Catalytically Active SiO<sub>2</sub> Aerogels Comprising Chelate Complexes of Palladium
Nataliya A. Sipyagina,
Nikita E. Vlasenko,
Alena N. Malkova,
Gennady P. Kopitsa,
Yulia E. Gorshkova,
Sergey Yu. Kottsov,
Sergey A. Lermontov
Affiliations
Nataliya A. Sipyagina
Institute of Physiologically Active Compounds of Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences, 1 Severnij pr., Chernogolovka 142432, Russia
Nikita E. Vlasenko
Institute of Physiologically Active Compounds of Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences, 1 Severnij pr., Chernogolovka 142432, Russia
Alena N. Malkova
Institute of Physiologically Active Compounds of Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences, 1 Severnij pr., Chernogolovka 142432, Russia
Gennady P. Kopitsa
Institute of Silicate Chemistry of Russian Academy of Sciences, 2 Adm. Makarova nab., St. Petersburg 199155, Russia
Yulia E. Gorshkova
Joint Institute for Nuclear Research, 6 St. Joliot-Curie, Dubna 141980, Russia
Sergey Yu. Kottsov
Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, 31 Leninsky prosp., Moscow 119991, Russia
Sergey A. Lermontov
Institute of Physiologically Active Compounds of Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences, 1 Severnij pr., Chernogolovka 142432, Russia
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 N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), were acylated by natural amino acids ((S)-(+)-2-phenylglycine or L-phenylalanine), followed by gelation and supercritical drying (SCD). Lithium tetrachloropalladate was used as the metal ion source to prepare strong complexes of Pd2+ with amino acids covalently bonded to a silica matrix. Aerogels bearing chelate complexes retain the Pd2+ oxidation state after supercritical drying in CO2, but the Pd ion is reduced to Pd metal after SCD in isopropanol. Depending on the structure of amino complexes, Pd-containing aerogels showed catalytic activity and selectivity in the hydrogenation reactions of C=C, C≡C and C=O bonds.
