Five-Coordinate Aluminum Bromides: Synthesis, Structure, Cation Formation, and Cleavage of Phosphate Ester Bonds

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• 作者：Amitabha Mitra ; Lauren J. DePue ; Sean Parkin ; and David A. Atwood
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：February 1, 2006
• 年：2006
• 卷：128
• 期：4
• 页码：1147 - 1153
• 全文大小：262K
• 年卷期：v.128,no.4(February 1, 2006)
• ISSN：1520-5126

文摘

The alkane elimination reaction between Salen(^tBu)H₂ ligands and diethylaluminum bromide wasused to prepare three Salen aluminum bromide compounds salen(^tBu)AlBr (1) (salen = N,N'-ethylenebis(3,5-di-tert-butylsalicylideneimine)), salpen(^tBu)AlBr (2) (salpen = N,N'-propylenebis(3,5-di-tert-butylsalicylideneimine)), and salophen(^tBu)AlBr (3) (salophen = N,N'-o-phenylenenebis(3,5-di-tert-butylsalicylideneimine)). The compounds contain five-coordinate aluminum either in a distorted square pyramidal or atrigonal bipyramidal environment. The bromide group in these compounds could be displaced bytriphenylphosphine oxide or triphenyl phosphate to produce the six-coordinate cationic aluminum compounds[salen(^tBu)Al(Ph₃PO)₂]Br (4), [salpen(^tBu)Al(Ph₃PO)₂]Br (5), [salophen(^tBu)Al(Ph₃PO)₂]Br (6), and [salophen(^tBu)Al{(PhO)₃PO)}₂]Br (7). All the compounds were characterized by ¹H, ¹³C, ²⁷Al, and ³¹P NMR, IR, massspectrometry, and melting point. Furthermore, compounds 1-3 and 5-7 were structurally characterizedby single-crystal X-ray diffraction. Compounds 1-3 dealkylated a series of organophosphates instoichiometric reactions by breaking the ester C-O bond. Also, they were catalytic in the dealkylationreaction between trimethyl phosphate and added boron tribromide.