Navarro M Ángeles, Amaro-Gahete Juan, Ruiz José R, Jiménez-Sanchidrián César, Romero-Salguero Francisco J, Esquivel Dolores
Departamento de Química Orgánica, Instituto Universitario de Nanoquímica (IUNAN), Facultad de Ciencias, Universidad de Córdoba, 14071 Córdoba, Spain.
Dalton Trans. 2022 Mar 22;51(12):4884-4897. doi: 10.1039/d2dt00018k.
A new heterogeneous catalyst has been synthesized by immobilization of a copper complex on dipyridyl-pyridazine functionalized periodic mesoporous organosilica (dppz-vPMO). This ordered support was first prepared by a co-condensation reaction between vinyltriethoxysilane and 1,2-bis(trimethoxysilyl)ethane and further post-functionalized through a hetero Diels-Alder reaction with 3,6-di-2-pyridyl-1,2,4,5-tetrazine. Techniques such as XRD, N isotherms, TEM, C NMR, XPS and DRIFT, among others, were employed to characterize the surface functionalized materials. These results have proven the ordered mesostructure of the materials as well as the presence of novel nitrogen-chelating heterocyclic compounds on the pore surface after the post-modification process. Additionally, the successful anchoring of a copper complex on the dipyridyl-pyridazine (dppz) ligands has been confirmed. The resulting material was evaluated as a heterogeneous catalyst in the epoxidation of styrene using -butylhydroperoxide (TBHP) as an oxidant. Under the optimized reaction conditions, Cu@dppz-vPMO showed a high styrene conversion (86.0%) and a remarkable selectivity to styrene oxide (41.9%). Indeed, this catalyst provided excellent catalytic results in terms of stability, reaction rate, conversion and selectivity compared to other bipyridine-like copper catalysts.
通过将铜配合物固定在二吡啶基哒嗪功能化的周期性介孔有机硅（dppz-vPMO）上，合成了一种新型多相催化剂。这种有序载体首先通过乙烯基三乙氧基硅烷和1,2-双（三甲氧基硅基）乙烷之间的共缩合反应制备，然后通过与3,6-二-2-吡啶基-1,2,4,5-四嗪的杂环狄尔斯-阿尔德反应进行进一步的后功能化。采用XRD、N等温线、TEM、C NMR、XPS和DRIFT等技术对表面功能化材料进行了表征。这些结果证明了材料的有序介观结构以及后修饰过程后孔表面存在新型氮螯合杂环化合物。此外，还证实了铜配合物成功地锚定在二吡啶基哒嗪（dppz）配体上。以叔丁基过氧化氢（TBHP）为氧化剂，将所得材料作为多相催化剂用于苯乙烯环氧化反应的评价。在优化的反应条件下，Cu@dppz-vPMO表现出较高的苯乙烯转化率（86.0%）和对环氧苯乙烯的显著选择性（41.9%）。实际上，与其他联吡啶类铜催化剂相比，该催化剂在稳定性、反应速率、转化率和选择性方面提供了优异的催化结果。
