Host−Guest Complexation of Endohedral Metallofullerene with Azacrown Ether and Its Application

✍ Scribed by Tsuchiya, Takahiro; Sato, Kumiko; Kurihara, Hiroki; Wakahara, Takatsugu; Nakahodo, Tsukasa; Maeda, Yutaka; Akasaka, Takeshi; Ohkubo, Kei; Fukuzumi, Shunich; Kato, Tatsuhisa

• Book ID: 115458109
• Publisher: American Chemical Society
• Year: 2006
• Tongue: English
• Weight: 211 KB
• Volume: 128
• Category: Article
• ISSN: 0002-7863
• DOI: 10.1021/ja0608390

✦ Synopsis

Complexation of endohedral metallofullerene La@C82-A (1) with macrocyclic compounds, such as 1,4,7,10,13,16-hexaazacyclooctadecane (2), 1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacyclooctadecane (3), mono-aza-18-crown-6 ether (4), 18-crown-6 ether (5), and p-tert-butylcalix[n]arenes (n ) 4-8, 6-10), for the first time is examined. Among them, 1 forms a complex with azacrown ethers 2-4 while accompanying the electron transfer between them. This is characteristic of endohedral metallofullerene and caused by its low reduction potential. Activation energies, ∆Get, for the electron transfer from 2-4 to 1 are 4.6, 2.8, and 11 kcal/mol, respectively. These small ∆Get values indicate that the electron transfer from the azacrown ethers to 1 is facile in the ground state. Furthermore, the selective isolation of lanthanum endohedral metallofullerenes from the extracts of soot is accomplished by utilizing the complexation of 1 with 2.