Mimicking Base Interaction with Acidic Sites [Si-O( H)-Al] of Zeolites in Molecular Models.

LiAlH4, LiAlMe4, or NaAlH4 react with commercially available HOSi R3, (-OSi R3 = -OSi tBuMe2, -OSiPh3) to afford [Li(THF)2][Al(OSi tBuMe2)4] ( 1), [Na(THF)2][Al(OSi tBuMe2)4] ( 2), and [Li(THF)4][Al(OSiPh3)4] ( 3). Ligand exchange reactions at the alkali metal ions in 1 and 3 with pyridine, 2,2′-bipyrimidine, and water yielded complexes [Li(py)2][Al(OSi tBuMe2)4] ( 4), [Al(OSi tBuMe2)4Li(H2O)]2(bpym) ( 5), and [Li(THF)(H2O)][Al(OSiPh3)4] ( 6). The X-ray crystal structures of complexes 1, 3, 4, 5, and 6 are presented. The complex [quinuclidineH][Al(OSi tBuMe2)4] ( 7), was produced via reaction of quinuclidine ·hydrochloride with 2. It features a hydrogen bonding interaction between an N-H group with a Si-O-Al unit, as proposed for the surfaces of zeolites after base treatment. [ABSTRACT FROM AUTHOR]