Polyethyleneimine Nanofibers Functionalized with Tetradentate Schiff Base Complexes of Dioxomolybdenum (VI) as Efficient Catalysts for Epoxidation of Alkenes

摘要

Three tetradentate Schiff base ligands (H2L1-3 ) were prepared from the reaction of 5-sustituted-2-hydroxybenzaldehydes and 3,4-diaminobenzoic acid. The obtained ligands were reacted with molybdenyl acetylacetonate in ethanol to prepare the corresponding dioxomolybdenum(VI) complexes (MoO2L1-3 ) in good yields (80-82%). Immobilization of the abovementioned complexes on polyethyleneimine (PEI) was achieved viacondensation of carboxylic functional groups of the complex with amine functional groups of the polymer in presence of dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). The obtained hybrid materials were then converted to electrospun nanofibers and used as recyclable catalysts for the epoxidation of alkenes.