Mono- and di-cyclopentadienyl zirconium derivatives containing the dimethylsilylcyclopentadienyl ligand. Agostic linear Si–H–Zr interaction in the molecular structure of [Zr{η5-C5H4(SiMe2H)}Cl3]2 †
作者:Gemma Ciruelo、Tomás Cuenca、Rafael Gómez、Pilar Gómez-Sal‡、Avelino Martín ‡
DOI:10.1039/b010221k
日期:——
Dimethylsilyl substituted mono- and di-cyclopentadienyl zirconium chlorides have been prepared and their reactions with amido and alkyl reagents studied. The silylcyclopentadienes C5H5(SiMe2H) 1, C5H4(SiMe2H)22 and C5H4(SiMe3)(SiMe2H) 3 can be prepared by reaction of Na(C5H5) with the appropriate chlorosilane reagent. The lithium salt Li[C5H4(SiMe2H)] reacts with ZrCl4 or [Zr(C5H5)Cl3] to give the metallocene complexes [Zr(C5H4R)C5H4(SiMe2H)}Cl2] (R = SiMe2H 4 or H 5) whereas the reaction of the disilylcyclopentadiene C5H4(SiMe2H)2 with ZrCl4 afforded the monocyclopentadienyl complex [ZrC5H4(SiMe2H)}Cl3] 6, which exchanges the SiâH and ZrâCl bonds. The reaction of 6 with lithium amides produces different products depending on the basicity of the nitrogen atom and the steric demands of its amido substituents. The reaction with LiN(SiMe3)2 and LiNH(2,6-Me2C6H3) afforded the corresponding amido zirconium complexes [ZrC5H4(SiMe2H)}(NRRâ²)Cl2] (R = Râ²Â = SiMe37; R = H, Râ²Â = 2,6-Me2C6H38), but in the case of the reaction with LiNHtBu the known cyclopentadienylsilylamido derivative [Zr(η5,η1-C5H4SiMe2NtBu)Cl2] was formed. The monoamido, diamido and dialkyl dicyclopentadienyl complexes [Zr(C5H4R)C5H4(SiMe2H)}X(Y)] (R = SiMe2H 9 or H 10, X = Cl, Y = NHtBu; R = SiMe2H 11 or H 12, X = Y = NHtBu; R = SiMe2H 13 or H 14, X = Y = Me) have been synthesized by reaction of 4 and 5 with the appropriate amido or methyl reagent. Compound 9 reacts with a stoichiometric amount of water with selective hydrolysis of the Zrâamido bond to give the corresponding μ-oxo dinuclear complex [Zr[C5H4(SiMe2H)]2Cl}2(μ-O)] 15. The molecular structure of [ZrC5H4(SiMe2H)}Cl3] 6 was established by X-ray crystallography. Compound 6 is a dimer, in the solid state, in which dimerization occurs through ZrâHâSi agostic interactions and two chloride bridges.
已经制备了二甲基硅烷取代的单环戊二烯基和二环戊二烯基锆氯化物,并研究了它们与氨基和烷基试剂的反应。通过Na(C5H5)与适当的氯硅烷试剂反应,可以制备硅基环戊二烯C5H5(SiMe2H) 1、C5H4(SiMe2H)22和C5H4(SiMe3)(SiMe2H) 3。锂盐Li[C5H4(SiMe2H)]与ZrCl4或[Zr(C5H5)Cl3]反应,得到金属茂配合物[Zr(C5H4R)C5H4(SiMe2H)}Cl2](R = SiMe2H 4或H 5),而二硅基环戊二烯C5H4(SiMe2H)2与ZrCl4反应得到单环戊二烯基配合物[ZrC5H4(SiMe2H)}Cl3] 6,该配合物交换了Si–H和Zr–Cl键。6与锂胺反应,根据氮原子的碱性和其氨基取代基的立体要求,产生不同的产物。与LiN(SiMe3)2和LiNH(2,6-Me2C6H3)反应得到相应的氨基锆配合物[ZrC5H4(SiMe2H)}(NRR')Cl2](R = R' = SiMe37;R = H,R' = 2,6-Me2C6H38),但在与LiNHtBu反应的情况下,形成了已知的环戊二烯基硅基氨基衍生物[Zr(η5,η1-C5H4SiMe2NtBu)Cl2]。通过4和5与适当的氨基或甲基试剂反应,合成了单氨基、二氨基和二烷基二环戊二烯基配合物[Zr(C5H4R)C5H4(SiMe2H)}X(Y)](R = SiMe2H 9或H 10,X = Cl,Y = NHtBu;R = SiMe2H 11或H 12,X = Y = NHtBu;R = SiMe2H 13或H 14,X = Y = Me)。化合物9与化学计量水反应,选择性水解Zr–氨基键,得到相应的μ-氧二核配合物[Zr[C5H4(SiMe2H)]2Cl}2(μ-O)] 15。通过X射线晶体学确定了[ZrC5H4(SiMe2H)}Cl3] 6的分子结构。化合物6在固态下是二聚体,二聚化通过Zr–H–Si暂稳相互作用和两个氯桥实现。