Surface decorated magnetite nanoparticles with birhodanine and MoO2Cl2(dmf)2 as a new magnetic catalyst for epoxidation of olefins

In this work, the synthesis and characterization of a new magnetically supported Mo6+ complex have been reported as a catalyst for epoxidation of olefins. For this purpose, a new silylating compound containing a birhodanine moiety, i.e. [(E)-5-(3-(3-(trimethoxysilyl)propyl)-4-oxo-2-thioxothiazolidin-5-ylidene)-3-phenethyl-2-thioxothiazolidin-4-one] (TMOS-BIRD) has been synthesized and used for silylation of magnetite nanoparticles (MNPs). The magnetically supported catalyst was then prepared by deposition of dioxomolybdenum(VI) adduct, dichlorobis(dimethylformamide) dioxomolybdenum (MoO2Cl2(dmf)2), on MNP@BIRD. The prepared supported magnetic catalyst was characterized in detail by FT-IR, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and energy-dispersive X-ray (EDX) analyses. Cyclooctene was used as a model substrate to optimize the epoxidation reaction conditions, and the prepared magnetically retrievable catalyst was then used for epoxidation of cyclohexene, cyclooctene, styrene, indene, trans-trans-cis-1,5,9-cyclododecatrien, 1-octene, 1-heptene, α-pinene, 1-dodecene and trans-stilbene using tert-butyl hydroperoxide (TBHP) as oxidant under solvent-free conditions. The catalyst showed excellent conversion, good turn over frequency, and a short reaction time at 95 °C for epoxidation of cyclooctene.