Catalytically Active SiO Aerogels Comprising Chelate Complexes of Palladium.

A series of silica-based aerogels comprising novel bifunctional chelating ligands was prepared. To produce target aerogels, two aminosilanes, namely (3-aminopropyl)trimethoxysilane (APTMS) and -(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), were acylated by natural amino acids (()-(+)-2-phenylglycine or -phenylalanine), followed by gelation and supercritical drying (SCD). Lithium tetrachloropalladate was used as the metal ion source to prepare strong complexes of Pd with amino acids covalently bonded to a silica matrix.

The AM-4 Family of Layered Titanosilicates: Single-Crystal-to-Single-Crystal Transformation, Synthesis and Ionic Conductivity.

Flexible crystal() structures, which exhibit() single-crystal()-to-single-crystal() (SCSC) transformations(), are attracting attention() in many applied aspects: magnetic() switches, catalysis, ferroelectrics and sorption. Acid treatment() for titanosilicate material() AM-4 and natural() compounds with the same structures led to SCSC transformation() by loss() Na, Li and Zn cations with large structural() changes (20% of the unit()-cell() volume()). The conservation() of crystallinity through complex() transformation() is possible due() to the formation() of a strong hydrogen bonding() system().

Hemolytic Activity and Cytotoxicity of Synthetic Nanoclays with Montmorillonite Structure for Medical Applications.

The factors influencing the appearance of toxicity in samples of synthetic montmorillonite with a systematically changing chemical composition Na(Al, Mg)SiO(OH) nHO, which are potentially important for their use in medicine as drug carriers, targeted drug delivery systems, entero- and hemosorbents have been studied. Samples synthesized under hydrothermal conditions had the morphology of nanolayers self-organized into the nanosponge structures. The effect of the aluminum content, particle sizes, porosity, and ζ-potential of the samples on their toxicity was studied.

Crystal nucleation in a glass during relaxation well below T.

Until quite recently, in almost all papers on crystal nucleation in glass-forming substances, it was assumed that nucleation proceeds in a completely relaxed supercooled liquid and, hence, at constant values of the critical parameters determining the nucleation rate for any given set of temperature, pressure, and composition. Here, we analyze the validity of this hypothesis for a model system by studying nucleation in a lithium silicate glass treated for very long times (up to 250 days) in deeply supercooled states, reaching 60 K below the laboratory glass transition temperature, T. At all temperatures in the considered range, T < T, we observed an enormous difference between the experimental number of nucleated crystals, N(t), and its theoretically expected value computed by assuming the metastable state of the relaxing glass has been reached.

Mass spectrometric study and modeling of the thermodynamic properties of SrO-Al O melts at high temperatures.

Rationale: The SrO-Al O system holds promise as a base for a wide spectrum of advanced materials, which may be synthesized or applied at high temperatures. Therefore, studying vaporization and high-temperature thermodynamic properties of this system is of great practical importance.

Methods: Samples of the SrO-Al O system were obtained by solid-state synthesis and identified by X-ray fluorescence analysis, X-ray phase analysis, scanning electron microscopy, electron probe microanalysis, simultaneous thermal analysis, and thermogravimetric analysis.

Particles Morphology Impact on Cytotoxicity, Hemolytic Activity and Sorption Properties of Porous Aluminosilicates of Kaolinite Group.

A comparative study of the properties of aluminosilicates of the kaolinite (AlSiO(OH)∙nHO) group with different particles morphology has been carried out. Under conditions of directed hydrothermal synthesis, kaolinite nanoparticles with spherical, sponge, and platy morphologies were obtained. Raw nanotubular halloysite was used as particles with tubular morphology.

High-temperature mass spectrometric study of thermodynamic properties in the TiO -Al O -SiO system and modeling.

Rationale: The TiO -Al O -SiO system is the base for various glass-ceramic materials, which have great practical value for a large number of modern technologies. Many TiO -Al O -SiO materials are synthesized or applied at high temperatures, which justifies the relevance of the present study.

Methods: The samples in the TiO -Al O -SiO system were synthesized using the method of induction melting in a cold crucible.