PYRAZOLYL-BRIDGED IRIDIUM DIMERS .2. CONTRASTING MODES OF 2-CENTER OXIDATIVE ADDITION TO A BIMETALLIC SYSTEM AND REDUCTIVE ACCESS TO THE STARTING COMPLEX - 3 KEY DIIRIDIUM STRUCTURES REPRESENTING SHORT NON-BONDING AND LONG AND SHORT BONDING METAL-METAL INTERACTIONS

International audiencexx

Para-acyl-calix-arene based solid lipid nanoparticles (SLNs): a detailed study of preparation and stability parameters.

International audienceThe preparation and stability parameters of para-acyl-calix[4]arene based solid lipid nanoparticles (SLNs) have been investigated. Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) show a mean particle size of 130 nm. In terms of preparation parameters, using the solvent displacement method, the nature and the volume of the organic solvent, the concentration of the amphiphile and the presence of a co-surfactant in the organic phase have been shown to affect significantly the size of the produced SLNs. In contrast, the stirring speed, the viscosity and the acidity of the aqueous phase and the amphiphile hydrophobic chain length have been shown to have no effect. In terms of stability parameters, the ionic strength has been shown to affect the short-time SLN stability depending on both the anion and the cation studied, with sodium sulphate causing precipitation. Ultrasonic, ultraviolet or microwave treatments of the SLN suspensions have no effect on the size of the SLNs. The study of the effects of short time thermal treatment revealed that the SLNs are not affected by one freezing-defreezing cycle and are stable at 100 degrees C in suspension. It is difficult to reconstitute the SLN suspensions after freeze-drying. Finally, the temporal stability of these suspensions in water has been shown to be superior to 1 year. The long-term temporal stability of suspensions stored in saline solution has been investigated. It has been demonstrated that the most destabilising effects arise from the presence in the storage suspension of sulphate ions.1H NMR, X-ray powder diffraction (XPD) and AFM have also been carried out on the calix-arene based SLNs and demonstrate the presence of a semi-organised matrix structure for the SLNs.The preparation and stability parameters of para-acyl-calix[4]arene based solid lipid nanoparticles (SLNs) have been investigated. Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) show a mean particle size of 130 nm. In terms of preparation parameters, using the solvent displacement method, the nature and the volume of the organic solvent, the concentration of the amphiphile and the presence of a co-surfactant in the organic phase have been shown to affect significantly the size of the produced SLNs. In contrast, the stirring speed, the viscosity and the acidity of the aqueous phase and the amphiphile hydrophobic chain length have been shown to have no effect. In terms of stability parameters, the ionic strength has been shown to affect the short-time SLN stability depending on both the anion and the cation studied, with sodium sulphate causing precipitation. Ultrasonic, ultraviolet or microwave treatments of the SLN suspensions have no effect on the size of the SLNs. The study of the effects of short time thermal treatment revealed that the SLNs are not affected by one freezing-defreezing cycle and are stable at 100 degrees C in suspension. It is difficult to reconstitute the SLN suspensions after freeze-drying. Finally, the temporal stability of these suspensions in water has been shown to be superior to 1 year. The long-term temporal stability of suspensions stored in saline solution has been investigated. It has been demonstrated that the most destabilising effects arise from the presence in the storage suspension of sulphate ions.1H NMR, X-ray powder diffraction (XPD) and AFM have also been carried out on the calix-arene based SLNs and demonstrate the presence of a semi-organised matrix structure for the SLNs

Crystal engineering of a calix-arene dimer embedded in a hydrophobic cavity formed by a diammonium host matrix

International audiencexx

A comparative structural study of four para-sulphonato-calix-[4]-arene organic di- and triammonium cation complexes

International audiencexx

Hybrid ultramicroporous materials (HUMs) with enhanced stability and trace carbon capture performance

Fine-tuning of HUMs through pillar substitution can significantly enhance trace CO2 sorption performance and stability.</p