Reactivity and Derivatization of Five-Coordinate, Chelated Aluminum

• Published in: Inorganic chemistry Vol. 40; no. 26; pp. 6782 - 6787
• Main Authors: Munoz-Hernandez, Miguel-Angel, Keizer, Timothy S, Wei, Pingrong, Parkin, Sean, Atwood, David A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 17.12.2001
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic010759r

The convenient five-coordinate starting materials, Salen( t Bu)AlCl (Salen( t Bu) = N,N‘-alkylene (or arylene) bis (3,5-di-tert-butyl-2-hydroxybenzylideneamine) (1−4) can be used in a wide range of reactions to form five-coordinate aluminum compounds. Herein, these reagents were used to produce new five-coordinate azides, LAlN3 (L = Salen( t Bu) (5), Salpen( t Bu) (6), and Salomphen( t Bu) (7)) through trimethylsilylhalide elimination. The decomposition of the azides produce first hydroxide (LAlOH (L = Salen( t Bu) (8)) and, subsequently in the presence of chlorotrimethylsilane, the siloxide compounds, LAlOSiMe3 (L = Salen( t Bu) (9), Salpen( t Bu) (10), and Salomphen( t Bu) (11)). Alkane elimination reactions may also be used to access this type of compound as evidenced by the formation of Salomphen( t Bu)AlOSiPh3 (12). Additionally, the first structurally characterized five-coordinate monomeric amide, Salcen( t Bu)AlN(SiMe3)2 (13), can prepared by a salt elimination utilizing Salcen( t Bu)AlCl (4). The compounds were characterized by spectroscopic methods (1H and 27Al NMR, MS, and IR) and, in the case of 2 (Salpen( t Bu)AlCl), 3 (Salomphen( t Bu)AlCl) 9, 11, 12, and 13, by X-ray analysis. Several of the compounds were explored as potential catalysts for the living polymerization of propylene oxide.