Design of a new unsymmetrical bis (imino) pyridine Schiff-base co-complex with an ionic liquid group as a recyclable green catalyst to prepare chromenes derivatives from benzylic alcohol

The preparation and characterization of a new unsymmetrical ligand on Fe₃O₄@SiO₂ with its cobalt complex including an ionic liquid (ILs) group by ¹H-NMR, ¹³C-NMR, FTIR, SEM, EDX, TGA, XRD, and VSM. The catalyst was used in the reaction to prepare chromene compounds from alcohol. Catalyst amount, temperature, solvent, and solvent amount were investigated as factors affecting the reaction. For the synthesis of chromene derivatives at optimum conditions, the alcohol derivatives were first oxidized by the catalyst, followed by malononitrile and diketone additions to the reaction vessel. Recovery and reusability of the catalyst were investigated, which showed excellent results. The presence of ionic liquid groups increased the solubility of the heterogeneous catalyst in green solvents, which increased the efficiency and reduced the reaction time.

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