The nano-magnetic chiral selectors PR(+)Si–MSNPs and PS(–)Si–MSNPs were prepared by single-enantiomer compounds P(=O)((NH-R-(+)CH(CH3)C6H5)2(NH(CH2)3Si(OCH3)3) (1) and P(=O)((NH-R-(–)CH(CH3)C6H5)2(NH(CH2)3Si(OCH3)3) (2) supported on the Fe3O4@SiO2 composite, and characterized by FT-IR, TEM and VSM. The nanoparticles were regularly spherical and uniformly mesoporous with an average diameter of around 80 nm. These materials were effectively used in chiral separation of five racemic mixtures ((±)-α-methylbenzylamine, DL-alanine, DL-valine, DL-tartaric acid, DL-phenyl alanine). After ending the process, PR(+)Si–MSNPs and PS(–)Si–MSNPs, collected by using an external magnetic field, were washed with H2O/CH3OH under ultrasound irradiation for examination of their chiral separation abilities in a new cycle. The abilities of these functionalized MSNPs remained almost constant after three recycling processes investigated. The spectroscopic characterization of silicon-based phosphoramide are also investigated.

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