Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 33. Synthesis of Mixed-Ligand Metallacarboranes of Yttrium and Lanthanides Derived from Open η<sup>5</sup>-Pentadiene and C<sub>2</sub>B<sub>4</sub>-Carborane: A Synthetic and Structural Investigation
作者:Jianhui Wang、Chong Zheng、Graciela Canseco-Melchor、Daniel J. Hilby、John A. Maguire、Narayan S. Hosmane
DOI:10.1021/om060751v
日期:2007.1.1
The reactions of nido-2-R-3-(Me3Si)-2,3-C2B4H6 (R = Me3Si, 1; R = Me, 2) with [eta(5)-2,4-(Me)(2)C5H5](3)M in a molar ratio of 1:1, in toluene at elevated temperature (70 degrees C), produced mixed-ligand dimeric lanthanacarboranes of the type [(eta(5)-2,4-(Me)(2)C5H5)(eta(5)-2-R-3-(Me3Si)-2,3-C2B4H4)M](2) (3, M = Y, R = Me3Si; 4, M = Y, R = Me; 5, M = Gd, R = Me3Si; 6, M = Gd, R = Me; 7, M = Tb, R = SiMe3; 8, M = Tb, R = Me; 9 M = Dy, R = Me3Si; 10, M = Dy, R = Me; 11, M = Ho, R = Me3Si; 12, M = Ho, R = Me; 13, M = Er, R = Me3Si; 14, M = Er, R = Me; 15, M = Tm, R = SiMe3; 16, M = Tm, R = Me; 17, M = Lu, R = Me3Si; 18, M = Lu, R = Me) as crystalline solids in 75-88% yields. All the compounds were characterized by IR spectroscopy and elemental analyses. While the diamagnetic species 3, 4, 17, and 18 were characterized by H-1, C-13, and B-11 NMR spectroscopy, compounds 3-8, 10, 12-14, and 18 were also characterized by single-crystal X-ray diffraction analyses. On the basis of the reactivity pattern and isolated products, an intramolecular H-transfer reaction mechanism is proposed for the formation of these species.