Metal Atoms Collinear with the Spiro Carbon of 6,6-Open Adducts, M2@C80(Ad) (M = La and Ce, Ad = Adamantylidene)
journal contributionposted on 30.01.2008, 00:00 by Michio Yamada, Chika Someya, Takatsugu Wakahara, Takahiro Tsuchiya, Yutaka Maeda, Takeshi Akasaka, Kenji Yoza, Ernst Horn, Michael T. H. Liu, Naomi Mizorogi, Shigeru Nagase
The photochemical reaction of M2@C80 (M = La and Ce) with 2-adamantane-2,3‘-[3H]-diazirine (1) affords the corresponding adducts by carbene addition. The adducts were characterized by spectroscopic and single-crystal X-ray structure analyses. Crystallographic data for the adduct La2@C80(Ad) (2, Ad = adamantylidene) reveal that the two La atoms are collinear with the spiro carbon of the 6,6-open adduct. It is noteworthy that the La−La distance is highly elongated by the addition of carbene. Paramagnetic 13C NMR spectral analysis of the adduct Ce2@C80(Ad) (3) indicates that the two Ce atoms are also collinear with the spiro carbon at room temperature in solution. The unique metal positions were confirmed by density functional calculations.