Chromatographic separation of enantiomers on N,N'-diallyl-L-tartardiamide-based network-polymeric chiral stationary phases

A series of network-polymeric chiral stationary phases, based on para-substituted N,N'-diallyl-L-tartardiamide dibenzoates, has been investigated with respect to differences in the enantioselectivity displayed during liquid chromatography of varying racemates in the straight-phase mode. These phases are thought to operate via a different hydrogen bonding ability of the analyte enantiomers, Although a rationalization of retention data in terms of a chiral recognition model is not possible at the present stage, it seems clear that an alkyl or a phenyl para-substituent generally improves the enantioselectivity of the phase. Further, from an applications point of view it is of interest that the 4-phenylbenzoate gives a sorbent showing particularly high chromatographic enantioselectivity towards the series of profens (alpha-arylpropionic acids) investigated (alpha-values ranging between 1.22 and 1.80).