Synthesis, thermal evolution and magnetic investigations of SBA-15 silica functionalized with anchored iron phosphonate molecules.

In the current work, we report on the synthesizing of a series of novel nanocomposite materials obtained by functionalizing the SBA-15 silica matrix with anchored iron phosphonate molecules and the following thermal treatment. The obtained results reveal the formation of a unique amorphic layer of Fe-based compounds on the surface of silica walls of SBA-15 channels as a result of the organic groups' decomposition after moderate thermal treatment. Due to their unique structure, represented in an active Fe-containing amorphous coating spread over a large surface area, these materials are of great interest for their potential applications in fields such as catalysis, adsorption, and non-linear optics. The obtained materials remain amorphous, preserving the SBA-15 mesoporous structure up to temperatures of approximately 800 °C, after which the partial melting of the silica backbone is observed with the simultaneous formation of nanocrystals inside the newly-formed glassy mass. All obtained materials were characterized using such techniques as thermogravimetry, transmission and scanning electron microscopy combined with energy dispersive x-ray spectroscopy mapping, Raman spectroscopy, N2sorption analysis, x-ray diffraction, x-ray photoelectron spectroscopy, Mössbauer spectroscopy, and SQUID measurements.

Functionalised Anodised Aluminium Oxide as a Biocidal Agent.

In this article, we describe the antimicrobial properties of a new composite based on anodic aluminium oxide (AAO) membranes containing propyl-copper-phosphonate units arranged at a predetermined density inside the AAO channels. The samples were prepared with four concentrations of copper ions and tested as antimicrobial drug on four different strains of Escherichia coli (K12, R2, R3 and R4). For comparison, the same strains were tested with three types of antibiotics using the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than antibiotics such as ciprofloxacin, bleomycin and cloxacillin. The described composites are highly specific for the analysed model Escherichia coli strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA. We have also observed that the intermolecular distances between the functional units play an important role for the antimicrobial properties of the used material. Hence, we utilised the idea of the 2D solvent to tailor them.

Synthesis of Vertically Aligned Porous Silica Thin Films Functionalized by Silver Ions.

In this work, we have developed a chemical procedure enabling the preparation of highly ordered and vertically aligned mesoporous silica films containing selected contents of silver ions bonded inside the mesopore channels via anchoring propyl-carboxyl units. The procedure involves the electrochemically assisted self-assembly co-condensation of tetraethoxysilane and (3-cyanopropyl)triethoxysilane in the presence of cetyltrimethylammonium bromide as a surfactant, the subsequent hydrolysis of cyano groups into carboxylate ones, followed by their complexation with silver ions. The output materials have been electrochemically characterized with regard to the synthesis effectiveness in order to confirm and quantify the presence of the silver ions in the material. The mesostructure has been observed by transmission electron microscopy. We have pointed out that it is possible to finely tune the functionalization level by controlling the co-condensation procedure, notably the concentration of (3-cyanopropyl)triethoxysilane in the synthesis medium.

Nanostructured Silica with Anchoring Units: The 2D Solid Solvent for Molecules and Metal Ions.

The ability to organize, separate and manipulate individual molecules and ions on a surface opens up almost unlimited opportunities. However, it often requires complex techniques and a proper support material. With this in mind, we show a new concept of 2D solid solvents and review a simple and efficient procedure which is based on nanostructured forms of silica with anchoring units. We describe silica supports, such as spherical nanoparticles and mesoporous silica structures, as well as review the methods for chemical modification of the surface of silica with the functional groups. Finally, we present a few particular examples of the immobilization of molecules and ions on the surface of 2D solid solvents along with the experimental investigation of the obtained materials.

Cu(I) Arylsulfonate D€-Complexes with 3-Allyl-2-thiohydantoin: The Role of the Weak Interactions in Structural Organization.

The present work is directed toward preparation and structural characterization of two novel Cu(I) arylsulfonate ?-complexes with 3-allyl-2-thiohydantoin, namely [Cu2(Hath)4](C6H5SO3)2 (1) and [Cu2(Hath)4](p-CH3C6H4SO3)2·2H2O (2) (Hath = 3-allyl-2-thiohydantoin), obtained by the means of alternating current electrochemical synthesis and studied with X-ray diffraction method. In both structures, the inner coordination sphere is represented by the cationic dimer [Cu2(Hath)4]2+ with one crystallographically independent copper(I) atom which has a trigonal pyramidal coordination environment formed by three Hath thiogroup S atoms and double C=C bond of its allyl group. [Cu2(Hath)4]2+ fragments in both coordination compounds are very similar, despite some divergences such as a big difference in Cu?S distance to the apical S atom (3.0374(8) ? in 1 and 2.7205(9) ? in 2). This difference was explained by the impact of the system of weak interactions, which are quite different.