Iron-substituted cubic silsesquioxane pillared clays: Synthesis, characterization and acid catalytic activity.

Novel pillared structures were developed from the intercalation of iron-substituted cubic silsesquioxanes in a sodium and an acid-activated montmorillonite nanoclay and evaluated as acid catalysts. Octameric cubic oligosiloxanes were formed upon controlled hydrolytic polycondensation of the corresponding monomer (a diamino-alkoxysilane) and reacted with iron cations to form complexes that were intercalated within the layered nanoclay matrices. Upon calcination iron oxide nanoparticles are formed which are located on the silica cubes (pillars) and on the surfaces of the clay platelets.

Synthesis of novel quaternary silica hybrid bioactive microspheres.

Purpose: To survey the preparation of novel hybrid microspheres of quaternary silicate glassy composition (SiO P O CaONa O) and the prospect of using them as an osteogenic system with enhanced bioactive properties for the development of hydroxyapatite.

Method: In line with our previous synthetic procedure a two-step process was followed, wherein polystyrene (PS) microspheres were prepared by the emulsifier free-emulsion polymerization method and constituted the core for the sol-gel coating of the silicate inorganic shell. The development of the hybrid microspheres was based on silane and phosphate precursors and was assesses at different ratio of ethanol/water (of 9/1, 4/1, and 2/1, in mL) and at varied ammonia concentration of 4.

A functionalized phosphonate-rich organosilica layered hybrid material (PSLM) fabricated through a mild process for heavy metal uptake.

A phosphonate-rich organosilica layered hybrid material (PSLM) made of 3-(trihydroxysilyl)propyl methylphosphonate, monosodium salt, as the single silica source, has been obtained from its aqueous solution through a xerogel process and mild thermal aging. The method is simple, affording bulk quantities of powdered PSLM in a single-step. The hybrid is stable in water and possesses a high content of phosphonate groups fixed on the solid matrix.

Synthesis and characterization of monodispersed rhodium nanoparticles organized in 3-D symmetrical structures soluble in organic media.

Monodispersed rhodium nanoparticles were synthesized through a flexible and very simple approach in a monosurfactant system by thermolysis of RhCl3, in which oleyl amine serves as capping, reducing agent, and high boiled solvent. The coated rhodium nanoparticles are monodispersed with 4 nm diameter and well characterised by TEM microscopy, UV-Vis spectroscopy, and X-ray diffraction measurements. The as prepared rhodium nanoparticles have the tendency to aggregate forming well-organized large symmetrical and spherical 3-D superstructures which generally have diameters between 40-60 nm as revealed by the characteristic TEM images.

Shape fabrication of millimeter-sized metal-containing carboxymethyl cellulose hollow capsules.

Dropwise addition of an aqueous carboxymethyl cellulose solution to a solution of a copper or iron salt in n-butanol, leads to self-assembled, permeable millimeter sized metal-ion derivatized carboxymethyl cellulose hollow capsules of uniform dimensions and different morphologies.

Organoclay Derivatives in the Synthesis of Macrocycles.

As an alternative to the rotaxane method, an organoclay can be used as a template for the efficient formation of macrocycles (ring in schematic representation) which are easily extracted from the clay interlayer space. The four-step synthesis involved preparation of a pillared clay from the dihydrochloride salt of p-xylylenediamine, insertion of neutral p-xylylenediamine into the pillared structure, reaction of the neutral p-xylylenediamine in the layers with isophthaloyl chloride and formation of the tetramide macrocycle, and extraction of the product from the clay.