ИСТИНА

Coordination compounds of 3d and 4f elements are of high interest for various fields of application – as precursors for the synthesis of inorganic nanomaterials, as materials for luminescent devices, as magnetic materials, catalysts, etc. In recent years, the rational design of porous metal-organic frameworks (MOF) with polynuclear metal-containing secondary building units has been actively developed. Formation of polynuclear species with bridging OH- groups occurs in solution due to partial hydrolysis of metal salts. In the present work we have developed a self-controlled hydrolysis process which allow one to reproducible synthesize polynuclear lanthanide hydroxocarboxylates with different topology of {LnxOy} core. Self-assembly of complexes with {LnxOy} core in solution in a presence of aliphatic amines have been monitored by total X-ray scattering techniques with pair distribution function (PDF) analysis1. It has been revealed, that in situ formed lanthanide hydroxytrifluouroacetates promotes the absorption of CO2 by diethylenetriamine and stabilize the resulting diethylenetriamine dicarbamate in a form of chelating ligand within the complex cationic species [Ln4(OH)4(tfa)3(deta)4(detadcH)2]3+. The later ones have been isolated in a form of single crystals and their X-ray crystal structures have been revealed2. Pre-synthesized polynuclear species with {CexOy} core have been also applied for tailored synthesis of a novel Ce-based MOF and its composite with nano-CeO2. It has been shown that aliphatic amines play a key role in formation of a MOF with a certain composition, while the Ce-containing precursors determine the morphology of MOF. In oxidative conditions MOF prepared from hydroxocaroxylates are readly transformed to MOF-derived nano-CeO2 which has been tested as catalyst for CO oxidation. Molecular species with {Ce6O8} core have been also applied as precursors for nano-CeO2 formation via further hydrolysis in mild conditions at 120ºC. As a result particles with an average size of ca. 3 nm have been reproducibly obtained. The later has been applied as a carier for Pd-cluster deposition by chemical routed and the resulting material have been tested as the selective heterogeneous catalyst for hydrogenation of phenylacetlene.