Synthesis of COF-SO3H immobilized on manganese ferrite nanoparticles as an efficient nanocomposite in the preparation of spirooxindoles

Samira Moein Najafabadi; Javad Safaei Ghomi

doi:10.1038/s41598-023-49628-7

Synthesis of COF-SO₃H immobilized on manganese ferrite nanoparticles as an efficient nanocomposite in the preparation of spirooxindoles

Sci Rep. 2023 Dec 20;13(1):22731. doi: 10.1038/s41598-023-49628-7.

Authors

Samira Moein Najafabadi¹, Javad Safaei Ghomi²

Affiliations

¹ Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Islamic Republic of Iran.
² Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Islamic Republic of Iran. safaei@kashanu.ac.ir.

Abstract

The synthesis of sulfonamide-functionalized magnetic porous nanocomposites is highly significant in chemistry due to their exceptional properties and potential as catalysts. COFs are a new class of organic porous polymers and have significant advantages such as low density, high chemical and thermal stability, and mechanical strength. Therefore, we decided to synthesize COFs based on magnetic nanoparticles, by doing so, we can also prevent the agglomeration of MnFe₂O₄. MnFe₂O₄@COF-SO₃H possesses a large specific surface area, supermagnetism, and is acidic, making it an optimal catalyst for organic reactions. This particular catalyst was effectively employed in the green and rapid synthesis of various spiro-pyrano chromenes, while several analytical techniques were utilized to analyze its structural integrity and functional groups. The role of a specific site of MnFe₂O₄@COF-SO₃H was confirmed through different control experiments in a one-pot reaction mechanism. It was determined that MnFe₂O₄@COF-SO₃H acts as a bifunctional acid-base catalyst in the one-pot preparation of spirooxindole derivatives. The formation of a spiro skeleton in the multicomponent reaction involved the construction of three new σ bonds (one C-O bond and two C-C bonds) within a single process. The efficiency of the MnFe₂O₄@COF-SO₃H complex is investigated in the synthesis of spirooxindoles of malononitrile, and various isatins with 1,3-dicarbonyles. The nanocatalyst demonstrated excellent catalytic activity that gave the corresponding coupling products good to excellent yields. Furthermore, the heterogeneous magnetic nanocatalyst used in this study demonstrated recoverability after five cycles with minimal loss of activity.