Creating Well-Defined monolayers of phosphine linkers incorporating ethoxysilyl groups on silica surfaces for superior immobilized catalysts
Creating Well-Defined monolayers of phosphine linkers incorporating ethoxysilyl groups on silica surfaces for superior immobilized catalysts
复制标题
在二氧化硅表面上创建结合乙氧基甲硅烷基的明确定义的膦连接体单层，以获得优异的固定化催化剂
DOI：
10.1016/j.apsusc.2023.156380
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发表时间：
2023
影响因子：
6.7
通讯作者：
Blümel, Janet
中科院分区：
文献类型：
--
作者：
Shakeri, Ehsan;Blümel, Janet
通过双官能膦连接体固定在固体载体如二氧化硅上的催化剂的许多应用仍然受到其分解、浸出、团聚和不受控制的纳米颗粒形成的阻碍，所有这些都会改变其活性和选择性。通常，固定化催化剂的成功关键取决于连接体及其与氧化物载体的连接。在这篇文章中，描述了一种通过乙氧基硅烷基团将膦连接基与二氧化硅共价结合的改进方法。该方法导致在二氧化硅表面上的连接体的良好限定的亚单层，而没有连接体的交联，这通常导致在催化期间堵塞的孔和金属附聚，因此需要较低活性和选择性的催化剂。新的固定化方法已支持多核经典CP/MAS固态NMR光谱，以及悬浮液NMR的浆料。它已被证明通过TEM，镍配合物协调的固定膦接头在一个明确的亚单层覆盖不形成较大的聚集体或纳米粒子在催化环三聚的苯乙炔在各种条件下，在均匀的催化运行中的类似的配合物。
Many applications of catalysts immobilized on solid supports like silica via bifunctional phosphine linkers are still hampered by their decomposition, leaching, agglomeration, and uncontrolled nanoparticle formation, all of which change their activities and selectivities. In general, the success of an immobilized catalyst is crucially dependent on the linker and its attachment to the oxide support. In this contribution, an improved method for covalently binding phosphine linkers to silica via ethoxysilane groups is described. This method leads to well-defined sub-monolayers of linkers on silica surfaces without cross-linking of the linkers, which typically leads to clogged pores and metal agglomeration during catalysis, thus entailing less active and selective catalysts. The novel immobilization method has been supported by multinuclear classical CP/MAS solid-state NMR spectroscopy, as well as suspension NMR of slurries. It has been demonstrated by TEM that nickel complexes coordinated by immobilized phosphine linkers in a well-defined sub-monolayer coverage do not form larger aggregates or nanoparticles during the catalytic cyclotrimerization of phenylacetylene under various conditions, in contrast to analogous complexes in homogeneous catalytic runs.