Immobilization Of Palladium And Transmetals On Silica Surface And Their Applications In Heck Reaction

There are many Si-OH on the surface of silica material, thus, silica modification can occur via the reaction of a particular molucule. A wide variety of novel materials can be prepared through the chemical modification of silica with inorganic and organic species. In the present dissertation, we have reported the synthesis of silica-supported various Palladium and other transmetals (Ni²⁺, Co²⁺, Cu²⁺) complexes and their application as heterogeneous catalyst for Heck reaction. The research contents includes the following main points:1. The immobilization of organic species onto SiO₂ surface was investigated.Various function groups (such as: -NH₂(CH₂)₂ NH₂, - N( C₂H₅)₂, -NHBu, et.) can be immobilized on the SiO₂ surface via reaction of the silanol groups with oxyalky-silica compounds. The results of UV-VIS spectra and BET indicate that the surface aera of organically modified silica decreased markedly.2. Silica supported cyano-palladium (0, â…¡) complex were prepared, we studied its catalytic performances in Heck arylation. It was found that the cyano-palladium (0) complexe is highly active and stereoselective for the arylation of aryl iodides with styrene, acrylic acid and methyl acrylat at 90℃ after treated by KBH₄. The datas of UV-VIS and XPS indicated that -CN react with Pd.3. We prepared a series of silica supported amine-palladium (0, â…¡ ) complexes and y -salicylaldehyde-palladium (0) complexe, studied their catalytic performances in Heck arylation. It was found that the amine-palladium (0) complexes are highly...