A chiral magnetic molybdenum disulfide nanocomposite for direct enantioseparation of -propranolol.

We herein report a novel chiral magnetic molybdenum disulfide nanocomposite (MMoS/PNG-CD) with a high enantioselectivity and excellent thermosensitivity and magnetism. The prepared MMoS/PNG-CD shows temperature-dependent chiral discrimination and enantioselectivity toward a chiral drug -propranolol (-PPL), which is based on the molecular recognition ability of beta-cyclodextrin (β-CD) and the thermosensitivity of poly(-isopropylacrylamide) (PNIPAM). The synthesized MMoS/PNG2-CD by using a monomer molar ratio of GMA to NIPAM of 2 : 1 demonstrates a high selectivity toward -PPL over -PPL due to the synergistic effect of the PNIPAM moieties and β-CD hosts. The thermo-induced volume phase transition (VPT) of the introduced PNIPAM moieties significantly affects the inclusion constants of the β-CD/-PPL complex, and thus the loading and desorption of -PPL on the MMoS/PNG2-CD. The enantioselectivity at temperatures below the lower critical solution temperature (LCST) of the PNG-β-CD grafting chains is much higher than that at temperatures above the LCST. As a result, the regeneration of the MMoS/PNG2-CD is easily achieved simply changing the operating temperature. Moreover, the regenerated MMoS/PNG2-CD can be readily recovered from the -PPL solution under an external magnetic field for reuse. Such a multifunctional molybdenum disulfide nanocomposite with a high enantioselectivity and excellent thermosensitivity and regenerability is promising to serve as a high-performance nanoselector for direct resolution of various β-blocker drugs.