Synthesis of Heteroatom-Bridged Multinuclear Complexes and Application to Catalytic Transformations

杂原子配体桥接的多金属配合物由于其潜在的适用性，近年来受到了广泛的关注。最近，我们发现巯基和硒基二钌络合物[Cp^*RuCl(μ-YR)]_2对丙炔醇与多种亲核试剂的丙炔取代反应具有独特的催化活性。与此形成鲜明对比的是，碲酸盐桥接的二钌配合物在这些反应中并没有作为有效的催化剂，这表明桥接配体的性质在这些二钌配合物的催化中起着重要的作用。这些结果促使我们设计和制备其他杂原子桥接的二钌配合物。最近，我们成功地制备了单磷桥接的二钌配合物[Cp^*RuCl(μ-PMe_2)(μ-Cl)RuClCp^*](1)，并发现1的催化活性与[Cp^*RuCl(μ-YR)]_2不同。此外，由于1有一个桥接氯配体，可以很容易地被各种杂原子配体取代，因此有望作为由不同杂原子桥接的二钌配合物的有用前体。事实上，我们还成功地制备了多种杂化磷-硫代偶联配合物[Cp^*RuCl(μ-PMe_2)(μ-SR)RuClCp^*]。

Considerable attention has recently been paid to multimetallic complexes bridged by heteroatom ligands because of their potential applicability to various organic transformations. Recently, we disclosed a unique catalytic activity of thiolato- and selenolato-bridged diruthenium complexes [Cp^*RuCl(μ-YR)]_2 toward propargylic substitution reactions of propargylic alcohols with a variety of nucleophiles. In sharp contrast, tellurolato-bridged diruthenium complexes did not work as effective catalysts for these reactions, suggesting that the nature of bridging ligands plays an important role on the catalysis of these diruthenium complexes. These results prompted us to design and prepare other heteroatom-bridged diruthenium complexes. More recently, we succeeded in the preparation of the monophosphido-bridged diruthenium complex [Cp^*RuCl(μ-PMe_2)(μ-Cl)RuClCp^*] (1) and found a different catalytic activity of 1 from that of [Cp^*RuCl(μ-YR)]_2. In addition, 1 is expected to work as a useful precursor for diruthenium complexes bridged by different heteroatoms because 1 have a bridging chloride ligand which may easily be substituted with a variety of heteroatom ligands. In fact, we also succeeded in the preparation of a variety of hybrid phosphido- and thiolato-bridged complexes [Cp^*RuCl(μ-PMe_2)(μ-SR)RuClCp^*].