Unusual 4-membered ring strained metalla-cycloallenes of the early transition metals Titanium, Zirconium and Hafnium

这个项目的结果应该是早期过渡金属钛、锆和氢的不寻常的金属循环，以不寻常的四元金属环烯为例，找出这种环-张力体系存在的局限性。作为这种不寻常的五元金属环，在金属钛、锆和氢中存在金属环茂烯(1-金属环戊烷-2，3，4-三烯)、金属环戊烯(1-金属环戊烷-3-YNES)和金属环烯丙烯(1-金属环戊二烯-2，3-二烯)。而金属环烯烃(1-金属环-丁二烯-2，3-二烯)等较小的4-环在这些金属中是未知的。这类化合物的合成很有趣，因为-就像五元金属环一样-这类有机金属化合物的合成和理论方面有望有更好的知识，这对未来催化C-C偶联反应是相关的。人们可以理解过去几年中获得的化合物(由于其他DFG项目的支持)在成键情况方面更好，因为它们是从理论上研究的。意外的稳定性和化学惰性是基础计划的一部分，应该扩展到两个方向：-5元杂环丁烯和杂金属环炔-4元全C-金属环，如金属环烯(1-金属环-丁二烯)和相应的4元杂金属环。而在基础计划中，用R2C=C=C=X，X=C=C=X；X=O，S或R2C=C=C=XR，RX=C=C=XR等杂丁三烯对N，P，O，S等杂原子的扩展进行了很好的研究；X=N，P，本项目的新研究集中在其他1-金属-二杂环-2，3-二烯的合成、1-金属-单杂环-2，3-二烯的合成和(利用基础项目的理论结果)和新的合成方法上。

The result of this project should be unusual metallacycles of the early transition metals Titanium, Zirconium and Hafnium to find the limitations for the existence of such ring-strained systems for the example of unusual 4-membered metalla-cycloallenes. As such unusual 5-membered metallacycles exist metallacyclocumulenes (1-metallacyclopenta-2,3,4-trienes), metallacyclopentynes (1-metallacyclopenta-3-ynes) and metallacycloallenes (1-metallacyclopenta-2,3-dienes) odf the metals Ti, Zr and Hf,. whereas the smaller 4-rings like metallacycloallenes (1-metallacyclo-buta-2,3-dienes) are unknown for these metals. The synthesis of such compounds is interesting, because - like for the 5-membered metallacyclen - a general better knowledge of synthetical and theretical aspects for such organometallic compounds is expected which is relevant for catalytic C-C coupling reactions in the future. One can understand the compounds which were obtained during the last years are (as a result of other supported DFG-projects) better regarding the bonding situation because they were studied theoretically. The unexpected stability together with the chemical inertness was a part of the basic project and should be extended into two directions: - 5-membered hetero-metallacyclocumulenes and hetero-metallacycloalkynes - 4-membered all-C-metallacycles like metallacycloallenes (1-metallacyclo-buta-2,3-dienes) and corresponding 4-membered hetero-metallacycles Whereas in the basic project an extension to the hetero atoms such as N, P, O, S for such unusual ring systems was very well investigated by using hetero-butatrienes like R2C=C=C=X, X=C=C=X; X = O, S or R2C=C=C=XR, RX=C=C=XR; X = N, P, the new investigations of this project are concentrated to the synthesis of other 1-metalla-dihetero-cyclo-buta-2,3-dienes, of 1-metalla-monohetero-cyclo-buta-2,3-dienes and (by using the theoretical results of the basic project) and new synthetical methoids again to 1-metalla-all-C-cyclo-buta-2,3-dienes.