SynthesisThe chiral vanadyl salen complex was immobilized onto mesoporous silica (silicagel from ALFA-AESER, 300 m2 g-1) by multi-grafting method according to theprocedure shown in Scheme 1. In addition, the homogenous VO(salen) complex ofthe similar structure to the immobilized one was synthesized following the methoddescribed by Zamian et al. [25] and used as a reference to prove the compleximmobilization and to compare the catalytic activity. The synthetic procedure forthe homogenous complex is also shown in Scheme 2.Immobilization of chiral vanadyl salen complex on mesoporous silicaA suspension of (3-aminopropyl) triethoxysilane (443 mg, 2 mmol) and 2 g ofsilica gel in 15 mL of toluene was heated under reflux with stirring under nitrogenatmosphere. After heating for 24 h, the powder (sample 3) was filtered, washed withdiethylether and dried under vacuum at 40 C. The density of aminopropyl groupsScheme
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