Synthesis and Properties of Transition Metal Complexes Having New Chelate Ligands with Silicon as a Coordinating Atom

本研究的目的是稳定硅基配体，并利用其强大的σ供体能力来激活过渡金属络合物。我们成功地合成了一系列以硅为配位原子的具有螯合配体的过渡金属配合物。在这个研究过程中，我们发展了两种新的方法来制备通过杂原子和硅与金属配位的配合物：(1)在三元金属环上加成一个极化双键；(2)在六元双(硅烯)络合物上加醇，然后还原消除一个烷氧基硅烷。在这两种方法中，起始络合物本身具有前所未有的结构，因此我们对上述反应和相关反应进行了机理研究，并得到了有趣的结果。我们还合成了一些含有非常丰富的电子中心的(2-膦乙基)硅基稀土络合物，发现Rh[(κ^2-Si，Rh^2-Si，Rh^2-Si)P)-Me_2SiCH_2CH_2…较多的PPh_2](Pme_3)_2能诱导叔硅烷HSiMe_2Ph的脱氢偶联，高产率地生成二硅烷(SiMe_2Ph)_2。我们合成了具有双(硅基)螯合配体xantsil[(9，9-dimethylxanthene-4，5-diyl)bis(dimethylsilyl)]，的第8族金属配合物，即(Xantsil)M(CO)_4(M=Fe，Ru，Os)，并对其进行了X-射线晶体结构分析。其中，在甲苯中简单加热，Ru(Xantsil)(CO)(η^6-甲苯)可定量转化为甲苯络合物。发现该络合物中的甲苯配体在室温下很容易解离，形成高度配位的不饱和物种。由于这种独特的反应活性，这种甲苯络合物可以在温和的条件下导致各种其他配体的络合物，并作为HSiMe_2SiMe_3齐聚/解聚的优良催化剂。较少

The purpose of this research was to stabilize silyl ligands and make use of its strong σ-donating ability to activate transition metal complexes. We succeeded in synthesizing a number of transition metal complexes having chelate ligands with silicon as a coordinating atom. In the course of this research, we developed two new methods of preparing complexes having chelate ligands coordinated to the metal through a heteroatom and a silicon :(1) Addition of a polarized double bond to a three-membered metallacycle(2) Addition of an alcohol to a six-membered bis(silylene) complex followed by reductive elimination of an alkoxysilaneIn both methods, the starting complexes themselves had unprecedented structures, so that we carried out the mechanistic studies on the above reactions and the related reactions, and got interesting results.We also synthesized some (2-phosphinoethyl)silylrhodium complexes containing an extremely electron-rich metal center, and found that Rh[(κ^2-Si,P)-Me_2SiCH_2CH_2 … More PPh_2](Pme_3)_2 induces the dehydrocoupling of tert-silane HSiMe_2Ph to give disilane (SiMe_2Ph)_2 in high yield.We prepared the group 8 metal complexes having a bis(silyl) chelate ligand xantsil [(9,9-dimethylxanthene-4,5-diyl)bis(dimethylsilyl)], I.e., (xantsil)M(CO)_4 (M = Fe, Ru, Os), and revealed their X-ray crystal structures containing extremely long metal-silicon bonds. Among them, the ruthenium complex was converted quantitatively to the toluene complex Ru(xantsil)(CO)(η^6-toluene) on simple heating in toluene. The toluene ligand in this complex was found to dissociate readily at room temperature to give a highly coordinatively unsaturated species. Thanks to this unique reactivity, this toluene complex can be led to the complexes having various other ligands under mild conditions, and works as an excellent catalyst for the oligomerization/deoligomerization of HSiMe_2SiMe_3.In conclusion, we found that silyl ligands have a distinctive electronic effect that is stronger than we have expected, and have enough potential to grow as a promising supporting ligand. Less