A La-Schiff base complex on MCM-۴۱ as a recyclable nanocatalyst in thehomoselective synthesis of tetrazoles

Recyclable and high efficient catalysts are one of the principles of green chemistry [۱].Therefore difficult recovering of the homogeneous catalysts and low catalytic activity of theheterogeneous catalysts are main challenges chemists [۲]. To overcome on these problems, thenanostructure catalysts emerged as ideal catalysts because nanocatalysts have a heterogeneousnature with high surface area [۳]. Therefore, nanocatalysts exist as a border between heterogeneousand homogeneous catalysts because they have advantages from both, such as efficiency, selectivityand reusability [۳,۴]. Therefore, various nanoparticle have been employed in catalysis applications.Amongst them, mesoporous nanomaterials especially MCM-۴۱ were widely used as a support forimmobilization of various catalysts [۵]. Because MCM-۴۱ has unique properties e.g. excellentstability, high surface area, easy surface modification, homogeneous hexagonal channel structure,large pore volumes, and easy separation from the reaction mixture [۶]. Therefore, we investigateda new lanthanum-Schiff-base complex on MCM-۴۱ (La@Schiff base@MCM-۴۱) as an efficient,stable and reusable nanocatalyst in the homoselective synthesis of ۵-substituted ۱H-tetrazoles.La@Schiff base@MCM-۴۱ was characterized by ICP, CHN, XRD, TGA, BET, FT-IR, SEM, EDSand WDX techniques. This catalyst has good stability and heterogeneity nature which can easilyrecovered and reused for several times without significant loss in catalytic activity. The recoveredLa@Schiff base@MCM-۴۱ catalyst was characterized by FT-IR, SEM and AAS techniques.

Keywords:

Mesoporous MCM-۴۱ , tetrazoles , lanthanum , selective catalyst , Schiff-base complex