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Strong Organic Bases as Building Blocks of Mesoporous Hybrid Catalysts for C–C Forming Bond Reactions
Author(s) -
Gianotti Enrica,
Diaz Urbano,
Velty Alexandra,
Corma Avelino
Publication year - 2012
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201200716
Subject(s) - chemistry , mesoporous material , catalysis , hybrid material , knoevenagel condensation , organic base , silylation , naphthalene , silicon , organic reaction , mesoporous silica , organic synthesis , organic chemistry
1,8‐Bis(tetramethylguanidino)naphthalene (TMGN), a neutral organic base that combines the properties of guanidine and the properties of proton sponges, was used as a building block to produce organic–inorganic silica‐based mesoporous hybrids with strong basic properties. The TMGN‐based mesoporous hybrids (TMGN/SiO 2 ) were prepared by a sol–gel route working at a neutral pH and low temperatures, which avoided the use of SDAs. TMGN has been modified in order to have two terminal reactive silyl groups able to perform co‐condensation with a conventional organosilane (TMOS) used as a silicon source. This synthesis has allowed us to directly introduce the unmodified, functionalized TMGN as part of the walls of the mesoporous silica by a one‐pot synthesis. TMGN/SiO 2 hybrid materials present excellent catalytic properties for C–C bond forming reactions: Knoevenagel, Henry (nitroaldol), and Claisen–Schmidt condensations. The activity of the hybrid materials is higher than that of the counterpart homogeneous catalyst.