Nowadays, the application of solid base catalysts as a perfect replacement for homogenous basic catalysts has attracted the attention of researchers. In this study, core–shell magnetic mesoporous N-doped silica nanoparticles N(x wt%)-MSN, as a heterogeneous base catalyst, were synthesized. The N(x wt%)-MSN composite was fabricated by adding different amounts of diethanolamine as a source of nitrogen, besides using tetraethylorthosilicate as a precursor of silica. The as-prepared catalyst was employed efficiently for the synthesis of some arylpyrimido[4,5-b]quinoline-dione derivatives under green conditions. The highly efficient catalyst N(1.3 wt%)-MSN was characterized via XRD, FESEM, HRTEM, BET and XPS techniques, and the results of these analyses proved that the nitrogen was doped into the silica structure. Also, the results demonstrated the core–shell structure of the as-synthesized composite.

中文翻译：

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核壳磁性介孔N掺杂二氧化硅纳米粒子：在绿色条件下制备芳基嘧啶并[4,5-b]喹啉二酮的固体碱催化剂

如今，固体碱催化剂作为均相碱催化剂的完美替代品的应用引起了研究人员的关注。在这项研究中，合成了核壳磁性介孔 N 掺杂二氧化硅纳米粒子 N( x wt%)-MSN 作为非均相碱催化剂。除了使用原硅酸四乙酯作为二氧化硅的前体外，还通过添加不同量的二乙醇胺作为氮源来制造N( x wt%)-MSN 复合材料。所制备的催化剂在绿色条件下有效地用于合成一些芳基嘧啶并[4,5 - b ]喹啉二酮衍生物。高效催化剂 N(1.3 wt%)-MSN通过以下方式表征XRD、FESEM、HRTEM、BET和XPS技术，以及这些分析的结果证明氮掺杂到二氧化硅结构中。此外，结果证明了合成后的复合材料的核壳结构。