Liu Dongmei, Dang Li, Sun Yi, Chan Hoi-Shan, Lin Zhenyang, Xie Zuowei
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
J Am Chem Soc. 2008 Nov 26;130(47):16103-10. doi: 10.1021/ja8067098.
A hydrogen-mediated Ru-C to Ru-B bond conversion was observed experimentally and supported by the theoretical calculations. Treatment of [eta(5):sigma(C)-Me(2)C(C(5)H(4))(C(2)B(10)H(10))]Ru(COD) (1) bearing a Ru-C(cage) sigma bond with PR(3) in the presence of H(2) gave Ru-B(cage) bonded complexes [eta(5):sigma(B)-Me(2)C(C(5)H(4))(C(2)B(10)H(10))]RuH(2)(PR(3)) (R = Cy (2), Ph (3)) (sigma(C): Ru-C(cage) sigma bond; sigma(B): Ru-B(cage) sigma bond). Complex 3 was converted to [eta(5):sigma(B)-Me(2)C(C(5)H(4))(C(2)B(10)H(10))]Ru(L(2)) in the presence of L(2) (L(2) = dppe (4), PPh(3)/P(OEt)(3) (5), PPh(3)/pyridine (6)) via liberation of H(2) upon heating. These complexes were fully characterized by various spectroscopic techniques, elemental analyses, and single-crystal X-ray diffraction studies. DFT calculations show that this conversion process is both kinetically and thermodynamically favorable and requires involvement of a hydride ligand.
通过实验观察到了氢介导的Ru-C键到Ru-B键的转化，并得到了理论计算的支持。在H₂存在下，用PR₃处理带有Ru-C（笼）σ键的[η(5):σ(C)-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(COD)（1），得到了Ru-B（笼）键合的配合物[η(5):σ(B)-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]RuH₂(PR₃)（R = Cy（2），Ph（3））（σ(C)：Ru-C（笼）σ键；σ(B)：Ru-B（笼）σ键）。在L₂（L₂ = dppe（4），PPh₃/P(OEt)₃（5），PPh₃/吡啶（6））存在下，配合物3通过加热释放H₂转化为[η(5):σ(B)-Me₂C(C₅H₄)(C₂B₁₀H₁₀)]Ru(L₂)。通过各种光谱技术、元素分析和单晶X射线衍射研究对这些配合物进行了全面表征。密度泛函理论计算表明，这种转化过程在动力学和热力学上都是有利的，并且需要氢化物配体的参与。
