Optical rotatory properties of polyaldehydes

We have studied the optical rotatory properties of several polyaldehydes possessing optically active side chains, such as poly‐(R)(+)‐citronellal, poly‐(R)(+)‐6‐methoxy‐4‐methylhexanal, and poly‐(S)(+)‐2‐methylbutanal. An enhancement is observed for the optical activity of the polymers compared to their model compounds. The magnitude of the enhancement depends on the separation between the asymmetric site and the main chain. Specific rotation values are independent of intrinsic viscosity and crystallinity of the polymers over the range measured. It was shown that the rotatory dispersion and the temperature dependence of the rotatory dispersion are essentially the same both for the polymers and their model compounds. We conclude from these data that the enhancements of the optical activity arise from a conformational rigidity around the asymmetric center in the side chain of the polymer.