Reactivity differences between molecular and surface silanols in the preparation of homogeneous and heterogeneous olefin metathesis catalysts
作者:Frédéric Blanc、Mathieu Chabanas、Christophe Copéret、Bernard Fenet、Eberhardt Herdweck
DOI:10.1016/j.jorganchem.2005.04.028
日期:2005.11
The reaction of Mo(N)(CH2tBu)3 (1) and SiO2-(700) generates (SiO)Mo(NH)(CHtBu)(CH2tBu) (2) when performed in C6H6 (material [1/SiO2-(700)]C6H6[1/SiO2-(700)]C6H6). The grafting occurs presumably by protonation of the nitrido ligand to form an intermediate (SiO)Mo(NH)(CH2tBu)3 (3), a pentacoordinated complex, which decomposes into 2 and 2,2-dimethylpropane. While [1/SiO2-(700)]C6H6[1/SiO2-(700)]C6H6
Mo(N)(CH 2 t Bu)3(1)与SiO 2-(700)的反应在C中进行时会生成(SiO)Mo(NH)(CH t Bu)(CH 2 t Bu)(2)6 H 6(材料[ 1 / SiO 2-(700) ] C 6 H 6 [1 / SiO2-(700)] C6H6 )。接枝反应大概是通过硝化配体的质子化作用而形成的中间体(SiO)Mo(NH)(CH 2 t Bu)3(3),一种五配位复合物,其分解为2和2,2-二甲基丙烷。[ 1 / SiO 2-(700) ] C 6 H 6 [1 / SiO2-(700)] C6H6在烯烃复分解中具有很高的活性,而[ 1 / SiO 2-(700) ] CH 2 Cl 2 [1 / SiO2 -(700)] CH 2 Cl 2和[ 1 / SiO 2-(700) ] THF分别是活性较差或惰性的催化剂。相反,当Mo(N)(CH 2 t Bu)3与分子硅烷醇衍生物(