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

该项目的结果应该是早期过渡金属钛、锆和铪的不寻常金属环，以发现这种环应变系统存在的局限性，例如不寻常的4元金属环联烯。因此，不寻常的5元金属杂环存在金属杂环戊烯（1-金属杂环戊-2，3，4-三烯）、金属杂环戊炔（1-金属杂环戊-3-炔）和金属杂环联烯（1-金属杂环戊-2，3-二烯），它们都是金属Ti、Zr和Hf的。而较小的4-环如金属环丙二烯（1-金属环丁-2，3-二烯）对于这些金属是未知的。这种化合物的合成是令人感兴趣的，因为-像对于5-元金属环烯-期望对这种有机金属化合物的合成和理论方面有更好的了解，这与将来的催化C-C偶联反应有关。人们可以理解，在过去几年中获得的化合物（由于其他DFG项目的支持）在键合情况方面更好，因为它们是在理论上研究的。非预期的稳定性和化学惰性是基本项目的一部分，应扩展到两个方向：-5-元杂-金属环枯烯和杂-金属环炔（1-金属环-丁-2，3-二烯）和相应的4-元杂金属环。通过使用杂丁二烯如R2 C =C=C=X，X=C=C = X; X = O，S或R2 C =C=C=XR，RX=C=C=XR，很好地研究了这种不寻常的环系统的S; X = N，P，本项目的新研究集中于其它1-金属-二杂环-丁-2，3-二烯的合成，1-金属-单杂环-丁-2，3-二烯的合成，3-二烯和（利用基础项目的理论结果）再合成1-金属-全-C-环丁-2，3-二烯的新方法。

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.