Revisiting the Aufbau Reaction with Acetylene: Further Insights from Experiment and Theory

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• 作者：Samuel S. Karpiniec ; David S. McGuinness ; Michael G. Gardiner ; Brian F. Yates ; Jim Patel
• 刊名：Organometallics
• 出版年：2011
• 出版时间：March 28, 2011
• 年：2011
• 卷：30
• 期：6
• 页码：1569-1576
• 全文大小：859K
• 年卷期：v.30,no.6(March 28, 2011)
• ISSN：1520-6041

文摘

The first steps of acetylene chain growth at AlEtb>3b>, via migratory insertion, have been investigated both experimentally and theoretically. The first insertion into the Al鈭扙t bond occurs readily, leading to the stable alkenyl-bridged dimer [{Etb>2b>Al(渭-CH鈺怌HEt)}b>2b>] (<b>1b>). The alkenyl bridging mode has been observed through isolation and structural analysis of Alb>2b>Etb>2b>(OCb>6b>Hb>3b>Phb>2b>)b>2b>(渭-CH鈺怌HEt)(渭-OCb>6b>Hb>3b>Phb>2b>) (<b>2b>), synthesized by way of controlled reaction of <b>1b> with 2,6-Phb>2b>Cb>6b>Hb>3b>OH. This stable binding mode increases the barrier to a second insertion of acetylene, as insertion proceeds through monomeric Al-acetylene adducts. The energetics of further chain growth, dimer formation, and chain termination via hydrogenolysis were investigated theoretically. The results provide further insight and explanation for previous experimental findings in relation to the Aufbau reaction with acetylene.