Ferrocene-based covalent organic framework-carbon nanotube hybrid modified with Cu(OAc)2 as a robust catalyst for the preparation of tetrazoles

The emergence of covalent organic framework-carbon nanotube hybrid composites (COF-CNT) has opened up a promising approach for the development of heterogeneous catalysis. In this research, a new ferrocene-based COF was wrapped onto the surface of a carbon nanotube and modified with Cu(OAc)₂ (denoted as FCOF-CNT-Cu(OAc)₂) for boosting the catalytic performance for the preparation of tetrazoles. Ferrocene segments played a decisive role in assisting Cu(OAc)₂ as catalytically active sites for the preparation of 5-substituted 1H-tetrazoles and acrylonitrile-linked tetrazoles. FCOF-CNT-Cu(OAc)₂ had a high specific surface area of 117 m² g⁻¹, which accelerated the catalytic process. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analyses revealed that the catalyst was ordered with a tubular morphology and spherical COF grown on the outer surface of the CNT. This work presents FCOF-CNT-Cu(OAc)₂ as a superior catalyst toward the preparation of 5-substituted 1H-tetrazoles and acrylonitrile-linked tetrazole derivatives. Consequently, tetrazole derivatives were synthesized in short reaction times under green and mild reaction conditions.