A chiral recognition polymer based on polyaniline

When polyaniline is doped with either R- or S-camphorsulfonic acid (CSA) it adopts a chiral structure. Removing the chiral acid dopant leads to a new form of chiral polyaniline. Such chiral dedoped polyanilines have the abili ty to discriminate among enantiomers of amino acids such as DL-phenylalanin e. For example, the dedoped form of R-CSA polyaniline preferentially comple xes with L-phenylalanine as indicated by a "doping" type absorption observe d at similar to 450 nm in circular dichroism spectra. Since the dedoped for m of R-CSA polyaniline does not complex with D-phenylaniline, this chiral p olymer can be used to separate racemic mixtures of DL-phenylalanine. Moreov er, the amino acid enantiomer bound by the chiral polyaniline can be releas ed by an organic solvent. The chiral separation mechanism is further explor ed by examining the interactions of phenylalanine derivatives with the chir al dedoped polyanilines.