Solid-state NMR characterization of Wilkinson's catalyst immobilized in mesoporous SBA-3 silica.
Solid-state NMR characterization of Wilkinson's catalyst immobilized in mesoporous SBA-3 silica.
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固定在介孔 SBA-3 二氧化硅中的 Wilkinson 催化剂的固态 NMR 表征。
DOI：
10.1002/chem.200903322
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
G. Buntkowsky
中科院分区：
文献类型：
--
作者：
Anna Grünberg;Xu Yeping;H. Breitzke;G. Buntkowsky
将威尔金森催化剂[RhCl(PPh(3))(3)]固定在胺功能化介孔二氧化硅材料SBA-3的孔内，并通过结合不同的固态NMR方法测定了改性二氧化硅表面和固定铑配合物的结构。 (29)Si CP-MAS NMR 实验证实了二氧化硅表面的成功修饰。 T(n) 峰的存在证实了载体的成功官能化，并显示了有机基团与中孔表面结合的方式。进行 (31)P-(31)P J 分辨 2D MAS NMR 实验，以表征固定化催化剂与附着在二氧化硅表面的连接体的胺基团的结合。纯催化剂表现出相当大的 (31)P-(31)P J 耦合，在 2D MAS NMR 实验中可很好地解析。该J-偶联用于确定催化剂与二氧化硅表面上的连接体的结合模式以及被胺基配位键取代的三苯基膦配体的数量。由于在离魔角旋转实验以及慢速旋转 MAS 实验中不存在任何可解析的 (31)P-(31)P J 偶联，因此得出结论，两个三苯基膦配体被取代，并且催化剂通过两个连接分子键合到二氧化硅表面。
The Wilkinson's catalyst [RhCl(PPh(3))(3)] has been immobilized inside the pores of amine functionalized mesoporous silica material SBA-3 and The structure of the modified silica surface and the immobilized rhodium complex was determined by a combination of different solid-state NMR methods. The successful modification of the silica surface was confirmed by (29)Si CP-MAS NMR experiments. The presence of the T(n) peaks confirms the successful functionalization of the support and shows the way of binding the organic groups to the surface of the mesopores. (31)P-(31)P J-resolved 2D MAS NMR experiments were conducted in order to characterize the binding of the immobilized catalyst to the amine groups of the linkers attached to the silica surface. The pure catalyst exhibits a considerable (31)P-(31)P J-coupling, well resolvable in 2D MAS NMR experiments. This J-coupling was utilized to determine the binding mode of the catalyst to the linkers on the silica surface and the number of triphenylphosphine ligands that are replaced by coordination bonds to the amine groups. From the absence of any resolvable (31)P-(31)P J-coupling in off-magic-angle-spinning experiments, as well as slow-spinning MAS experiments, it is concluded, that two triphenylphosphine ligands are replaced and that the catalyst is bonded to the silica surface through two linker molecules.