Synthesis and Properties of Carborane-Appended C3-Symmetrical Extended π Systems

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• 作者：Barada Prasanna Dash ; Rashmirekha Satapathy ; Elizabeth R. Gaillard ; John A. Maguire ; Narayan S. Hosmane
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：May 12, 2010
• 年：2010
• 卷：132
• 期：18
• 页码：6578-6587
• 全文大小：416K
• 年卷期：v.132,no.18(May 12, 2010)
• ISSN：1520-5126

文摘

A series of C₃-symmetric π-conjugated compounds containing three to six o-carborane clusters have been synthesized by employing palladium-catalyzed Suzuki coupling reactions and palladium-catalyzed acetylation reactions, followed by silicon tetrachloride mediated trimerization reactions. Carborane-containing extended trimers were found to emit blue light. Incorporation of o-carborane clusters into extended π-conjugated systems led to 22−70% enhancement of their relative fluorescence quantum yields. Decapitation of o-carborane clusters made these extended trimers water soluble, and their aqueous solutions were also found to be fluorescent, but with a reduced fluorescence intensity. The carborane-appended π-conjugated compounds are found to be extremely thermally stable, and for some of these compounds only 10% mass loss occurred at temperatures close to 500 °C. The DSC thermograms of smaller C_cage-appended trimers indicate the occurrence of solid−solid phase transitions.