A new ONO-tridentate Schiff base ligand (H₂L) derived from 3-methoxysalicylaldehyde and nicotinic hydrazide was synthesized and characterized by elemental analysis, FT-IR, ¹H NMR, ¹³C NMR, UV–Vis, and powder XRD studies. Then, oxovanadium(V) and dioxomolybdenum(VI) Schiff base complexes, VOL and MoO₂L, were also prepared and characterized by different techniques. Moreover, the catalytic activities of both complexes were investigated for the synthesis of benzimidazoles, benzoxazoles, and benzothiazoles under reflux conditions as well as through ultrasonic irradiation. The results revealed several advantages of this procedure, including high product yields, short reaction times, facile work-up procedure, simplicity in operation, eco-friendly reaction conditions, and green aspects by avoiding toxic catalysts and solvents.

Graphic abstract

中文翻译：

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用于在热和超声条件下制备苯并咪唑、苯并恶唑和苯并噻唑的新型钒和钼席夫碱配合物的合成、表征和催化潜力

合成了一种源自 3-甲氧基水杨醛和烟碱酰肼的新型 ONO-三齿席夫碱配体 (H ₂ L)，并通过元素分析、FT-IR、¹ H NMR、¹³ C NMR、UV-Vis 和粉末 XRD 研究进行表征。然后，氧钒（V）和二氧钼（VI）席夫碱络合物，VOL和MoO ₂L, 也用不同的技术制备和表征。此外，研究了这两种配合物在回流条件下以及通过超声辐照合成苯并咪唑、苯并恶唑和苯并噻唑的催化活性。结果揭示了该方法的几个优点，包括产品收率高、反应时间短、后处理简单、操作简单、反应条件环保，以及避免使用有毒催化剂和溶剂的绿色方面。

图形摘要