Deng Liang, Chan Hoi-Shan, Xie Zuowei
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong, China.
J Am Chem Soc. 2005 Oct 12;127(40):13774-5. doi: 10.1021/ja054207+.
Transition metal-benzyne complexes have found many applications in organic synthesis, mechanistic studies, and the synthesis of functional materials. In sharp contrast, the reaction chemistry of transition metal-carboryne complexes is virtually unknown although the theoretical calculations indicated that the formation of carboryne (1,2-C2B10H10) and benzyne is very energetically comparable. This communication reports a novel zirconocene-carboranyl complex Cp2Zr(mu-Cl)(mu-C2B10H10)Li(OEt2)2 (1), an efficient precursor of the zirconocene-carboryne species, prepared from the reaction of Cp2ZrCl2 with 1 equiv of Li2C2B10H10 in Et2O. The reactivity studies indicated that 1 resembles zirconocene-benzyne in reactions with polar unsaturated organic molecules. On the other hand, it shows no reactivity toward alkynes and alkenes, a reactivity pattern which is quite different from that of zirconocene-benzyne. This work also furnishes a novel method for the preparation of functional o-carboranes and their metal complexes which cannot be synthesized by other methods presently known.
过渡金属-苯炔配合物在有机合成、机理研究和功能材料合成中已有许多应用。与之形成鲜明对比的是，尽管理论计算表明碳硼炔（1,2-C2B10H10）和苯炔的形成在能量上非常相近，但过渡金属-碳硼炔配合物的反应化学却几乎不为人知。本通讯报道了一种新型的二茂锆-碳硼烷配合物Cp2Zr(μ-Cl)(μ-C2B10H10)Li(OEt2)2（1），它是二茂锆-碳硼炔物种的有效前体，由Cp2ZrCl2与1当量的Li2C2B10H10在Et2O中反应制备而成。反应活性研究表明，1在与极性不饱和有机分子反应时类似于二茂锆-苯炔。另一方面，它对炔烃和烯烃没有反应活性，这种反应模式与二茂锆-苯炔的反应模式有很大不同。这项工作还提供了一种制备官能邻碳硼烷及其金属配合物的新方法，这些化合物目前无法通过其他已知方法合成。
