6,6'-DINITROBIPHENYL-2,2'-DICARBOXYLIC ACID IONICALLY BONDED TO AMINOPROPYL SILICA - NEW AXIALLY CHIRAL PHASE OF C-2 SYMMETRY FOR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF ENANTIOMERIC AMINO ALCOHOL DERIVATIVES

(R)-(+)-6,6'-Dinitrobiphenyl-2,2'-dicarboxylic acid, ionically bonded to 3-aminopropylsilanized silica (CSP 1), is the first ionically bonded axially chiral phase of C-2 symmetry. The phase is specifically efficient for the separation of a wide range of enantiomeric vicinal benzamido alcohols, whether open-chain, cyclic or polycyclic. To assess the steric and polar effects of the 6,6'-substituents, the performance of CSP 1 is compared with that of the analogous (but less effective) phase CSP 2, based on (S)-(+)- 6,6'-dimethylbiphenyl-2,2'-dicarboxylic acid. Some conclusions about the relation between the separation effectivity and the analyte structure, as well as about the factors involved in the chiral recognition process, are given.