ELSEVIER PolymerVol. 37 No. 2, pp. 359-362, 1996 Copyright p 1996 ElsevierScienceLtd Printed in Great Britain. All tights reserved 0032-3861~96/$15.00+0.00 Facile synthesis of optically active polyaniline and polytoluidine Mir Reza Majidi, Leon A. P. Kane-Maguire” and Gordon G. G. Wallace Intelligent Polymer Research Laboratory, Department of Chemistry, University of Wollongong, Northfields A ve, Wollongong, NS W 2522, Australia Films of optically active polyaniline salts (PAN/HCSA) have been obtained by casting from solutions of emeraldine base doped with (lS)-(+)- or (lR)-(-)-lo-camphorsulfonic acid (HCSA) in various solvents (NMP, DMF, DMSO or CHQ). The mirror-imaged circular dichroism spectra for the salt films derived using (+)- and (-)-HSA, respectively, indicate enantioselectivity in the doping process. The first optically active ring-substituted polyanilines, namely poly(o-toluidine)/(+)-HCSA and poly(o-toluidine)/(-)HCSA. have also been produced in solution and as films via a similar doping procedure in DMSO. (Keywords: polyanik salts; optical activity; synthesis) Introduction In late 1993l and in a subsequent paper2 we reported the first and remarkably facile synthesis of optically active polyaniline via the enantioselective electropolym- erization of the achiral monomer, aniline, in the presence of aqueous (1 S)-(+)- or (1 R)-(-)-lo-camphorsulfonic acid (HCSA). Dark green films of the conducting emeraldine salts (la, A- = (+)-CSA-; and lb, A- = (-)-CSA-) were deposited on indium-tin-oxide (ITO)-coated glass electrodes under potentiostatic con- ditions (+l. 1 V vs. Ag/AgCl). The intense and mirror imaged circular dichroism (c.d.) spectra of salts la and lb were rationalized’12 in terms of enantioselective electro- polymerization in which one helical screw sense of the polymer chain is preferentially produced depending on which hand of the chiral CSA- anion is incorporated. (1) We have subsequently found3 that optically active polyaniline salts la and lb can also be generated chemically in various organic solvents (NMP, DMF, DMSO, CHCls) via the dopin! of neutral emeraldine base (EB) with 0.1 moldm- (+)- or (-)-HCSA, respectively (equation (1)). The nature of the solvent can have a marked influence on the chiroptical properties. For example studies by Havinga et al4 and in our laboratories *$ have shown that solutions of la obtained by analogous doping of EB with (+)- HCSA in m-cresol solvent do not exhibit any visible cd. bands. Nevertheless, Havinga et 01.~ reported that *To whom correspondence should be addressed an optically active film of la could be spun-cast onto poly(methy1 methacrylate) from such a m-cresol solution. We have similarly found that optically active films of both la and lb can be readily cast onto ITO-coated glass following enantioselective doping (equation (1)) in each of the solvents NMP, DMF, DMSO and CHC13. The c.d. and u.v.-visible spectra and electroactivities of these films are reported below and their solvent dependence examined. Also reported for the first time is the preparation of optically active poly(toluidine) salts (2, X = Me) both in solution and as films, via analogous doping of neutral poly(o-toluidine) base with (+)- or (-)- HCSA in DMF or DMSO solvent. Experimental Emeraldine base (EB) and the corresponding poly(toluidine) base were synthesized via oxidation of aniline or o-toluidine with ammonium persulfate in l.Omol dm-3 HCl at O”C, followed by de-doping with NH40H and washing as previously described . In order to obtain solutions suitable for casting films of salt 1, the acid doping of EB was carried out under POLYMER Volume 37 Number 2 1996 359