Synthesis, characterization and immobilization of cobalt (III) salen complex on CoFe2O4@SiO2 nanoparticle and their application in the synthesis of di-indolyloxindole

The preparation, characterization, and immobilization of cobalt (III) salen complex on CoFe2O4@SiO2 nanoparticle (CoFe2O4@SiO2@ Co(III) salen complex) are described. Co(III) salen complex loaded on ferrite cobalt-silica nanoparticle is characterized by TEM, SEM-EDX, VSM and FT-IR analyses. The efficiency of CoFe2O4@SiO2@Co(III) salen complex as a catalyst was carried out in the 3-indolylation reaction of indole with isatin derivatives in the water at 80 ℃. Di-indolyloxindole was achieved with excellent yield (95%), using indole, isatin, and CoFe2O4@SiO2@Co(III) salen complex within 2 h in water as solvent at 80 ℃. Moreover, the recoverability and reusability of CoFe2O4@SiO2@Co(III) salen complex were investigated.