[(acridine)BCl2]+: A Borenium Cation That Is a Strong Boron- and Carbon-Based Lewis Acid

详细信息    查看全文

• 作者：Ewan R. Clark ; Michael J. Ingleson
• 刊名：Organometallics
• 出版年：2013
• 出版时间：November 25, 2013
• 年：2013
• 卷：32
• 期：22
• 页码：6712-6717
• 全文大小：339K
• 年卷期：v.32,no.22(November 25, 2013)
• ISSN：1520-6041

文摘

[(acridine)BCl₂][AlCl₄] was synthesized by halide abstraction from (acridine)BCl₃ with AlCl₃. The hydride ion affinity of the C9 position in [(acridine)BCl₂]⁺ was calculated to be 14 kcal mol^鈥? greater than that at boron. [(acridine)BCl₂][AlCl₄] reacts with 1 equiv of acridine to form the strained boronium cation [(acridine)₂BCl₂][AlCl₄] and with P(mesityl)₃ by photoinduced one-electron transfer to form the 9,9鈥?biacridane moiety by radical coupling. A stable frustrated Lewis pair (FLP) was formed on combining [(acridine)BCl₂][AlCl₄] and 2,4,6-tri-tert-butylpyridine (TBP), which heterolytically activated H₂ at 100 掳C. The ultimate location of the hydride from H₂ activation was the C9 position of acridine and not boron. Carbon Lewis acid based reactivity also occurred when thieno[3,2-b]thiophene was added to the [(acridine)BCl₂][AlCl₄]/TBP FLP or to [(acridine)₂BCl₂][AlCl₄], with arylation of acridine at C9 observed for both.