Rosenthal Uwe
Leibniz-Institute for Catalysis at the University of Rostock, Albert-Einstein-Strasse 29A, 19059 Rostock, Germany.
Chem Soc Rev. 2020 Apr 7;49(7):2119-2139. doi: 10.1039/c9cs00637k.
In this account, examples of the influence of equilibrium and mesomerism/valence tautomerism on reactions of selected group 4 metallocene complexes will be discussed. Complexes of bis(trimethylsilyl)acetylene Me3SiC2SiMe3 (mono-functional alkynes: C[triple bond, length as m-dash]C) in Cp'2M(η2-Me3SiC2SiMe3) (Cp' = substituted η5-cyclopentadienyl), of α-di-Ph2P- (hetero-tri-functional: P, C[triple bond, length as m-dash]C, P) in Cp'2M(η2-Ph2C2PPh2), and of α-mono-SiH- (hetero-bi-functional: C[triple bond, length as m-dash]C, SiH) and α-di-SiH-substituted alkynes (hetero-tri-functional: SiH, C[triple bond, length as m-dash]C, SiH) in Cp'2M(η2-Me3SiC2SiMe2H) and Cp'2M(η2-HMe2SiC2SiMe2H), respectively, were considered. Additionally, unusual all-C-metallacycles like metallacyclopentynes Cp'2M[η2-C(R2)-C2-C(R2)-] (formed by coordination of tri-functional trienes: C[double bond, length as m-dash]C, C[double bond, length as m-dash]C, C[double bond, length as m-dash]C), five-membered metallacycloallenes Cp'2M[η2-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-C(R2)-] (formed by coordination of bi-functional enynes: C[double bond, length as m-dash]C, C[triple bond, length as m-dash]C), metallacyclocumulenes Cp'2M[η2-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-] (formed by coordination of bi-functional diynes: C[triple bond, length as m-dash]C, C[triple bond, length as m-dash]C), and seven-membered metallacyclocumulenes Cp'2M[η2-C(R)[double bond, length as m-dash]C(C2R)-C(R)[double bond, length as m-dash]C[double bond, length as m-dash]C[double bond, length as m-dash]C(R)-] (formed by coordination of two bi-functional diynes: C[triple bond, length as m-dash]C, C[triple bond, length as m-dash]C), with M = Ti, Zr, and Hf were selected as examples for considerations of equilibrium and mesomerism/valence tautomerism. On the basis of spectroscopic investigations, their molecular structures and selected calculations, it is discussed how the different interpretations of the equilibrium and mesomerism/valence tautomerism are in line with observed reactivity patterns.
在本报告中，将讨论平衡以及中介效应/价互变异构对选定的第4族金属茂配合物反应的影响实例。考虑了双（三甲基硅基）乙炔Me3SiC2SiMe3（单官能炔烃：C≡C）在Cp'2M(η2-Me3SiC2SiMe3)（Cp' = 取代的η5-环戊二烯基）中的配合物、α-二-Ph2P-（杂三官能：P、C≡C、P）在Cp'2M(η2-Ph2C2PPh2)中的配合物，以及α-单-SiH-（杂双官能：C≡C、SiH）和α-二-SiH-取代的炔烃（杂三官能：SiH、C≡C、SiH）分别在Cp'2M(η2-Me3SiC2SiMe2H)和Cp'2M(η2-HMe2SiC2SiMe2H)中的配合物。此外，还选择了一些不寻常的全碳金属环，如金属环戊炔Cp'2M[η2-C(R2)-C2-C(R2)-]（由三官能三烯：C═C、C═C、C═C配位形成）、五元金属环丙二烯Cp'2M[η2-C(R)═C═C(R)-C(R2)-]（由双官能烯炔：C═C、C≡C配位形成）、金属环累积多烯Cp'2M[η2-C(R)═C═C═C(R)-]（由双官能二炔：C≡C、C≡C配位形成）以及七元金属环累积多烯Cp'2M[η2-C(R)═C(C2R)-C(R)═C═C═C(R)-]（由两个双官能二炔：C≡C、C≡C配位形成），其中M = Ti、Zr和Hf作为平衡以及中介效应/价互变异构研究的实例。基于光谱研究、它们的分子结构以及选定的计算，讨论了平衡以及中介效应/价互变异构的不同解释如何与观察到的反应模式一致。
