Kuchma O. Silicas with supramolecular surface layer: synthesis, structure, properties

The dissertation is devoted to the research of influence of synthesis conditions, porous structure of silica matrix, structures of macrocycles and a way of their fixing on the carrier surface on structure of silicas with supramolecular surface layer and their adsorption properties caused by ability to "guest-host" complexing. The analysis of quantum-chemical simulations has shown that such factors, as composition and structure of the functional groups in calixcrown and a fixing way of a macrobicircle onto matrix surfaces influence on conformation behavior of calix[4]arene-crowns-6 and, accordingly, on their adsorption properties. An influence of structure of coordination sphere of cesium cation on stability of its complexes with calix[4]arene-crowns-6 was investigated by quantum-chemical method. The synthesis technique of 26,28-dipropoxy-5,17-bis[3-(triethoxysilyl) propyl]calix[4]arene-crown-6 in 1,3-alternate conformation was developed. The structure and properties of the synthesized alkoxysilyl derivative was investigated. Polysiloxane xerogels with the incorporated calix[4]arene and covalently bounded calix[4]arene-crown-6, diaminodibenzo-18-crown-6, cyclodextrin groups were synthesized by sol-gel method. It was established that the concentration of macrocyclic ligands in xerogels, the structure of macrocycles, and a way of their fixing into the polysiloxane matrix as well essentially influence on gelation in these systems and structure formation of synthesized xerogels. The modification techniques of mesoporous silica SBA-15 and silicagel Davisil surface by macrocyclic groups were developed. The composition and structure of the obtained materials was specified by FTIR, 13С and 29Si CP/MAS NMR spectroscopy. The adsorption properties of synthesized sorbents toward Cs+.was investigated. It was shown, that adsorption properties of the obtained materials are determined by the macrocyclic ligands structure, their concentration in samples, fixing way of macrocycles and porosity of the matrix. It was established that the xerogels containing crown-ether groups selectively adsorb К+. It was shown that SBA-15 modified by calix[4]arene groups shows high adsorption activity to 137Cs and 90Sr. It was determined by gas-chromatography method that sorbents with cyclodextrin groups are characterized by high adsorption ability toward oxygencontain organic compounds.