Conformational analysis of chiral polymers in solution

Relationships between chiroptical properties (Optical Rotatory Dispersion, ORD, and Circular Dichroism, CD) and Conformation of structur— ally simple isotactic polymers and copolymers derived from optically active monomers are reviewed. Both experimental and calculated values fit with chain cotiformations consisting prëdomirantly of one screw sense helical sections due to dissyinmetric cooperative interactions among chiral side chains. This effect can be transmitted along isotactic sequences of units derived from a nomchiral comonomer, which than contribute to copolymer ORD and CD. In particular this latter shows a typical "couplet" connected to exciton splitting due to interactions among chromophoric moieties disposed in a mutual chiral arrangement with a predominant handness. Similar phenomena are observed also in the corresponding nonstereoregular polymers even if to a lower extent, thus suggesting the existence of local order determined by next—neighbour interactions.