Synthesis and Reactivity of Small Metallacyclic Alkynes

小环炔通常被认为是不稳定的，因为它们在三键周围有很高的应变。事实上，环庚烷化合物，七元环炔烃是迄今为止以纯形式分离出来的最小的例子。杂原子允许一个较小的环稳定和四硅环己烷分离和结构确定。我最近发现，在环上含有过渡金属的五元环炔很容易制备，而且非常稳定，并报道了它们的分子结构。在这个项目中，我对这些独特化合物的分子结构和反应性进行了研究，发现如下：1。发现了一种多用途合成非取代锆环戊烷的方法，并确定了其分子结构。它与被取代的配合物具有基本相似的结构，尽管它比被取代的配合物更稳定，这可能是因为它没有空间排斥。非取代的锆环戊烷化合物与其他低价锆环戊烷反应生成双金属配合物。结果表明，锆环戊烷反应为炔类化合物。在没有中性配体的情况下，得到对称的双核配合物。此外，还合成了钛、铪等金属环戊烷配合物，并对其结构进行了表征。以锆-炔化合物和丁三烯为原料，合成了七元炔配合物，并通过x射线衍射分析确定了其分子结构。这是一个少见的环系中含有过渡金属的七元炔的例子。由于三键与金属的相互作用，该化合物具有一个应变的七元环。

Small cyclic alkyne are, in general, believed to be unstable due to their high strain around the triple bond. Indeed, cycloheptyne compounds, seven-membered cyclic alkynes are the smallest examples ever isolated in a pure form. Heteroatoms allowed a smaller ring stable and tetrasilacylohexane was isolated and structurally determined. I recently found that five-membered cyclic alkyne that contain a transition metal in the ring are readily prepared and remarkably stable, and reported their molecular structures. In this project I pursued the molecular structure and reactivity of these unique compounds and found the followings.1.A versatile synthetic method of non-substituted zirconacyclopentyne was found, and its molecular structure was determined. It has fundamentally similar structure to the substituted one, although it was more stable than the substituted complexes probably because the absence of steric repulsion.2.The non-substituted zirconacyclopentyne compound reacted with other low-valent zirconocne to give bimetallic complexes. This result revealed that the zirconacyclopentyne reacted as an alkyne compound. In the absence of neutral ligands such as photphines, symmetric dinuclear complex was obtained.3.Metallacyclopentyne complexes of other group 4 metals, titanium and hafnium, were also synthesized and structurally characterized.4.A seven-membered alkyne complex was prepared by the reaction of a zirconium-alkyne compound and a butatriene and its molecular structure was determined by X-ray diffraction analysis. This is a rare example of seven-membered alkyne that contains a transition metal in the ring system. The compound has a strained seven-membered ring due to interaction of the triple bond to the metal.