Abstract: New monomers were synthesized and evaluated for their molecular imprinting performance by a recently discovered methodology referred to as one monomer molecularly imprinted polymers (OMNiMIPs). The structural design of the new monomers was based on a lead compound methacrylamidoethyl methacrylate (1) used for the synthesis of OMNiMIP1, and introduced alkyl groups of various sizes at the ?-amino position of the lead compound. Enantioselectivity, determined by liquid chromatography, was used to compare the performance of the imprinted polymers. Methyl substitution provided crosslinker 5 (2-methacrylamidopropyl methacrylate), which upon imprint polymerization afforded OMNiMIP5 with approximately the same enantioselectivity (α = 3.8) as OMNiMP1 ( α =3.7) made with the lead compound (1). The other two monomers (6 and 7) with larger alkyl substitutions (isopropyl and sec-butyl respectively) resulted in OMNiMIPs with low selectivity values ( α = 1.0 and 1.2 respectively). Last, a strong influence of diastereomeric complexes on OMNiMIP5 selectivity was determined, with L/L and D/D monomer/template pairs giving α values of 3.6 - 3.8, while L/D and D/L monomer/template pairs had α values of 2.3 - 2.4. There is no intrinsic enantioselectivity seen for the OMNiMIP5 control polymer made without template at all, giving an α value of 1.03
Author keywords: molecular imprinting, resolution, OMNiMIPs, Crosslinkers, enantioselectivity, chromatography