Easily Immobilized Di- and Tetraphosphine Linkers: Rigid Scaffolds that Prevent Interactions of Metal Complexes with Oxide Supports
作者:Yuan Yang、Björn Beele、Janet Blümel
DOI:10.1021/ja800541c
日期:2008.3.1
Di- and tetraphosphines with rigid phenyl-, bilphenyl-, and tetraphenylstannane, -silane, and -methane scaffolds, and various substituents F, have been synthesized and immobilized via triethoxysilane-propagated formation of one or two surface-bound phosphonium moieties. The remaining phosphine groups can be coordinated to metal complexes. All the detective work and proof is done by solid-state NMR spectroscopy.
New linker systems for superior immobilized catalysts
The rigid linkers E(p-C6H4PPh2)4 (E = Si, Sn) have been synthesized from the corresponding precursors E(p-C6H4Br)4 and immobilized by forming one (E = Si) or three (E = Sn) phosphonium groups that are attached to the silica support by electrostatic interactions. The remaining unquaternized phosphines are coordinated to Wilkinson-type Rh complexes. The catalyst immobilized by the rigid scaffold with three surface-bound phosphonium groups (E = Sn) displays superior catalytic activity and lifetime with respect to the hydrogenation of dodecene. This catalyst can be recycled 30 times in a batchwise manner under standardized conditions.
刚性连接体 E(p-C6H4PPh2)4 (E = Si, Sn) 是通过相应前体 E(p-C6H4Br)4 合成的,并通过形成一个 (E = Si) 或三个 (E = Sn) 磷铵基团与硅酸盐支撑物发生静电相互作用。剩余的未季铵化磷配体与 Wilkinos 型 Rh 络合物配位。由刚性框架固定化的触媒(具有三个表面结合的磷铵基团,E = Sn)在十二烯的氢化反应中表现出优越的催化活性和寿命。该催化剂在标准化条件下可以循环使用 30 次。