l'acquisition de données sur cette variabilité nécessite des jeux dedonnées dont l'obtention est limitée par le coût des analyses physico-chimiques, mais aussi, danscertains cas, par la quantité de matériau disponible. Pour les études liées à la séquestration ducarbone dans les sols et à leur vulnérabilité aux changements d’usage et aux changementsclimatiques, des limites supplémentaires apparaissent dans les sols carbonatés, car les formesorganiques et inorganiques du carbone doivent être distinguées. Partant de l’hypothèse que laspectroscopie proche infrarouge (SPIR) pourrait permettre de dépasser ces limites, cettecommunication présente quelques résultats obtenus avec la SPIR à travers deux exemples d'étudesen milieu agricole carbonaté, l’un dans le bassin versant de la Rhéraya (Haut-Atlas du Maroc) etl’autre dans la plaine languedocienne (France). Ces exemples montrent notamment que selon le casétudié et les méthodes physico-chimiques mises en œuvre, une procédure de prédiction par SPIRpeut être soit efficiente pour prédire le Corg et non efficiente pour prédire les carbonates, soitmoyennement efficiente pour prédire le Corg et très efficiente pour prédire les carbonate