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Amino-functionalized SBA-15 type mesoporous silicas having unique hexagonal platelet morphologies with short channels (100-300 nm) running parallel to the thickness of the nanostructured hexagonal platelet type morphologies have been directly synthesized by co-condensation of aminopropyltriethoxysilane (APTES) and sodium metasilicate as a silica source in the presence of Pluronic P123 triblock copolymer as a structure directing agent.

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The immobilized N-heterocyclic carbene-Pd complex was readily prepared by reaction of silica gel-supported imidazolium chloride with Pd(OAc) 2 . The Pd complex exhibited excellent catalytic activity in the coupling reaction of aryl halides with arylboronic acid. The heterogeneous Pd catalyst was reusable as well as air-stable to allow easy use.

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A mesoporous LTA zeolite (MP-LTA)-supported palladium catalyst was developed for the highly efficient Suzuki-Miyaura reaction of aryl and heteroA C H T U N G T R E N N U N G aryl chlorides. The couplings of various aryl chlorides with arylboronic acids in aqueous ethanol were efficiently achieved in the presence of 1.0 mol% of the catalyst. Furthermore, the scope of this catalyst was extended to the coupling of heteroaryl chlorides. Regardless of the substituents, all of the coupling reactions were very clean and highly efficient under mild heating. It shows that our catalyst is one of the most powerful heterogeneous catalysts for the coupling of a wide range of aryl and heteroaryl chlorides. The catalyst could be repetitively used at least 10 times without a significant loss of its catalytic activity. Compared to mesoporous SBA-15 and MCM-41 materials, the MP-LTA support proved to be very stable and robust to prevent degradation upon reuse.

Silica gel-supported b-ketoiminatophosphane-Pd complex (Pd@SiO 2 ) was shown to be a highly active and long-lived catalyst for aqueous Suzuki, Stille and Sonogashira coupling reactions of heteroaryl chlorides. A wide range of heteroaryl chlorides could be efficiently coupled with different nucleophilic partners in the presence of only 0.5 mol% catalyst and under mild conditions. This is one of the most powerful heterogeneous catalysts for the couplings of diverse heteroaryl chlorides. Furthermore, the catalyst could be reused with almost consistent activity.Scheme 1 Synthesis of silica gel-supported b-ketoiminatophosphanyl palladium complex 3.

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