GL-522

Organic solvent nanofiltration (OSN) requires membranes with excellent chem. stability and mol. sieving properties to sep. small mols. in organic solvents.Integrally skinned hollow fiber membranes are geometrically and structurally preferred owing to their larger surface area and smaller footprint per module; however, their relatively low selectivity remains the major drawback.Herein, we report an integrally skinned outer-selective Torlon hollow fiber membrane that has been molecularly engineered with tris(2-aminoethyl)amine (TAEA) and 4-sulfocalix[8]arene (SCA8) to synergistically improve its chem. stability and mol. sieving capability.The tripodal amines of TAEA constructs an extraordinary crosslinked network of Torlon chains with remarkable chem. stability in N,N-dimethylformamide (DMF).Addnl., TAEA ionically binds SCA8 mols. via their sulfonic acid groups that creates homogenously SCA8-impregnated crosslinked membranes possessing not only tunable free volumes but also enhanced sieving capabilities.The SCA8 impregnated membranes can precisely sieve methylene blue (size: 12.1 Å x 4.7 Å) over N,N-dimethyl-4-nitroaniline (size: 6.9 Å x 2.5 Å) in a mixed methanol solution with a separation factor of 14.5.This study may open up an innovative and facile strategy to design OSN membranes with sharp mol. sieving capability by impregnating integrally skinned hollow fiber membranes with 3D-macrocycles to sep. mols. of different spatial sizes.

The comparative encapsulation of the Alzheimer's drug memantine (3,5-dimethyladamantan-1-amine), used as its hydrochloride salt, within the cavity of two different sized para-sulfonatocalix[n]arenes (sCX[n]; n = 4 or 8) was analyzed by ¹H NMR spectroscopy.Addition of either macrocycle to memantine results in selective upfield shifts of all drug proton resonances of between 0.50 and 1.72 ppm for sCX[4] and between 0.80 and 1.53 ppm for sCX[8].Memantine binding results in the observation of an extra sCX[4] resonance for the macrocycle's methylene protons, which is not observed for the larger sCX[8], indicating a potential change in shape of the sCX[4] upon host-guest formation.Difference in changes to the chem. shift of the memantine doublet-of-doublets resonance for both macrocycles indicates a potential change in shape of memantine upon host-guest formation.From Job Plots, memantine binds to sCX[4] in a 1:1 ratio with a binding constant of 6.6 x 10⁶ M^-1, whereas binding to sCX[8] is in a 1:2 host-guest ratio.Overall, the results indicate that memantine forms subtly different host-guest complexes with different sized sCX[n] homolog, which could be used to tune the drug delivery potential of the macrocycle for different pharmaceutical applications.