Induced optical activity in the complex of poly(<scp>L</scp>‐arginine) with azo dyes

Abstract

Abstract The absorption and CD spectra of the complexes of poly( L ‐arginine) (PLA) and azo dyes have been measured in aqueous solution. On complexation, Blue‐shifted additional absorption bands were observed. In the wide pH 4–11 range, induced CD was observed at the visible wavelengths corresponding to the blue‐shifted absorption bands. The induced CD arose from the dimeric dye molecules bound to PLA in the α‐helical structure. When a modified analysis of induced CE is made by the excition chirality method, the origin of the induced CD can be assigned to the dipole coupling. The PLA–dye complexes showed the counterlockwise (negative, S ) chirality of the transition dipole moments of dyes.