Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 22. Synthetic, Spectroscopic, Structural, and Bonding Studies on Half- and Full-Sandwich Gallacarboranes of 2,3- and 2,4-C2
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- 作者：Narayan S. Hosmane ; Kai-Juan Lu ; Hongming Zhang ; and John A. Maguire
- 刊名：Organometallics
- 出版年：1997
- 出版时间：November 25, 1997
- 年：1997
- 卷：16
- 期：24
- 页码：5163 - 5170
- 全文大小：266K
- 年卷期：v.16,no.24(November 25, 1997)
- ISSN：1520-6041
文摘
The reaction of the TMEDA-solvated group 1 salts ofthe carborane dianions[2,n-(SiMe3)2-2,n-C2B4H4]2-(n = 3, 4) with GaCl3 in a 2:1carborane-to-GaCl3 molar ratio gave thecorresponding full-sandwich gallacarboranes[2,2',n,n'-(SiMe3)4-1,1'-commo-Ga(1,2,n-GaC2B4H4)2]-(n = 3 (I), 4 (II)) in 36% and 38%yields, respectively. Lowering the carborane-to-GaCl3 molar ratio to 1:1 produced the half-sandwichchlorogallacarboranes 1-(TMEDA)-1-Cl-2,n-(SiMe3)2-1,2,n-GaC2B4H4(n = 3 (III), 4 (IV)) in 51% and41% yields, respectively.Compounds I-IV were characterized on thebasis of 1H, 11B, and 13C NMRspectra, IR spectra,and single-crystal X-ray analyses. The structures of thegallacarboranes show that thegallium atoms are not equally bonded to the atoms in theC2B3 faces of the carboranes butare slipped toward the more boron rich sides of the faces.Slippages in I and II are suchthat maximum differences in the Ga-C2B3distances were 0.34 Å in I and 0.45 Å in II.Thedistortions were much larger in III and IV suchthat the carboranes are better described asbeing 
3- and 2-bonded, respectively.
3- and 2-bonded, respectively.